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Fossils, Anatomy, and DNA

Evidence for Evolution. Fossils, Anatomy, and DNA. Evidence for Evolution. Three types of evidence: Fossils Anatomical Molecular. Fossil Evidence. Fossils Vocab:

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Fossils, Anatomy, and DNA

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  1. Evidence for Evolution Fossils, Anatomy, and DNA

  2. Evidence for Evolution Three types of evidence: • Fossils • Anatomical • Molecular

  3. Fossil Evidence • Fossils • Vocab: • Transitional species: species that have been found in the fossil record that are intermediates between two other species in the evolutionary process. • Radioactive dating: a dating technique that measures amount of radioactive material in a rock or fossil.

  4. Fossil Evidence • Fossils • Any traces of dead organisms • dinosaur bones • insects trapped in tree sap • leaf impressions

  5. Fossil Evidence Relative Dating Radiometric Dating • To fossilize an organism must be buried by sediment. • In swamps, mud, tar pits, or the ocean bottom. • Hard stuff fossilizes (bones, nails). • Radiometric and relative dating are used to find out how old the fossil is.

  6. Fossil Evidence • Fossils show: • Life has been around for millions of years • Transitional species link older to newer species • Darwin proposed the idea of transitional species, though he had no evidence • Today we have evidence: • Archaeopteryx • Whales • Tiktaalik Fossil, etc.

  7. Fossil Evidence-Archaeopteryx WINGS BEAK

  8. Fossil Evidence • Whales--60 million years of evolution • Descended from 4-legged wolf-like animals that were also ancestors to cows and horses • Fossil evidence shows slow loss of legs • Pelvis still remains with no rear legs

  9. Fossil Evidence-Whales Whale Video

  10. Anatomical Evidence • Homologous structures: Bone structure the same (homo) but not function • Bird wing, dolphin fin, and a human arm • Function not the same! • Show that these species shared a common ancestor. • Similar structures resulted from accumulated mutations and modifications.

  11. Homologous Structures

  12. Anatomical Evidence • Analogous structures: Bone structure different but serve the same function. • Function = flight: Butterfly wing, bat wing, fly wing • Structure not the same! • Show different species evolved structures with similar function through different evolutionary pathways. • EVOLUTION IS NOT RANDOM!

  13. Anatomical Evidence

  14. Anatomical Evidence • Vestigial structures: • Structures that no longer serve a function • These structures are the remnants of an evolutionary past and show common anatomy with other species

  15. Evidence for Evolution • DNA  RNA  proteins • ***Mutations and sexual reproduction are a cause of variation (differences) in a species’ DNA. • Differences in DNA are seen in differences in protein

  16. Evidence for Evolution • Molecular: DNA and protein molecules • Ultimate tools for scientists studying evolution  DNA controls traits • Same genetic basis for all organisms: A, C, T, and G shows we are all related • Species with more similar DNA are more closely related on the evolutionary tree—less time to accumulate mutations (and, therefore, differences)

  17. What evolution IS NOT Biological Evolution... • is NOT an educated guess, it is a THEORY • is NOT something one should believe in...(it's based on science, not faith). • is NOT concerned with the origin of life... (it deals only with the origin of species). • is NOT just concerned with the origin of humans...(no more than any other species). • was NOT discovered or first explained by Charles Darwin...

  18. What evolution IS NOT • is NOT the same thing as natural selection • is NOT something that happened only in the past... • is NOT something that happens to individuals...(it happens to POPULATIONS). • is NOT an accidental

  19. What evolution IS NOT • does NOT have any evidence against it • was NOT contrived to undermine religion...(we tried to make sense of observations of life in a testable way). • does NOT deny the existence of God, it is neutral; God is neither required nor eliminated. For all we know, evolution could be part of God's creation, but science cannot determine that. If these popular misconceptions about evolution are all wrong, then what IS evolution?

  20. What evolution IS Biological Evolution is... • The genetic change of a population of species over time. • The idea that new species develop from earlier species by accumulated genetic mutations descent with modification. • life comes from life • speciation proceeds with time, increasing the number of species that become increasingly different. • Has been directly observed in some species, and inferred in many others from clear independent evidence mainly in anatomy, embryology, paleontology, geology, and molecular biology.

  21. What evolution IS • Natural selection is observed constantly, and its role as the main driving force of evolution (as Charles Darwin proposed) has been observed, tested and challenged many times and in many ways. • The Theory of Evolution by Natural Selection holds the high status of near certainty: it’s a scientific theory • There are no observations of life, living or extinct, that evolution cannot explain. • Why is evolution controversial anyway?

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