Deck 54: Community Ecology

Question 1

In what symbiotic relationships are humans involved

Answer 1

Humans are involved in numerous symbiotic relationships of different types. Humans that own pets or domesticated animals are an example of symbiosis. While the human will feed and care for the pet, the pet in return may offer benefits of protection or assistance in the case of disabled owners.
Humans are also in a symbiotic relationship with intestinal bacteria: intestinal bacteria are important in aiding digestion of foods in the GI tract. In turn, the bacteria are provided with a host to survive in. Humans that own cultivated plants are another example of symbiosis.

Question 2

A limiting resource does all of the following except that it

A)tends to restrict the ecological niche of a species
B)is in short supply relative to a species' need for it
C)limits the presence of a species in a given community
D)results in an intermediate disturbance
E)may be limiting for only part of an organism's life cycle

Answer 2

A limiting resource does not cause an intermediate disturbance, but can have rather significant effects on a species. Limiting resources can both restrict the ecological niche of a species or their presence within an environment. Thus, the correct answer is d.
Limiting resources restrict the ecological niche of a species. They have this effect due to their scarce supply relative to minimum need of a species, or the fact that they may be unfavorable. This eliminates choices (a) and (b).
Limiting resources are factors that are smaller than the required minimum of a species for survival, which limits their presence within a community. This means choice (c) is eliminated.
Additionally, limiting resources may affect only part of an individual's life cycle; adult blue crabs do not permanently settle in freshwater because their larvae require salt water. Salt water is a limiting resource that prevents blue crabs from establishing their niche and presence in freshwater. This implies (e) is incorrect.

Question 3

SCIENCE, TECHNOLOGY, AND SOCIETY. Describe the ecological niche of humans. Do you think our realized niche has changed during the past 1000 years Why or why not What role has technology played

Answer 3

Humans have developed a distinct ecological niche due to the development of unique adaptations. Humans are the top predator in the ecosystem, and their niche has become that of expansion and predation at the expense of the ecosystem and its components.
Since, humans have more evolved brains developed with a sense of consciousness, they have been able to adapt and thrive in any environment, capable of exploiting resources and out-competing other species to enhance their own survival.
Our realized niche has grown in the past 1000 years, since technological advancements have allowed humans to expand and predate even more rapidly and efficiently. For example, technology such as cars, ships, and planes that developed in the past millennium has provided humans a means of mass transportation over long distances, spanning nearly the entire planet.
This furthered our realized niche as we had an efficient means to discover new areas and resources to consume. Humans often discover new land, will exploit what resources are available, and disturb the environment by removing species to institute man-made structures.

Question 4

Based on current evidence, monarch and viceroy butterflies are probably an example of

A)Batesian mimicry
B)character displacement
C)resource partitioning
D)Müllerian mimicry
E)cryptic coloration

Question 5

How is the vertical distribution of barnacles in Scotland an example of competitive exclusion

Question 6

A symbiotic association in which organisms are beneficial to one another is known as

A)predation
B)interspecific competition
C)intraspecific competition
D)commensalism
E)mutualism

Question 7

In your opinion, are humans a dominant species or a keystone species Explain your answer.

Question 8

A species' _____ is the totality of its adaptations, its use of resources, and its lifestyle.

A)habitat
B)ecotone
C)ecological niche
D)competitive exclusion
E)coevolution

Question 9

Many plants that produce nodules for nitrogen-fixing bacteria are common on disturbed sites. Explain how these plants might simultaneously compete with and facilitate other plant species.

Question 10

Competition with other species helps determine an organism's

A)ecotone
B)fundamental niche
C)realized niche
D)limiting resource
E)ecosystem

Question 11

EVOLUTION LINK. The rough-skinned newt, which lives in western North America, stores a poison in its skin and is avoided by predators. However, several populations of garter snakes have undergone one or a few mutations that enable them to tolerate the toxin, and these snakes eat the newts with no ill effects. How has natural selection affected this predator-prey relationship Based on what you have learned about evolutionary arms races, predict what may happen to the newts and the poison-resistant garter snakes over time.

Question 12

"Complete competitors cannot coexist" is a statement of the principle of

A)primary succession
B)limiting resources
C)Müllerian mimicry
D)competitive exclusion
E)character displacement

Question 13

EVOLUTION LINK. Competition is an important part of Darwin's theory of evolution by natural selection, and the evolution of features that reduce competition increases a population's overall fitness. Relate this idea to character displacement and resource partitioning in Darwin's finches.

Question 14

The _____ signifies that species richness is greater where two communities meet than at the center of either community.

A)edge effect
B)fundamental niche
C)character displacement
D)realized niche
E)limiting resource

Question 15

EVOLUTION LINK. Ecologist Charles Krebs said that "evolution operates through natural selection, which is ecology in action." Explain what he meant and relate his idea to one example of ecosystem regulation from the bottom up or the top down.

Question 16

Primary succession occurs on

A)bare rock
B)newly cooled lava
C)abandoned farmland
D)a and b
E)a, b, and c

Question 17

ANALYZING DATA. Examine the top and middle graphs in Figure. Are these examples of exponential or logistic population growth Where is K in each graph (You may need to refer to Chapter 53 to answer these questions.)
FIGURE Animated G. F. Gause's classic experiment on interspecific competition

Question 18

The tendency for two similar species to differ from each other more markedly in areas where they occur together is known as

A)Müllerian mimicry
B)Batesian mimicry
C)resource partitioning
D)competitive exclusion
E)character displacement

Question 19

ANALYZING DATA. Examine Figure (shown below). Approximately what percentage of species have colonized islands 2000 km from New Guinea 6000 km from New Guinea Based on your answers, explain the relationship between species richness and geographic isolation.
FIGURE The distance effect

Question 20

An unpalatable species demonstrates its threat to potential predators by displaying

A)character displacement
B)limiting resources
C)cryptic coloration
D)aposematic coloration
E)competitive exclusion

Question 21

An ecologist studying several forest-dwelling, insect-eating bird species does not find any evidence of interspecific competition. The most likely explanation is

A)lack of a keystone species
B)low species richness
C)pronounced intraspecific competition
D)coevolution of predator-prey strategies
E)resource partitioning

Question 22

Support for the individualistic model of community structure includes

A)the decline of honeybees because of two species of parasitic mites
B)the identification of fig trees as a keystone species in tropical forests
C)the competitive exclusion of one Paramecium species by another
D)the distribution of trees along a moisture gradient in Wisconsin forests
E)the effects of the removal of a dominant rodent species from an Arizona desert.