Evidence for Evolution Evidence Supporting Evolution n Fossil
- Slides: 25
Evidence for Evolution
Evidence Supporting Evolution n Fossil record • shows change over time n Anatomical record • comparing body structures n n n homology & vestigial structures embryology & development Molecular record • comparing protein & DNA sequences n Artificial selection • human caused evolution
Fossil Record n Layers of rock contain fossils • new layers cover older ones n creates a record over time • fossils show a series of organisms have lived on Earth n over a long period of time
Fossils Tell A Story the Earth is old Life on Earth has changed
Evolution of Birds Today’s organisms descended from ancestral species Fossil of Archaeopteryx lived about 150 mya n links reptiles & birds n
We found the fossil — no joke! Land Mammal ? e h t e ar ? e e r Whe mediat r inte sils? fos Complete series of transitional fossils Someone’s idea of a joke! But the joke’s on them!! Ocean Mammal ? ?
Evolution from Sea to Land n 2006 fossil discovery of early tetrapod • 4 limbs n Missing link from sea to land animals
Anatomical Record n n On the outside, animals may look different. , But when you look under the skin… It tells an evolutionary story of common ancestors
Anatomical Record n The same bones under the skin • limbs that perform different functions are built from the same bones How could these different organisms have the same bones?
Homologous Structures n Structures that come from the same origin homo- = same n -logous = information n n Forelimbs of human, cats, whales, & bats • same structure n on the inside • same development in embryo • different functions n on the outside • evidence of common ancestor
But Don’t Be Fooled By These… n Analogous structures • look similar n on the outside • same function • different structure & development How is a bird like a bug? n on the inside • different origin • no evolutionary relationship
Analogous Structures n n Dolphins: aquatic mammal Fish: aquatic vertebrate • both adapted to life in the sea • not closely related Watch the tail!
Convergent evolution n 3 groups with wings • Does this mean they have a recent common ancestor? They just came up with the NO! same answer! Flight evolved 3 separate times — evolving similar solutions to similar “problems”
Convergent evolution led to mimicry n Why do these pairs look so similar? Monarch male Viceroy male poisonous edible Which is the moth vs. the bee? fly vs. the bee? fly bee moth bee
Vestigial organs n Hind leg bones on whale fossils Why would whales have pelvis & leg bones if they were always sea creatures? Because they used to walk on land!
Comparative embryology n Development of embryo tells an evolutionary story • similar structures during development all vertebrate embryos have a “gill pouch” at one stage of development
3. Molecular record n Comparing DNA & protein structure • everyone uses the same genetic code! n DNA Human Macaque Dog Bird Frog Lamprey 8 32 45 67 125 § compare common genes § compare common proteins number of amino acids different from human hemoglobin 0 10 20 30 40 50 60 70 80 90 100 110 120
Building “family” trees Closely related species are branches on the tree — coming from a common ancestor
4. Artificial selection n How do we know natural selection can change a population? • we can recreate a similar process • “evolution by human selection” “descendants” of wild mustard
Selective Breeding Humans create the change over time “descendants” of the wolf
Artificial Selection gone bad! n Unexpected consequences of artificial selection Pesticide resistance Antibiotic resistance
Insecticide resistance n Spray the field, but… • insecticide didn’t kill all individuals n variation • resistant survivors reproduce • resistance is inherited • insecticide becomes less & less effective
Any Questions? ?
Parallel Evolution Niche Placental Mammals Burrower not closely related Mole Anteater Nocturnal insectivore Climber marsupial mammal Glider Mouse Marsupial mole Numbat Marsupial mouse placental mammal Spotted cuscus Lemur Flying squirrel Stalking predator Australian Marsupials Ocelot Sugar glider Tasmanian cat filling similar roles in nature, Wolf so have similar adaptations Tasmanian “wolf” Chasing predator
Vestigial organs n Structures on modern animals that have no function • remains of structures that were functional in ancestors • evidence of change over time n n n some snakes & whales have pelvis bones & leg bones of walking ancestors eyes on blind cave fish human tail bone
- How is the fossil record evidence for evolution
- Chapter 14 section 1 fossil evidence of change answer key
- The history of life section 1 fossil evidence of change
- Fossil and mountain chain evidence
- Pangea fossil evidence
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