Question

1. scientists researching pacific sea otters find that many members of the population are infected by a parasite, and a number of the sea otters must be destroyed to save the entire sea otter population. one of the main foods of sea otters is sea urchin, which eat kelp. the kelp forest is home to many species of fish. how is destroying some of the sea otters most likely to affect fish living in the kelp forest?

a. destroying the sea otters will cause the fish population to increase.
b. destroying the sea otters will cause the fish population to become extinct immediately.
c. destroying the sea otters will allow the fish population to remain constant.
d. destroying the sea otters will cause the fish population to decrease.

1. what is the greatest threat to biodiversity today?

a. rainforests
b. reduction of hunting or fishing
c. habitat destruction
d. conservation efforts

1. when farmers clear a forest and plant crops, how will the biodiversity of the land be affected?

a. the biodiversity will decrease with higher populations of fewer species.
b. the biodiversity will increase with lower populations of more species.
c. the biodiversity will decrease with lower populations of more species.
d. the biodiversity will increase with higher populations of fewer species.

1. which factors best help determine an increase in population size?

a. birth rates and death rates
b. emigration rates and death rates
c. birth rates and immigration rates
d. emigration rates and immigration rates

Explanation:

Question 54

The sea urchins eat kelp, and the kelp forest is home to many fish species. If sea urchins are destroyed, the kelp will not be eaten as much, so the kelp forest can thrive. This provides a better habitat for the fish, so the fish population should increase. Option a says destroying sea urchins will cause fish population to increase, which matches this reasoning. Option b says fish become extinct immediately, which is too extreme. Option c says constant, but the habitat is improving so population should increase. Option d says fish population decreases, which is opposite.

Habitat destruction (like deforestation, urbanization) is a major threat to biodiversity as it removes the homes of many species, leading to species loss. Rainforests are a type of habitat, not the threat itself. Reduction of hunting/fishing is positive for biodiversity. Conservation efforts help protect biodiversity, not threaten it. So habitat destruction (option c) is the greatest threat.

When farmers clear a forest and plant crops, they are replacing a diverse ecosystem (forest with many species) with a monoculture (crops, few species). This reduces the number of species, so biodiversity (variety of life) decreases. So with higher populations of fewer species (since crops are one or few species, their population may be high but species count is low), biodiversity decreases. Option a says biodiversity decreases with higher populations of fewer species, which matches. Option b: more species would mean higher biodiversity, but clearing forest reduces species. Option c: lower populations of more species is not the case here (crops are few species, high population). Option d: higher populations of fewer species should lead to decreased biodiversity, not increased.

Answer:

a. Destroying the sea otters will cause the fish population to increase.

Question 55