Which statement best describes a keystone species?

Which phrase describes the process of succession?

One community gradually replacing another community

Which statement best describes how this ecosystem changes during primary succession?

Perennial plants decrease as shrubs and grasses increase.

Why does it matter if biodiversity is lost in an ecosystem?

Potential sources of medicines are lost when biodiversity declines

An invasive species has the same niche as the squirrel in the community shown here. What would be a likely result of the invasive species joining this community?

A decline in the size of the native squirrel population.

Which characteristic is most likely to be shared by plants in a tundra ecosystem and those in a desert ecosystem?

A shallow root system.

Which phrase describes a climax community?

A stable community formed by succession.

Which of these leads to competition between two species?

An overlap in the two species' niches

Which situation results from increased biodiversity in an ecosystem?

Increased stability

As biodiversity increases in an ecosystem, what else increases?

Stability

Which of the following changes occurs in an ecosystem when its biodiversity increases?

Stability increases.

A biologist began studying a population of bullfrogs. In 1998, she found that most of the male frogs croaked, but some did not. A bat species known to prey on male frogs migrated to the area in 2005. The biologist returned to the area in 2008 and repeated population counts of male frogs. Based on the data, which statement is a plausible explanation for the change in the frog population between 2004 and 2008?

The bat's response to the croaking behavior of male frogs led to selective pressure against the croaking trait in frogs.

Which events are likely to be catastrophic to an ecosystem? Select the three correct answers.

Tornado, Volcanic eruption, Introduction of a species that reproduces quickly

Which events are likely to be catastrophic to an ecosystem? Select the three correct answers.

Tsunami, Hurricane, introduction of an aggressive invasive species

Species A and species B have the same niche. Species A is a superior competitor. What is most likely to happen to species B?

it will die out.