EVOLUTION REVIEW Evidence for Evolution What do we

EVOLUTION REVIEW

Evidence for Evolution • What do we use in order to determine evolutionary relationships? • Fossil Record • Anatomical Evidence • Molecular Evidence • Embryological Evidence

Evidence for Evolution • Fossil Record

Evidence for Evolution • Anatomical Evidence • Homologous Structures – Same anatomy, different function • Conclude close evolutionary relationships

Evidence for Evolution • Anatomical Evidence • Analogous Structures – Different anatomy, same function • Not closely related, do NOT share a recent common ancestor

Evidence for Evolution • Anatomical Evidence • Vestigial Structures – No longer serve a purpose • All us to draw conclusions regarding the past

Evidence for Evolution • Molecular Evidence • The more similar the molecules (DNA, protein, etc), the closer the relationship.

Evidence for Evolution • Embryological Evidence • The more similar the embryo in early development, the closer the relationship.

Let’s Review! • Directional Selection • Selection towards a single direction • Disruptive Selection • Selection against the mean (middle) • Selection towards extremes • Stabilizing Selection • Selection towards the mean (middle) • Selection against extreme

Do you get it?

Evolution Scenarios A. Directional Selection B. Disruptive Selection C. Stabilizing Selection

Evolution Scenarios

Evolution Scenarios A. Directional Selection B. Disruptive Selection C. Stabilizing Selection

Evolution Scenarios

Evolution Scenarios A. Directional Selection B. Disruptive Selection C. Stabilizing Selection

Evolution Scenarios

That brings us to speciation… • Speciation: the creation of a new species as a result of evolution. • How do you know when you have a new species? • They can no longer reproduce! • Rate of Speciation Theories • Gradualism • Evolution occurs slowly and gradually, with very small changes accumulating over a long period of time until a new species develops. • Punctuated Equilibrium • Evolution occurs in short, rapid bursts of change followed by long period of no change.

Do you get it? A. Gradualism B. Punctuated Equilibrium

Do you get it? A. Gradualism B. Punctuated Equilibrium

Let’s Switch Gears…Patterns of Evolution • Divergent Evolution • Related species becoming more and more different due to living in different types of environments • Convergent Evolution • Unrelated species becoming similar due to living in similar types of environments • Coevolution • The simultaneous evolution of two species due to their close interaction/relationship

Patterns of Evolution Scenarios A. Convergent Evolution B. Divergent Evolution C. Coevolution • In tropical regions bats visiting flowers to eat nectar. The fur on the bat's face and neck picks up pollen, which the bat transfers to the next flower it visits. Bats that feed at flowers have a slender muzzle and a long tongue with a brushed tip. These adaptations aid the bat in feeding. Flowers that have coevolved with bats are light in color. Therefore, bats, which are active at night, can easily locate them. The flowers also have a fruity odor attractive to bats.

Patterns of Evolution Scenarios A. Convergent Evolution B. Divergent Evolution • Adaptive Radiation of marsupials in Australia C. Coevolution

Patterns of Evolution Scenarios A. Convergent Evolution B. Divergent Evolution • This picture shows four different animals from around the globe. They may look similar, but it’s not because they are close relatives. Instead, they’ve evolved similar adaptions because they occupy similar niches – dining on ants, hunting in the high grass or swimming in the dark – although their evolutionary origins are quite different. C. Coevolution