What term describes a series of predictable and orderly changes within an ecosystem over time?

The term that refers to a series of predictable and orderly changes within an ecosystem over time is "succession." Succession describes the process by which ecosystems change and develop over time, typically following a disturbance or the creation of a new habitat. There are two primary types of succession: primary succession, which occurs in lifeless areas where soil has not yet formed, and secondary succession, which takes place in areas where a disturbance has cleared out a community but the soil remains intact.

During succession, the structure of the ecosystem evolves as different species colonize and establish themselves in the area. Early pioneer species often modify the environment in ways that can be beneficial to later species, leading to a more complex and diverse ecosystem over time. This process is predictable, meaning that ecologists can observe certain patterns in the species that colonize an area and how they change it.

The other terms listed in the question refer to different biological concepts. Evolution is the process of change in the genetic composition of populations over generations, adaptation refers to the changes organisms undergo to better survive in their environment, and migration is the movement of organisms from one place to another. These concepts are related to biology but do not describe the specific process of ecological change over time like succession does.