Biodiversity

Which of the following statements about migration is true?

a.
Migration is always from one region to another.
b.
Animals always migrate within a region.
c.
Migration always negatively impacts an ecosystem.
d.
Animals migrate for various reasons.

D

An increase in the biodiversity of an ecosystem leads to an increase in its productivity.

True

A variety of different mechanisms in nature help create diversity in organism populations. The tundra found in the northernmost parts of the planet is the world’s youngest biome. The tundra is home to a variety of plants and animals. Organisms that can be found in the tundra include shrubs, mosses, caribou, polar bears, and wolves. Which mechanism do the different organism populations found across the tundra exemplify?

species diversity

An increase in biodiversity generally causes _______.

a.
a decrease in ecosystem stability
b.
random fluctuations in ecosystem stability
c.
an increase in ecosystem stability
d.
no change to ecosystem stability

C

What happened to the greenish warbler birds as they migrated from the southern portion of their range up around the Tibetan Plateau?

a.
They evolved separately as they moved north and became two separate species.
b.
The original species died off, but the ones that were able to adapt to a northern climate evolved into a new species.
c.
As a whole the species was able to adapt to a colder climate, but no significant changes occurred.
d.
They were unable to adapt and evolve to ensure their survival and became extinct.

A

Consider the following food chain:

Plants are eaten by grasshoppers, which are eaten by mice, which are eaten by snakes.

What is likely to happen if a new organism that feeds off mice is introduced?
a.
The mice population will increase in response to the arrival of the new organism.
b.
The mice population, grasshopper population, and plant population will all increase.
c.
The new organism will compete with the snake population for resources.
d.
The populations of the existing organisms will remain unaffected.

C

Which of the following is not a possible reason for migration?

a.
climate changes
b.
diminished food supply
c.
reproduction patterns
d.
increased biodiversity

D

A mutation that causes resistance in a population of beetles is an example of _______.

a.
macroevolution
b.
microevolution
c.
migration
d.
reproduction

B

What is a possible cause for a decrease in ecosystem productivity?

a.
an increase in the biodiversity of the ecosystem
b.
a decrease of the biodiversity of an ecosystem
c.
the biodiversity of an ecosystem experiencing no change
d.
an ecosystem becoming more stable

B

Organisms can have positive or negative impacts on the ecosystem they live in. The cane toad, or Rhinella marina, was introduced to the Hawaiian Islands in 1932 by sugar cane farmers. Farmers released the toads in their crops to help control pests that were damaging the sugar cane. The cane toad has few natural predators, as it secretes a poisonous toxin from its skin that deters larger organisms from eating it. As a result, the cane toad population thrived and grew to number hundreds of thousands by 1935.
Which role does the cane toad play in the Hawaiian Islands?

invasive species