Communities Quiz in Open Learning Initiative

CommunitiesQuiz

Schedule:

Available now. Due 07/21/2013 11:59 PM EDT

Question 1

Select one answer.

10 points

In Africa, grasses are the main vegetation in savanna communities. Acacias and other

trees are few and widely scattered. Elephants range over very large territories and are

not very abundant in any one location. However, they strongly affect the community by

uprooting and consuming trees and shrubs, maintaining suitable habitat for grasses and

grassland animals. Many species of birds and insects live in the savanna grasses. Based

on this information, which of the species or groups above would best be described as

keystone species?

 grasses

 acacia trees

 elephants

 birds and insects

Question 2

Select one answer.
10 points

Which of the following would probably have a greater richness of native plant species

per acre?

 a polluted and heavily disturbed lot in an industrial park

 old, healthy forest

Question 3

Select one answer.
10 points

What type of relationship exists between the hummingbird and the flower?

 Competition

 Predation

 Mutualism

Question 4

Select one answer.
10 points

Occasionally American alligators are sighted in rivers or lakes in New York City, far

north of their usual range. These alligators are usually escaped pets. There is no self-

sustaining population of alligators in New York, and they have no important influence

on other populations there. Is the American alligator a member of the ecological

community in New York?

 No

 Yes

Question 5

Select one answer.
10 points

By damming streams, American beavers produce swamp, open marsh, and pond

habitats that would not otherwise exist. Ecologists have compared the species diversity

in regions with and without beaver populations. If the beaver is a keystone species, what

do you think they found?

 Species diversity was higher in areas with beaver.

 Beaver did not influence the diversity of other species.

 Species diversity was higher in areas without beaver.

Question 6

Select one answer.
10 points

Species richness is

 The number of species in a population

 The number of organisms in a community

 The total weight, or biomass, of living organisms in a given

area

 The number of different species in an area

Question 7

Select one answer.
10 points

Which of the following is a direct interspecific interaction?

 Through their effects on antelope behavior, lions increase the

survival of some plant species.

 Hormones circulating within a lion affect her levels of hunger

and motivation to hunt.

 Individual lions compete with each other for food and mates.

 Lions eat antelope; in the presence of lions the antelope

population is reduced.

Question 8

Select one answer.
10 points

A sample of insects and other invertebrates is collected from an urban stream. A total of

244 individuals is collected from 2 m2 of stream bottom habitat. In this sample there are

22 recognizably different types of invertebrate. The average total length of the

individuals is 6.7 mm. What is the best estimate of species richness based on these data?

 122

 244

 22

 6.7

Question 9

Select one answer.
10 points

Two species with very similar resource requirements that live in the same area are most

likely to interact in what way?

 mutualism

 predation

 competition

Question 10

Select one answer.
10 points

Relate the terms population and community.

 A community is used to describe plants, a population is used to

describe animals

 A population is used to describe plants, a community is used to

describe animals

 A population is made of communities

 A community is made of populations