What factors can lead to evolution?

1. What factors can lead to evolution? • Several factors can lead to evolution: genetic drift, gene flow, mutation, sexual selection, and natural selection. • Gene flow is the exchange of genes between populations. • The more gene flow that exists between populations, the more similar the populations will be. • The less gene flow, the more likely the two populations will be different. • If there is nogene flow between two population then a new species can arise.

2. What are Isolated Populations? • When gene flow stops, the populations are said to be isolated. • Isolated Populationsresult in populations becoming more and more genetically different. • Members of the two populations will begin to look and behave differently from one another. • When members of different populations can no longer mate successfully, reproductive isolation occurs.

3. Reproductive isolation is the final step of becoming separate species (speciation.) Speciation is the evolution of 2 or more species from one ancestral species. Reproductive Isolation

4. Have a Convo  1) Gene flow…How does this flow work? 2) What happens when gene flow stops? 1) What happens when populations become isolated? 2) “O My” what about reproductive isolation?

5. What causes Reproductive Isolation? • Behavioral, Geographic, and Temporal behaviors

6. Evolution Notes Round Up • Use your Biology book (p. 344) and answer the following questions. You DO NOT have to write the questions BUT answer questions in a COMPLETE SENTENCE. • How can reproductive isolation lead to speciation? • What are three types of barriers that can lead to reproductive isolation? • How can lack of gene flow between two populations lead to speciation? • Turn In 

7. Patterns of Evolution • Natural Selection • Convergent Evolution • Divergent Evolution • CoEvolution • Extinction

8. Natural Selection: individuals with traits that are better adapted for their environment have a better chance of surviving and reproducing. Natural Selection

9. Peppered Moth Journal ArticlePeppered Moth Lab Simulation

10. Convergent Evolution • Convergent Evolution:evolution towards similar characteristics in unrelated species Dolphins, which are mammals, and sharks, which are fish, have evolved similar tail fins to adapt to similar environmental conditions.

11. Divergent Evolution • Divergent Evolution: closely related species evolve in different directions • For Example; the Kit fox and Red fox

12. Coevolution • Coevolution: two or more species evolve in response to changes in each other • For example: Humming birds pollinating flowers • Flowers pollinated by insects and other animal evolve in a trumpet style. In response to this, birds evolved longer, slender beaks.

13. Extinction • Extinction:the elimination of a species from Earth • How does extinction occur? species can not adapt to their environment • Two types of extinction are background extinction and mass extinction.

14. Background Extinction Mass Extinction Very intense and very rare Occurs on a global level Result of a catastrophic event such as an iceage or asteroid impact • Occurs continuously but at a very slow rate • Affects one or a few species at a time

15. Theory of Punctuated Equilibrium • Paleontologists have noticed repeating patterns of evolutionary activity followed by long periods of stability. • Punctuated Equilibrium states that episodes of speciation occur suddenly in time and are followed by long periods of little evolutionary change.

16. Patterns of Evolution Natural Selection Define How can you remember? Natural Selection Definition How can you remember the definition Illustration Illustration

17. Patterns of Evolution Research, Draw, and Tell Activity Research: Define and explain to class. Use construction paper to write definition NEATLY in MARKER. Illustrate: Draw and show/explain to class. Drawing must be on construction paper as well. Drawing must be in color and labeled.