Which type of evolution occurs when unrelated species develop similar traits?

The type of evolution that occurs when unrelated species develop similar traits is known as convergent evolution. This process typically happens when different species adapt to similar environments or ecological niches, leading to the development of analogous structures—traits that serve similar functions but evolved independently. A classic example of this is the wings of bats and the wings of birds; despite their different evolutionary backgrounds, they both serve the function of flight and exhibit structural similarities.

In contrast, adaptive evolution refers to the process by which species become better suited to their environments through natural selection, while co-evolution involves two or more species influencing each other's evolution, often through interactions like predation or symbiosis. Divergent evolution is the process where related species become more different over time, often due to different environmental pressures.