Lecture 1 Notes BILD 3

• Overview of Evolution


  • Mutation
  • More favorable traits more likely to be passed down
  • External environment shapes the species
  • Traits that lend to higher reproduction rates spread over time
• Evolution


  1. Mutation

  2. More favorable traits more likely to be passed down

  3. External environment shapes the species

  4. Traits that lend to higher reproduction rates spread over time
• Evolution


  • Unity & diversity of organisms
• Mutations happen over generations
• Species accumulate difficulties from ancestors
• Trait


  Something you can measure about an organism
• Evolution


  1. Mutation

  2. Traits that lend to higher reproduction

  3. Rules spread over time

  4. Traits that are more favorable

  5. Traits that are more likely to be passed
• Enteral environment


  Shapes the species
• Adaptation


  Organisms adapt to their environment
• Traits


  • Something you can measure about an organism
• Unity and diversity of organisms
• Mutations happen over generations
• Species accumulate differences from ancestors
• Evolution tree
• More recent
• Common ancestor
• Dragonfly


  • Bones
  • Wings
• Hummingbird


  • Wings
• Macaw


  • Backbone
• As lineages become more recent, they have a common ancestor in time
• Lineages become most recent (backbone)
• Lineage the wings are beginning or start of a species
• Convergent evolution


  The process where traits arise separately in different lineages
• Backbone evolution = growth, wings are not
• Homology


  A trait that both species get from a common ancestor
• Evolution


  1. Random genetic

  2. Natural selection
• Observation #1


  Members of a population often vary in their inherited traits
• Observation #2


  All species can produce more offspring than their environment can support, and many of these offspring fail to survive and reproduce
• The conventional wisdom in England and Europe at the time was that each species were thought to have been created individually by God via "special creation"
• Most scholars accepted that the Earth was older than 6,000 years but how old (a few million years?) was unclear
• Paleontologists were finding fossils and documenting extinctions and changes over time
• Principle of Succession


  Living Organisms look similar to the fossils in their region. This is because they are descended from those ancestors, with modification
• Darwin returned to England in 1859 after the voyage
• What Darwin did for 23 years


  Collected reams of evidence to support his ideas that would eventually give rise to the Origin of Species
• Artificial selection


  Darwin bred pigeons and created different kinds of one species simply by selecting for certain traits. This was artificial selection.
• Adaptive radiation


  The diversification of species originating from a common ancestor into a wide variety of ecological niches
• Two main ideas in Darwin's Origin of Species

  • All organisms evolved from a common ancestor via descent with modification & divergence
  • The mechanism was natural selection
• Microevolution


  Short time scales, changes in the gene pool (mutation, gene flow/genetic drift, natural selection). E.g. beak sizes, antibiotic resistance
• Macroevolution


  Long time scales, major changes in traits, origin of new species. E.g. evolution of whales, adaptive radiation of Galapagos Finch species
• Fossil


  Any trace of an organism that lived in the past