Biology- Chapter 15 PowerPoint

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  • 1. EVOLUTION Chapter 15Chapter 15
  • 2. Charles Darwin
  • 3. Question for Thought  Earth has millions of other kinds ofEarth has millions of other kinds of organisms of everyorganisms of every imaginable shape, size, and habitat.imaginable shape, size, and habitat. This variety of living things is calledThis variety of living things is called biologicalbiological diversitydiversity. How did all these different. How did all these different organisms arise?organisms arise?  How are they relatedHow are they related??
  • 4. Darwin’s Theory of Evolution  EvolutionEvolution, or change over time, is the, or change over time, is the process by which modern organisms haveprocess by which modern organisms have descended from ancient organisms.descended from ancient organisms.  A scientificA scientific theorytheory is a well-supportedis a well-supported testable explanation of phenomena thattestable explanation of phenomena that have occurred in the natural world.have occurred in the natural world.
  • 5. How do you think Darwin came up with his theory?
  • 6. Voyage of the Beagle
  • 7. Voyage of Beagle  Dates:Dates: February 12th, 1831February 12th, 1831  ShipShip: H.M.S. Beagle: H.M.S. Beagle  Destination:Destination: Voyage around the world.Voyage around the world.  Findings:Findings: evidence to propose aevidence to propose a revolutionary hypothesis about how liferevolutionary hypothesis about how life changes over timechanges over time
  • 8. Patterns of Diversity  Darwin visited Argentina and Australia which hadDarwin visited Argentina and Australia which had similar grassland ecosystems.similar grassland ecosystems.  those grasslands were inhabited by very differentthose grasslands were inhabited by very different animals.animals.  neither Argentina nor Australia was home to theneither Argentina nor Australia was home to the sorts of animals that lived in European grasslands.sorts of animals that lived in European grasslands.
  • 9. Patterns of Diversity  Darwin posed challenging questions.Darwin posed challenging questions.  Why were there no rabbits in Australia, despite theWhy were there no rabbits in Australia, despite the presence of habitats that seemed perfect for them?presence of habitats that seemed perfect for them?  Why were there no kangaroos in England?Why were there no kangaroos in England?
  • 10. Living Organisms and Fossils  Darwin collected the preserved remains ofDarwin collected the preserved remains of ancient organisms, calledancient organisms, called fossilsfossils..  Some of those fossils resembled organisms thatSome of those fossils resembled organisms that were still alive today.were still alive today.
  • 11. Living Organisms and Fossils     Others looked completely unlike any creature he hadOthers looked completely unlike any creature he had ever seen.ever seen.  As Darwin studied fossils, new questions arose.As Darwin studied fossils, new questions arose.  Why had so many of these species disappeared?Why had so many of these species disappeared?  How were they related to living species?How were they related to living species?
  • 12. Fossils
  • 13. The Galapagos Island  The smallest, lowest islands were hot,The smallest, lowest islands were hot, dry, and nearly barren-Hood Island-sparsedry, and nearly barren-Hood Island-sparse vegetationvegetation  The higher islands had greater rainfall andThe higher islands had greater rainfall and a different assortment of plants anda different assortment of plants and animals-Isabela- Island had richanimals-Isabela- Island had rich vegetationvegetation..
  • 14. The Galapagos Island  Darwin was fascinated in particular by the landDarwin was fascinated in particular by the land tortoises and marine iguanas in the Galápagos.tortoises and marine iguanas in the Galápagos.  Giant tortoises varied in predictable ways fromGiant tortoises varied in predictable ways from one island to another.one island to another.  The shape of a tortoise's shell could be used toThe shape of a tortoise's shell could be used to identify which island a particular tortoiseidentify which island a particular tortoise inhabited.inhabited.
  • 15. Animals found in the Galapagos  Land TortoisesLand Tortoises  Darwin FinchesDarwin Finches  Blue-Footed BoobyBlue-Footed Booby  Marine IguanasMarine Iguanas
  • 16. Animals
  • 17. The Journey Home  Darwin observed that characteristics ofDarwin observed that characteristics of many plants and animals varied greatlymany plants and animals varied greatly among the islandsamong the islands  Hypothesis:Hypothesis: Separate species maySeparate species may have arose from an original ancestorhave arose from an original ancestor
  • 18. Ideas that shaped Darwin’s Thinking  James Hutton:James Hutton:  1795 Theory of1795 Theory of Geological changeGeological change  Forces changeForces change earth’s surfaceearth’s surface shapeshape  Changes are slowChanges are slow  Earth much olderEarth much older than thousands ofthan thousands of yearsyears
  • 19. Ideas that Shaped Darwin’s Thinking  Charles LyellCharles Lyell  Book:Book: Principles ofPrinciples of GeographyGeography  Geographical featuresGeographical features can be built up or torncan be built up or torn downdown  Darwin thought ifDarwin thought if earth changed overearth changed over time, what about life?time, what about life?
  • 20. Lamarck
  • 21. Lamarck’s Theory of Evolution  Tendency toward Perfection(GiraffeTendency toward Perfection(Giraffe necks)necks)  Use and DisuseUse and Disuse  Inheritance of Acquired TraitsInheritance of Acquired Traits
  • 22. Population Growth  Thomas MalthusThomas Malthus-- 19th century English19th century English economisteconomist  If population grewIf population grew (more babies born(more babies born than die)than die)  Insufficient livingInsufficient living spacespace  Food runs outFood runs out  Darwin applied thisDarwin applied this theory to animalstheory to animals
  • 23. Publication of Orgin of Species  Russel Wallace wroteRussel Wallace wrote an essay summarizingan essay summarizing evolutionary changeevolutionary change from his field work infrom his field work in MalaysiaMalaysia  Gave Darwin the driveGave Darwin the drive to publish his findingsto publish his findings
  • 24. Natural Selection & Artificial Selection  Natural variationNatural variation--differences among--differences among individuals of a speciesindividuals of a species  Artificial selectionArtificial selection- nature provides the- nature provides the variation among different organisms, andvariation among different organisms, and humans select those variations they findhumans select those variations they find usefuluseful..
  • 25. Evolution by Natural Selection  The Struggle for ExistenceThe Struggle for Existence-members of-members of each species have to compete for food,each species have to compete for food, shelter, other life necessitiesshelter, other life necessities  Survival of the FittestSurvival of the Fittest-Some individuals-Some individuals better suited for the environmentbetter suited for the environment
  • 26. Natural Selection  Over time, naturalOver time, natural selection results inselection results in changes in inheritedchanges in inherited characteristics of acharacteristics of a population. Thesepopulation. These changes increase achanges increase a species fitness in itsspecies fitness in its environmentenvironment
  • 27. Descent  Descent with ModificationDescent with Modification-Each living organism has-Each living organism has descended, with changes from other species over timedescended, with changes from other species over time  Common DescentCommon Descent- were derived from common ancestors- were derived from common ancestors
  • 28. Evidence of Evolution  The Fossil RecordThe Fossil Record  Geographic Distribution of LivingGeographic Distribution of Living ThingsThings  Homologous Body StructuresHomologous Body Structures  Similarities in Early DevelopmentSimilarities in Early Development
  • 29. Evidence for Evolution  The Fossil RecordThe Fossil Record-- Layers show changeLayers show change  GeographicGeographic Distribution of LivingDistribution of Living ThingsThings  Homologous BodyHomologous Body StructuresStructures  Similarities in EarlySimilarities in Early DevelopmentDevelopment
  • 30. Evidence of Evolution  The Fossil RecordThe Fossil Record  GeographicGeographic Distribution ofDistribution of Living Things-Living Things-similarsimilar environments haveenvironments have similar types ofsimilar types of organismsorganisms  Homologous BodyHomologous Body StructuresStructures  Similarities in EarlySimilarities in Early DevelopmentDevelopment
  • 31. Homologous Structures  Homologous StructuresHomologous Structures-structures that-structures that have different mature forms in differenthave different mature forms in different organisms, but develop from the sameorganisms, but develop from the same embryonic tissueembryonic tissue
  • 32. Evidence for Evolution  Vestigial organsVestigial organs-organs that serve-organs that serve no useful function in an organismno useful function in an organism  i.e.) appendix, miniature legs, armsi.e.) appendix, miniature legs, arms
  • 33. Similarities in Early Development
  • 34. Summary of Darwin’s Theory  Individuals in nature differ from oneIndividuals in nature differ from one anotheranother  Organisms in nature produce moreOrganisms in nature produce more offspring than can survive, and many ofoffspring than can survive, and many of those who do not survive do not reproduce.those who do not survive do not reproduce.
  • 35. Summary of Darwin’s Theory  Because more organisms are produce thanBecause more organisms are produce than can survive, each species must struggle forcan survive, each species must struggle for resourcesresources  Each organism is unique, each hasEach organism is unique, each has advantages and disadvantages in theadvantages and disadvantages in the struggle for existencestruggle for existence
  • 36. Summary (cont.)  Individuals best suited for the environmentIndividuals best suited for the environment survive and reproduce.survive and reproduce.  Species change over time.Species change over time.
  • 37. Summary (cont.)  Species alive today descended with modificationsSpecies alive today descended with modifications from species that lived in the pastfrom species that lived in the past  All organisms on earth are united into a singleAll organisms on earth are united into a single family tree of life by common descentfamily tree of life by common descent