Presentation on theme: "Evolution: Change Over Time"— Presentation transcript:
1Evolution: Change Over Time The EvidenceThe EvidenceEvolution: Change Over TimeEvolution: Change Over TimeThe EvidenceThe Evidence
2Fossil Record Defined: Collection of every known fossil Most fossils found in sedimentary rockAge determined by depthLaw of Superposition: new rock forms on top of older rockA.k.a. Relative DatingEvidence Conclusions:1) Newer fossils are more complex2) Common ancestors: similarities between ancient & modern life
3Missing Link Fossils AKA: Transition Fossils Whale EvidenceLong spineFound in dried up oceansReptile EvidenceTeethBony tailFish evidenceScalesFinsFound in dried-up oceansAmphibian evidenceEyes on top of headWrist bonesLand EvidenceWolf-like teethHind legsBird EvidenceWishboneFeathersAKA: Transition FossilsArchaeopteryx: shares both bird & reptile featuresBasilosaurus: shares whale & land mammal featuresTiktaalik: shares fish & amphibian featuresEvidence Conclusion : Indicates common ancestry
5Comparing old fossils to modern life shows change Ancient KelpModern Kelp
6Radiometric DatingHelps determine age of fossils. More accurate than relative dating.Isotopes: atoms of the same element with differing neutronsEx: 12C and 14C12C = 6 protons + 6 neutrons14C = 6 protons + 8 neutronsOrganisms collect carbon throughout their lifetime.When organism dies: 14C starts to decay into 14 N at a known rate (half-life)Fossil age determined by comparing ratio of C to NWider ratio = older sampleBoth are Carbon
9The study of geography provides evidence of evolution. island species most closely resemble nearest mainland speciespopulations can show variation from one island to another
10Embryo Development Different species show similar development patterns Different body plans become noticeable later in developmentEvidence Conclusion : Indicates common ancestryEmbryoDevelopment
11flipper arm leg wing Homologous Structures walking grasping swimming flightDefined: similar body structures with very different functionsDifferent environments lead to adaptationsEx: The forelimbs of animalsEvidence Conclusion : Indicates common ancestry
12Homologous structures are different than analogous structures Analogous structures have similar functions but different structures.Human handBat wingMole footFly wingAnalogous structures are not evidence of a common ancestor.
13Vestigial StructuresDefined: Organs or structures which have lost most or all their original functionVestigial Human Parts:Gill slits = once used to breath oxygen in waterYolk sac = once used to nourish developing embryoTailbone = once used for balanceAppendix = once used to digest plantsWisdom teeth = once used to grind plant tissueEvidence Conclusion : Indicates common ancestry
16Biochemical Evidence DNA, RNA, proteins compared Genetic code same for most lifeMore related species have more similar biochemistryEvidence Conclusion : Indicates common ancestry
17Constant creation of chemicals for human use is eliminating the “unfit” (invading)organisms Ex: Antibiotics eliminating unfit bacteriaEx: Pesticides eliminating unfit pestsEx: Antivirals…Ex: Fungicides…Allows resistant to survive and reproduceResistantOrganisms
22ReviewHow does antibiotic and pesticide resistance show natural selection?How do the following lines of evidence show change over time?FossilsHomologous structuresVestigial structuresResistant organismsEmbryo developmentBiochemical (molecular) evidenceFossil age can be determined two ways. What are they?Which type of anatomical structures do not show evidence of common ancestry?