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Evolution is not “just” a theory!!!

Evolution is not “just” a theory!!!. It is a scientific theory (well supported by different lines of evidence). The evidence for evolution is overwhelming. Evidence for evolution. Fossil Record Biogeography Comparative embryology and anatomy Molecular biology Lab and field experiments.

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Evolution is not “just” a theory!!!

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  1. Evolution is not “just” a theory!!! • It is a scientific theory (well supported by different lines of evidence) The evidence for evolution is overwhelming.

  2. Evidence for evolution • Fossil Record • Biogeography • Comparative embryology and anatomy • Molecular biology • Lab and field experiments http://www.pbs.org/wgbh/evolution/educators/teachstuds/svideos.html

  3. 1. Fossil RecordsFossils: evidence of ancient life Learn about the age, and features of extinct animals Date layers of rock; Age of organisms by radiocarbon dating

  4. The fossil record documents the process of natural selection.

  5. Valley of the Whales An Egyptian desert, once an ocean, holds the secret to whale evolution https://www.youtube.com/watch?v=q553LpBWaVM

  6. Current News: Homo Naledi, New Species in Human Lineage, Is Found in South African Cave Sept 2015

  7. Age of fossil?? Old or young? The oldest rock layers (and therefore the oldest fossils) are on the bottom, and the youngest are on top.

  8. Radiometric dating confirms that the earth is very old and makes it possible to determine the age of fossils. • By analyzing fossil remains, paleontologists can reconstruct what organisms looked like long ago, learn how organisms were related to each other, and understand how groups of organisms evolved over time

  9. If an element has a half-life of twenty million years, and there is 25% of it remaining in a rock, how old is the rock? • 10 million years • 20 million years • 40 million years • 60 million years

  10. Fossils are an incomplete record. Why? - No fossils for many species - Environment can lead to variations - Few fossils from ocean - Most fossils from northern hemisphere

  11. Transitional forms • Fossils or organisms that show the intermediate states between an ancestral form and that of its descendants are referred to as transitional forms.

  12. How do you find the transitional or intermediate forms of fossils? Find rocks of the right age and right type that the transitional fossil should be in.

  13. The half-life of an element is _____ A.The amount of particles that the element loses in half of its life. B.The amount of time it takes for half of the molecules of that element to transform into the daughter element. C.The amount of time it takes that element to lose half of its daughter elements.

  14. Most mammals do not drink milk after they are weaned because they lose the ability to digest lactose. This is true for about 60% of people. But, most people of northern European descent can drink milk (areas where dairy farming is historically prevalent). What type of evolution would this exemplify? A. Directed selection B. Stabilizing selection C. Disruptive selection

  15. 2. Biogeography:Geographic patterns of species distributions reflect species’ evolutionary histories

  16. Distribution of certain fossils provide evidence that the continents have moved (continental drift) During this time, 255 million years ago, Glossopteris was found all over a large supercontinent called Gondwanaland. When this supercontinent split apart into separate land masses (continents), the plants were simply carried along with the land.

  17. South American and Australian midges (a type of insect), are more closely related to one another than they are to New Zealand species, and the midges of all three land masses are more closely related to one another than they are to African species. Which continent split off first? • South America • Africa • New Zealand • Australia

  18. 3. Comparative anatomy and embryology reveal common evolutionary origins.

  19. Homologous StructuresDivergent evolution

  20. Another example of divergent evolution

  21. Analogous structuresConvergent Evolution Analogous traits: Features that are produced by convergent evolution Analogous structures all developed from different original structures. • Evolved separately as adaptations to similar environments. • Eg: Insect wings and bird wings • Insect wings and bat wings

  22. Another example of Convergent evolution

  23. Analogous structures in plants Canary Island cacti American cactus

  24. Homologous Structures/Features/traits Common Ancestry Evolved Form A Ancestral Basic Form Evolved Form B Evolved Form C Morphological Divergence

  25. Analogous Features (different ancestry) Ancestral Form A Similar Forms Ancestral Form B Morphological Convergence Ancestral Form C

  26. Vestigial Structures Vestigial structures: had value once upon a time; evolutionary leftovers Eye sockets in cave fish Molars in vampire bats Nictitating membrane in humans

  27. In _______ , the unrelated species become more similar as they adapt to the same kind of environment A. Convergent evolution B. Divergent evolution C. Stabilizing selection D. Disruptive selection

  28. 4. Molecular biology Darwin’s hypothesis: All forms of life are related to some extent • Compare DNA, RNA, proteins, even lipids of different organisms • Universal genetic code: UUA = leucine • Homeotic genes, housekeeping genes • Vestigial genes

  29. Vestigial genes • Genes for yolk protein • Genes for making Vitamin C • Olfactory receptor genes Homeotic genes Genes involved in Development of body Patterns. http://www.pbs.org/wgbh/evolution/library/03/4/l_034_04.html Eyeless gene

  30. Recency of Common Ancestry • Estimates of evolutionary relatedness made from: • Comparative Anatomy • Embryology • The Fossil Record • “Molecular Clocks” The longer two species have been evolving on their own, the greater the number of genetic differences that accumulate.

  31. Evolutionary treePhylogenetic treeCladogram Trees show the degree of relatedness among different species Nodes The common ancestor points at which species diverge Nodes Nodes Nodes

  32. Which species is the common ancestor of gorillas, humans, chimps and bonobos? • Species A 2. Species B 3. Species C Species C Species B SpeciesA

  33. From the diagram below, gorillas are more closely related to humans than they are to orangutans • True • B. False

  34. Humans are more closely related to birds than to frogs. Which image shows that? • Image A • Image B • Both images A and B

  35. 5. Laboratory and field experiments enable us to watch evolution in progress. From observations of multi generation experiments Replicated, controlled laboratory selection experiments and long-term field studies of natural populations allow us to watch and measure evolution as it occurs We can also do Mathematical modeling

  36. Changes in the Frequency of the Various Alleles

  37. Fossils Biogeography Molecular biology Experiments Anatomy Puzzle pieces provide evidence for: • Different organisms are related to one another • All species diversified from a common ancestor • Evolution, explains the unity and diversity of life. Embryology

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