LESSON 3

• Evolution


  Process where organisms are thought to have developed gradually from a simple to a complex form
• Fossil Records


  • Most direct evidence of evolution
  • Study fossils and sedimentary rocks to learn about past environments
• Fossil


  Preserved remains of previously living organisms or their traces from sedimentary deposits, we can know their age through dating of rocks
• Dating Methods


  • Relative Dating - Not Specific, deeper strata were older, upper ones are younger
  • Absolute Dating (Through Radiometric Age Dating) - Specific, significant factor is the degree of radioactive decay, the older the rock, the more isotopes are decayed
• Biogeography


  A discipline in biology that studies the present and past distribution patterns of biological diversity
• Organisms that had already evolved before the breakup of Pangea (200 mya)

  Tend to be distributed worldwide
• Organisms that evolved after the breakup

  Appears
• Comparative Anatomy


  • Helps determine evolutionary relationships between organisms to know if they share common ancestors
• Homologous Structures


  • Similar physical features but completely different functions (shared common ancestors)
  • Present throughout tetrapod but have been modified to serve different functions based on living conditions
• Forelimbs


  • Monkeys - much elongated and adapted for climbing and swinging
  • Horses - used in running and modified for an elongation of the third digit bearing a hoof
  • Anteaters - used their enlarged 3rd digit for tearing down ant nests
  • Whales - forelimbs become flippers for steering during swimming
• Analogous Structures


  Similar physical features and function but do not share a common ancestor
• Embryology


  • All embryos exactly look the same during early stages (vertebrates)
  • Comparative embryology reveals anatomical homologies are not visible in adult organisms
• Evolution


  Process where organisms are thought to have developed
• Gradual development


  From a simple to a complex form
• Fossil Records


  • Most direct evidence of evolution
  • Study fossils and sedimentary rocks to learn about past environments
• Fossil


  Preserved remains of previously living organisms or their traces from sedimentary deposits, we can know their age through dating of rocks
• Relative Dating


  Not Specific, deeper strata were older, upper ones are younger
• Absolute Dating (Through Radiometric Age Dating)


  Specific, significant factor is the degree of radioactive decay, the older the rock, the more isotopes are decayed
• Vestigial Structures


  Remnants of features that served important functions in the organism's ancestor
• Vestigial Structures


  Organs, tissues, or cells that has no clear physiological function known
• Vestigial Structures of Humans


  • Wisdom Teeth
  • Appendix
  • Tailbone
• Wisdom Teeth


  Our diet has evolved
• Appendix


  Acts as a storehouse for good bacteria rebooting the digestive system after illness (theory)
• Tailbone


  Connecting point for many pelvic floors muscle
• Ostrich wings are too small to allow an ostrich to fly
• Vestigial structures are an authentication of evolution and were helpful in explaining adaptation
• Closely related species will be more like one another
• Molecular similarities provide evidence for the shared ancestry of life
• Chimpanzees and Baboons are human's closest relations (similarities only differ 1.2%)
• Central Dogma


  Theory stating that genetic information flows only in one direction (DNA -> RNA -> PROTEIN)