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Evolution Review

Evolution Review. Do Now: Turn in cladogram labs from yesterday. Part I: Phillosophy of Truth. What is science? Observable, measurable quantities only! Hypotheses require mechanisms (how) with supporting evidence Truth and Logic in Science

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Evolution Review

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  1. Evolution Review Do Now: Turn in cladogram labs from yesterday

  2. Part I: Phillosophy of Truth • What is science? • Observable, measurable quantities only! • Hypotheses require mechanisms (how) with supporting evidence • Truth and Logic in Science • Negative proof is impossible (Russell’s Teapot, Flying Spaghetti Monster) • Occam’s Razor: the least complex solution to a problem has the highest probability of being correct • Parsimony: measure of complexity. More parsimonious = simpiler.

  3. Part II: Evolution Basics • Evolution: how species change over time. • Natural selection: the mechanism of evolution. • the process by which heritable traits that make it more likely for an organism to survive and successfully reproduce become more common in a population over successive generations.

  4. Natural Selection • For natural selection to function, there are 3 requirements • Variation • Differential mortality • heritability

  5. 1: Variation • For natural selection to work, there must be a range of characteristics in a population.

  6. 2: Differential Mortality • Some characteristics or variations allow an organism to survive and/or reproduce more than others.

  7. 3: Heritability • The characteristics that lead to increased survival and reproduction must be able to be passed on to subsequent generations

  8. Types of Evolution • Speciation: The evolution of new species from pre-existing ones • Two types of speciation • Phyletic speciation: One species replaces an older one (think fossils) • Divergent speciation: One species evolves into two new species.

  9. Phyletic vs. Divergent Speciation

  10. 2 Modes of Evolution • Gradual Evolution: small changes over long periods of time • Punctuated Equilibrium: big changes in short time periods.

  11. Gradualism vs. Punctuated Equilibrium

  12. Fossils • Fossil: preserved remains or traces of an ancient organism. • Most are formed by mineralization (turning to rock) • Trace fossil: not the organisms itself, but from an organism (dung, footprints, etc.) • Other fossils: amber, ice, tar

  13. Fossil Geology • Sedimentary rock: rocks made of compressed layers of sediment. Only type of rocks that contain fossils

  14. Fossil Geology • Law of Superposition: Older rocks are found below newer ones, since layers of sediment are deposited over time.

  15. Darwin • Charles Darwin proposed the theory of evolution by natural selection in his 1859 book The Origin of Species. • His evidence came from an expedition around South America on the H.M.S. Beagle. • Most important to his work are the unique creatures of the Galapagos Islands

  16. Representing Change • Phylogram (aka cladogram): A diagram representing evolutionary relationships.

  17. Homologous Structures • Homologous structures are similar in form and composition in different species.

  18. Phylogeny • Phylogeny is the relatedness among different species (note: phylogenetic tree shows phylogeny) • It is based on: • Fossil evidence • Homology (including genetics)

  19. That’s Evolution Part 1! • BIG quiz tomorrow – study this guide!!!

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