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Natural Selection & Evolution

Natural Selection & Evolution. Change or evolve over time. Evolution. Evolution -the gradual change in the characteristics of a species over time . Charles Darwin is the founder of modern evolutionary theory. natural selection is how populations of organisms evolve (change).

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Natural Selection & Evolution

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  1. Natural Selection& Evolution

  2. Change or evolve over time

  3. Evolution • Evolution-the gradual change in the characteristics of a species over time.

  4. Charles Darwin is the founder of modern evolutionary theory. • natural selectionis how populations of organisms evolve(change) Charles Darwin1809-1882 The Theory of Evolution

  5. process by which individuals that are better suited to their environment survive and reproduce most successfully. • It is a mechanism of evolution. Natural Selection

  6. Natural selection in a nutshell Birds and green beetles - Which color beetle has batter chance of survival? Which genetic trait do you think natural selection selects against?

  7. Industrial revolution: late 19th century England

  8. Natural selection: peppered moth

  9. Peppered moths were originally light colored • Pollution caused lichen trees to darken • Light colored moths were eaten • Natural selection favored dark moths (by 1895 , 98 % moths were black) Natural Selection :Peppered Moth

  10. Organisms with less favorable variations(differences) are less likely to survive and pass on traits to the next generation.

  11. Results of Natural Selection • - Speciation • - Diversity • - Extinction

  12. Speciation- is the evolution of a new species. • Occurs only when either interbreeding or the production of fertile offspring (children) is prevented. Speciation

  13. Diversity Variations (differences) are genetic: they are controlled by an organism’s genes

  14. diversity variations: spread through a population as it produces offspring a NEW species may evolve over time from the existing species. - Evolution of an ancestral (old) species into an arrangement of species that occupy different niches is called adaptive radiation.

  15. Extinction Triceratops Wooly mammoth

  16. Extinction Thylacine dodo

  17. Extinction- when the last member of a species dies. • Extinction is a natural event • each species must become adapted to a changing environment • Result: The best genetically adapted species will escape extinction or change through natural selection. Extinction

  18. How do we know Evolution occurred? • 1. the fossil record of change in earlier species • 2.the chemical and anatomical similarities of related life forms • 3.the geographic distribution of related species • 4.  the recorded genetic changes in living organisms over many generations

  19. Fossil Record • Remains of animals and plants found in sedimentary rock deposits are a record of past changes through time.  • It confirms that species are not fixed but can evolve into other species over time.

  20. Fossil Record

  21. Fossil Record

  22. Chemical Similarities • There are tens of thousands of types of proteins in living organisms • yet they are made of only 20 kinds of amino acids.  • Our genetic codes are nearly the same

  23. 3 billion letters A,G,C,T

  24. Compared to a human being…. 96 % 60 % 88% 60%

  25. 90 % 79% 69 % 80 %

  26. Anatomical Similarities • Same types of bone (humerus, radius, and ulna) : • Human arms • Wings of birds • Forelegs of cats and dogs

  27. Why? because they have retained these traits of their shared common ancient vertebrate ancestor.

  28. Anatomical similarities - Homologous features

  29. Anatomical Similarities

  30. Embryological similarities

  31. biogeography Biogeography is a branch of geography that studies the past and present distribution of the world's many species.

  32. Biogeography: the supercontinent (Pangaea)

  33. Biogeography: geographic isolation

  34. Biogeography: geographic isolation

  35. Phylogeny • Comparing present day life with the remains of ancient (old) life forms is an example of phylogeny (evolutionary history) of a species

  36. Phylogeny

  37. End

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