biology

Organisms are placed in taxonomic classifications based on differences and similarities of their traits. If you know what critical traits to look for, it is possible to separate any animal into a taxonomic category using a dichotomous key.The common taxonomic categories are Domain, Kingdom, Phylum, Class, Order, Family, Genus and Species (Specific Epithet.) We are looking at the Phylum and Class categories in this assignment.Assignment details:Part 1: The assignment document contains a table with nine images. The images are examples of nine different Animal phyla: Porifera, Cnidaria, Nematoda, Arthropoda, Platyhelminthes, Annelida, Mollusca, Echinodermata, and Chordata.DownloadU5IP_Table.Next, Download Dichotomous KeyUse the Dichotomous Key to determine the Class category as shown for each animal (picture), and write the Class names under the Classification Column on the table.List in column 2, all of the dichotomous key steps you chose when using the key to arrive at the classification for each animal.You will also need to list the Phylum name for each animal picture in column one using the nine Phyla listed above. Once you have identified the Class category for each animal using the Key, look up the correct Phylum category using a credible reference. 

1. For help on how to use the Dichotomous Key, download and review the document called How to Use the Dichotomous Key.
2. Save a copy of the table with your name in the file name.

Part 2: Answer the following questions as they relate to the nine phyla in the assignment table. (Porifera, Cnidaria, Nematoda, Athropoda, Platyhelminthes, Annelida, Mollusca, Echinodermata, and Chordata.)

1. Which phyla lack organs? What type of symmetry do they have?
2. List all of the phyla that show cephalization.
3. Do all organisms on the table have 3 germ layers (endoderm, ectoderm, and mesoderm)? If not, which phyla have fewer than three germ layers?
4. One phylum on the table has more species than all the others. State the name of this phylum, and provide several different examples of species found in this phylum.
5. Fish do not all have the same skeletal structure. Describe the differences among fish skeletal structures from the most primitive to more advanced types of fish.
6. Describe the three types of mammals based on how their young develop.

Provide references in APA format. This includes a reference list and in-text citations for references used throughout the assignment.

Unit 5 Individual Project

Name:      

Date:      

Part 1. There are 9 animals in nine different Phyla. Be sure to look at every page.

Animal

Phylum

Dichotomous Key (steps)

Classification

1

     

     

     

2

     

     

     

3

     

     

     

4

     

     

     

5

     

     

     

6

     

     

     

7

     

     

     

8

Image Rights: Allen G.
Collins and the UC Museum of Paleontology

     

     

     

9

Image Rights: Courtesy of University of Minnesota

     

     

     

Part 2: Answer the following questions as they relate to the nine phyla in the assignment table. (Porifera, Cnidaria, Nematoda, Athropoda, Platyhelminthes, Annelida, Mollusca, Echinodermata, and Chordata.)

1. Which phyla lack organs? What type of symmetry do they have?

2. List all of the phyla that show cephalization.

3. Do all organisms on the table have 3 germ layers (endoderm, ectoderm, and mesoderm)? If not, which phyla have fewer than three germ layers?

4. One phylum on the table has more species than all the others. State the name of this phylum, and provide several different examples of species found in this phylum.

5. Fish do not all have the same skeletal structure. Describe the differences among fish from the most primitive to more advanced types of fish.

6. Describe the three types of mammals based on how their young develop.

© 20010-2011 Career Education Corporation University Group

2

3

7

8

9

10

12

13

15

16

18

Couplet Number	Statement Choices	Classification
1	a. Symmetry is irregular (neither bilateral or radial); aquatic; body structure without tissues or organs	Class Demospongiae
b. Symmetry is radial or bilateral		2
a. Radial symmetry, lacks a well defined head		3
b. Bilateral symmetry (similar right and left body halves, anterior head end and posterior tail end)	6
a. No spines or arms present	4
b. Spines or arms present	5
4	a. Barrel-shaped body, short tentacles at one end surrounding mouth, adults attached to a substrate	Class Anthozoa
b. Saucer-shaped, transparent body with thin tentacles, free floating	Class Scyphozoa
5	a. Five arms present, body surface knobby	Class Asteroidea
b. Many-spined animal, resembles a pincushion	Class Echinoidea
6	a. Animal has no apparent skeleton, or may have an exoskeleton (hard outer covering), or may have a shell; invertebrate		7
b. Animal has internal skeleton; vertebrate		16
a. No hard outer covering, no exoskeleton, or no shell; worm-like		8
b. Hard outer covering, exoskeleton, or shell; not worm-like	1 1
a. Body is segmented	Class Clitellata
b. Body is not segmented		9
a. Body long and tubular	Class Secernentea
b. Body flattened		10
a. Free living, aquatic, ribbon-like, smooth	Class Turbellaria
b. Endoparasites (live inside host); may look segmented	Class Cestoda
11	a. No jointed appendages		12
b. Jointed appendages	1 4
a. Soft body inside bivalve shell (hinged shell with 2 halves), no head	Class Bivalvia
b. Soft body, obvious head		13
a. May or may not have a shell; head with tentacles, small eye or eye spot	Class Gastropoda
b. Large head with tentacles and large eyes present	Class Cephalopoda
14	a. Two pairs of antennae, large claws often present	Class Crustacea
b. One pair of antennae or none, no large claws		15
a. Four pairs of legs, no antennae or wings	Class Arachnida
b. Three pairs of legs, wings present	Class Insecta
a. Fishlike, flattened body; appendages finlike not jointed	1 7
b. Not fishlike, body not flattened, appendages jointed or absent		18
17	a. Fish, scales on body do not overlap; skeleton of cartilage	Class Chondrichthyes
b. Fish, scales on body overlap; skeleton bony	Class Osteichthyes
a. Body covered by scales, zero or four legs	Class Reptilia
b. Body not covered by scales	1 9
19	a. Claws absent	Class Amphibia
b. Claws or nails present on toes; skin covered with feathers or hair	2 0
20	a. Feathered, claws present	Class Aves
b. Hair present	Class Mammalia

HOWTO USE A DICHOTOMOUS KEY

Dichotomous means “divided or cut into two parts.” A dichotomous key is a tool used by
scientists to classify organisms into classification categories or taxa. The key is made up
of a series of numbered couplets, and within each couplet are two opposing statements
which you read, choosing the one that best fits the animal picture.

To use the key, you always start at the first couplet (look for a ‘1’ in the first column).
Read the two couplet choices (labeled ‘a’ and ‘b’ in the second column), and consider
them carefully. If you do not know the meaning of a word, as some of these terms are
technical, look them up in a reference, a dictionary, or your textbook glossary, perhaps.

Look at your animal. Choose the statement (a or b) that best fits your animal. All parts of
the statement must be true.

If you select a statement and arrive at a Class with some name after it, you have found
the classification (Class) to which your organism belongs, and you have finished
identifying the animal!

If the selected statement has a number at the end, go to that couplet number (skip all the
others) and read the couplet choices (a and b statements) that you find there.

Again, you would choose the couplet choice that best describes characteristics of your
animal. If your choice is a number, go to that couplet number and continue using the
key. Continue choosing from the indicated couplets until you come to the couplet choice
that provides you with the classification name of your organism.

Here’s an example: Blue Land Crab

Always start at Couplet Number 1:

1

a. Symmetry is irregular (neither bilateral or radial);

aquatic; body structure without tissues or organs
Class Demospongiae

b. Symmetry is radial or bilateral 2

The crab has bilateral symmetry, so choose statement b and go to Couplet 2.

Couplet Number 2:

2
a. Radial symmetry, lacks a well defined head 3

b. Bilateral symmetry (similar right and left body

halves, anterior head end and posterior tail end)
6

Choice b describes a crab with bilateral symmetry, right and left body halves, so go to
Category 6. Completely skip Couplets 3, 4 and 5 since these will not apply to the crab.

Couplet Number 6

6
a. Animal has no apparent skeleton, or may have an

exoskeleton (hard outer covering), or may have a

shell; invertebrate

7

b. Animal has internal skeleton; vertebrate 16

The crab has an exoskeleton or shell. If you are not sure about a characteristic of the
organism, you could use www.google.com to help you determine if a statement is true or
false. For example, you could look up the key words ‘crab’ and ‘skeleton’. You will find
sites that describe the crab’s exoskeleton.

You will select choice 6a and go to Couplet 7.

Couplet Number 7

7
a. No hard outer covering, no exoskeleton, or no shell;

worm-like
8

b. Hard outer covering, exoskeleton, or shell; not

worm-like
11

A crab’s shell is hard, and a crab is not worm-like. Go to Couplet 11.

Couplet Number 11

11 a. No jointed appendages 12

b. Jointed appendages 14

The crab’s legs are jointed and you would choose b. Go to Couplet 14.

Couplet Number 14

14 a. Two pairs of antennae, large claws often present Class Crustacea

b. One pair of antennae or none, no large claws 15

The crab has antennae and large claws; so you will select a, Class Crustacea. You will
write Class Crustacea on the Classification Column for your table.

On your Unit 5 IP, in the column labeled “Dichotomous Key (steps)” you will fill in the list
of your choices. In the column “Classification” fill in the class you have found. Your
results will look like this:

Organism Phyla Dichotomous Key (steps) Classification

1

Crab

Arthropoda 1b, 2b, 6a, 7b, 11b, 14a Class Crustacea

By writing in your couplet choices, you demonstrate that you used the key, and you may

earn partial credit, even if you ended up at the wrong answer. Use this method to identify

the Classes for each of the 9 nine animals on your table. Have fun!