Biodiversity

Which of the following statements about migration is true?

d. Animals migrate for various reasons.

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

d. increased biodiversity

macroevolution

evolution of an entire family of organisms in relation to all other organisms

biodiversity

the diverse range of organisms, genes, and ecosystems found in the biosphere

How does a decrease in biodiversity impact an ecosystem?

A decrease in biodiversity causes a decrease in ecosystem stability, because a change to one organism will have a greater impact on the entire ecosystem. With greater biodiversity, the loss of one type of organism could be moderated by the adaptation of other organisms to fill its role. This is less likely in an ecosystem with less biodiversity.

When might an increase in biodiversity lead to a decrease in the stability of an ecosystem?

An increase in biodiversity usually leads to an increased stability, but in the case of an invasive species it would lead to a decreased stability.

Explain how microevolution and migration can affect an ecosystem.

Migration can negatively impact an ecosystem if the migration is permanent and leads to the loss of native species. Temporary migration, such as in the case of birds flying south in the winter, can maintain the biodiversity of an ecosystem. Microevolution, like migration, can aid the survival of native species.

What happens when an organism is removed from a food chain?

Removing an organism from a food chain causes the populations of the other organisms in the food chain to change as well. They will increase or decrease depending on the location of the organism in the food chain.

What are the possible consequences of adding an organism to a food chain?

The organism that is added will compete for food resources with an existing organism. This could possibly lead to competitive exclusion.

What happens to the other organisms in a food chain when an organism in the middle of the food chain is lost?

The organisms below it will increase in number, while the organisms above it will decrease in number.

How can an increase in biodiversity lead to an increase in ecosystem stability?

b. A more biodiverse ecosystem has a higher chance of adapting to species changes.

Variation of ecological habitats within a species is characteristic of which type of diversity?

b. Ecosystem diversity

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

b. a decrease of the biodiversity of an ecosystem

The variety of organisms within an ecosystem is characteristic of which type of diversity?

c. Species diversity

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?

c. The new organism will compete with the snake population for resources.

An increase in biodiversity generally causes _______.

c. an increase in ecosystem stability

Consider the following food chain: Plants are eaten by grasshoppers, which are eaten by mice, which are eaten by snakes.What will happen to snakes in the long term if mice become extinct?

d. Snakes will die out if they do not find an alternative food source.

Consider the following food chain: Plants are eaten by grasshoppers, which are eaten by mice, which are eaten by snakes.What would happen to the other members of the food chain if the plant population was wiped out?

d. The populations of grasshoppers, mice, and snakes would decrease.

The water hyacinth is an invasive species that can spread extremely fast, blanketing a water surface in a very short period of time. It can limit boat traffic, swimming, and fishing, and it can deprive native plants and animals of sunlight and oxygen, thus reducing the local biodiversity. This situation demonstrates _______.

d. how changes in biodiversity impact an ecosystem

microevolution

evolution that occurs within a single population of organisms

Adding an organism to a food chain does not affect the other members of the food chain, but removing an organism does.

false

Macroevolution occurs within a population.

false

Migration is always temporary.

false

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

true

Ecosystems with greater biodiversity have an increased stability.

true

The loss of an organism at the bottom of a food chain negatively impacts all organisms in the chain.

true

genetic diversity

variation of genes within a species

ecosystem diversity

variety of ecological habitats in an ecosystem

regional diversity

variety of landscapes within an ecosystem

species diversity

variety of organisms within an ecosystem