Question

1. removal of a ____________ from a community affects community structure significantly.

• 1 point

a) niche
b) predator
c) keystone species
d) competitor

1. since wolves were not present in yellowstone for many years, the deer population ______ which caused the amount of vegetation to ______

• 1 point

a) increased, decrease
b) increased, increase
c) decreased, decrease
d) decreased, increase

1. true or false: a change in a biotic factor in the ecosystem can result in the change of an abiotic factor in the ecosystem.

• 1 point

a) true
b) false

Explanation:

Question 2

A keystone species has a disproportionately large impact on its community structure relative to its abundance. Removing a niche (A) is not about a species, a predator (B) may or may not be a keystone, and a competitor (D) removal has less significant community - wide impact compared to a keystone species. So the correct answer is the one related to keystone species.

Wolves are predators of deer. Without wolves, the deer population (their predator is removed) will increase. Deer eat vegetation, so with more deer, the amount of vegetation will decrease. So the first blank is "increased" and the second is "decrease".

Biotic and abiotic factors in an ecosystem are interrelated. For example, if a plant species (biotic) that helps in soil retention is removed, the soil (abiotic) structure and erosion rate (abiotic factor) can change. So a change in a biotic factor can lead to a change in an abiotic factor.

Answer:

C) keystone species

Question 3