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Evolution

Evolution. Biology RiverDell High School Ms. C. Militano. I. Evidence of Evolution A. Fossils. 1. definition - trace or remains of organisms that are preserved 2. types a. mold (rock imprint) b. cast (mold that is filled) c. petrified

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Evolution

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  1. Evolution Biology RiverDell High School Ms. C. Militano

  2. I. Evidence of EvolutionA. Fossils 1. definition - trace or remains of organisms that are preserved 2. types a. mold (rock imprint) b. cast (mold that is filled) c. petrified d. preserved in amberor tar pits

  3. Mold Fossil Cast Fossil

  4. Fossil in AmberPetrified Wood

  5. Dinosaur Fossils Toe of a Dinosaur

  6. Plant Fossils Flower Fossil ConeFossil

  7. I. Evidence of EvolutionA. Fossils 3. location a. sedimentary rock b. amber or tar pits 4. distribution a.Law of Superposition(Steno 1638-1686) 1) relative age 2) absolute age b. biogeography

  8. Fossils Are Found in Tar Pits

  9. Sedimentary Rock Showing Layers

  10. Law of Superposition – younger fossils are closer to the surface – older fossils are deeper

  11. I. Evidence of EvolutionB. Comparative Anatomy 1. homologous structures a. similar structure, evolution, development b. wing, arm, flipper) 2. analogous structures a. similar function b. wing of a bird and an insect

  12. Homologous vs Analogous Structures

  13. I. Evidence of EvolutionB. Comparative Anatomy 3. vestigial structures a. useful in past organisms but not now b. appendix, tail vertebrae, ear muscles

  14. Vestigial Structures Appendix in Humans Leg Bones in a Whale

  15. I. Evidence of EvolutionC. Embryology Similarities 1. Haeckel(1834-1919) [German] a. “ontogeny recapitulate phylogeny” 1) embryo undergoes changes that repeat evolutionary development

  16. Diagram Showing Similarities in Early Stages of Embryo Development

  17. I.Evidence of EvolutionD. Biochemistry 1. similarity in amino acids in specific proteins 2. similarity in RNA and DNA base sequences

  18. Comparing Amino Acid Differences of Several Organisms to Humans

  19. II. Theories of EvolutionA. Lamark (1744-1829) 1. Acquired traits – traits that develop during one generation can be passed to the next generation 2. Law of Use and Disuse – if a trait is not used it will be lost

  20. Lamarck and Law of Use and Disuse • According to Lamarck the giraffes pictured grew longer necks in order to reach the leaves in taller trees • The longer necks were then passed to the next generation

  21. II. Theories of EvolutionB. Charles Darwin(1809-1882) 1. Biography a. Darwin attended medical school b. studied to be a clergyman c. 22 years old - signed on HMS Beagle 1) collect specimens as a naturalist 2) refined data for 21 years

  22. Charles Darwin Darwin’s Home

  23. HMS Beagle in Sydney Australia Harbor

  24. Darwin’s Voyage

  25. II. Theories of EvolutionB. Charles Darwin(1809-1882) 2. The Origin of Species (1859) a.Descent with modification 1) all species descend from a small number of original types 2) there is variation among organisms

  26. II. Theories of EvolutionB. Charles Darwin(1809-1882) b. Modification by Selection 1) environment limits growth of populations -competition for life’s necessities -specific traits are selected 2) adaptive advantage - trait favorable for a given environment - adaptations make some organisms more likely to survive than others

  27. II. Theories of EvolutionB. Charles Darwin(1809-1882) 3) fitness - ability of an organism to make a genetic contribution to the next generation 4) natural selection allows individuals with survival adaptations to pass traits to offspring

  28. II. Theories of EvolutionB. Charles Darwin(1809-1882) 5) speciation - formation of new species as favorable adaptations accumulate 6) “survival of the fittest” - those organisms with favorable traits reproduce and pass their traits to future generations

  29. III. Patterns of EvolutionA. Coevolution 1. changes in two or more species closely associated 2. examples a. predator and prey b. parasite and host c. plants and plant pollinators

  30. III. Patterns of Evolution B. Convergent Evolution 1. similar phenotypes are selected but ancestors are very different a. natural selection of analogous structures 2. examples a. wings in insects and birds b.fins & shape of sharks, fish, porpoise

  31. Examples of Convergent Evolution

  32. III. Patterns of EvolutionC. Divergent Evolution 1. two or more related populations or species become more dissimilar a. speciation - new species may form 2. example geographic isolation a. brown bear  polar bear

  33. III. Patterns of EvolutionC. Divergent Evolution 3. adaptive radiation a. many species evolve from same ancestor 1) ancestor migrates to different environments (example) - Galapagos finches

  34. Adaptive Radiation – Darwin’s Finches

  35. Beak shape Depends Upon Food Source

  36. Adaptive Radiation – Hawaiian Honeycreepers

  37. IV. Variation in Populations A. Distribution of variations 1. graph is a bell curve B. Natural Selection and Changes in Populations 1. Stabilizing Selection– favors average form 2. Directional Selection– average shifts to one extreme or the other 3. Disruptive Selection – extreme forms are favored- number of individuals withtheaverage form is reduced

  38. Stabilizing Selection

  39. Directional Selection

  40. Disruptive Selection

  41. Comparing Types of Selection

  42. Comparing Three Types of Selection

  43. IV. Variation in PopulationsC. Genetic Sources of Variation 1. Mutations a) a specific gene mutates in 1/10,0000 gametes b) thousands of genes in each gamete c) some mutations in every zygote d) most mutations are recessive

  44. IV. Variation in PopulationsC. Genetic Sources of Variation 2. Genetic Recombination a) random meeting of sperm and egg b) crossing over c) independent assortment 3. Genetic Drift a) occurs in small populations b) elimination of some genes by chance c) may decrease variation

  45. IV. Variation in PopulationsC. Genetic Sources of Variation 4. Non-random Mating 5. Migration a) immigration- movement into an area or population b) emigration – movement out of an area or population

  46. IV. Variation in PopulationsD. Genetic Equilibrium 1. Hardy-Weinberg Principle a) allele frequencies are stable across generations b) sexual reproduction alone does not affect genetic equilibrium 2. Conditions Necessary a) no immigration b) no mutations c) no natural selection d)large populations e) random mating

  47. IV. Variation in PopulationsE. Mathematics/Hardy Weinberg 1. gene pool - all the genes in a population 2. allele frequency - % occurrence of a specific allele in a population 3. phenotype frequency - % occurrence of an individual in a population with a trait 4. genotype frequency - % occurrence of individuals in a population with a specific genotype

  48. IV. Variation in PopulationsE. Mathematics/Hardy Weinberg 5. applying mathematics a) p = frequency of the dominant allele q = frequency of the recessive allele b) p + q = 1 c) p2 + 2pq + q2 = 1

  49. IV. Variation in PopulationsE. Mathematics/Hardy Weinberg d) q2 = recessive phenotype/genotype frequency p2+2pq = dominant phenotype frequency p2 = pure dominant genotype frequency 2pq= heterozygous genotype frequency

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