Question 1

Which of the following best describes the difference between a habitat and a niche?

Accepted Answer

A habitat is the physical place where an organism lives, while a niche is the organism's role and all its interactions with biotic and abiotic factors in that environment.

Question 2

Which type of symbiotic relationship is illustrated by the interaction between the fungus and the alga in a lichen (as seen in the images)?

Accepted Answer

Mutualism

Question 3

A tapeworm living inside the intestine of a mammal is an example of which type of symbiotic interaction?

Accepted Answer

Endoparasitism

Question 4

Which of the following best explains why there are usually few apex predators in a food web?

Accepted Answer

Only about 10% of energy is transferred from one trophic level to the next, limiting the energy available to support apex predators.

Question 5

Which formula is used to calculate the relative abundance ($$P_i) of a $$species in a community?

Accepted Answer

$$P_i = \frac{n_i}{N}$$

Question 6

In a salt marsh, the presence of Juncus (a grass species) increases the number of plant species present. What type of interaction is this?

Accepted Answer

Facilitation

Question 7

Which of the following is an example of commensalism?

Accepted Answer

A remora fish attaching to a shark and feeding on leftover scraps, while the shark is unaffected.

Question 8

Which of the following best describes a keystone species?

Accepted Answer

A species that has a disproportionately large effect on its community relative to its abundance.

Question 9

Which hypothesis explains the limitation of food chain length due to energy loss at each trophic level?

Accepted Answer

Energetic hypothesis

Question 10

A bird builds its nest in a tree without affecting the tree. What type of symbiotic relationship is this?

Accepted Answer

Commensalism

Question 11

Which of the following is a likely effect of an intermediate level of disturbance in an ecosystem, according to the intermediate disturbance hypothesis?

Accepted Answer

It increases species diversity compared to low or high disturbance levels.

Question 12

Which of the following equations correctly represents Simpson’s diversity index ($$D$$)?

Accepted Answer

$$D = 1 - \sum P_i^2$

Question 13

Which of the following best describes the bottom-up model of community control?

Accepted Answer

The abundance of primary producers determines the structure and abundance of higher trophic levels.

Question 14

Which of the following is an example of a fundamental (ecosystem engineer) species?

Accepted Answer

A rabbit that changes the structure of dune vegetation, affecting many other species.

Question 15

Which of the following scenarios best illustrates competitive exclusion?

Accepted Answer

Two species of barnacles compete for the same space on a rock, and one species is eliminated from that area.

Question 16

Which of the following is NOT a characteristic of a dominant species?

Accepted Answer

It always has the largest effect on community structure due to its ecological role, not abundance.

Question 17

Which of the following is an example of top-down control in an ecosystem?

Accepted Answer

The removal of wolves leads to an increase in deer populations, which then reduces plant abundance.

Question 18

Which of the following best describes the effect of a severe disturbance, such as a wildfire, on community diversity?

Accepted Answer

It can reduce diversity by eliminating many species, but may also create opportunities for new species to colonize.

Question 19

Which of the following is a correct statement about food webs?

Accepted Answer

They show complex feeding relationships and energy flow between multiple species in a community.

Question 20

Which of the following is the best example of mutualism?

Accepted Answer

A hermit crab and a sea anemone, where the crab gets protection and the anemone gets food scraps.

Ecology: Community Structure, Species Interactions, and Diversity

Guida di studio - Domande di pratica

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