Patterns of Evolution

Extinction More than 99% of all species that have ever lived are now extinct Reasons for extinction Competition for resources Environmental change Some species adapt and survive (others do not)

Divergent Evolution (Adaptive Radiation) Many diverse species evolved from a similar, common ancestor Ex: Galapagos finches Occurs due to natural selection, etc.

Adaptive Radiation

Convergent Evolution Unrelated organisms come to resemble one another Ex: shark and dolphin

Coevolution Two or more species evolve in response to changes in each other over time Often occurs with organisms that are closely connected with one another Symbiotic relationships! Ex: Many flowering plants can reproduce only if the shape, color and odor of their flowers to attract specific pollinators Bees are attracted to certain types of plants and butterflies are attracted to certain types of plants (some may be the same, others may be different)

Punctuated Equilibrium Long stable periods are interrupted by brief periods of more rapid change