2. Evolution Definition: Process of change through time

3. Theory of Evolution  Provides an explanation for the differences in structure, function, and behavior among life forms  Evolution is based on COMMON ANCESTORY!

4. One Common Ancestor - Protozoa

6. Evidence of Evolution  Fossils:  Remains of organisms preserved in sedimentary rock, amber, ice, or tar

7. Upper Strata – more complex organisms/youngest Lower Strata – less complex/oldest

10. Comparative Cytology  The cell is the unifying structure for all living things  Organelles similar in most organisms

11. Comparative Biochemistry  Nucleic Acids  similar in all organisms (DNA/RNA)  Similar proteins (enzymes, hormones)  More similarities  More closely related

12. Comparative Anatomy  Similarity in bone structure  Homologous Structure: Same structure different function  EX. Arms of humans, flippers of whales, wings of bat

13. Homologous Structures Notice that the types and number of bones are relatively the same.

14. Comparative Embryology  Similar embryological structure  Common ancestry ***Mature growth is very different from embryological growth.

15. Comparative Embryology  Notice that as organisms develop they become more and more distinguishable from one another.

16.  Parts that no longer serve a purpose  Structures were used in the past  Genes still produce these structures  Ex. Appendix, tail bone (coccyx) Vestigial Structure:

17. Charles Darwin Origin of Species Origin of Species written in 1859 Studied finches, found differences on the Galopogos Islands Theory of Evolution - evolution based on variation and natural selection **Natural Selection: evolution is controlled by nature rather than by people.

18. Theory of Evolution  Based theories on species variation and natural selection.- (There are 5 points to natural selection) 1.Overproduction- within a population more offspring are born than can possibly survive. 2. Competition- depends on number of individuals in a population  struggle for survival - compete for food, shelter, living space - compete for food, shelter, living space

19. Darwin (cont.) 3. Survival of the fittest- the “strongest” or best adapted to its environment will survive. 4. Reproduction- individuals that survive will reproduce and transmit favorable traits and variations to offspring.

20. Darwin (cont.) 5. Speciation- new species have evolved from a COMMON ANCESTOR

21. Weakness of Darwin’s Theory  Even though Darwin was able to tell us that there were many variations of all living things on the planet….. -He could not explain why. -Did not explain how variations arose.

22. Darwin’s Theory

23. Hugo DeVries  Hugo DeVries- - Found that something called a mutation were the source of variation in a population. - Favorable mutations among competing species resulted in modern species.

24. Modern Evolutionary Theory  The Modern Evolutionary Theory supports Darwin's theory of variation and natural selection but incorporates the reason for the variation (mutation).

25. What Produces Variation? 1.Variation: mutation and natural selection. 2.Mutations: spontaneous 3.Sexual reproduction - sorting and recombination of alleles.

26. Examples of Evolution in Modern Times 1. Peppered Moth: light vs. dark (industrialization influence)  Moth was originally light in color  a mutation occurred  moth turned black  at same time the trees were getting darker because of industrialization, those that were dark blended into the trees better and SURVIVED

27. 2. Insect resistance to insecticide: Insect gets a mutation and becomes resistant to the insecticide  Resistance is not in response to insecticide. (Insecticide=spray that kills insects) 3.Bacteria resistant to penicillin:  One bacteria becomes resistant to PCN  bacteria reproduce ASEXUALLY  offspring are also resistant

28. Modern Evolutionary Theory (cont.)  -involves the struggle of organisms to survive and reproduce in a given environment.  Good traits will passed on and will increase in frequency within a population  Bad traits will decrease in frequency within a population

29. Geographic Isolation  Favors speciation (development of new species) by segregating a small group from the main population.  Ex. Mountains, deserts, cities, bodies of water.

30. Reproductive Isolation  As a result of geographic isolation, organisms become so different they cannot mate and produce fertile offspring therefore a new species evolves

31. 2 Theories of Evolution Rate  Gradualism:  - evolutionary change is slow, gradual and continuous.

32.  Punctuated Equilibrium:  - long periods of stability interrupted by significant change.

33. Gradualism Punctuated Equilibrium