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Published byAnnabelle Strobridge Modified over 10 years ago
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But first, a very quick cartoon show.
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The Fossil Record
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Nature of fossils
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Archaeopteryx Lucy Ida Famous Fossils
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Distribution of fossils RELATIVE AGE
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Distribution of fossils LAW OF SUPERPOSITION
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Distribution of fossils ABSOLUTE AGE
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W HEN SCIENTISTS USE RADIOMETRIC DATING, THEY USE A MASS SPECTROMETER TO ANALYZE THE ISOTOPES PRESENT IN THE MATERIAL, BOTH OF THE OLD MATERIAL AND OF THE NEW, DECAYED ISOTOPE. U SING THE KNOWN HALF - LIFE OF MATERIALS ( FOR EXAMPLE, THE HALF - LIFE OF CARBON -14 IS 6,000 YEARS ), SCIENTISTS CAN COMPARE HOW MUCH OF EACH TYPE OF ISOTOPE ( THE ORIGINAL ISOTOPE, KNOWN AS THE PARENT, AND THE DECAYED ISOTOPE, KNOWN AS THE DAUGHTER ISOTOPE ) IS PRESENT IN THE MATERIAL. U SING THIS INFORMATION, HIGHLY ACCURATE DATING CAN BE ESTABLISHED FOR EVEN VERY OLD OBJECTS. R EAD MORE : H OW D OES R ADIOMETRIC D ATING W ORK ? | E H OW. COM HTTP :// WWW. EHOW. COM / HOW - DOES _5185123_ RADIOMETRIC - DATING - WORK _. HTML # IXZZ 1EL XI K T 6DH OW D OES R ADIOMETRIC D ATING W ORK ? | E H OW. COM HTTP :// WWW. EHOW. COM / HOW - DOES _5185123_ RADIOMETRIC - DATING - WORK _. HTML # IXZZ 1EL XI K T 6D
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Absolute Aging
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Distribution of fossils SUCCESSION OF FORMS
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Extinction
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Distribution of fossils MASS EXTINCTION
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K-T
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K-TPermian
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VIDEO dramatization
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immediate 6 months 10 years 50 years 65 million years
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Video
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MODERN BIOLOGY CHAPTER 15.2
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Lamarcks Explanation FIRST TO PROPOSE A UNIFYING THEORY ABOUT SPECIES MODIFICATION –SIMILAR SPECIES DESCENDED FROM A COMMON ANCESTOR –RELATED FOSSILS TO EXTANT ORGANISMS BASED ON PHYSICAL CHARS.
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Lamarcks Explanation
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Lamarcks Problem –ACQUIRED TRAIT –FIERCELY ATTACKED, PRIMARILY BY SCIENTISTS WHO WERE VIOLENTLY OPPOSED TO THE IDEA OF EVOLUTION
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The beginning of modern evolutionary thought NATURAL SELECTION: ORGANISMS BEST SUITED TO THEIR ENVIRONMENTS ARE BETTER ABLE TO SURVIVE AND THEREFORE REPRODUCE MORE, LEAVING MORE OFFSPRING POPULATION: A GROUP OF INTERBREEDING INDIVIDUALS WITHIN A SPECIES
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Charles Darwin BORN IN 1809 MEDICAL SCHOOL AND CLERICAL SCHOOL H.M.S. BEAGLE
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A 5-Year Tour
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Darwins Beginnings Analysis of Darwin's data –Returned to England in October, 1836 with thousands of specimens, each carefully documented –13 similar, but distinctly different species of finches Young islands
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The Finches Similar but not the sameSimilar but not the same Identify the islandIdentify the island
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Darwins Beginnings Publication –Wallaces move –On the Origin of Species By Means of Natural Selection Was published in 1858 Sold out on its first day
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Darwins theories Evolution: defined by Darwin as descent with modification –Newer forms are refined forms of earlier fossils –All must have developed from a few common ancestors –Accounts for the similarities in organisms in a geographical area and the fossils found there
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Darwins theories Natural selection: defined by Darwin as the means of evolution –Competition –Some individuals are better able to survive –Eventually the frequency of that trait changes in the population
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Lamarck v. Darwin
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Darwins theories Survival of the fittest –Not always true –Fitness means ability to reproduce, not healthiest –Oversimplification
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Evolution A CHANGE IN THE FREQUENCY OF ALLELES WITHIN A POPULATION OVER GENERATIONS
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Requirements for natural selection If these are present, selection will occur. –Differential selection –Variation –Heritability
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Evidence of Evolution Homologous structures –Same origin; different function
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Evidence of Evolution Analogous structures –Same function, different origin
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Evidence of Evolution Vestigial structures –Left-overs
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Evidence of Evolution Macromolecule comparison –All organisms have the same dna structure and the same amino acids –Many related organisms have very similar proteins
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Patterns of evolution CO-EVOLUTION
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Patterns of evolution Convergent evolution –Different origins similar characteristics –Similar environment similar solution
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Patterns of evolution Divergent evolution –Similar background –Different environment; different solution –Adaptive radiation
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Patterns of evolution Divergent evolution –Speciation –Artificial selection
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… when the last individual of a race of living things breathes no more, another heaven and another earth must pass before such a one can be again." --William Beebe
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