Activity 8: Using Fossils to Investigate Whale Evolution

phylogen

diagram showing evolutionary relationships of organisms with a common ancestor; resembles a tree

phylogeny

The evolutionary history of a species or group of related species

transitional fossil

Fossil that bears a resemblance to two groups that in the present day are classified separately.

gradualism

Gradualism is the idea that organisms change gradually and steadily over time, punctuated equilibrium is equilibrium that is interrupted by brief periods of more rapid change

natural selection

A process in which individuals that have certain inherited traits tend to survive and reproduce at higher rates than other individuals because of those traits.

vestigial structures

A structure that is present in an organism but no longer serves its original purpose