EVOLUTION

1. EVOLUTION

2. VERY SIMPLY PUT--Evolution is change in a species over time.

3. How long did it take to CHANGE? 66 million years ago 54 million years ago 37 million years ago 26 million years ago Present Day

4. There are two models for HOW this change occurs. Gradualism Punctuated Equilibrium periods of rapid change in species are separated by periods of little or no change. • gradual change over a long period of time

5. We have learned about the origins of evolutionary thought. 1787- The U.S Constitution is signed 1798- Thomas Malthus 1831- Charles Darwin 1858- Alfred Wallace 1773- Boston Tea Party Share out some of the contributions of the scientists that led to today’s model of evolution. 1785- James Hutton 1809- Jean-Baptiste Lamarck 1833- Charles Lyell 1850- California Gold Rush 1859- Darwin publishes The Origin of the Species 1861- U.S. Civil War Begins

6. Who was Charles Darwin?

7. How did Darwin come up with the theory of natural selection? • He collected evidence in the Galapagos Islands that pointed towards his theory of natural selection. Geological Formation of the Islands Darwin’s Finches Adapted to their Food Source The Galapagos Tortoise

8. What is natural selection? easier to survive more likely to reproduce Better traits In a nut shell… Over time better traits dominate a population

9. What type of mouse is more likely to survive to produce offspring?

10. Biological Fitness • Fitness—an organisms ability to reproduce and pass their genes on to their next generation Survival of the Fittest Those who are more “Fit” will be more likely to survive. More Likely To Survive and Reproduce More Attractive Smarter Stronger

11. Which species is most fit for this exam? Why?

12. Natural Selection What did Darwin call the process? Quick Question Organisms well suited to their environment a. reproduce at a greater rate than those less suited to the same environment. b. are always larger than organisms less suited to that environment. c. always live longer than organisms less suited to that environment. d. need less food than organisms less suited to that environment.

13. Natural Selection operates on 4 factors: • Genetic variation: all the genes that make up the population. • Overproduction of offspring: more is better. • Struggle for existence: compete for food, territory, and mate (survival of the fittest) • Survival and reproduction: individuals that are better able to cope or have advantages over another will leave more offspring

14. Successful reproduction of the fittest members of a population eventually leads to an adaptation within that population. Adaptation A trait produced by natural selection that has become common in a population because it provides a selective advantage.

15. Organisms adapt to their environments in many ways…

16. Storage Adaptations Conserves water – not stored in hump Stored fat provides insulation

17. Reproductive Adaptations

18. Protection

19. Camouflage Fish Wasp moth Owl moth

20. Adaptations to food Specialized beaks Specialized teeth Parasite orchids Parasitic Carnivorous plants

21. Plant adaptations Water dispersal Wind dispersal Animal dispersal

22. So how do adaptations occur?

23. Other Mechanisms of Evolution that lead to adaptions. • Mutations • Gene flow (migration) • Genetic drift

24. Mutations • A mutation is any change to the genetic material of a cell. • They may produce a different phenotype that may be an advantage for a species. A mutation could cause parents with genes for bright green coloration to have offspring with a gene for brown coloration. That would make the genes for brown beetles more frequent in the population.

25. Gene Flow (Migration) • Some individuals from a population of brown beetles might have joined a population of green beetles. That would make the genes for brown beetles more frequent in the green beetle population.

26. Gene Flow (Migration) • The amount of gene flow within a population varies. • Very mobile organisms have a higher rate of gene flow than organisms that are immobile. Which would have a higher rate of gene flow? This is corn.

27. Effects of Gene Flow on Evolution • Within a population • Across populations • Can introduce genes into a population increasing genetic variation • Can make distant populations genetically similar to one another. • When the brown beetle joins the green beetle population, the brown beetle genes enter the populations gene pool.

28. Genetic Drift A random change in allele frequencies that occur in small populations. Usually brought on by natural disasters or catastrophic events such as ? Several green beetles were killed when someone stepped on them and had no offspring. The next generation would have a few more brown beetles than the previous generation—but just by chance.

29. Genetic Drift Can decrease genetic variation, especially in small populations! • Bottleneck effect • Population’s size is reduced for at least one generation • Reduced variation may affect the ability to adapt to natural selection pressures- climate change, shift in resources. • Founder’s effect • A new colony is started by a few members of the original populations. • Colony will have reduced genetic variation.

30. SPECIATIONHow do these changes lead to the formation of new species? • Eventually the gene pools of the populations become too different. • The populations can no longer interbreed. • This is called REPRODUCTIVE ISOLATION.

31. Why does evolution matter now? If it happens as a long slow process, how does it affect me?

32. Tampering with Evolution • Artificial Selection–Humans breed organisms for specific traits • Interbreeding animals that would not normally interbreed in nature to create new species

33. Artificial Selection is an example of evolution where humans choose which plants/animals reproduce to make cuter pets or better crops. We like to call it “breeding”. Cockapoo Wild tomatoes Tomato crop