For example, a trait can evolve because it served one particular function, but subsequently it may come to serve another.

Dinosaurs are long dead, making it harder to test ideas about why certain traits evolved, and what they were adapted for.

Instead, he believed that these traits evolved to aid in the ability of an animal to acquire a mate.

This trait has evolved at least 3 times within this genus.

This situation, where different traits of an animal evolve at different rates, is known as mosaic evolution.

I wonder where that trait "evolved" from?

Both traits may have evolved due to extreme food scarcity in the ocean depths.

This is well established as how traits evolve.

The traits of the literary vampire have evolved from the often repulsive figures of folklore.

The samples could show how traits have evolved over 250 years.