Succession

Termites are able to digest wood because of microbes that live in their gut. The relationship between a termite and the microbes inside it is an example of what type of symbiosis?

• parasitism

• mutualism

• commensalism

• a predator-prey relationship

Thomas is describing an example of secondary succession. Which of the following events is most useful for him to include?

• Lichens begin growing on rocks that formed from a volcanic eruption.

• Many fishes die in a pond when oxygen levels decrease.

• The populations of wolves and rabbits change in a cyclical pattern.

• Small plants and animals return to the land after a forest fire.

A community of lichens, mosses, and a few grasses cover a field of volcanic rocks. Why will the community change over many years?

• The community dies out, and then larger plants replace it.

• The small plants of the community grow into larger plants.

• The community breaks apart the rocks and allows larger plants to grow.

• Seasonal weather causes cyclic changes in the community.

From 1970 to 2016, scientists were regularly observing the Joshua County Nature Reserve. Their data show that a community of grasses and other small plants was gradually replaced by a pine forest. Which claim about the history of the nature reserve could be supported by the data and logical reasoning?

• Several years before 1970, a forest fire burned down a pine forest.

• For several years until 1970, a pine forest was gradually replaced by grasses and other small plants.

• The land was used for a commercial pine forest before 1970, but was then abandoned.

• The land had always supported grasses and other small plants until 1970.

Which of these events is most likely to be followed by primary succession in the area where the event occurs?

• A fire burns most of the trees of a forest

• Floodwaters cover and then drain away from a valley

• A volcanic eruption covers a mountain side with molten rock

• A farmer stops raising crops on a field

A tropical rain forest is an example of a climax community. It is a stable community that generally, but not always, returns after a disturbance. Which of these disturbances is most likely to result in a permanent change to the tropical rain forest, meaning that the rainforest community is not likely to return over time?

• A fire burns down all the trees within a 10-meter radius of a lightning strike.

• A hurricane blows down rainforest trees along a coastline.

• The rain forest trees are cleared, and the land is used for farming.

• A fungal infection kills several rainforest trees from various species.

Scientists have classified the sea otter as a keystone species in communities along the Pacific coast of North America. This classification depends on which property of the sea otters?

• Sea otters have the highest population in the community.

• Sea otters act to maintain a wide variety of other populations in the community.

• Sea otters are the largest, most massive members of the community.

• Sea otters provide food for all of the predators of the community.

Autotrophs can be classified into two groups according to which of these properties?

• energy source, either sunlight or chemicals

• food type, either plant matter or animal matter

• food quality, either living matter or dead matter

• water quality, either fresh water or salt water

What is one difference between primary and secondary succession?

• Primary succession is slow, and secondary succession is rapid.

• Secondary succession begins on soil, and primary succession begins on newly exposed surfaces.

• Primary succession modifies the environment, and secondary succession does not.

• Secondary succession begins with lichens, and primary succession begins with trees.

Which factor can influence continual change in an ecosystem?

• further disturbances

• introduction of nonnative species

• long-term climate changes

• all of the above