Deck 34: Communities in Ecology

Question 1

In a typical ecosystem, an organism that is photosynthetic and whose removal would have a bigger impact than any other would be known as a:

A) keystone consumer.
B) passive consumer .
C) dominant consumer.
D) keystone producer.

Answer 1

keystone producer.

Question 2

Ecological dominants:

A) are keystone species in individual communities.
B) are those species that are abundant in a community.
C) are collections of populations in a given area that can potentially interact with each other.
D) are those species whose absence would bring about significant change in community structure.

Answer 2

are those species that are abundant in a community.

Question 3

An accidental spill of a pesticide locally wiped out one species of an endangered butterfly in coastal California. Several bird species had fed on this butterfly, but they switched prey items fairly quickly to more abundant moths, and thus the birds showed little change in population size. The endangered butterflies were:

A) keystone species, and thus they were driven to extinction very easily.
B) part of a predator-prey interaction.
C) ecological dominants, but they were not keystone species.
D) pioneer species.

Answer 3

part of a predator-prey interaction.

Question 4

A really productive community is one that has a lot of:

A) predators.
B) prey species.
C) keystone species.
D) biomass.

Question 5

Which level of organization is often dominated by only a few species?

A) biosphere
B) communities
C) ecosystems
D) habitats

Question 6

Sea stars consume barnacles and clams. This identifies them as:

A) a predator.
B) a keystone species.
C) an ecological dominant.
D) a parasite.

Question 7

Which of the following is an example of intraspecific competition?

A) two hawks nesting in different parts of the forest
B) barnacles growing on a rocky coast
C) kudzu replacing native species
D) lions chasing hyenas away from a dead wildebeest

Question 8

Cowbirds and cuckoo birds that lay their eggs in another bird's nest for the new mother to care for are identified as:

A) parasites.
B) predators.
C) commensals.
D) hosts.

Question 9

Resource partitioning:

A) explains the apparent sharing of some resource.
B) explains the rapid spread of some non-native species.
C) is only possible with vital resources.
D) is inevitable in similar species.

Question 10

The relationship between a tree and a bird that both nests in its branches and eats its seeds is both ________ and ________.

A) parasitic; predatory
B) mutualistic; predatory
C) parasitic; competitive
D) commensalistic; predatory

Question 11

A top predator may increase the diversity of species lower on the food chain by:

A) eliminating ecological dependents.
B) decreasing competition.
C) increasing genetic diversity in prey species.
D) increasing competition.

Question 12

Competition between members of two different species is:

A) most intense when the species have similar niche preferences, and it is referred to as interspecific.
B) least intense between species with similar niche preferences because of habitat exclusion.
C) most common in species that cannot interbreed.
D) referred to as intraspecific when the two species actively compete with each other.

Question 13

A zoologist has found that a certain species of woodpecker nests only in dense, old-growth forests and feeds on large insect larvae from the upper canopy. She has described this species':

A) resource band.
B) resource spectrum.
C) habitat.
D) niche.

Question 14

An ornithologist has observed two species of nuthatch that appear to live in similar environments: both species forage for insects on the same trees, but one species forages in the upper canopy, and the other species forages in the lower canopy. This is probably an example of:

A) intraspecific competition that leads to habitat separation.
B) territorial competition leading to niche overlap.
C) territorial competition leading to competitive exclusion.
D) coexistence through resource partitioning.

Question 15

Two species of squirrel lived along a hillside in California. One species had a range that extended from sea level to about 5,000 meters in elevation; the other species had a principal range from 5,000 meters to 10,000 meters. However, when a viral epidemic greatly reduced the population of the low-elevation species, the high-elevation species increased its range down to 3,000 meters. This suggests that ________ was occurring and that coexistence was due to ________.

A) competitive exclusion; habitat exclusion
B) intraspecific competition; habitat partitioning
C) interspecific competition; resource partitioning
D) competitive exclusion; habitat partitioning

Question 16

The zebra mussel, Dreissena polymorpha, was introduced to the United States in the late 1980s from its native habitat in eastern Europe, brought accidentally by ships entering the canals of the Great Lakes. The dense populations are threatening many native species of mollusc with extinction. This is an example of:

A) intraspecific competition.
B) competitive exclusion.
C) resource partitioning.
D) niche separation.

Question 17

In 1975 in Sweden, mange mites were found to infest the carnivorous red fox, causing hair loss, skin deterioration, and finally death. At its peak, this mange, specific to this fox, reduced the population of the fox by over 70 percent in Sweden. Biologists noted that hare and grouse populations increased in number by a factor of 2 to 4. Most likely, the hare population increased because:

A) competitive exclusion reduced the population of the host parasite of the hare.
B) the predator mange decreased the numbers of the main parasite of the hare.
C) the parasitic mange decreased the numbers of the main predator of the hare.
D) Both A and C are plausible conclusions.

Question 18

Population cycles in herbivores are due to:

A) population cycles in their main parasites.
B) linked cycles between host and parasites, predators, and prey.
C) population cycles in their predators.
D) possibly any of the above

Question 19

A very tasty butterfly evolved to have the same coloration of a butterfly that it is not closely related to it but has high concentrations of extremely toxic compounds in its wings. This is an example of:

A) Batesian mimicry.
B) Müllerian mimicry.
C) Antennarius mimicry.
D) mutualism.

Question 20

Several lizard species have bright red lines or spots on their backs, and all are either toxic or poisonous to their predators. This is an example of:

A) Batesian mimicry.
B) Müllerian mimicry.
C) Antennarius mimicry.
D) mutualism.

Question 21

Which of the following is an example of coevolution?

A) honeybees seeing colors in plants that they pollinate
B) an insect dying from the tannin produced by an oak tree
C) bean plants producing chlorophyll for photosynthesis
D) insects eating mites off the skin of owls

Question 22

Oak leaves contain high concentrations of tannins, which make them unpalatable to humans and many herbivores. However, several insects feed on oak leaves. These phenomena provide a good example of :

A) mimicry by predatory insects.
B) commensalism by predatory insects.
C) the evolutionary arms race of predator-prey interactions.
D) commensalism, because the insects do not kill the host plant.

Question 23

A population biologist notes a curious fact when observing a population of small voles in a field in Michigan: although he traps and removes a significant percentage (>15 percent) of the breeding adults for study each year, the density of the voles does not seem to decrease in the following year. This suggests that ________ is occurring.

A) niche overlap
B) niche separation
C) intraspecific competition
D) competitive exclusion

Question 24

Wildebeest and zebras are abundant mammals on the African savanna. These species are identified a ecological dominants.

Question 25

Lions on the African savanna are identified as ecological dominants.

Question 26

Zebras are identified as top predators on the African savanna.

Question 27

A community with high biodiversity is characterized by geographic diversity.

Question 28

Wolves and foxes may be competitors for small mammals as food in the forest.

Question 29

Lichens represent mutualistic forms of life.

Question 30

Mimicry is a common way for prey to avoid a predator.

Question 31

What is the role keystone predators play in an ecosystem?

Question 32

An insectivorous gray lizard was once very abundant in disturbed habitats of a small island off the coast of the eastern United States. When the black lizard, a close relative, was introduced from South America, the range of the gray lizard was reduced in size, and over the course of a few decades, the average jaw size of the gray lizard increased. Explain these phenomena, giving the names for the phenomena.

Question 33

Explain the difference between a primary succession and a secondary succession. In which one would you expect soil fertility to be greater? Give an example of each type of succession.