Evolution does not necessarily mean long-term progress is going to go in a certain direction.

Evolutionary changes often appear to be like the growth of a bush.

-Some branches survive from the beginning with little or no change, many die out altogether, and others branch out repeatedly, sometimes giving rise to more complex organisms.

Direction of Evolution:

-Note the divergence of the various groups from a common ancestor and the fact that some branches became extinct.

-Extinction of a species occurs when the environment changes and the adaptive characteristics of a species are insufficient to allow its survival.

-The fossil record indicates that many organisms that lived long ago are extinct.

-Extinction of a species is common; most of the species that have lived on earth no longer exist.