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EVOLUTION

EVOLUTION. Evidence of Change. Evolution:. The process by which modern organisms have descended from ancient organisms. Charles Darwin. First published his book “ Origin of the Species by Means of Natural Selection” in 1859. .

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EVOLUTION

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  1. EVOLUTION Evidence of Change

  2. Evolution: The process by which modern organisms have descended from ancient organisms

  3. Charles Darwin • First published his book “Origin of the Speciesby Means of Natural Selection” in 1859. .

  4. In this book, he explained that if you look back far enough in time, you would see that all species have a common ancestor. He called this the principle of Common Descent.

  5. He also explained that because of the VARIATION that naturally occurs within species, some individuals will have more FITNESS to survive than others. Those individuals will have a better chance ofREPRODUCING, and passing on the advantageous GENES. • He called this process ADAPTATION.

  6. http://www.hww.ca/hww2.asp?id=94 The mountain sheep is very agile, it has high ability to climb steep terrain How does a longer neck help a giraffe adapt to its environment? Birds keep track of 7 others -gives them ability to stay close together http://www.gla.ac.uk/~gbza22/jpegs/birds/starling.jpg http://www.youtube.com/watch?v=YadP3w7vkJA&feature=related

  7. Adaptations Inuit people, who live in the extreme cold of the Arctic, have short, stout bodies that conserve heat.

  8. Plant adaptations Venus Fly Trap • Captures animals • Acquires minerals for photo- synthesis

  9. An example: Bird vocalization • Birds call/sing to • Attract mates • Defend their territory Cawing crow Songbird Owl hoots

  10. Reid et al. (2005) used 20 years of data from song sparrows on Mandarte Island, B.C., Canada • Result: males with larger song repertoires contributed more offspring and grand-offspring to the population • This was not because females mated to males with larger repertoires laid or hatched more eggs • Rather, these males (1) lived longer; and (2) reared a greater proportion of hatched chicks to independence http://209.85.173.104/search?q=cache:FQlkM9-WVrIJ:www.sjsu.edu/faculty/fry/123/birdsong2.pdf+bird+songs,+fitness&hl= en&ct=clnk&cd=3&gl=ca A recent study by Reid et al. (2005) used 20 years of data A recent study by Reid et al. (2005) used 20 years of data A recent study by Reid et al. (2005) used 20 years of data A recent study by Reid et al. (2005) used 20 years of data from song sparrows on Mandarte Island, B.C., Canada from song sparrows on Mandarte Island, B.C., Canada from song sparrows on Mandarte Island, B.C., Canada from song sparrows on Mandarte Island, B.C., Canada • Result: males with larger song repertoires contributed more • Result: males with larger song repertoires contributed more • Result: males with larger song repertoires contributed more • Result: males with larger song repertoires contributed more offspring and grandoffspring to the population offspring and grandoffspring to the population offspring and grandoffspring to the population offspring and grandoffspring to the population • This was not because females mated to males with larger • This was not because females mated to males with larger • This was not because females mated to males with larger • This was not because females mated to males with larger repertoires laid or hatched more eggs repertoires laid or hatched more eggs repertoires laid or hatched more eggs repertoires laid or hatched more eggs • Rather, these males (1) lived longer; and (2) reared a greater • Rather, these males (1) lived longer; and (2) reared a greater • Rather, these males (1) lived longer; and (2) reared a greater • Rather, these males (1) lived longer; and (2) reared a greater proportion of hatched chicks to independence proportion of hatched chicks to independence proportion of hatched chicks to independence proportion of hatched chicks to independence

  11. Where is the evidence? • Fossil evidence (palaeontology) • Radioactive dating in sedimentary rock (stratigraphy) • Comparative embryology • Comparative biochemistry

  12. EVIDENCE OF EVOLUTION IN STONE • Hutton and Lyell proposed that Earth was very old and had changed slowly and gradually over time. James Hutton Charles Lyell

  13. FOSSILS: Geologists have discovered fossils of organisms that no longer EXIST, but have very similar CHARACTERISTICS to present-day species.

  14. Many of these fossils could be compared and placed in a plausible SEQUENCE of change from ANCIENT organisms to the present day. This isn’t proof, but it is a piece of EVIDENCE.

  15. Fossils are formed along with SEDIMENTARYrock. Sometimes, parts of organism’s bodies are PRESERVED.

  16. Other times, rock forms around the HARDER parts of the dead organisms, (the BONES, WOOD, SHELLS) and it creates a bit of a MOLD. The ORGANIC material from the bodies will eventually be REPLACED by harder, longer lasting INORGANIC compounds inside those “molds”. They call this process PETRIFICATION.

  17. Fossilization is a tricky process, requiring VERY SPECIFIC CONDITIONS, and so the fossil record has to be put together like a PUZZLE that has many broken and lost pieces!

  18. Fossil succession of the Trilobite genera Cambrian Ordovician Wherever these fossils are found they always occur in the same succession. Silurian Devonian

  19. http://cache.eb.com/eb/image?id=46897&rendTypeId=4 http://www.geocities.com/mrbbug1/meso4.jpg • Discovery of fossils • Some of the fossils resembled living organisms; others did not

  20. The Fossil Record What are sedimentary rocks? • Rock that forms when grains of eroded rock and other materials are carried to the bottom of a body of water and build up under pressure into layers http://www.ucmp.berkeley.edu/education/explorations/tours/stories/middle/C7.html Most fossils are found in sedimentary rock

  21. B. Sedimentary Rocks and Geology • Using the LAW OF SUPERPOSITION geologists can find the RELATIVE date of fossils.

  22. The law states that the LOWER layers of SEDIMENTARY rock are OLDER than the upper layers. Fossils found in the layers of rock are the same RELATIVE AGE as the rock itself.

  23. Through RADIOACTIVE DATING geologists are able to tell the ABSOLUTEage of some preserved bones that have been uncovered, or determine the absolute age of some of the ELEMENTS that are found in the IGNEOUS rocks surrounding the fossils.

  24. Using RADIOACTIVE DATING, geologists have calculated that the Earth is about 4.5 BILLIONyears old.

  25. The fossil record shows us that change happened first on the EARTH, and then change in the organisms FOLLOWED.

  26. 2. EVIDENCE IN COMPARATIVE EMBRYOLOGY When you compare EMBYROSof several species in an EARLY STAGE of their development, they are very SIMILARin APPEARANCE. Later, the EMBRYOS look vastly DIFFERENT. Why?

  27. The theory of EVOLUTION explains these different animals had a COMMON ANCESTOR that passed down the sequence of developmental GENES. As the animals evolved, they added steps to the developmental sequence.

  28. 3. Evidence in Comparative Anatomy • Many species have HOMOLOGOUS structures – body parts that have very similar INTERNAL structure but they have different FUNCTIONS.

  29. Homologous structures: parts of different organisms, often quite dissimilar, that developed from the same ancestral body parts. Bird Wing Porpoise Flipper

  30. Homologous structures: body parts that have very similar internal structurebut they have different functions Bird Wing Porpoise Flipper

  31. Examples include: human arm and BAT WINGS human arm and WHALE FLIPPERS One of the classic examples of a homologous structure is the pentadactyl (= five digit) limb.

  32. VESTIGIAL STRUCTURES There are also many VESTIGIAL structures – body parts present that are similar to those of other organisms, but are NO LONGER USED.

  33. Examples include: HUMAN APPENDIX SNAKE LEGS

  34. Wisdom teeth Cassowary Male breast tissue and nipples Human tail bone

  35. The wings on flightless birds (e.g. The cassowary) • Wings of a bird are adapted for flight • Not completely useless, use for balance during running • Human tail bone (coccyx) • Fused vertebrae, only vestige left of tail that other animals use for balance, communication, (for some primates as a prehensile limb) • Wisdom teeth • Human jaw got smaller over time • How may have it been beneficial to our ancestors? • Male breast tissue and nipples • Was man descended from a woman? No! During early stages of fetal development a fetus is sexless. Later in development testosterone causes sex differentiation. • A small number of men have been able to lactate. • Cancer can grow on male and female breast tissue

  36. Hind leg bones in whales Whiptail lizards

  37. Fake sex in virgin whiptail lizards (vestigial behaviour) • Only females exist in several species of lizards • Reproduce by parthenogenesis (unfertilized egg develops into a new individual, forming clones of themselves) • They still try copulating, though futile • Hind leg bones in whales • Biologists believe that for 100 MYA the only vertebrates on Earth were water-dwelling creatures with no arms or legs • The “fish” began to develop hips and legs, eventually able to walk out of water • Land dwelling creatures evolved, some mammals moved back into water (50 MYA) ancestors of modern whales • Traces of hind legs—can be seen even now.

  38. The Sexual Organs of Dandelions The Blind Fish Astyanax Mexicanus

  39. Sexual organs of dandelions • Like many flowers that have proper organs (stamen and pistil) for sexual reproduction, but do not use them • Instead, they make clones of themselves • Asexual reproduction can be a good strategy in an environment that is constant, if species are well suited • Blind fish • Species of fish dwell in caves deep underground off the coast of Mexico; they cannot see • Has eyes, but as they develop in egg, their eyes degenerate • Born with collapsed remnant of eye covered by a flap of skin • Fish of the same species that live directly above the blind fish, near the surface where there is plenty of light, have functioning eyes • Scientists have removed lenses from surface water fish, implant them into blind eye fish, can develop functional eye with pupil, cornea, and iris.

  40. Human appendix Biologists believe it is a vestigial organ left behind from a plant-eating ancestor Snakes “legs”

  41. **do not confuse HOMOLOGOUS structures with ANALOGOUS structures – ANALOGOUSstructures have a similar FUNCTIONS but have very different INTERNAL structure.

  42. Bird Wing Fly wing EXAMPLES: Bird Wings and FLY WINGS

  43. Analogous: Whale fin and Fish Fin

  44. Comparative anatomy structures Analogous: • Different ancestors • “analogy”=like • Different underlying structures • Same Function • Similar Environments Homologous: • Same ancestor • “homo”=same • Same underlying structures • Different Functions • Different Environments

  45. Comparative Biochemistry • Almost all living organisms use the same basic biochemical molecules, including DNA, ATPand many enzymes. • In fact, molecules such as hemoglobin have been used to determine how distantly related some species are. http://www.sciencecollege.co.uk/SC/biochemicals/haemoglobin.jpg Haemoglobin is the iron-containing protein attached to red blood cells that transports oxygen from the lungs to the rest of the body

  46. The greater the number of differences in the molecule, the more distantlyrelated the organism are. http://newsimg.bbc.co.uk/media/images/42343000/gif/_42343831_evolution_tree_2_416.gif

  47. Comparative Biochemistry • similar DNA sequences= similar gene segments of the DNA • Code for similar traits in closely related species

  48. NATURAL VARIATION

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