Students are looking for examples that show how competition for limited resources affects populations of organisms.

Question

Which scenario shows evidence that competition for limited resources affects the population of a species?

Answer options with 4 options
A.
A population of grasshoppers destroys large fields of crops.

B.
The mouse population in an area increases as the fox population decreases.

C.
The deer population on an island rises steadily and then levels out for many years.

D.
The population of geese in an area decreases when they migrate south for the winter.

Answer 1

The correct answer is B. The mouse population in an area increases as the fox population decreases. This scenario suggests that the limited resources for the mouse population (e.g., food, shelter) are becoming less limited due to a decrease in competition from the fox population.

Answer 2

Which relationship is an example of commensalism?

Answer options with 4 options
A.
Deer and dogs are hosts to ticks that suck out small quantities of blood for nourishment.

B.
Plants produce brightly colored flowers with nectar, which attract insects to pollinate them.

C.
Acacia ants live on and protect the acacia tree, and they eat the nectar provided by the tree.

D.
Cattle egrets follow livestock and eat insects that are disturbed by the livestock's movement.

Answer 3

The correct answer is D. Cattle egrets follow livestock and eat insects that are disturbed by the livestock's movement. This is an example of commensalism because the cattle egrets benefit from the relationship by getting a source of food, while the livestock are unaffected (neither harmed nor benefited) by the presence of the egrets.