| A | B |
| adaptation | any inherited characteristic that increases an organisms lifetime |
| On the Origin of the Species | book Darwin wrote |
| acquired traits | characteristics obtained during an organism's lifetime |
| fossils | any evidence of past life |
| descent with modification | each living species has descended with modification from ancestor |
| vestigal structure | structure reduced in function, no useful purpose |
| gene pool | entire collection of genes among population |
| behavioral isolation | difference in mating or courting rituals |
| temporal isolation | occupy same area but reproduce at different times |
| analogous structure | body parts are same in function, different in structure |