2. Evolution Change over time; the process by which modern organisms have descended from ancient organisms

3. Evolutionary history Linnaeus: taxonomy Hutton: gradualism Lamarck: evolution Malthus: populations Cuvier: paleontology Lyell: uniformitarianism Darwin: evolution Mendel: inheritance Wallace: evolution

4. Darwin’s Voyage Charles Darwin – “The Father of the Theory of Evolution” 1809-1882

5. Evolution Evolution: the change over time of the genetic composition of populations Natural selection: populations of organisms can change over the generations if individuals having certain heritable traits leave more offspring than others (differential reproductive success) Evolutionary adaptations: a prevalence of inherited characteristics that enhance organisms’ survival and reproduction November 24, 1859

6. H.M.S. Beagle Sailed around the world in 1831 Darwin began to make observations about the species in the world

7. Darwin’s Observations An enormous number of species inhabit the earth Organisms are well suited to their environment Organisms have many ways to survive and produce offspring

8. Where Organisms Live Certain organisms live in some areas but not others –Rabbits and Kangaroos live in the same type of environment –Australia has Naturally Kangaroos but not Rabbits –England has Rabbits but not Kangaroos

9. Fossils Some fossils look like organisms that are alive today Other fossils look unlike any creature Darwin had ever seen Why do species disappear? How are organisms in fossils related to living species?

10. Galapagos Island Islands are close together with very different climates Darwin saw finches with different shaped beaks on different islands Could similar organisms on different islands once have been members of the same species? Fruit CactusSeeds Insects

11. Darwin’s finches Darwin’s conclusions –small populations of original South American finches landed on islands variation in beaks enabled individuals to gather food successfully in the different environments –over many generations, the populations of finches changed anatomically & behaviorally accumulation of advantageous traits in population emergence of different species

12. Essence of Darwin’s ideas Natural selection –variation exists in populations –over-production of offspring more offspring than the environment can supportmore offspring than the environment can support –competition for food, mates, nesting sites, escape predatorsfor food, mates, nesting sites, escape predators –differential survival successful traits = adaptationssuccessful traits = adaptations –differential reproduction adaptations become more common in populationadaptations become more common in population

13. Evolution is: Descent with Modification Each living species has descended, with changes, from other species over time Populations evolve over many generations

14. Types of Evolution Convergent evolution-two different lineages evolve similar traits –Dolphins & fishes –Wings of bees & bats Divergent evolution-a lineage splits to have organisms with different traits –Darwin’s finches –Adaptive radiation

15. CONVERGENT EVOLUTION

16. Parallel Evolution Convergent evolution in common niches –filling similar ecological roles in similar environments, so similar adaptations were selected –but are not closely related marsupial mammals marsupial mammals placental mammals placental mammals

17. How fast does evolution occur? Gradualism –Species change slowly over time Punctuated Equilibrium –Species can make rapid “leaps” in evolution Modern Synthesis –Parts of both are correct

18. Evolution evidence: Biogeography Geographical distribution of species Examples: Islands vs. Mainland Australia vs. Continents

19. Fossils Scientists have used the fossil record to construct a history of life on Earth. –Earth’s life forms appeared 3.5 billion years ago –Fossil indicate that life forms have change over time

20. Evolutionary change in horses Millions of years ago 50 100 150 200 250 300 350 400 450 500 550 605550454035302520151050 Equus Hyracotherium Mesohippus Merychippus Nannippus Body size (kg)

21. Evolution of birds Smithsonian Museum, Washington, DC Archaeopteryx –lived about 150 mya –links reptiles & birds

22. 2006 Fossil Discovery of Early Tetrapod Tiktaalik –“missing link” from sea to land animals

23. Anatomy –Homologous Structures - different organisms sharing similar structures from the same evolutionary origin

24. Anatomy –Analogous Structures – different organisms sharing the same structure to perform similar functions from different evolutionary origins (evolved twice)

25. Anatomy Vestigial Structures – structures that have lost their function through evolution They once had a purpose

26. Embryology Embryos of many organisms are alike in early stages of development. These similarities suggest that we are all related, but have developed differences

27. DNA AND MOLECULAR BIOLOGY Organisms that are closely related should have similar DNA Similar DNA indicates sharing a common ancestor at one time. Life Sciences-HHMI Outreach. Copyright 2006 President and Fellows of Harvard College.

28. Molecular Biology  DNA & proteins are a molecular record of evolutionary relationships

29. Comparative hemoglobin structure Number of amino acid differences between hemoglobin (146 aa) of vertebrate species and that of humans Number of amino acid differences between hemoglobin (146 aa) of vertebrate species and that of humans 1002030405060708090100110120 LampreyFrogBird Dog MacaqueHuman 32845 67 125