Question

which statement best describes ecological succession?

it is always caused by human intervention.

it occurs after a disturbance.

it never occurs in a predictable pattern.

it is a series of rapid changes in an ecosystem.

Explanation:

• For the first option: Ecological succession isn't always caused by human intervention; natural events like wildfires or volcanic eruptions can also trigger it.
• For the second option: Ecological succession (both primary and secondary) occurs after a disturbance (natural or human - made). Secondary succession follows a disturbance like a forest fire, and primary succession follows a disturbance like a volcanic eruption that creates new land.
• For the third option: Ecological succession does follow a somewhat predictable pattern as species colonize, change the environment, and are then replaced by other species in a sequential manner (e.g., pioneer species to climax community in some cases).
• For the fourth option: Ecological succession is a series of gradual changes, not rapid changes, in an ecosystem over time as species composition and community structure evolve.

Answer:

The statement "It occurs after a disturbance" best describes ecological succession. (Assuming the options are labeled as follows: First option: It is always caused by human intervention; Second option: It occurs after a disturbance; Third option: It never occurs in a predictable pattern; Fourth option: It is a series of rapid changes in an ecosystem. So the answer is the second option, e.g., if the second option is B, then B. It occurs after a disturbance)