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Evolution unit notes


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Evolution unit notes

  1. 1. EvolutionUnit NotesCharles Darwin – Voyage of the Beaglecommons.wikimedia.org©2013
  2. 2. Evolution UnitGoals1. I can explain, using evidence, how biological evolutionaccounts for the diversity of species on Earth today.• Include evidence from Developmental Biology comparisons2. I can give examples of plant and animal adaptations thatincrease the success of an organism during an environmentalchange:• Show evidence that Natural Selection causes Genetic traits to vary overtime• Show how organisms have improved Survival & Reproduction over time• Using math to support my explanations1. I can infer how closely related two species are based on theiranatomical features• Using evidence from the Fossil Record• Using Evidence from Comparative Anatomyjschmied©2013
  3. 3. Activity 94 – A Meeting ofMindsCharles Darwin – Voyage of the• I can give examples of plant and animal adaptationsthat increase the success of an organism during anenvironmental change.In this activity you should be able toa. Properly define 4 key evolutionary conceptsb. Explain why tall (or short people) often have tall(or short) offspring. Also other differences like blue eyes,blond hair, PTC tasting Etc…..c. Describe the similarities and differences between CharlesDarwin and Jean-Baptiste-LaMarck’s theories of Evolution.d. Explain why scientists find Darwin’s theory more convincine. Describe unique adaptations of at least two species on Earthand explain how these adaptations help the species survivein its environmentjschmied©2013
  4. 4. Jean-Baptiste-LaMarck’s TheoryJean-Baptiste-LaMarcken.wikipedia.org1. Evolutionary Change comes through use and disuse- Lamarck was struck by the similarities of many of theanimals he studied, and was impressed by the plentifulfossil record.• He argued that life was not fixed. So if the environmentchanged, the organisms had to change their behavior tosurvive. Thus if an organism used an organ more than theyhad before, it would increase in its lifetime.• Example: If a giraffe stretched its neck for leaves, forexample, a "nervous fluid" would flow into its neck andmake it longer. Also Its offspring would inherit the longerneck, and continued stretching would make it longer stillover several generations. Meanwhile organs that organismsstopped using would shrink.2. Organisms are driven to greater complexity -Lamarck stated As organisms adapted to theirsurroundings, nature constantly drove them from simpleforms to increasingly complex ones.Lamarck believed that life had begun through spontaneous generation. But he also claimedthat new primitive life forms sprang up throughout the history of life. For example: todaysmicrobes are simply "the new kids on the block."Lamarck believed that the long necks ofgiraffes evolved as generations of giraffesreached for ever higher leavesjschmied©2013
  5. 5. There is variation in traits.For example, some beetles are green and some are brown.There is differential reproduction.Since the environment cant support unlimited population growth, not all individuals get toreproduce to their full potential. In this example, green beetles tend to get eaten by birds andsurvive to reproduce less often than brown beetles do.There is heredity.The surviving brown beetles have brown baby beetles because this trait has a genetic basis.End result:The more advantageous trait, brown coloration, which allows the beetle to have moreoffspring, becomes more common in the population. If this process continues, eventually, allindividuals in the population will be brown.’s Theory of Natural selectionNatural selection is one of the basic mechanisms of evolution, along withmutation, migration, and genetic drift.Darwins grand idea of evolution by natural selection is relatively simple butoften misunderstood. To find out how it works, imagine a population of beetles:jschmied©2013
  6. 6. can be dated relative to one another by noting theirpositions in layers of rocks, known as strata. Thus fossilsfound in lower strata (layers) were generally depositedearlier and are older than those on upper layers.This is called the Law of SuperpositionRock Layers and Fossil Dating
  7. 7. Fossil Types for our Core SamplesAmmoniteTrilobiteElrathi kingiKnightiaFernAlethopteris serii
  8. 8. Fossils can be dated relative to one another bynoting their positions in layers of rocks, known asstrata. Thus fossils found in lower strata (layers)were generally deposited earlier and are older.This is called the Law of Superposition. Click onthe image at the left to see this phenomena.Scientists can date the rocks, this gives us thegeneral age of the fossils.In the example at right, we can deduce that the oldest rocks are those that are cutthrough by other rocks. The next oldest rocks are those that are “doing thecutting” through the oldest rocks, and the youngest rocks lie on top of these layersand are not cut through at all. By making careful observations, we can detect theseinterruptions in the vertical pattern and use them to get more information aboutthe relative ages of different layers.Sometimes geologic processes interrupt thisstraightforward, vertical pattern . Forexample, a mass of rock may cut across otherlayers, erosion may interrupt the regularpattern of deposition, or the rock layers mayeven be bent and turned upside-down. Click onthe image on the right to see this,.Rock Layers and Fossil DatingLearn More At:
  9. 9. Stratigraphy using fossils©2013
  10. 10. Darwin also used Evidence from EmbryologyComparisonswww.geology.ohio-state.eduEmbryology data shows that organisms look the same at their earlier stages.This idea could support evolution. Evolution is the idea that many organisms havecommon ancestors, so it was reasoned that is why they have similar traits.jschmied©2013
  11. 11. Mutations:jschmied©2013Beneficial MutationsGenetic variant in cowsproduces more milk.Sickle cell anemia in redblood cells wards offmalaria.Harmful MutationsHeart Disease Mutationproduces high amounts ofheart diseasNeurological Disorder inGolden Retrievers caused bymutation in mitochondrialDNA
  12. 12. Adaptations:jschmied©2013
  13. 13. Adaptations:jschmied©2013
  14. 14. The evolution ofwhales!©2013The evolution of whalesThe first thing to noticeon this evogram is thathippos are the closestliving relatives ofwhales, but they are notthe ancestors of whales.In fact, none of theindividual animals onthe evogram is the directancestor of any other, asfar as we know. Thatswhy each of them getsits own branch on thefamily tree.
  15. 15. Cool Resource on Evolution!©2013