adoptations

An adoptation is a biological term referring to a trait or characteristic that has evolved in an organism and is later exapted for a new function. This is distinct from a true adaptation, where a trait evolves specifically for its current purpose. In essence, an adoptation is a repurposing of a pre-existing feature.

The concept of adoptation was introduced by paleontologists Elisabeth Vrba and Stephen Jay Gould as a way to explain the evolution of complex structures and behaviors that may not have arisen with their current function in mind. For example, feathers in birds are now crucial for flight, but it is hypothesized that they may have initially evolved for insulation or display purposes before being co-opted for aerial locomotion.

The distinction between adaptation and adoptation lies in the evolutionary history and intended purpose of the trait. While an adaptation's origin is directly tied to its present function, an adoptation arises from a trait that served a different purpose in an ancestral lineage. This process highlights the opportunistic nature of evolution, where existing structures can be modified and utilized in novel ways over time, leading to the diversification of life. Understanding adoptations helps explain how seemingly complex features can arise without a direct, step-by-step evolutionary path towards their current function.