In ecological terms, a population fully adapted to its environment is known as?

A population fully adapted to its environment is best described as a climax community. This term refers to a stable and mature ecological community that has reached a state of equilibrium, where species composition and community structure remain relatively unchanged over time. In this state, the species present are well-suited to the environmental conditions and have interactions that support the sustainability of the community.

A climax community results from ecological succession, where a series of plant and animal communities replace each other over time until a stable community is formed. This concept also emphasizes that the organisms in a climax community have adapted to local conditions, thus maximizing their survival and reproductive success.

The other terms provided have distinct meanings that do not align with the idea of a fully adapted population. Punctuated equilibrium relates to the theory of evolutionary change, suggesting that species remain stable for long periods and undergo rapid changes due to environmental pressures at specific intervals. Evolutionary fitness refers to an organism's genetic contribution to the next generation, emphasizing reproductive success rather than community stability. Adaptive radiation describes a process where a single ancestor species rapidly diversifies into a variety of forms to adapt to different environments, which contrasts with the established stability of a climax community.