Question 1

Dinoflagellates are important to coral and coral-dwelling animals because they
A)produce energy that is used by coral animals through photosynthesis.
B)provide shelter for the fast-growing seaweeds associated with coral.
C)produce CO₂ and nitrogen for coral.
D)are toxic to species that prey on reef-dwelling fish.

Accepted Answer

Dinoflagellates are photosynthetic organisms that form symbiotic relationships with corals, providing them with energy through photosynthesis. Corals are not able to survive without their dinoflagellate counterparts, as they rely on this energy source to grow and reproduce.

Question 2

If an overlap develops between the ranges of two closely related species, and if the species occupy the same niche in the zone of overlap, what will probably happen in the zone of overlap?
A)A new species will arise by hybridization.
B)Both species will coexist, provided the environment in the zone of overlap is different from that in either individual range.
C)Both species will coexist, provided the environment in the zone of overlap is similar to that of one of the individual ranges.
D)One species will take over most or all of the zone of overlap.

Accepted Answer

When two closely related species occupy the same niche in a zone of overlap, competitive exclusion is likely to occur, leading to one species dominating the zone of overlap. This is because two species competing for the exact same resources cannot coexist indefinitely; one will outcompete the other.

Question 3

One predator avoidance mechanism that has evolved in prey is
A)chemical defenses.
B)secretion of digestive enzymes that hydrolyze glucose.
C)secretion of enzymes that break down toxic plant compounds.
D)development of a short gestation period.

Accepted Answer

Chemical defenses, such as toxins or bad taste, can deter predators from attacking the prey. This is a common predator avoidance mechanism that has evolved in many different species of prey. The other choices do not relate to predator avoidance mechanisms.

Question 4

In an ecosystem, you would expect to find interspecific competition between
A)males and females of a species in which both sexes occupy the same niche.
B)populations of two species that occupy the same niche.
C)a prey species and its predator.
D)two wasp species that mimic each other's appearance.

Accepted Answer

Interspecific competition occurs between populations of two different species that occupy the same niche. This competition could involve a variety of resources, such as food, space, or mates. In contrast, option A refers to intraspecific competition, which occurs between members of the same species, and option C refers to predator-prey interactions, which cannot be classified as competition. Option D refers to a form of mutualistic symbiosis where the two species benefit from looking alike.

Question 5

The prokaryotes that cause tooth decay have a ________ relationship with humans.
A)parasitic
B)predatory
C)mutualistic
D)competitive

Accepted Answer

The prokaryotes that cause tooth decay, particularly Streptococcus mutans, feed on sugars present in the human mouth and produce acid as a waste product. This acid can erode tooth enamel, leading to cavities and other dental problems. This relationship is considered parasitic as the prokaryotes benefit from the host (humans) while causing harm.

Question 6

In addition to abiotic factors, community composition of plants can be severely compromised by
A)parasites and pathogens.
B)introduction of chestnut trees.
C)non-native birds.
D)rapid coevolution.

Accepted Answer

Parasites and pathogens can have a significant impact on plant community composition. They can reduce the growth rates and survival of certain plant species, causing a shift in the dominance of the community. This can have effects on ecosystem function and overall biodiversity. The introduction of non-native species or rapid coevolution can also have an impact, but in general, parasites and pathogens are more likely to have a direct and immediate effect. The introduction of chestnut trees is a specific example and not a general factor that affects community composition. Non-native birds can have indirect effects on plant communities through their interactions with other species and the spread of seeds, but this is less common than the impact of parasites and pathogens.

Question 7

The sum total of a population's use of the biotic and abiotic resources of its habitat constitutes its
A)environment.
B)evolution.
C)range.
D)niche.

Accepted Answer

The concept of a species' niche refers to the specific role that a species plays within its ecosystem or habitat, including its use of resources, interactions with other species, and its impact on the environment. Therefore, the sum total of a population's use of the biotic and abiotic resources of its habitat constitutes its niche. Option A (environment) refers to the physical, chemical, and biological components of an organism's surroundings, which can influence its survival and reproductive success, but do not necessarily encompass its interactions with other species. Option B (evolution) refers to the gradual process of biological change over time, which can lead to the development of new species with distinct niches. Option C (range) refers to the geographic area or habitat in which a species is found, but does not encompass its interactions with other species or the resources it uses.

Question 8

Within an ecosystem, a tree is a
A)secondary consumer.
B)detritivore.
C)primary consumer.
D)producer.

Accepted Answer

A tree is a producer, meaning it synthesizes its own food through photosynthesis and serves as the base of the food chain, providing energy for all other organisms in the ecosystem.

Question 9

Most plants have a variety of chemicals, spines, and thorns because the plants
A)cannot run away from herbivores.
B)feed on the organisms that try to eat them.
C)are camouflaged into their surroundings.
D)must rely on photosynthesis for food.

Accepted Answer

The presence of chemicals, spines, and thorns on plants is a defense mechanism because plants cannot run away from herbivores. These physical and chemical barriers make it more difficult for herbivores to consume the plant, reducing the chances of the plant being eaten.

Question 10

The freshwater leech is an organism that feeds off of the blood of other organisms such as frogs and turtles. Which of the following describes the relationship between freshwater leeches and frogs or turtles?
A)herbivory
B)predation
C)mutualism
D)parasitism

Accepted Answer

The freshwater leech is feeding off of the blood of other organisms, which harms the host while benefiting the leech. This type of relationship is characteristic of parasitism.

Question 11

One reason it is important to understand community ecology is
A)to understand the life cycle of fish, such as cichlids.
B)for identification of stomach microbes.
C)to aid in conservation of endangered species.
D)to provide an enriched habitat for humans.

Accepted Answer

Understanding community ecology can aid in the conservation of endangered species by ensuring that their habitat and ecosystem are protected and maintained.

Question 12

A hypothetical community on a barren mid-Atlantic island consists of two fish-eating seabirds (the booby and the noddy), the fungi and microorganisms that live on the birds' dung, a tick that feeds on these two birds, a cactus, a moth that feeds on cast-off feathers, a beetle that lives on dung organisms, and spiders that eat the other arthropods. There are no other plants and no lichens. Which of the following choices incorrectly pairs a member of this assemblage with its position in the trophic structure?
A)fungi-detritivores
B)booby-primary consumer
C)moth-detritivore
D)cactus-producer

Accepted Answer

The booby is a secondary consumer, as it feeds on fish, which are the primary consumers in this ecosystem.

Question 13

An owl and a hawk both eat mice. Which of the following describes the relationship between a hawk and an owl?
A)predation
B)competition
C)mutualism
D)parasitism

Accepted Answer

The relationship between a hawk and an owl is competitive because they both rely on the same food source, which is mice.

Question 14

Camouflage typically evolves as a result of
A)predation.
B)interspecific competition.
C)mutualism.
D)herbivory.

Accepted Answer

Camouflage typically evolves as a result of predation because organisms that blend in with their surroundings are less likely to be detected by predators, giving them a better chance of survival and passing on their genes to the next generation. Camouflage can also make it easier for predators to sneak up on their prey. Interspecific competition, mutualism, and herbivory may also play a role in shaping an organism's appearance, but camouflage is most closely associated with predator-prey interactions.

Question 15

Which of the following is an example of predation?
A)a lizard's camouflage
B)a hawk swooping down quickly to capture, kill, and eat a prairie king snake
C)a goldfinch feeding on the seeds of a thistle plant
D)the vivid colors of the poison-arrow frog in Costa Rica

Accepted Answer

Predation involves one organism (the predator) capturing, killing, and consuming another organism (the prey). In this scenario, the hawk is the predator and the prairie king snake is the prey.

Question 16

A community is composed of
A)potentially interacting populations of different kinds of organisms.
B)one species of organism living in a specific environment on Earth.
C)living organisms and their nonliving environment.
D)the factors that constitute an organism's niche.

Accepted Answer

A community is defined as a group of potentially interacting populations of different species living in the same geographical area and having a common set of interacting species. B is incorrect because a community is made up of multiple species, not just one. C describes an ecosystem, which includes both living and nonliving components. D describes an organism's niche, not a community.

Question 17

In a hypothetical food chain consisting of grass, grasshoppers, sparrows, and hawks, the grasshoppers are
A)primary consumers.
B)primary producers.
C)secondary consumers.
D)secondary producers.

Accepted Answer

Grasshoppers feed on grass, which makes them primary consumers.

Question 18

Some herbivore-plant interactions evolved through a series of reciprocal evolutionary adaptations in both species. This process is called
A)herbivory.
B)coevolution.
C)selection.
D)trophism.

Accepted Answer

Coevolution refers to the process of reciprocal evolutionary adaptations between two species. In the case of herbivores and plants, both have evolved adaptations in response to each other's interactions, such as the evolution of chemical defenses in plants and specialized digestive systems in herbivores.

Question 19

When a crocodile eats a fish, the interspecific interaction between the two could be expressed as ________ for the crocodile and ________ for the fish.
A)-; -
B)+; +
C)+; -
D)-; +

Accepted Answer

The crocodile benefits from the interaction (+) as it gains food, while the fish is harmed (-) as it has become a meal for the crocodile. Therefore, the interaction can be expressed as + for the crocodile and - for the fish.

Question 20

When two different populations in a community benefit from their relationship with each other, the result is called
A)herbivory.
B)mutualism.
C)parasitism.
D)competition.

Accepted Answer

Mutualism is a symbiotic relationship where two different populations benefit from their interaction with each other. This can include mutualistic relationships between plants and pollinators, as well as between different species of animals. Herbivory is a type of interspecific interaction, but it refers specifically to animals consuming plants. Parasitism is a relationship where one organism benefits at the expense of another, and competition refers to interactions where both organisms are negatively affected in their attempt to utilize a shared resource.

Quiz 37: Communities and Ecosystems

Dinoflagellates are important to coral and coral-dwelling animals because they

If an overlap develops between the ranges of two closely related species, and if the species occupy the same niche in the zone of overlap, what will probably happen in the zone of overlap?

One predator avoidance mechanism that has evolved in prey is

In an ecosystem, you would expect to find interspecific competition between

The prokaryotes that cause tooth decay have a ________ relationship with humans.

In addition to abiotic factors, community composition of plants can be severely compromised by

The sum total of a population's use of the biotic and abiotic resources of its habitat constitutes its

Within an ecosystem, a tree is a

Most plants have a variety of chemicals, spines, and thorns because the plants

The freshwater leech is an organism that feeds off of the blood of other organisms such as frogs and turtles. Which of the following describes the relationship between freshwater leeches and frogs or turtles?

One reason it is important to understand community ecology is

An owl and a hawk both eat mice. Which of the following describes the relationship between a hawk and an owl?

Camouflage typically evolves as a result of

Which of the following is an example of predation?

A community is composed of

In a hypothetical food chain consisting of grass, grasshoppers, sparrows, and hawks, the grasshoppers are

Some herbivore-plant interactions evolved through a series of reciprocal evolutionary adaptations in both species. This process is called

When a crocodile eats a fish, the interspecific interaction between the two could be expressed as for the crocodile and for the fish.

When two different populations in a community benefit from their relationship with each other, the result is called