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Why do all the life forms other than man exist? Why are they all here?
Evaluate and analyze the arguments in Presentation: A Biblical Basis of Life’s Significance. Construct a single sentence of 40 words or less. Include within it four terse carefully crafted phrases that argue that life forms other than man are significant – they were worth creating. Start your sentence with the words:
“Life forms are significant because…”
Then tack on four phrases, separating each with a comma. Order your phrases such that the most important significance comes first and the least significant comes last. Your sentence – your work of art!
BIOL 101
Individual Assignment 1 Instructions
Many of you have spent hours thinking about why human beings exist. Most of you are very satisfied with the Biblical answers to that question. But, entertain this question for a few moments: Why do all the life forms other than man exist? Why are they all here?
Evaluate and analyze the arguments in Presentation: A Biblical Basis of Life’s Significance. Construct a single sentence of 40 words or less. Include within it four terse carefully crafted phrases that argue that life forms other than man are significant – they were worth creating. Start your sentence with the words:
“Life forms are significant because…”
Then tack on four phrases, separating each with a comma. Order your phrases such that the most important significance comes first and the least significant comes last. Your sentence – your work of art!
Your assignment:
1. Write out your masterful sentence.
Life is Significant. A Presentation that explores a Biblical basis for Life’s Significance.
s Life Significant? The very first principle I want to teach you is that Life is Significant. Now a parent or a pastor or your own Bible reading may have taught you that Life is Significant. So you probably don’t want me to simply state that the principle is true and then move on to another principle! Instead, let’s pose the principle as a question. That way we can arrive at the principle by reason, rather than something we’ve assumed a priori.
Is Life Significant? To answer that question we have to define two terms. First, what’s meant by the term “life”? And second, what is “significance”?
We use the term “life” to refer to the overall quality of all physical things that are alive. But what happens when we try
to define the term without using it in the definition—that’s what dictionaries are required to do. The answer is that no truly adequate definition exists! I apologize for your having paid all these tuition dollars to the university in order to be taught by a biology professor who can’t even define the word life! But guess what–no biology professor at any other university can satisfy you here either. We can’t define life.
A Dictionary might define life as “a tendency toward negative entropy”. Problem is: that definition just focuses on a single feature of life. Life’s orderly. But this definition could also describe a highly-ordered but non-living salt crystal. There simply is NO concise, one sentence definition that sets apart all living things from all non-living ones.
So if we can’t define this term “life” what are we left with? We are forced to string phrases together. If we list enough of the basic characteristics of life, soon no non-living thing is left standing.
So we can say life is a property of anything that:
is highly complex
stores its information in either DNA or RNA
is capable of reproducing itself, and
exchanges energy and materials with its surroundings.
When we pile up all these characteristics, the non-living salt crystal loses out. (it contains no DNA or RNA) and only the living flower remains standing.
Now…….what do we mean by the term “significance”? We mean that life itself has a value or importance that goes beyond what our five senses are able to tell us. The idea of significance implies a “why” question. “Is Life Significant?” is basically asking “Why is life here?” If there is NO REASON for life’s existence, then it really doesn’t matter how complex or beautiful it all is, the answer to our question is “No, Life is Not Significant.”
The question “Why is Life Here?” poses a huge problem for us in the sciences. The methods of science rest squarely on the limitations of the human sensory system. We can gather data; we can describe HOW things work. But we can’t get to the WHY question: scientific methodology just can’t do that!
And tragically this is where many scientists stop. But as human beings most of us find it far too frustrating to stop there! When you have something as beautiful and integrated as life forms, we really need an answer to this question.
Let’s begin our thinking on this question with an instructive analogy. Consider the wonderful machine pictured to the left. Ask yourself this question: Is a piano significant? Why does it exist? We know the answer to this question! This machine exists because somebody wanted to be able to reproduce musical sounds. How do I know that? Well there is a purposeful quality to it’s design! In its complexity–in its function–it has been so utterly well constructed for the service it performs. Well then, consider the photograph to the right on this slide. Here we have an Allium flower taken from the living world. Consider this beautiful machine and ask yourself this question: Is this machine significant? Why does it exist?
The more you know about HOW a flower reproduces a plant, the more breathtakingly designed this structure is. It leaves our piano “in the dust”. So then, by analogy, is the flower significant? You bet it is. We’re being led to a dangerously probable conclusion here: If the piano has a Designer, then so should this flower!! And if we grant this conclusion, then biology becomes: the art of a great Creator, the art of a GOD who is greater than men.
Therefore, one significance of Life—one reason for its existence—is that it reveals to us evidence of a great Creator we might otherwise have overlooked!
Let’s keep thinking! A Creator powerful enough to create a reproductive organ like a flower or a human brain would probably be powerful enough to communicate with the mind housed in that brain. Has the Creator communicated propositionally with us? Because if He has, then His communication might also address the question of life’s significance! It might do so in a highly elegant way!
Down through history, a variety of documents have purported to represent specific words, truths FROM this God. Curious scholars have evaluated the scientific and historic validity of many of these documents. Others have studied their content of wisdom and moral quality. From all this study, one document clearly emerges as highly dignified and authoritative by comparison with the others: that document is the Bible. From the majesty and accuracy of Genesis 1, to the microbiological wisdom of Leviticus, to the archeological validity of Old Testament history, this book gives high quality evidence that its come to us from God.
If you wish to read further on evidence for the supernatural quality of scripture consider these sources. They are representative of many other sources like them. These authors and others have concluded that aside from the Bible, no book has comparable evidence for its Divine authorship.
Therefore, we humbly approach the Bible with the question: Is life significant?
Its answer is YES, for several very worthy reasons! Consider the following passage of scripture and what it states regarding the significance of physical life on earth.
Psalms 104: May the glory of the Lord endure forever; may the Lord rejoice in His works.
One significance of the panoply of living things on earth is simply the joy it gave God to create them. (He is a consummate Artist). He enjoys observing the creations of His own hands. He rejoices in the glory of the things He has made.
Is Life Significant? Consider another passage from the book of Job. Here Job asks God a searching question:
“What is man that You make so much of him, that You give him so much attention, that you examine him every morning and test him every moment?”
Here, Job portrays God as being entirely fascinated with the moral qualities of man. But to see those moral qualities played out, God required a physical arena for man to live in. So the glorious creation of life in all its various forms is part of the physical network—the context—in which man lives out his physical life. But on that physical life is superimposed the moral content of all the decisions we make each day. And God is highly interested in those decision.
Now on to Paul’s letter to the Romans for a third Biblical argument for the Significance of Life:
You may recall from Psalm 19 that the heavens declare God’s glory. Well Paul, in this passage includes living things in his apologetic argument here in Romans 1. “What has been made” is so well made that it represents a powerful apologetic for the existence of a great Creator-Designer. God—apart from written Scriptures—is knowable to man through God’s creative wonders!! Life is significant: it shows us God.
Finally, we return to the Psalms to see yet another dimension of Life’s great Significance: The created order is God’s gift to mankind. It provides his food to sustain his physical life. It provides his clothing for modesty and his much of his shelter from the storms of nature. The horse has born the burden of human civilization until very recently. The dog has become man’s best earthly friend. The birds have taught man to sing. What a glorious gift the created order represents. And the Designer selects man as both its recipient and its manager. Is Life Significant? Your physical existence absolutely depends on it.
Let’s summarize! Life is a joy to its Designer, a stage for man’s spirit, a quiet hand that points to God and a precious gift that grants life to the human body? Is Life Significant? It certainly is! And any otherwise liberally educated scholar would be a fool to avoid studying it. Why take a biology course? Because Life Is Significant
|
Contents |
Chapter 1 Life Is
Significant by
Design
1.1 Design That Talks
Its Glory
1
Its Speech 2 Its Mandate 2
1.2 Design at Multiple Levels
Microbiological Architecture 4 Macro biological Systems 8
Comparing Truth Sources 33
Limits to Truth 3
4
The Value of Truth from Two Sources 34
Questions for Review 35 Questions for Thought 36 Glossary 36
Chapter 3 Complexity I:
4
Versatile Elemental
Structure
1.3 Unity within Diversity
Diversity of Styles 12
Unity in Essence 14
Toward a Description of Life 17
1.4 Teleology, Start to Finish
To Summarize 22
Questions for Review 22 Questions for Thought 23 Glossary 23
Chapter 2 Understanding
Life’s Design
25
2.1 How Design Is Understood
25
Doing Science 25
Results as Puzzle Pieces 27
2.2 Rational Experimentation: Two Examples
The Effect of Sleep on Disease Resistance 29 Experimenting with Prayer 31
2.3 Seeing a Bigger
Picture
Approaching Truth 33
3.4 Water was Designed!
29
High Heat Capacity
51
Asa Solvent 51
Its Cohesion 52
Questions for Review 54 33
Questions for Thought 54
Glossary 54
Contents
iii
Chapter 4 Complexity II:
Molecular Efficiency
and Variety
56
4.1 The Centrality of Carbon to the Organic Molecules of Life
58
4.2 Construction and Degradation of Organic Molecules
61
4.3 Carbohydrates: Structure and Function
Sugars 64
Carbohydrate Polymers 65
4.4 Lipids: Structure and Function
68
The Wonderfully Functional Fat Molecule 68 The Amazing Phospholipid 71
Mighty Testosterone 72
4.5 Proteins: Structure and Function 75
A Glorious Structure Supports
Myriads of Functions 75
Crossing Biomolecular Class Lines 78
4.6 Proteins Conceal Wisdom
80 Prokaryotic Organization 101 Eukaryotic Intricacies 103 Eukaryotic Organization 113
5.3 Complexity at the Cellular Level:
Are There Limits?
117
Questions for Review 119 Questions for Thought 119 Glossary 1
20
Chapter 6 Energy-Driven
6.1 Living Systems Require a
Flow of Energy
122
6.2 Laws of Energy Flow in the
Living World
126
6.3 Energy Flows in Chemical
Reactions
128
6.4 Enzymes Direct Energy Flow
130
6.5 Energy Flow in Reaction
Pathways: Metabolism
132
4.7 Nucleic Acids: Structure and Function
Nucleotides: The Monomers 83 The Polymers: DNA and RNA 84
4.8 Living Things Need Just a Few Good Molecules
Questions for Review 87 Questions for Thought 87 Glossary 88
6.6 Energy Pools in the Cell: ATP
135
83
6.7 Energy Flow from Carbohydrates
to ATP: Respiration
136
Aerobic Respiration: Stage 1—Glycolysis 137 Aerobic Respiration: Stage 2—The Krebs Cycle 137 Aerobic Respiration: Stage 3—Electron Transfer
86
Phosphorylation 139
6.8 Energy Flow from Carbohydrates
to ATP: Fermentation
142
|
Chapter 5 Complexity III: The Glory of the Cell 90 |
6.9 Energy Flow from Photons to Carbohydrates: Photosynthesis 144 Photosynthesis: Stage 1—Light-Dependent Reactions 145 Photosynthesis: Stage 2—Light-Independent Reactions 149 |
5.1 What Is a Cell?
Definition 93
Cell Theory 93
Generalizations: At Once Brilliant and Naïve 95
5.2 Living Cells Are Complex
Prokaryotic Intricacies 98
93
6.10 Energy Flow: An Integrated
Picture
Questions for Review 155 Questions for Thought 156 97
Glossary 157
Chapter 7 Information
and Its Expression in
the Cell
7.1 The Need for Biological
Information
160
7.2 The Nature of Biological
Information
164
Biological Information Is Stored in the
Base Sequence of DNA 164
Biological Information Is Stored in Chromosomes 170
8.3 Cell Division Is Part of a Cycle:
The Cell Cycle
220
8.4 Mitosis
224
The Reason for Mitosis: Chromosomes 224
The Process of Mitosis: A Sequence of Stages 224
8.5 Cytokinesis
230
8.6 Cancer: Mutation Threatening Design
233
The Unifying Basis of Cancer 233 A Tale of Two Cancer Genes 234
Questions for Review 238 Questions for Thought 239 Glossary 240
7.3 The Expression of Biological Information
A Context for Understanding Gene Expression Transcription: Using Some Genes Now
and Some Not At All 175
Translation: Making Proteins 181
The Genetic Code 188
173
173
Chapter 9 Complexity IV:
From Cell to Organism 242
7.4 The Application of Information Expression
Our Deep Desire to Control
Information Expression 190
Information Expression as Problem Solving 191 Essentials of Recombinant DNA Technology 195 The Sobering Early History of Human
Gene Therapy 204
7.5 A Hidden Drama: Information Expression at Its Very Best
207
Questions for Review 207 Questions for Thought 208 Glossary 209
Chapter 8 Informational
Continuity in Cells 213
8.1 A Thin Skin of Life
Chasing Death
213
8.2 Cell Division:
A Requirement of Life
216
14.6 Classification: Persistent Problems
14.7 Classifying Man
Questions for Review 535 Questions For Thought 536 Glossary 536
Chapter 15 Ecology:
Interactivity by
Design
15.1 Thinking Like an Ecologist:
Exploring a Lake
15.2 Hierarchical Organization in Ecology
15.3 Organismal Ecology 15.4 Population Ecology
Population Size and Density 548
Population Distribution Patterns 549 Age Structure and Sex Ratios 551 Population Growth 551
15.5 Community Ecology
Interspecific Competition 557
One Species Benefits and the Other Is Adversely Affected 561
Both Species Benefit 566
15.6 Ecosystems: Energy Flow through 530
Sets of Interacting Organisms 569
532
15.7 A Final Word about Our
Interaction with God’s
Household
575
Questions for Review 576 Questions for Thought 577 Suggested Reading 577 Glossary 578
Chapter 16 Life Is
Finite
580
544
16.1 Definitions
582
16.2 Theories of Aging
584
546
16.3 Observations:
5
47
Cellular Processes
585
548
16.4 Observations: Organ-Systemic
Processes
590
16.5 Theory Evaluation
592
16.6 Why Do We Die? Programmed
556
Aging from two Perspectives 594
Questions for Review 597 Questions for Thought 597 Glossary 598
|
Introduction |
T
HE CONCEPT of this book—Life by Design—is so traditional that it is now novel! Encyclopedic texts crafted for the generic college biology
course are everywhere available along with the online search engines that are powerfully superseding them. Yet all such resources are symptomatic of “the big problem” in college biology classes: too much content for students to learn. Compounding this problem is the inherent character of naturalistic philosophy, which finds few things in the living world more or less important than all of the rest. And everything is interesting! The inherent wisdom of each life-form fully engages us. The result is that even most of the smaller introductory texts still feebly attempt an encyclopedic coverage, skimming the surface with anecdotal illustrations that tend to fragment the discipline.
Life by Design possesses a unity of purpose absent from most of these encyclopedic survey texts. It seeks a unifying logia both within and above the biology it explores.* One result of this is a distillation of biology into 12 principles of life. A few in-depth examples of interest to the student become rich context in which each principle is manageably unpacked and rejoiced in. A predictable result of our approach is that many well-studied systems in biology are ignored. But the logic of life is woven deeply into the pages of this text. Especially for new instructors who wish to see biology from the perspective of unifying concepts, we offer these 12 principles.
Scientists steeped in the frigidity of the last century’s philosophical mechanism often feel constrained to eliminate any emotion from their prose. We cannot do this. For us there is only rejoicing in works that show such glory. As a result, there is constant use of the terms such as design and glory throughout the text. Such vocabulary is scientifically unorthodox. But the authors are more than scientists. Observing the living world with
Introduction
IX
|
About the Authors |
CHARLES DETWILER is a Pennsylvania German boy who grew up loving nature
and spending many enjoyable hours in it long before studying it formally. His postgraduate work at Cornell University and Cambridge University focused on gene fine structure using the common vinegar fly, Drosophila melanogaster, as a model system. His Christian faith has strongly informed and enriched his study of the living world.
KIMBERLY MITCHELL is originally from Michigan but moved to Lynchburg in
1995 to attend Liberty University for her undergraduate education and has remained in central Virginia. Her research interests include nucleoside diphosphate kinase (NDPK; a protein involved in many cellular functions and linked to cancer) and primary cilia (cellular organelles involved in development and kidney disease). She holds an M.S. and Ph.D. from the University of Virginia. When she’s not in the lab or classroom, Dr. Mitchell enjoys hiking, running, reading, gardening, sewing, and caring for her many pets. In addition, she teaches cake decorating and (during the summer and holidays) operates a specialty cake business.
NORMANREICHENBACH teaches ecology, zoology, and environmental science to undergraduate students. His research interests range from toxicology to ecology to community development, and he has worked with a wide variety of organisms, ranging from insects to sea cucumbers to snakes. His current research projects, which typically engage teams of undergraduate students, have an ecological/conservation emphasis and include work on the Peaks of Otter salamander, red-spotted newt, eastern box turtle, timber rattlesnake, and Plains garter snake. He is a native of Ohio and received all his degrees, including a B.S. and M.S. in zoology and a Ph.D. in entomology, from Ohio State University. He and his wife, Susan, have been married 21 years and have two children, Faith and Keith.
All three authors are members of the Department of Biology at Liberty University in Lynchburg, Virginia.
xi i
About the Authors
Life Is Significant
by Design
DESIGN THAT TALKS
Its Glory
What do you see when an oak tree towers above you as its branches resist the winds of an approaching storm, or when your dog stares penetratingly into your eyes while you’re enjoying a roast beef sandwich? What do you hear in the majestic orchestral harmonies of Handel’s chorus, “And the Glory of the Lord”? Biology, the study of life, is fascinating because it reveals to us legions of such wonders! Nature is replete with them. In the tropics, we’re dumbfounded by ant colony-cities reaching to hundreds of cubic feet in size with finely tuned underground humidity and gas flow climate controls to optimize growth of their cultivated fungal food source. In the oceans, we gasp at the muscular coordination that launches 180 tons of blue whale out of the water as it breeches. Such sources of amazement abound in the living world.
Well then, what about journeying below the level of human sensation? Perhaps phenomena there will become highly unified and much simpler. Study utterly falsifies that speculation. The intricacy of a modern automobile with all of its computerized components pales by comparison with the interworkings of a tiny vertebrate liver cell (see Figure 1.1). Communication between swarming bacterial cells amazes us with both its responsiveness to the environment and its value to the survival of the population.
1
1
38
1 7)
20
3.1 A Brief History of Understanding Matter
Revealing Matter’s Complexity 38
Revealing Continuity between Living and Nonliving Matter 41
38
3.2 Atomic Structure
What’s an Atom?
43
What Are Its Parts? 43
How Do Atoms Differ from Each Other? 43 Do Neutrons Make any Difference?
What’s an Isotope? 44
How Are the Parts of an Atom Arranged? 44
3.3 Chemical Bonding
Ion Formation and Ionic Bonding 47 Covalent Bonding 48
Polarity in Water Molecules and Hydrogen Bonding 49
43
47
51
64 Inventions 122
153
9.1 Development: Decoding a
Master Plan 242
190 What Can Be Done with a Fertilized Egg? 242
Getting from One Cell to You or to a Tree 243
9.2 Gingko Biloba:
How to Make a Tree 250
Early Development 250
Cell Specialization: Tissue Types Emerge 253 Morphogenesis: Organ Formation 255
9.3 Development of a Human Being 259
Early Events 259
Embryonic Differentiation of Organ Systems 262 Organogenesis of the Brain 267
Cooperation of Organs in�Organ Systems 270
9.4 Asking and Answering
Questions 273
Elegant Experiment #1 — Induction 273
Elegant Experiment #2 — Genomic Potency 275
Questions for Review 277 Questions for Thought 277 Glossary 278
540
Sanford/Agliolo/Corbis
Survey Questions
1.1 Design That Talks
Does nature show the observer complexity only, or is there evidence of design?
What does the apparent design of nature”say”to the observer?
1.2 Design at Multiple Levels
What challenges exist when attempting to design a system that functions at multiple levels of organization?
What names are given to the levels of organization seen in living things?
Does design at one level influence or account for design at other levels?
1.3 Unity within Diversity
How diverse is life on this planet?
How have we attempted to order or organize this diversity?
How are life’s unifying features related to its diversity?
What are some examples of unifying features of all life-forms?
1.4 Teleology, Start to Finish
What does the term teleology mean?
Is teleology an appropriate concept to use when studying life?
biology—the study of life and of those objects that possess the quality of being alive.
Microbiological Architecture
Picture a computer architect brooding over her model of a new
design
for a processor. It’s a wonderful new chip with circuits made from parts of bacterial cells. It will be another breakthrough in the efficiency of information storage (see Figure 1.4).Now, imagine the great Designer fashioning man in a similar way. Instead of using silicon and bacterial parts, He uses dust. This simple comparison misses much of the transcendent power of the Designer of man. You see, the computer chip designer has no control over the structure of the silicon wafer itself or the bacterial cells because someone else designed those. She only wrestles with the arrangement of the cell’s parts in a circuit pattern on the chip. She creates on only two levels of reality: the chip, or molecular level, and the level of the processor chip as a unit. To improve our analogy, we must imagine the computer architect designing structural features of the bacteria, features of the molecules within the cells, and patterns of silicon compounds within the chip. Further, she must simultaneously see new architectural possibilities for other related components of both the computer as a whole and the computer network it will be part of. By analogy, that is closer to what the Designer of the human body has done.
And so you, as a human being, are structured as an interwoven assembly of highly complex systems. Your muscular system helps you to procure nutrients. Your digestive system processes the nutrients. Your circulatory system distributes the nutrients throughout your body, and so on (see Figure 1.5). You are an interwoven collection of 11 different body systems, but each system is composed of integral parts called organs. Your heart is an organ that fulfills one of the
Figure 1.4 Computer chips”evolve”very quickly because human intelligence is used to create them. The one shown here is rather”primitive”.
primary functions of your circulatory system: It is a pump (see Figure 1.6). As it pumps blood throughout your body, the blood’s chemical content regulates many of your body’s other activities. When you begin to examine structure and function within the heart, you discover that the Designer has invested it with the same level of efficiency and integrity as He has
system
a combination of body organs that performs some sig‑
nificant body function.
organ—a combination of body tissues that performs some significant body function.
Figure 1.6 The human heart is an amazing pump; the thin boundary layer lining the inner chambers represents its endothelium, a tissue critical to maintaining blood pressure and healthy blood flow.
the entire circulatory system of which it’s a part. For example, heart muscle function is elegantly controlled from outside the heart using parts of the nervous system that enervate the heart. Hormones also affect the work of the heart, as does the chemistry of the blood. All of this control is finely tuned. So the Designer is an Artist-Engineer at multiple levels! Each separate design is so integrated within all of the others that we generalize this to say that life is internally integrated. The current version of evolutionary theory possesses no ordering force powerful enough to generate the levels of integration we are currently observing. (We have not observed them all.)
Your heart is composed of various tissues. A tissue is a large group of cells that serves a constituent role within an organ (See Figure 1.7). For example, muscle tissue contracts to propel blood forward. Another tissue lines and lubricates the inner heart surfaces to enhance blood flow. Still another tissue adds structural toughness to the exterior of the heart so the muscles have something to contract against.
All of these tissues are composed of individual cells. Cells are the smallest units of tissue structure that can
Figure 1.7 The wall of your heart contains powerful muscle tissue, shown here as strands of inter-connected muscle fibers (composed of cells.) They are stained pink for better visibility of cell parts. Nuclei of individual cells appear dark pink. Magnification here is about 400 times actual size.
be said to be independently alive. For example, we can tease apart the cells of the tissue that lines your heart. In a supportive (cell culture) medium, we can keep individual cells alive. If we examine them closely using a microscope (see Figure 1.8) and various biochemical tests, we make another amazing discovery. An individual cell in the lining of our heart “solves” each of life’s fundamental problems at its own structural level. And this requires a complexity far greater than we once thought possible or necessary. Once again, while the Designer was fashioning the glory of an organ that beats 2.5 billion times in a human lifetime, He was simultaneously crafting the architectural intricacies of the cells that comprise it.
Consider now that tiny, invisible, problem-solver cell that, with billions of others like it, helps line the interior of your heart’s chambers. Let’s imagine expanding that cell to the size of a basketball. Then within it, we would be able to see directly vast arrays of intricate structures called organelles. These intracellular parts cooperate in multiple, intricate, and interdependent ways, to keep the individual cell thriving
Life Is Internally Integrated—one of the 12 principles of life on which this book is based.
tissue
a combination of body cells that performs some role im‑
portant to the correct functioning of an organ.
cell
the smallest unit part of a tissue that, of itself, possesses
the quality of life.
organelle—a specialized part of a cell that performs some important function for it.
Figure 1.8
Individual endothelial cells grown in artificial culture and stained
to reveal various cell parts: nucleus (blue), structural tubules (green), energy-generating organelles (orange).
University of Pennsylvania, School of Engineering and Applied Sciences, Bioengineering Imaging Core Facility
and growing (see Figure 1.9). On this scale, organelles would range in size from a baseball down to a grain of sand. Some of them process information, others harness energy, still others are sites of synthesis. Others are sites of import and export. The cell is like a molecular city in three dimensions. Its inhabitants have no knowledge of each other, yet they interact seamlessly with each other in patterns of life maintenance and in
Figure 1.9 This”stylized” diagram from within a single animal cell depicts a variety of organelles within its structure. Each type of organelle helps to keep the cell alive.
response to the cell’s changing environment. And these patterns are truly elegant.
But each organelle is composed of a collection of macromolecular structures (see Figures 1.10)! These
macromolecular structure—a component part of a cell’s organelle composed of two or more kinds of biomolecules.
0
0
Figure 1.10 (a)The cell nucleus shown on the left is an organelle. Within this organelle, two macromolecular structures: the nucleolus and chromatin are indicated, (b) Chromatin seen at enormous magnification.
structures contribute specific processes and functions to the organelle they serve. The nucleus of a cell, for example is known to carry the hereditary instructions for building and operating that cell. When we peer inside the nucleus with an electron microscope to see the form the information takes, we find it arranged within long, macromolecular strands having a particulate, granular profile. We call these strands chromatin. As the cell approaches its time to divide, the chromatin is condensed into shorter, thicker, chromosomes that can be distributed neatly to daughter cells.
But each macromolecular structure is composed of a collection of biomolecules (see Figure 1.11)! These molecules have, in turn, been precisely designed with the shape and alterability requisite to the function they perform (see Chapter 4). One such biomolecule has a water-loving and a water-fearing side so that it participates in the formation of a membrane surface (an inside-outside boundary for organelles and whole cells). Another biomolecule is long and can be tightly coiled. It holds information in the sequence of smaller molecular subunits of its structure. The biomolecules of a million kinds of cells have been grouped into just a few broad structural classes that are represented in virtually all cells. These classes—carbohydrates, lipids, proteins, and nucleic acids—are the colors on the palette of the Artist painting the glory of the functional organelle.
But biomolecules are constructed from atoms (see Figure 1.12)! For atoms, there are just three simple definitions for their best known parts. And so the naive student might guess that here, finally, the infinite creativity of the Designer distills down to a pleasing simplicity. Alas, nothing could be more wrong. Subatomic particles have still smaller constituent
particle-forces! On and on the complexity goes into a reality hardly detectable by very costly machines. We could wander further down this size scale to explore little-known features of subatomic particles. But atoms are the organizational level of
matter
at which biologists typically stop. Most biological processes can be studied either at or above the level of the atoms that support them. Of the 92 naturally occurring kinds of atoms, the Designer has selected about 25 or so of them to fashion the vast variety of biomolecules we find in nature.
By now we can see that an apparently simple biological action, like the beating of the heart within your chest, results from a multiple-level integration of all of the component categories we’ve just summarized (see Figure 1.17). One fundamental concept in all of biology is that Life Is Complex.
electron microscope—a device that magnifies objects sufficiently such that internal structures of cells are easily seen.
chromatin—strands of informational DNA and structural protein within the nucleus of the cell; the genetic material.
chromosomes—discrete lengths of chromatin, usually highly condensed into visible, stainable structures that are easily apportioned to daughter cells during cell division.
biomolecule—a collection of atoms bonded together into a struc‑
ture that serves some biological function within a living cell or organism.
atom—the smallest particle of an element having all the properties of that element; capable of combining with such particles of other elements.
Life Is Complex—one of 12 principles of life on which this book is based.
IN OTHER WORDS
1. Humans design their technology at one or a few ascending levels of reality. The Designer of life took at least 12 levels of reality into account as living things were fashioned.
2. Your body is organized into at least 11 systems that work together to support your life.
3. Each system of your body is composed of separate organs that support its function.
4. Each organ in your body is composed of separate tissues that support its function.
5. Each tissue in any organ of your body is composed of separate cells that cooperate to serve that tissue’s role.
6. Each cell in your body is composed of a variety of organelles that support its life functions.
7. Each organelle we’ve studied is fashioned from macromolecular structures that carry out the organelle’s role in the cell.
8. Each macromolecular structure is assembled from biomolecules that the cell has made or acquired from other cells.
9. Each kind of biomolecule is a collection of specific atoms bonded together in a way that enables the biomolecule to serve its unique role in the life of the cell.
10. Life Is Complex.
Sugar—phosphate
backbone
|
Minor groove |
|
Major groove |
|
34 |
|
0.34 nm |
|
2.0 nm |
O= hydrogen
•
, oxygen Q = carbon
CD
= atoms in
= phosphorus
base pairs 0
Figure 1.11 (a) If we take the outer lining (membrane) of the cell nucleus in the previous figure and greatly magnify its size, we see that it’s composed of millions of component biomolecules, each of which serves some role in helping the membrane do its job. (b) this biomolecule (DNA) is designed to store information in the sequence of its internal base pairs (yellow).
Space-filling model
| • |
Hydrogen (H)
Structural Formula
CH2OH
H/H
C \H
HO 01-\1.1.-1 OH
H OH (
3
Figure 1.12 Two models of a glucose molecule and one of a hydrogen atom. Glucose is the most common sugar in your bloodstream. (a) each sphere represents a single atom. Black: carbon atom Red: oxygen atom White: hydrogen atom. (b) each atom is represented by the first letter of its element’s name. The lines are bonds between atoms. (c) a simplistic model of a hydrogen atom, showing its two sub-atomic”particles”. Chapters 3 and 4 have more detailed information on atoms and molecules.
Macrobiological Systems
Perhaps your mind is now reeling, wondering how many atoms it must take to make a human being. Hang on. We must now stare off in the opposite direction! Let’s make you the “atom” in our description and build up from there! You are one of over 6 billion humans alive on this planet at this moment. All of these humans are distributed into somewhat discrete groups of individuals. They live in localized areas geographically, where they are more likely to interbreed with each other. These interbreeding, and hence biologically meaningful groups, are called populations (see Figure 1.13). The flow of genetic information (by mating), the day to day behavioral interactions between
population—all the members of a kind of organism (or species) that are proximate enough to each other to potentially interbreed.
Figure 1.13 These male and female blue-lined snappers are potentially interbreeding—so they constitute a population of organisms.
individuals and the transmission of disease pathogens are all significant biological processes that occur at the populational level.
But no population exists in isolation. Consider Manhattan Island in New York City. Surely only one kind of population exists there, correct? But wait. Some residents have dogs as pets. Others have snakes. A few have gerbils or albino rats. And all of us have tiny mites living in our eyebrows and over 500 different kinds of bacteria in our bowels, with a somewhat separate variety in our mouths and upper respiratory tracts. People raise tomatoes on their roofs and clean pigeon droppings off of sidewalks. Some of those droppings contain viruses that might infect a human being. No matter where you go on Earth, separate, diverse populations of organisms live in proximity to each other and interact biologically with each other. We call these assemblages communities (see Figure 1.14). There are pond communities, forest
Figure 1.15 A well-defined ecosystem. This campus courtyard has sharp structural boundaries. All the plant, animal, and microbial species, plus soil, water, light, temperature and other non-living features constitute this courtyard ecosystem.
communities, desert communities, and inside your mouth, an oral community whose member species require a microscope for study.
Communities interact with the physical world around them. A pond community is radically different from a prairie community. One reason for this is the huge difference in the amount of water present. Features such as moisture content, mineral content, or solar radiation levels vary from place to place. So in any given area, we combine the living community and these non-biological features and call their summation an ecosystem (see Figure 1.15). A pond community would be all of the organisms that live in a pond. A pond ecosystem includes all of those organisms plus the water, the mineral content of the mud in and around it, and the incident solar radiation it receives.
Ecosystems cover this planet. Sometimes we need to refer to all of them at once. Politicians and global ecologists do this a lot. So we have developed the term biosphere to refer to the total collection of ecosystems on the planet (see Figure 1.16). It is presumed that there are no life-forms in the
community—the sum total of all the populations of living organisms in a given area and the interactions that occur among them.
ecosystem—all the living organisms, and nonliving factors in a given area and the interactions among them.
biosphere—the totality of all ecosystems on and within planet earth.
magma of a volcano. Should the interior of a volcano be considered part of the biosphere?
As you work with various parts of this text, be aware of two things. First, our study of biology will, in general, take us up through this progression of levels from atoms to the higher levels of organization mentioned (see Figure 1.17). So secondly, try to be overtly aware of the level of organization at which we are studying. Most of us strongly desire a framework within which to build our biological awareness. Classifying what we learn according to the organizational level at which we are studying is a highly useful way of advancing our understanding!
Figure 1.16 All of the deserts, rainforests, grassland, temperate forests, tundra and other ecosystems of the earth’s surface are together called the biosphere.
IN OTHER WORDS
1. All the individuals of a species like our own, are arranged in large, potentially interbreeding groups called populations.
2. All the populations of species in a given area—populations that have the potential to interact with each other—are together called a community.
3. An ecosystem is a community of life-forms and its interactions with all the nonliving features of its surroundings
4. The sum of all ecosystems that comprise the”thin skin” of life on the surface of planet Earth are referred to as the biosphere.
|
organ composed of a variety of tissues whose collective function supports the major role of the organ. |
|
tissue composed of many identical cells working together at a common function. |
|
organ system composed of organs working together to perform a major function within an individual. |
|
atom composed of sub-atomic particles: protons, neutrons, electrons. |
UNITY WITHIN DIVERSITY
Diversity of Styles
When early naturalists began to examine living things, one of the first observations they must have made was the profuse diversity of life-forms around them. One of the most basic principles in the study of living things is their extreme diversity. Life Is Diverse. There are millions of different kinds or species of living things on this planet, perhaps 100 million. One major challenge, then, has been to classify the various kinds of organisms for further study.
Aristotle, the Greek philosopher (384-322 BC) (see Figure 1.18), has been widely recognized as the “father of biology.” His writings elucidated the structural and behavioral distinctions between plants and animals. Yet far earlier (by about 1300 BC), the Hebrew prophet Moses wrote an account of the origin of life that clearly placed the origin of plant and animal forms on separate days of creation. The same document granted the plant forms to the animal forms as
Life Is Diverse—one of 12 principles of life on which this book is based.
species—a group of organisms capable of interbreeding and producing fertile offspring.
E
Figure 1.18 Aristotle (left) (384-322 BC), an ancient Greek philosopher, and secular father of the science of biology. Moses (right) (1391-1271 BC) the Hebrew lawgiver whose characterization of life forms derived from Yahweh, life’s Designer.
Figure 1.19 Swedish naturalist Carl von Linne who Latinized his own name to Carol us Linnaeus (1707 — 1778).
food. So this basic distinction, found first in the Bible, and then in the writings of Aristotle, has until recent times been a mainstay in the classification of living forms relative to one another.
Working from the opposite extreme, the Swedish naturalist Carl von Linne (Linnaeus; 1707-1778; see Figure 1.19), began grouping together similar
plant species based on significant shared features they all possessed. He termed these larger groups genera
(genus, singular).
Thus, in his system, each kind of organism was assigned a twofold, genus and species name. That is how the tomato came to be called Solanum lycopersicum and the potato came to be called Solanum tuberosum (see Figure 1.20). They share characteristics common to their genus but are distinct enough to be considered separate species. Once a species is formally named in a given context, repeated references to it may be made using only the first letter of the genus name, as for example, S. lycopersicum for the tomato.
Similar genera soon came to be grouped into larger classes (see Figure 1.21) and classes into still higher groups. These higher levels of grouping are much more subjective. It is becoming clear that one would need the wisdom and knowledge of the Designer Himself, in order to objectively render a consistent, broad-based classification scheme for all organisms.
genus—a grouping employed by taxonomists that includes closely related species.
class—a grouping employed by taxonomists that includes closely related genera.
common name/scientific name
tomato/Solanum
lycopersicum
potato/Solanum tuberosum
|
Figure 1.21 Linnaeus used structural (morphological) features of plants to define species (“S” in the diagram) and assign related ones into Genera. Later systematists attempted to group related Genera into Classes. A more dynamic definition of a species includes all individuals capable of inter-breeding to form fertile offspring. What might cause a naturalist to describe a Genus having only one species in it? |
|
|
Class |
|
|
Genus |
|
It is not surprising, therefore, that students of biological classification vary considerably in how they prefer to classify organisms at higher levels. Over the centuries, the traditional Aristotelian groupings of plants and animals slowly expanded into three and then five major groups.
One currently popular scheme, born in the late 1900s, places all organisms into three large domains. Two of these domains, the Bacteria and the Archaea have small, simpler cells lacking a well-defined nucleus. Animals, plants, fungi, and protists all have well-defined nuclei in their cells so they represent separate kingdoms within a third large domain of
Bacteria—a domain of structurally small and simpler, walled cells, widely distributed in nature; distinguished from Archaeans by their molecular structure.
Archaea—a domain of structurally small and simpler, walled cells, widely distributed in extreme environments in nature.
animal—a macroorganism distinguished from plants by its locomotion and nonphotosynthetic metabolism.
plant—a macroorganism distinguished from animals by its lack of locomotion and its photosynthetic metabolism.
fungus—a nonmotile, nonphotosynthetic organism having large cells that are structurally complex (yeasts, molds, mushrooms).
protist—microscopic but structurally complex cells often possessing a loose, colonial form of association.
Eukarya
—a domain of organisms whose cells are larger and contain membrane-enclosed organelles; includes animals, plants, fungi and protists.
nucleus—the large, membrane-enclosed, usually central portion of a higher cell that contains its hereditary instructions.
organisms called the Eukarya. These major groups of life-forms are represented in Figure 1.2
2
In this scheme, then, the protists are defined as one-celled and colonial forms of life, yet like animals and plants, with cells large enough to contain organelles like a nucleus. Yet when we begin to compare all of the cells having these protistan features, we discover a diverse and hardly dissimilar grab bag of otherwise unrelated species. Are structural (microscopic) comparisons alone in revealing this dissimilarity among protists? The answer is, “No.”
Comparisons of important molecular components of individual protist species are also leading to a regrouping of not only protistan forms, but of the other kingdoms as well. These newer groupings show protists to be too diverse to be a singular group. The problem is that the number of basic, important features of individual cells is great enough that workers disagree as to which of them ought to be most important for classifying. Evolutionary assumptions are generally used to decide which characteristics are most primitive and therefore most important. There is some consensus on what those features are. These comparisons along with microscopic fossil finds, which are very difficult to interpret, are then subjected to conjectural evolutionary reasoning. Long, sometimes heated, arguments are the result. Classification of living things will remain a challenging and conjectural area of research as long as scientists have finite minds.
Unity in Essence
Two hundred years of biological study has led us to a very powerful generalization. Hidden beneath all of this amazing diversity is a highly pleasing unity of life at the subcellular and molecular levels!
Six Kingdoms:
Bacteria
Archaea
1 p.m
0 The large, rod-shaped bacterium Bacillus anthracis, a member of kingdom Bacteria, causes anthrax, a cattle and sheep disease that can occur in humans.
5 p.m
0 These archaea (Methanosarcina
mazei), members of the kingdom Archaea, produce methane.
| Eukarya |
Protista
Plantae
Animalia
Fungi
10 p.m
|
Unicellular protozoa (Tetrahymena) are classified in kingdom Protista. |
The plant kingdom claims many beautiful and diverse forms, such as the lady’s slipper (Phragmipedium caricinum). |
0 Among the fiercest members of the animal kingdom, lions (Panth‑ era leo) are also among the most sociable. The largest of the big cats, lions live in prides (groups). |
0 Mushrooms, such as these fly agaric mushrooms (Amanita muscaria), belong to kingdom Fungi. The fly agaric is poisonous and causes delirium, raving, and profuse sweating when ingested. |
Figure 1.22 Two currently accepted schemes for classifying all life forms. The domain-based scheme is represented by three colored bars. The Kingdom-based scheme is represented by the names indicated above each photo.
Those who see design in nature assume that this unity of pattern traces back to efficient, thematic thinking in the mind of a single Designer. The evolutionist sees this same unity as evidence for a singular, primitive life-form from which we have all derived by Darwinian evolution (see Chapter 13).
Early perceptions of this unity of design in life-forms predate modern science. Dogs grow and oak trees grow. In both cases this growth is accompanied by significant increases in the complexity of the organism. What drives this growth?
In all life-forms, growth and maintenance of life require energy. Life Is Energy-Driven. Scientists began to describe the molecules that growth is driven by. They discovered that in plants, animals, and bacteria the variety of energy-carrying molecules (especially the carbohydrates) was small.
Life is Energy-Driven—one of twelve principles of life on which this book is based.
Secondary Consumers
Figure 1.23 The flow of energy from the sun to a lion’s dinner plate. Solar energy drives photosynthesis which generates the nutrients in the grass. The zebra ingests those nutrients and then becomes nutrients for the lion. Where do the nutrients go after the lion utilizes them?
For example, glucose, a simple sugar (see Figure 1.12), is found in a wide variety of life-forms. And the flow of energy from the sun to the plants, bacteria, and to the animals (see Figure 1.23) is efficiently handled by a unified set of energy-transforming and energy-transferring molecules like chlorophyll, glucose, and adenosine triphosphate (ATP),whose structure we’ll note a bit later).
The pathways of chemical reactions that move energy along from molecule to molecule within the cell are termed metabolism. Not only do metabolic reactions move energy around within
metabolism—the sum total of all of the chemical reactions and their inter-relationships within a living organism.
Figure 1.24 The blue shape, shown astride this duplicating strand of DNA, represents a protein molecule. This protein is the enzyme DNA polymerase that copies existing strands of DNA in order to make new ones. See chapter 8 for further details. Actual replication of DNA is far more complex than represented here!
the cell, they also result in the production of all the different kinds of carbohydrates, lipids, proteins, and nucleic acids that a cell needs to sustain life. With time, scientists have discovered that many aspects of metabolism are similar or identical across large groups of living organisms.
We also assumed early on that growth is directed by information. Since both growth and maintenance of life require information, we say that Life Is Information Expressed. We now believe there is enough information in the nucleus of one cell of your body to remake an entire “you.” Scientists in the mid-1900s discovered that the information for growth resided in a class of biomolecules called nucleic acids. The specific nucleic acid molecule holding our biological (genetic) information is termed DNA (deoxyribonucleic acid). With time, except in a subgroup of viruses, DNA has been shown to be the archival informational molecule in virtually all life-forms! This warns us that information expression is likely to be a unified process in all of these organisms! One common way in which DNA’s information is expressed is in
the formation of proteins. Everywhere in the world of the cell, proteins are important both structurally and in many other ways Enzymes are proteins. Within their structures they have catalytic sites that facilitate specific chemical reactions. Hence, when you study the function of a common enzyme like DNA polymerase (the enzyme that builds DNA) (see Figure 1.24) you are studying a molecule that does this in the majority of organisms on planet Earth—a pleasing and unifying thought.
Finally, growth results in size increase to a point where the cell or multicellular organism can reproduce itself. Again, information is required for this. We say that Life Is Informational Continuity. A gloriously designed process exists to precisely replicate and distribute the DNA information of the parent organism into the daughter organism(s). In this way, species identity is retained into subsequent generations.
Toward a Description of Life
Can we define the term life? We have just seen a vast diversity of living things unified by some core structural and functional elements of formidable complexity. The result—as you might guess—is that two-sentence, dictionary definitions of terms like life or living organism are beyond our ability to compose. Lacking such a definition, the best we can hope to do is to so carefully describe living things that no nonliving entity remains that fits our description. So far, we have described life as significant, complex, internally integrated, diverse, energy-driven, information expressed, and informational continuity. But there are two more unifying features of life that arise gloriously from all of this diversity. They
Life is Information Expressed—one of twelve principles of life on which this book is based.
DNA
an abbreviation for deoxyribonucleic acid.This nucleic acid
is the archival repository of information for building the majority of all life-forms.
protein—a relatively large biomolecule composed of a sequence of amino acids; they performs some life functions usually at the chemical or cellular level of organization.
enzyme—a type of protein molecule that serves as an organic catalyst in solution. It reproducibly converts one specific sort of molecule into another: a specific substrate into its product.
Life Is Informational Continuity—one of 12 principles of life on which this book is based.
Figure 1.25 The responsive quality of life in higher organisms
help us to describe life more exclusively, and they bring still more tribute to its Designer.
Life Is Responsive. A universal feature of living things is their ability to moderate or correct their own internal activities in response to changes within themselves or within their surroundings. If you were to look up from this page and suddenly see the face and hear the voice of a person you knew to be dead, within seconds your heart rate would quickly increase (see Figure 1.25). Your mind would inform you of a severe incongruity. This would cause the amygdala region of your brain to generate an intense fear response that includes the ability to fight or flee from the circumstance. This would involve an increased heart rate, sweating, a fearful facial expression, and other potentially useful responses. Among millions of species on this planet, every one of them has a variety of ways in which its members respond to cold, to decreased oxygen, to heat, to starvation, to ultraviolet light. The list goes on and on. Living things differ from most nonliving things in their diversified abilities to respond to change. Well then, why don’t we simply define life as the ability to respond to changes in the surrounding environment? Can you think of anything nonliving that can respond to changes in its environment? If not, try flushing your toilet.
Another feature of life that amazes us is the widespread interactivity in nature among organisms of different species. When we say that Life Is Interactive, we mean that cows eat grass, humans drink their milk, and bacteria in your gut break down the milk sugar you may fail to degrade. We mean that photosynthetic bacteria live inside the cytoplasm of larger protozoan cells. We mean that Phytophthora infestans (a fungus that caused the Irish potato blight) was responsible for sending the Kennedy family to America and ultimately giving us John E Kennedy as the 35th president of the United States of America.
Interactivity between life-forms is something science will never comprehensively understand because the variety and extent of interspecific interaction is almost infinite. The best we can do is to explore specific examples of how one type of organism relates to and influences other types of organisms either directly or by means of changes it produces in the nonliving environment (see Figure 1.26). Such studies are undertaken in the discipline of ecology, a subdiscipline of biology where our increased knowledge is revolutionizing agriculture, urban planning, and numerous other facets of our civilization.
Figure 1.26 An ecologist studying the effects of species Homo sapiens (us) on fish in an Adirondack lake.
Life Is Responsive—one of 12 principles of life on which this book is based.
Life Is Interactive —one of 12 principles of life on which this book is based.
ecology—the science of the relationships among populations of organisms and their environments.
IN OTHER WORDS
1. There may be as many as 100 million kinds (species) of life-forms on this planet presently. They are all in need of being organized into a system for study.
2. Moses and Aristotle, in ancient times, ordered life-forms into two large groups, plants and animals.
3. In the 1700s, Linnaeus began describing individual species of life-forms and collecting them into groups of related species called genera (genus, singular)
4. Large groupings of organisms are far more subjective. In one scheme, plants, animals, fungi, and protists are grouped into one of three domains called Eukarya.
5. Two other domains, the Bacteria and Archaea, contain simpler life-forms.
6. One of these groups, the protists, is particularly artificial in nature.
7. Underlying this vast diversity of life-forms is a unity found in the molecules that are most basic to life processes.
8. The fuel sugar glucose and the energy storage compound ATP are two metabolically important molecules broadly distributed across nature’s life-forms.
9. The vast majority of life-forms appear to store their information in DNA molecules.
10. Enzyme molecules composed of protein catalyze metabolic reactions in the cells of virtually all life-forms.
11. All life-forms are able to alter their own metabolism and physical activities in response to changes in their environments that threaten their stability.
12. The discipline of ecology is a study of the vast array of interactions that occur between the different forms of life and nonliving aspects of their environments on Earth.
13. Life Is Highly Interactive.
T E•
Y, STARTTO FINISH
When a bush sends longer branches away from a wall, and shorter branches toward the wall, we assume that the bush is favoring growth in the direction of its light source. When a mouse flees to a dark corner of a room, when a bacterial cell swims toward a higher concentration of sugar molecules or away from some toxic substance, we again assume that we know reasons for these behaviors. There are endless examples in nature of what appears to be purposeful activity. Since the Greek word for end or purpose is telos, we refer to nature’s apparent purposiveness as teleology.
For a biologist who is also a Design theorist, teleology is an entirely predictable concept. The various life-forms all have a Creator who had a purpose for creating them in mind. The bush may not want to grow toward light, but the purpose of moving toward light is inherent in its design. Mice were given feet because it was desired that they should be able to run.
Many philosophers, called naturalists, assert that a God cannot be known to exist and that nature alone is real. They assert that the phenomenon of running exists only because a mouse has feet to do so (see Table 1.1). The mouse happens to have feet because mice without them do not survive in nature as well as mice with them. Therefore the mouse was not given feet so that it could run; rather, it runs because it happens to have feet. Most scientists would probably agree with this naturalistic view of life. The method they use to obtain knowledge from the natural world is amazingly powerful and predictive!
Table 1.1 A theist assumes that purpose lies behind (and outside of) the elegant act of running. A naturalist observes only that without feet, the mouse might not survive. Having feet, it runs and thus, perhaps survives.
Presupposition
Observation
Interpretation
–>
Theism
Mouse runs
Running
using feet
requires feet
Naturalism
Mouse runs
Feet enable
using feet
running They have come to trust it deeply, in part because of these virtues. Unhappily, this method is entirely incapable of establishing that anything possesses a purpose external to itself. Yet some naturalists are so enamored of this approach to truth that they go further. They assume that any approach to knowledge lying outside the scope of science’s method is also outside the bounds of rationality. They would say, “Since we cannot establish ultimate purpose using our method, it makes no sense to speak of purpose. So we will not.”
Can we be certain that our scientific method is the only rational approach to nature? Science is limited to the realm of what we can sense with our five senses either directly or indirectly through instruments. Is it legitimate to limit logic to the realm of things sensed? Among early naturalists like Aristotle, deductions flowed as much from reason as from observation. They did make some serious errors, but they came to some important and valid conclusions as well, like the fundamental difference between plants and animals. Design theorists argue that the order and complexity evident in nature can reasonably support the existence of a Designer Who accords purpose to what He designs. True, we cannot jam this Designer into a test tube to measure Him. But it is also myopic to decide that our senses are the sole path to truth. A clean room belonging to a consistently sloppy child is evidence that a parent probably exists. A less rational explanation is that a window in the room was left open and the room’s contents were blown to their correct positions. Our eyes may not show us the parent, but our minds can reason that the child is being helped.
This sort of reasoning, then, leads us to another major principle of life: Life Is Ultimate Art. This principle is a result of observation, limited experimentation, and rational thinking. We simply cannot allow the limitations of our experiments to
teleology—the philosophical study of design and purpose.
Life Is Ultimate Art—one of 12 principles of life on which this book is based.
leave us in ignorance regarding the origin of something as elegant as life. Honest, careful rationality leads us to accept life’s dependence on a sufficient cause. This principle, in turn, will guide our later examination of the origin of living things.
Finally, if the main purpose of living things is to live, we are faced with the odd reality that all but the simplest of them die. (Single-celled life-forms generally do not die, they simply divide to form daughter cells.) The processes supporting life are so elegant that naturalists have had a terrible time of it, trying to explain why life-forms die (see Table 1.2, Chapter 16). Yet the occurrence of death is so pervasive and the result so frustrating that we encapsulate this oddity in our last principle of life, Life Is Finite. Scientific methodology provides us a detailed physical description of several aspects of death and it is also beginning to help us to understand how we deteriorate physically to this terminus. Of course, civilization’s greatest written
work, the Bible, purports to tell us why Life Is Finite—why death occurs. As we complete our treatment of life, we will try to bring together the how and why of death into a satisfying picture of this troubling process, if there can be such a thing (see Chapter 16).
If you have read the introduction to another biology text, you will sense that the picture of biology presented here is a richer, more satisfying one. It is certainly more purposive. Perhaps as a nonscientist, you value this venture that lies both outside and within the scientific method. It assembles a more robust picture of life. Rational extrapolation from life’s complexity to its purpose will allow us to face scientific issues like environmental pollution and resource conservation with more than mere human selfishness as guide. However, our venture beyond the scientific method is not meant to belittle the tremendous value of that approach to truth. In the next chapter we will return explicitly to the scientific method in order to observe how the bulk of our scientific understanding has been derived.
Table 1.2 Scientific methodology searches for causes within the organism itself and ends up with wonderful accidents. A bit of additional humble rationality rescues our sanity and our society.
birth
life
death:
Life Is Finite—one of 12 principles of life on which this book is based.
triumph
>
tragedy
>
accident
>
accident #2
IN OTHER WORDS
1. Most activities that we observe in living things appear to have a purpose behind them, usually relating to the ultimate welfare of some organism.
2. Philosophers of science argue with each other about the ultimate cause of these apparently purposive activities.
3. The methods scientists use are incapable of establishing the reality of purpose behind the activities of living things.
4. Some progress in understanding nature has resulted simply from rational reasoning in regard to the living things observed.
5. It is dangerous to assume that the scientific method is the only route to truth available.
6. Observation and deductive reasoning can lead one to the conclusion that living things are derived from and dependent upon a Designer.
7. Most living things eventually deteriorate and die. Life Is Finite. Scientific study and revelation together help us to understand how and why this is so.
8. The limitations of the scientific method should not be taken as a reason for belittling or ignoring the valuable results it has achieved.
TO SUMMARIZE
We can summarize the content of our introduction
7.
by simply listing the 12 Principles of Life that form the framework upon which succeeding chapters are arranged: 8.
1. Life Is Significant. It’s worth studying (Chapter 1).
2. Life Can Be Understood. When we study it, progress is made (Chapter 2).
3. Life Is Complex. There are too many intricacies to begin to grasp (Chapters 3, 4, 5, 9).
4. Life Is Energy-Driven. Eating facilitates playing; starving is deadly (Chapter 6).
5. Life Is Information Expressed. Here’s where design is most clearly seen (Chapter 7).
6. Life Is Informational Continuity. Your parents produced you and informed your trait structure (Chapters 8, 12).
QUESTIONS FOR REVIEW
1. Explore your own memory. List three wonders of nature that have piqued your curiosity in the past. What is it that you would like to understand about each of them?
2. In this chapter, the Bible has been singled out from among other ancient literary works as a source for comments on the complexity and order of the living world. Is it fair to ignore other such sources? Have you encountered any evidence that the Bible is worthy of such exclusive attention?
3. Make up a nonsensical sentence where each succeeding word in the sentence begins with the letters A-B-M-O-C-T-O-S-I-P-C-E-B (i.e., A Big Monster On Crutches, etc.). What will you be able to remember in sequence when you’re finished?
4. Watch out for words that biologists borrow from society in general and then use differently!
What is the difference between the way society uses the word community and the way biologists use it?
5. Life Is Information Expressed. What sort of biomolecule contains this information within its structure? (What sort of biomolecule represents the most common form of expression of that information?)
6. Life Is Responsive. List three examples you are aware of in which your own body responds to changing environmental conditions.
7. Explain how farmers will benefit from the studies done by ecologists.
8. “A mouse has feet so that it can run.” Is that statement more agreeable to a theist or to a naturalist? Why?
QUESTIONS FOR THOUGHT
1. Consider the alternative to the principle Life Is Significant. Life Is Not Significant; life simply exists. Which alternative seems more rational to you? Why?
2. Suppose you were able to design a human skin 4.
cell that was able to use sunlight to do pho
–
5.
tosynthesis. What sort of problems might you encounter trying to incorporate that cell into a normal, healthy human being?
3. Consider the following organization of all living
6.
things: domain Bacteria, domain Archaea, and domain Eukarya (containing the kingdoms of the
animals, plants, fungi, and protists). What strikes you as odd about this sort of organization? Save your thoughts about this for Chapter 14, which delves into the diversity of life.
Explain how a dentist is an ecologist.
The scientific method has shown itself to be highly powerful in providing explanations for how nature works. What weakness is hidden within that power?
Life Is Finite. Who has an easier time explaining this problem, a theist or a naturalist? Explain your position.
GLOSSARY
animal—a macroorganism distinguished from plants
by its locomotion and nonphotosynthetic metabolism.
Archaea—a domain of structurally small and simpler, walled cells, widely distributed in extreme environments in nature.
atom—the smallest particle of an element having all the properties of that element; capable of combining with such particles of other elements.
Bacteria—a domain of structurally small and simpler, walled cells, widely distributed in nature; distinguished from Archaeans by their molecular structure.
biology—the study of life and of those objects that possess the quality of being alive.
biomolecule—a collection of atoms bonded together into a structure that serves some biological function within a living cell or organism.
biosphere—the totality of all ecosystems on and within planet earth.
cell—the smallest unit part of a tissue that, of itself, possesses the quality of life.
chromatin—strands of informational DNA and structural protein within the nucleus of the cell; the genetic material.
chromosomes—discrete lengths of chromatin, usually highly condensed into visible, stainable structures that are easily apportioned to daughter cells during cell division.
class—a grouping employed by taxonomists that includes closely related genera.
community—the sum total of all the populations of living organisms in a given area and the interactions that occur among them.
DNA—an abbreviation for deoxyribonucleic acid. This nucleic acid is the archival repository of information for building the majority of all life-forms.
ecology—the science of the relationships among populations of organisms and their environments.
ecosystem—all the living organisms, and nonliving factors in a given area and the interactions among them.
electron microscope—a device that magnifies objects sufficiently such that internal structures of cells are easily seen.
enzyme—a type of protein molecule that serves as an organic catalyst in solution. It reproducibly converts one specific sort of molecule into another: a specific substrate into its product.
Eukarya—a domain of organisms whose cells are larger and contain membrane-enclosed organelles; includes animals, plants, fungi and protists.
fungus—a nonmotile, nonphotosynthetic organism having large cells that are structurally complex (yeasts, molds, mushrooms).
genus—a grouping employed by taxonomists that includes closely related species.
Life Is Complex—one of 12 principles of life on which this book is based.
Life Is Diverse—one of 12 principles of life on which this book is based.
Life is Energy-Driven—one of twelve principles of life on which this book is based.
Life is Information Expressed—one of twelve principles of life on which this book is based.
Life Is Informational Continuity—one of 12 principles of life on which this book is based.
Life Is Interactive—one of 12 principles of life on which this book is based.
Life Is Internally Integrated—one of the 12 principles of life on which this book is based.
Life Is Responsive—one of 12 principles of life on which this book is based.
Life Is Significant—one of 12 principles of life on which this book is based.
Life Is Ultimate Art—one of 12 principles of life on which this book is based.
macromolecular structure—a component part of a cell’s organelle composed of two or more kinds of biomolecules.
metabolism—the sum total of all of the chemical reactions and their inter-relationships within a living organism.
nucleus—the large, membrane-enclosed, usually central portion of a higher cell that contains its hereditary instructions.
organ—a combination of body tissues that performs some significant body function.
organelle—a specialized part of a cell that performs some important function for it.
plant—a macroorganism distinguished from animals by its lack of locomotion and its photosynthetic metabolism.
population—all the members of a kind of organism (or species) that are proximate enough to each other to potentially interbreed.
protein—a relatively large biomolecule composed of a sequence of amino acids; they performs some life functions usually at the chemical or cellular level of organization.
protist—microscopic but structurally complex cells
often possessing a loose, colonial form of association.
species—a group of organisms capable of interbreeding and producing fertile offspring.
system—a combination of body organs that performs some significant body function.
teleology—the philosophical study of design and purpose.
tissue—a combination of body cells that performs some role important to the correct functioning of an organ.
MIL
Doing Science
It’s Christmas morning. Herbie jumps out of bed and heads for the Christmas tree. There is a package—just the right size—and two smiling parents to go with it. Tearing into the wrapping reveals a new laptop computer. Within minutes Herbie is exploring. Each screen in virtually every program he opens contains a link to a help menu that describes exactly how each aspect of the program works. In addition, Herbie’s parents have purchased a reference book to help him grapple with procedures and options. Herbie ignores both the book and the help screens. Within an hour or two he has mastered a game and some drawing software. How does he do this without reference to any instructions? Herbie lives in a computer world. His mind is filled with computer experiences. He thinks as programmers do. He wants the kind of understanding that comes from working directly with the software itself—not reading about it! He is not concerned with the writer’s agenda for the reference book. Herbie has his own reasons for exploring the software. Herbie is a scientist at heart (see Figure 2.1).
Brute exploration of a computer game is similar to brute exploration of the living world. Processes are occurring. You get as close to and as involved in those processes as possible, trying to figure out how they work. As Herbie struggles with his new game,
Figure 2.1
Biology is not “done” by reading textbooks. Text reading is
looking in from the outside. Biology”arises”from data. This worker is having fun gathering some of that data from the top of a redwood forest.
he is using several mental tools that scientists use every day:
1. Today, he is interested in a particular character or player in his new game. He has questions about several aspects of the role this player has in the game.
2. When he gets stuck, he gives up and checks the manual just long enough to see if his question is answered. Then he goes back to the game immediately. If he has his answer he moves on to the next question.
3. But if his question was not answered in the manual, he goes back to the game with a hunch—an idea about how the player he’s interested in functions in a given situation. Scientists call this hunch an hypothesis.
4. The hypothesis is hardly formed before he begins guessing as to how he can verify his hunch. “If I press these two buttons in this sequence (it’s worked in other games), I’ll bet he’ll move to the next level.” We refer to this momentary thought as a prediction.
5. Herbie quickly manipulates the keys to see if his prediction is born out. His manipulation of the system is called a test or an experiment. Notice here that Herbie is less dependent on the verbal descriptions of some author. He is more dependent on his fingers and his eyes. His senses inform him of whether or not his hunch is correct. He’s getting results that address his hypothesis. He’s learning how the system works and he knows that it will work for anyone else in the same way, regardless of how the written directions might have been interpreted.
6. Herbie discovers more and more individual moves for his player, and their utility becomes apparent. A model for how to use this particular player to win the game forms in Herbie’s mind. A model, then, is a big picture that explains how the actions of all the parts of a system cooperate to determine the overall behavior of the system.
7. If trying certain buttons fails to work as Herbie had expected, then other combinations of buttons are attempted. These attempts will be based on what Herbie knows of other games, and what he recalls from the help screens he’s read.
What goes through Herbie’s mind as he explores the game? Is he thinking in terms of words like hypothesis, prediction, or experiment? No, he does not, nor do scientists. For example, in understanding how one whale communicates with another whale 100 miles away, scientists jump into the inquiry process at different stages. They participate in the part of the inquiry process where they are most gifted or interested. Some well-read and curious types ask more questions than anyone could answer in a lifetime! Others love to design elegant experiments around their choice of a good question. Still others enjoy technology and simply gather lots of data (results) very carefully. There is always a critical thinker in the group who loves to interpret the results. “Hah! You thought those results would support your hypothesis.” But our thinker shows how those same results
question—an expression of inquiry regarding how something in nature works. In science, this inquiry must be
testable
.
hypothesis—an educated guess; a speculation regarding how something in nature works.
prediction—an assertion made in advance of the analysis that will validate or discredit it.
experiment—a test that is performed in order to evaluate the validity of an hypothesis.
results—data derived from an experiment that are used to validate a prediction and evaluate an hypothesis.
model—an explanation, based on experimentation, regarding how something in nature works.
interpretation—to clarify or explain the meaning of data from an experiment.
Interpretation
Results
Theory
Figure 2.2 Science doesn’t happen in neat circles like this one. However, the relationships in this diagram will help you to understand how science progresses. Good theories are very vulnerable to new results. Is evolution a good theory?
can support a rather different hypothesis, taking the model in a whole new direction. Meanwhile, the experiment designer listens carefully to this new interpretation, which now becomes a new hypothesis. She constructs a new experiment that can better distinguish between the now competing interpretations (see Figure 2.2). Suppose then, we were to place these scientific activities on a circle (see Figure 2.2) and start by asking a question, then gathering information, then forming an hypothesis, then making a prediction, then testing it, then harvesting results, then interpreting them, and finally asking a new, more penetrating question, starting around the circle again. Does scientific work follow in that precisely sequenced fashion? Sometimes it does, but rarely perfectly. If there really is a singular scientific method, it is a highly dynamic and fluid process in which sudden hunches, unexpected discoveries, and personal rivalries all influence the rate, pattern, and growth of knowledge. This is true in virtually all areas of the life sciences.
Results as Puzzle Pieces
Results enable us to evaluate a specific hypothesis. For example, receiving devices exist that can detect sounds emitted by whales. Data from such a device provides credence to the hypothesis that communication among whales may be based on the sounds they emit. But more ways of testing the hypothesis soon emerge. As more results come in, the hypothesis becomes formalized: We call it a model. Next we begin to speculate about how sounds of specific frequencies are received and responded to by a whale. As more data consistent
with the model come in, the model becomes more attractive, more likely to be correct. Slowly, with time, scientists treat the model as though it were very probably true; they begin to refer to it as a theory. A theory then evolves from an hypothesis that has generated so many predictions and has explained so many experimental results so well that the scientific community broadly accepts it as the probable explanation for a phenomenon or a system.
Hypothesis –> Model Theory
Does this mean that the theory is true? Historically, truth is an absolute term. It assumes the existence of a God—an ultimate Arbiter, an ultimate Knower. Man is finite. He is always guessing about how things exist and relate to each other. Scientific methodology is simply a very orderly way of fashioning guesses and then promoting them slowly toward the notion of truthfulness. We can never know if a theory has finally arrived—has become truth. The universality of gravity on the Earth’s surface is a highly respected theory. But it is remotely possible that tomorrow, when you turn on a faucet, the water will simply float out into the air. We cannot know that this will not happen. But certain theories—like oxygen being the driving force of respiration, and cell nuclei being repositories of cellular information—are widely accepted. Rarely are these theories seriously questioned anymore. They have been tested so many times.
Unhappily, the word theory is abused because of its intrinsic dignity. Historians use it. They derive this or that theory to explain how the idea of a global flood could show up in the folklore of so many ancient cultures. Natural historians use it too. They have a theory for how a wide diversity of life-forms could have evolved from only one or a few original life-forms. The historical sciences weaken the concept of theory by applying it to strictly
untestable
hypotheses. It is impossible to return to the past to apply rigorous tests to the two hypotheses described above. So when we use the term theory, it is important to note the context.
theory—an idea that has survived much testing and analysis.
|
Is its subject testable like cell respiration? Or does it derive from an historical context like natural history? (See Table 2.1.) In the historical sciences, hypotheses can be elaborated, and observations assembled to favor or discredit them, but rigorous testing is not possible. Many biologists are virtually certain that all life-forms have evolved from a single progenitor cell. But this notion encompasses so much time that it never has been rigorously tested, nor will it ever be. |
Table 2.1 |
|
Theory—Historical Science |
“soft science” |
|
“Cats and dogs had a common ancestor |
untestable |
|
Theory—Empirical Science |
“hard science” |
|
“Cats and dogs are intersterile.” |
testable |
IN OTHER WORDS
1. Scientists investigate the living world by interacting physically and very closely with it.
2. They usually have a burning question in their minds and an hypothesis (a hypothetical answer) for that question.
3. They design experiments to test their hypothesis and carefully interpret the results to see how well their hypothesis survives.
4. The scientific method, as illustrated in Figure 2.2, is a sequence of activities that is rarely followed in the orderly fashion indicated by the diagram.
5. An hypothesis that repeatedly survives experimentation with minimal modification eventually becomes referred to as a model. Continued success graduates the model to a theory.
6. The term theory has a tentative meaning in the historical sciences; it’s most precise meaning is found in the strongly empirical sciences.
lidliI
1_ EXPERDMENEK1ON:—WO EXAMP ES
Biologists usually engage life’s complexity by studying something of personal interest. They do this within the framework of one of the levels of biological complexity described in Chapter 1. Study usually begins in the literature, noting what earlier workers have discovered about the system—its structures and the processes (or functions) these structures support. The biologist then begins to either build on, or question, what has been written.
For any structural part or functional process in nature that is being studied, many, many factors (other structures, other processes) influence it. These factors are called variables. An hypothesis is made as to which variable or variables affect the structure or process of interest. Which variable modulates, alters, inhibits or accelerates the process under study? An experiment is then designed to examine the effects on the system of one variable at a time. Biologists have a powerful way of doing this. First, they design a part of their experiment in which, for the process they are studying, they retain all the variables as they would be under normal circumstances. They call this their control conditions. In the other part of their experiment they select one variable of interest and alter its presence, magnitude, or some other feature of the variable. This part of the experiment is called the experimental condition. Let’s observe
structure—any physical part or aspect of a living organism that in some way contributes to the viability of that organism or its offspring.
function—an activity performed or a role served by a structure that contributes to the viability of the organism or its offspring.
variable—an aspect of an organism or its environment that changes with time or context.
control conditions—a part of an experimental system in which all variables are maintained in a state most nearly corresponding to what is normal or typical.
experimental conditions—a part of an experimental system in which all variables, except for one of interest to the scientist, are maintained in a state most nearly corresponding to what is normal or typical.
the utility of such an approach by examining two specific examples. First, let’s consider an experiment from sleep research.
The Effect of Sleep on Disease Resistance
A group of scientists wanted to know how the variable “hours of sleep per night” relates to a person’s resistance to common illnesses like the flu. Influenza, or flu, is caused by a viral infection. The hypothesis was that decreasing sleep time would have an inhibitory effect on the subjects’ abilities to combat disease.
For their control conditions, they selected a group of 25 young men who slept between 7.5 and 8.5 hours per night. The scientists considered this a normal amount of sleep per night. (Studies suggest that as many as one-fourth of American teens average 6.5 hours per night or less. That is what adds interest to this experiment.) After four days of normal rest, the subjects’ immune systems were challenged with a vaccine that contained parts of the influenza virus’ outer surfaces. How well would they mount an immune response against the vaccine? Just before receiving the vaccine and 10 days after receiving it, their blood serum was analyzed to determine the levels at which they produced antibodies against the flu virus structures that were in the vaccine. So the first check on antibody levels on vaccination day is a control or baseline against which to measure how high antibody levels will go after being challenged with structural parts of the virus (see Figure 2.3).
|
Sleep Study — Control Group Sleep 8 hrs/night for 4 nights Introduce flu virus by injection on day 5 Check level of anti-flu antibodies same day |
Figure 2.3 Sleep Study — Control Group
For the experimental conditions, a second group of subjects was selected that was similar to the control group in sex, age, body mass index, and ethnic background. (All of these potential variables were kept constant.) However, the experimental individuals were allowed just 4 hours’ sleep per night for six successive nights. Notice that two more nights of sleep deprivation are added to the experimental conditions. (The control conditions take advantage of the fact that 8 hours of sleep per night is closer to what the control individuals were getting anyway; therefore less adjustment time was needed.) The experimental subjects were then challenged with the vaccine in the same way as the group under control conditions (see Figure 2.4).
The antibody levels in the control group at 10 days after vaccination averaged out to 1.15 X 106 times the initial level determined just before vaccination. The levels in the experimental group averaged out to 0.50 X 106 times their initial levels (see Table 2.2, Figure 2.5). In other words, the sleep-deprived individuals made less than half the antibody response compared to the control individuals. We may interpret these results to mean that individuals who constantly deny themselves the amount of sleep they would naturally enjoy will be less able to resist infection by influenza virus. This conclusion may be compared with results of an unrelated study suggesting that individuals who averaged more
Table 2.2 Sleep deprivation results in tabular form
As…
„CC
Figure 2.5
Sleep deprivation results in graphic form.
than 9 hours of sleep per night have a slightly shorter life expectancy. Apparently, there is a range of values for an optimal night’s sleep that centers around 8 hours. Figure 2.6 summarizes
Qit stion
How does loss of sleep relate to one’s ability to resist flu virus infection?
Hypothesis
Sleep deprivation will make a person more susceptible to viral infection.
Prediction
A sleep deprived individual will produce fewer antibodies against an influenza virus w cine.
Experiment
Control Conditions
Sleep 7.5-8.5 hrs/night
|
Results ir
1.15 X 106 fold increase |
Interpretation ler
–
Sleep deprivation results in a decreased ability of the body to challenge foreign antigens like viruses and bacterial pathogens.
Figure 2.6 Sleep deprivation, methodologically dissected
the sleep deprivation study by dissecting it into methodological steps.
Experimenting with Prayer
It is difficult to physically study a phenomenon that is essentially spiritual. But what if the spiritual phenomenon begins in a physical activity and has physical effects as a result? In one fascinating study, Dr. William Harris, at the Mid-America Heart Institute, asked this provocative question: Would continuous prayer for cardiac patients have any effect on the course of their disease during their hospital stay? The question itself had to be carefully defined. Harris didn’t want to know about the length of the hospital stay, or even the final result of the stay in isolation. He wanted to focus on the progression of the patients’ disease states during their stays. So he developed a coronary care unit course score, or CCU score. This value would be based on careful scoring of both the seriousness of the forms of intervention used on the patients and the outcome in terms of the patient’s health.
The hypothesis was simple: Prayer can improve the experience and outcome in the cardiac patient’s life. From this hypothesis we make a prediction. If intercessors believe that their prayer can influence another person’s life and are given cardiac patients to pray for, then that prayer will lower the patients’ CCU scores. The prediction is worded so as to exclude intercessors whose prayers would have no spiritual component to them.
Patients from two extreme groups—those receiving heart transplants and those who were in the hospital for less than 24 hours—were eliminated. The rest were randomly distributed into two groups, one containing 466 patients who received systematic prayer. The control group consisting of 524 patients did not receive systematic prayer. Other associated health problems such as diabetes or high blood pressure were fairly evenly distributed across both groups. That is, a variety of potentially important variables was being controlled for by being equalized across the two groups. Thus the only significant difference between the control and experimental groups is the presence or absence of prayer.
The CCU score of the control group receiving no (known, systematic) prayer was 7.13 ± 0.27, whereas the experimental group receiving systematic prayer was 6.35 ± 0.26. This was an 11% difference. Because of the small variation (±0.27 or 0.26) of individual scores around these average values (7.13 and 6.35) and because the number of individuals studied was large, this 11% difference was statistically meaningful.
For many experiments, interpretation of data is a complicated process. For this experiment, the complicated part was designing the CCU scoring regime. Once this regime suited the goals of the study, interpretation of the results was simple. To quote the authors: “This result suggests that prayer may be an effective adjunct to standard medical care” (see Figure 2.7).
Question
Does continuous prayer for cardiac patients have any effect on the course of their disease?
Hypothesis
Prayer will improve the experience and outcome in the cardiac patient’s life.
Prediction
NOw
If intercessors are given cardiac patients to prayer for, then that prayer will lower the patients’ CCU scores.
Experiment
n = 466 patients
n = 524 patients
prayed for
not prayed for
Results
CCU = 6.35 ± 0.26
CCU = 7.13 ± 0.27
Interpret Lion
Statistical analysis indicates that a difference between CCU values of the size seen here would only occur by chance at a rate of 4% of the time: the difference between the two groups is significant. Prayer should be used to support medical care of cardiac patients.
Figure 2.7 Effects of prayer on cardiac patients, methodologically dissected
IN OTHER WORDS
1. When designing an experiment, we divide subjects into separate experimental and control groups.
2. We try to keep all structural and functional variables across the two groups identical except for one variable, which is altered in the experimental group.
3. We then examine the results of our experiment to see the effects of the one altered variable on the system we are studying.
4. lithe altered variable is the amount of sleep a subject receives, we can observe the effect of sleep deprivation on the subject’s ability to respond immunologically to a flu virus challenge.
5. If the altered variable is the amount of prayer a cardiac patient is subjected to, we can observe the effect of the belief in prayer on the patient’s progress toward recovery.
6. In either study, much effort is required to determine that all the other variables that could possibly affect the outcome vary equally in both the experimental and control groups.
7. Sometimes differences between experimental and control groups are not large and statistics must be employed to determine whether the difference between the two groups is real.
S I Gik 51GGER PKTURE
Approaching Truth
Are scientists allowed to ask questions about the meaning of life? Are they allowed to question why life exists at all? No, not as scientists. Their method cannot address such questions. But scientists are not primarily scientists. They are human beings whose rationality enables them to appreciate truth both from within and from beyond the boundaries of the method they employ in their livelihoods.
Broadly speaking, humans have two fundamental approaches to truth. One is to receive it directly from a Designer capable of communicating it. We call this approach revelation (see Figure 2.8). A clearly supernatural book, a clearly magnificent creation, and a powerful Spirit are the resources with which we approach revelatory truth. The other approach is the one we’ve been examining—scientific methodology. Philosophers call this second approach empiricism. The man on the street calls
revelation—a process by which truth from an ultimate source reaches finite human beings.
scientific method—a rational approach to solving problems that employs observation, experimentation, and interpretation of results.
it common sense. Man’s unaided rational mind and his sensory system are the tools used to make progress toward scientific truth.
Comparing Truth Sources
Revealed truth possesses an inherent objectivity—it derives from a singular Designer whose relationship to reality is creational. Hence, He is not limited by the finite perceptions of the human mind. The power of this objectivity is seen in the quality of laws, life principles, and descriptions of mankind this truth brings to us. The best features of civilization derive from truths revealed in the Old and New Testament documents of the Bible. These documents have also given us the confidence to believe in the constancy of natural law. This constancy is what has allowed, historically, for our other approach to truth—the scientific method—to experience any progress at all.
Scientific knowledge, by contrast, possesses an inherent subjectivity since it derives from the finite minds of many men, some of whom passionately disagree with each other. The weakness of this subjectivity is seen in the grueling difficulty, slow pace, and temporarily misguided theories by which science explains the reality around us. This slow pace, however, does eventually lead us closer and
Sources of Truth
CATEGORY
CHARACTER
LIMITATION
Figure 2.8 Characterizing Truth
source guarantees objectivity
human language;
textual parameters
repeatability contributes objectivity
finite nature of human reason;
Survey Questions
2.1 How Design Is Understood
· What approach or method is used by biologists in order to understand life?
· What are the different parts or aspects of this method?
· What does it mean to understand something? What words do we use to describe something that is well understood?
2.2 Rational Experimentation: Two Examples
How does one rationally design an experiment in biology?
What two examples are illustrated in this section?
In each example, how was the
experiment set up, what were the results, and what new information was gained?
2.3 Seeing a Bigger Picture
· Where is truth found?
· Is the scientific method the only acceptable route to truth?
· How do other methods of seeing the big picture compare to the scientific method?
· Can different routes to the big picture be complementary in nature?
· Life is Significant. A Presentation that explores a Biblical basis for Life’s Significance.
· s Life Significant? The very first principle I want to teach you is that Life is Significant. Now a parent or a pastor or your own Bible reading may have taught you that Life is Significant. So you probably don’t want me to simply state that the principle is true and then move on to another principle! Instead, let’s pose the principle as a question. That way we can arrive at the principle by reason, rather than something we’ve assumed a priori.
· Is Life Significant? To answer that question we have to define two terms. First, what’s meant by the term “life”? And second, what is “significance”?
·
We use the term “life” to refer to the overall quality of all physical things that are alive. But what happens when we try
· to define the term without using it in the definition—that’s what dictionaries are required to do. The answer is that no truly adequate definition exists! I apologize for your having paid all these tuition dollars to the university in order to be taught by a biology professor who can’t even define the word life! But guess what–no biology professor at any other university can satisfy you here either. We can’t define life.
· A Dictionary might define life as “a tendency toward negative entropy”. Problem is: that definition just focuses on a single feature of life. Life’s orderly. But this definition could also describe a highly-ordered but non-living salt crystal. There simply is NO concise, one sentence definition that sets apart all living things from all non-living ones.
· So if we can’t define this term “life” what are we left with? We are forced to string phrases together. If we list enough of the basic characteristics of life, soon no non-living thing is left standing.
· So we can say life is a property of anything that:
· is highly complex
· stores its information in either DNA or RNA
· is capable of reproducing itself, and
· exchanges energy and materials with its surroundings.
· When we pile up all these characteristics, the non-living salt crystal loses out. (it contains no DNA or RNA) and only the living flower remains standing.
· Now…….what do we mean by the term “significance”? We mean that life itself has a value or importance that goes beyond what our five senses are able to tell us. The idea of significance implies a “why” question. “Is Life Significant?” is basically asking “Why is life here?” If there is NO REASON for life’s existence, then it really doesn’t matter how complex or beautiful it all is, the answer to our question is “No, Life is Not Significant.”
· The question “Why is Life Here?” poses a huge problem for us in the sciences. The methods of science rest squarely on the limitations of the human sensory system. We can gather data; we can describe HOW things work. But we can’t get to the WHY question: scientific methodology just can’t do that!
· And tragically this is where many scientists stop. But as human beings most of us find it far too frustrating to stop there! When you have something as beautiful and integrated as life forms, we really need an answer to this question.
· Let’s begin our thinking on this question with an instructive analogy. Consider the wonderful machine pictured to the left. Ask yourself this question: Is a piano significant? Why does it exist? We know the answer to this question! This machine exists because somebody wanted to be able to reproduce musical sounds. How do I know that? Well there is a purposeful quality to it’s design! In its complexity–in its function–it has been so utterly well constructed for the service it performs. Well then, consider the photograph to the right on this slide. Here we have an Allium flower taken from the living world. Consider this beautiful machine and ask yourself this question: Is this machine significant? Why does it exist?
· The more you know about HOW a flower reproduces a plant, the more breathtakingly designed this structure is. It leaves our piano “in the dust”. So then, by analogy, is the flower significant? You bet it is. We’re being led to a dangerously probable conclusion here: If the piano has a Designer, then so should this flower!! And if we grant this conclusion, then biology becomes: the art of a great Creator, the art of a GOD who is greater than men.
· Therefore, one significance of Life—one reason for its existence—is that it reveals to us evidence of a great Creator we might otherwise have overlooked!
· Let’s keep thinking! A Creator powerful enough to create a reproductive organ like a flower or a human brain would probably be powerful enough to communicate with the mind housed in that brain. Has the Creator communicated propositionally with us? Because if He has, then His communication might also address the question of life’s significance! It might do so in a highly elegant way!
· Down through history, a variety of documents have purported to represent specific words, truths FROM this God. Curious scholars have evaluated the scientific and historic validity of many of these documents. Others have studied their content of wisdom and moral quality. From all this study, one document clearly emerges as highly dignified and authoritative by comparison with the others: that document is the Bible. From the majesty and accuracy of Genesis 1, to the microbiological wisdom of Leviticus, to the archeological validity of Old Testament history, this book gives high quality evidence that its come to us from God.
· If you wish to read further on evidence for the supernatural quality of scripture consider these sources. They are representative of many other sources like them. These authors and others have concluded that aside from the Bible, no book has comparable evidence for its Divine authorship.
· Therefore, we humbly approach the Bible with the question: Is life significant?
· Its answer is YES, for several very worthy reasons! Consider the following passage of scripture and what it states regarding the significance of physical life on earth.
·
Psalms 104: May the glory of the Lord endure forever; may the Lord rejoice in His works.
· One significance of the panoply of living things on earth is simply the joy it gave God to create them. (He is a consummate Artist). He enjoys observing the creations of His own hands. He rejoices in the glory of the things He has made.
· Is Life Significant? Consider another passage from the book of Job. Here Job asks God a searching question:
· “What is man that You make so much of him, that You give him so much attention, that you examine him every morning and test him every moment?”
· Here, Job portrays God as being entirely fascinated with the moral qualities of man. But to see those moral qualities played out, God required a physical arena for man to live in. So the glorious creation of life in all its various forms is part of the physical network—the context—in which man lives out his physical life. But on that physical life is superimposed the moral content of all the decisions we make each day. And God is highly interested in those decision.
· Now on to Paul’s letter to the Romans for a third Biblical argument for the Significance of Life:
· You may recall from Psalm 19 that the heavens declare God’s glory. Well Paul, in this passage includes living things in his apologetic argument here in Romans 1. “What has been made” is so well made that it represents a powerful apologetic for the existence of a great Creator-Designer. God—apart from written Scriptures—is knowable to man through God’s creative wonders!! Life is significant: it shows us God.
· Finally, we return to the Psalms to see yet another dimension of Life’s great Significance: The created order is God’s gift to mankind. It provides his food to sustain his physical life. It provides his clothing for modesty and his much of his shelter from the storms of nature. The horse has born the burden of human civilization until very recently. The dog has become man’s best earthly friend. The birds have taught man to sing. What a glorious gift the created order represents. And the Designer selects man as both its recipient and its manager. Is Life Significant? Your physical existence absolutely depends on it.
· Let’s summarize! Life is a joy to its Designer, a stage for man’s spirit, a quiet hand that points to God and a precious gift that grants life to the human body? Is Life Significant? It certainly is! And any otherwise liberally educated scholar would be a fool to avoid studying it. Why take a biology course? Because Life Is Significant
Peter Lane Taylor
Hypothesis
�
Question Prediction
Experimentation
Model
Sleep Study — Experimental Group
Sleep 4 hrs/night for 6 nights Introduce flu virus by injection on day 7
Check level of anti-flu antibodies same day�Check level of anti-flu antibodies on day 17
Figure 2.4 Sleep Study — Experimental Group
Relative anti-viral Antibody Levels
1.4�1.2
1 0.8 0.6 0.4 0.2
0
��
Cntrl
Sleep Loss�
�
Experiment Conditions�Sleep 4 hrs/night
41,
0.50 X 106 fold increase�in antibody levels
Results:
Group�
�
Relative increase in Anti-viral Ab levels�
�
Control�
�
�
�
0.50 X 106�
�
Experimental�
�
1.15 x 106�
�
revelation
scientific method
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Figure 1.20 The common names suggest two species
that are quite different from each other. The scientific name reminds us that both plants found their way into the same Genus (originally named by Linnaeus). DNA studies are showing this Linnaean grouping of (now) over 1500 species to be artificial—not very biological.�
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Life Is Internally Integrated. Parts assist all other parts in enabling organismal activities (Chapter 10).
Life Is Responsive. When the ball’s pitched, you hit it, sometimes (Chapter 11).
Life Is Ultimate Art. Your properties aren’t pre�dictable from molecular properties (Chapter 13). Life Is Diverse. We are ignorant of how many millions of species there are on this planet (Chapter 14).
Life Is Interactive. You eat fish and sharks eat you (Chapter 15).
Life Is Finite. The healthiest old woman eventu�ally dies (Chapter 16).
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Life’s Design
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individual
somehow this level appears to be a “frame of reference” about which the Creator is ultimately concerned.�
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cell
composed of assorted organelles appropriate to the type of cell.
organelle
composed of a large variety of macro-molecular structures.
macro-molecular structure composed of various kinds of biomolecules.
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population Mir
composed of a typically large number of individuals that are potentially inter-breeding.
community
a collection of populations whose members interact by “eating and being eaten.”
ecosystem
the community in a given area plus the non-living aspects of the environment.�
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all of the ecosystems on planet earth taken together.�
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Figure 1.17 If God is the Creator, and if His creation is complex, then “life”wil I be subject to description at the many interlocking, inter-nested levels of organization pictured above. The arrows point toward increasing levels of complexity. Note that the cellular level is the lowest level that can be independently”alive”. Scholars who study life tend to select one or two of these 12 levels at which to study it.
Figure 1.5 The circulatory system
is a collection of organs like arteries,
veins, and the heart that work together, to get nutrients and oxygen to and
waste products and CO7 from all parts
of the body. That is the role of this body system.
Cengage Publishing
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Nuclear envelope
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Nucleolus
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Scott Barrow/Corbis
Figure 1.14 A freshwater pond. The grasses, rushes, trees, and all the animal life (insects, fish, birds, mammals) that live and interact with each other here are termed a community.
