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Evolution

This article explores Charles Darwin's theory of natural selection and the concept of "survival of the fittest" in species adaptation and evolution. It discusses various factors such as adaptation, genetic variation, speciation, and coevolution. The article also examines fossil records, comparative embryology, vestigial structures, and biochemical evidence as evidence for evolution. Additionally, it discusses the causes of variation, different types of selection, and the importance of classification and phylogenetic trees in understanding evolutionary relationships.

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Evolution

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  1. Evolution • How species change over time

  2. Charles Darwin &Natural Selection • “Survival of the fittest” which means those best adapted to their environment survive, reproduce & pass on their genes • So “fittest” means best adapted, NOT the strongest

  3. Adaptation GAMETES: egg & sperm • Any trait an organism has that helps it survive • What are some adaptations of this falcon?

  4. Fossils of Ancient Lobsters 220 million years ago 190 million years ago

  5. Similar Structures Insects wings are not alive Bird Wings are alive

  6. Comparative Embryology • insects & animals that have VERY similar development arecloselyrelated • All vertebrates have VERY similar development = common ancestor

  7. Comparative Embryology 8-9 wks

  8. Vestigial Structures ORGAN THAT ISNO LONGERUSED appendix in humans legs in snakes Congo snake

  9. BIOCHEMICAL EVIDENCE The more exact codons in a sequence the more related organisms are • Comparison of macromolecules (proteins, nucleic acids, lipids, carbs) between organisms • Ex. comparing eukaryotic ribosomes to prokaryotic ribosomes

  10. DO you think we still find and identify NEW species? http://www.youtube.com/watch?v=ZDI3RexF0UM&feature=em-subs_digest

  11. What is a Species? • Group of the same organisms • Live together • Mate a produce viable offspring; means the babies can have babies of their own

  12. Horse + donkey = Mule Mules are STERILE meaning, they CAN’T have babies!

  13. Causes of Variation • Genes have 2 forms (dominant and recessive) • Polygenetic traits (multiple variations; hair/eye color, skin…) • Complex genetics (codominance, multiple allele, sex-linked traits, incomplete dominance) • Mutations-changes of the DNA of genes • Can be bad (disease) or good (immunity to malaria) • Mutation can cause immunity (pesticide resistant plants, antibiotic resistant bacteria)

  14. How Species Evolve over Time AKA SPECIATION

  15. Directional Selection Woodpecker beaks homozygote • When one extreme phenotype has the best chance to survive • As a result, the frequency (number) of those with that phenotype shift over time

  16. Evolution of the horse • DIRECTIONAL selection • Using the diagram as evidence, how did the horse evolve over time? • Hypothesize why these changes could have happened.

  17. Directional selection • roadrunner Most run from enemies!

  18. Stabilizing Selection • heterozygote When the intermediate phenotype has the best chance to survive

  19. Disruptive Selection • When both extreme phenotypes have the best chance to survive • center: left snail = aa right snail = AA

  20. What type of selection? • What does “mimic” mean?

  21. Other Causes of Speciation

  22. Mutation of DNA • Immunity to Malaria in Africa • AA=smooth normal cells =die from Malaria • Aa=bumpy cells =immune to Malaria • aa=sickle-cell shape =die from either malaria or sickle-cell

  23. Sickle Cell Anemia red blood cells

  24. Geographic Isolation • Mountains, islands, etc. keep a population isolated • Means species changes and evolves into new species

  25. Geographic Isolation Leads to adaptive radiation, which is when one species evolves into many over time due to competition of habitat or food!

  26. Lemurs of Madegascar

  27. 2 different groups of mammals

  28. Variation • Differences in phenotype with in 1 gene • Example: eye color in humans • Brown eyes are naturally protected from suns glare

  29. Variation

  30. Coevolution • When one species evolves because of the presences of another species • Ex. Flowers and insects • Flowers pollinated by hummingbirds often have a narrow, tubular shape

  31. Coevolution stop after insect pollinators http://www.youtube.com/watch?v=4YQ5q1cjEU4

  32. Honey bee • summary darwin natural selection song http://www.youtube.com/watch?v=tfYqD7gT6YA

  33. Drug resistant Bacteria • A few bacteria will be naturally immune to drug. • They DON’T die, but reproduce spreading the immunity until most bacteria are immune. • Ex. dimatap, vicks 44D, zyterc were perscription drugs: now over the counter.

  34. Classification • Taxon is the latin name for group! • The classifications begin with the largest groupings and move down to the smallest (Kingdom->->species) • Taxon, Kingdom, Phylum, Class, Order, Family, Genus, Species • Easy way to remember-King Phillip Came Over For Grandma’s Spaghetti!!

  35. Scientific Name • The Genus species of an organism • Always written in italics (ex. Homo sapiens are humans) • Only species are able to interbreed!

  36. Phylogenetic Tree • Shows evolutionary relationship between organisms • Can help tell which organisms are more closely related than others

  37. Phylogenetic Trees • Which organism is most closely related to man? ______ How do you know? • Which organism is man more closely related: Whale or Dimetrodon? ____________________ • How do you know?

  38. Cladogram Shows relationships up close-characteristics they share

  39. Which group is most closely related to ? • Echinoderms? • Annelida? • Which Least related to? • Porafera?

  40. Dichotomous Keys • A key that helps to identify an organism • Uses questions to lead you to the scientific name of the organism • By looking at features of the organism, the key will help you to figure out what it is!

  41. Follow Steps to find out what organism #3 is? #7?

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