Evolution

1
Evolution

• Scientific theory that living things change over
  the course of time and all living things, to some
  extent, are genetically related to one another.

2

• 1859 - Darwin and Wallace
• Natural Selection
• -Individuals in a population vary
• -More individuals are produced then can survive
• -Life is difficult, there is competition, not
  all survive
• -The better adapted survive and reproduce
• Evidence of Natural Selection
• DDT resistant insects
• Bacteria resistant to antibiotics
• Industrial melanism
• the peppered moths
• artificial selection

3
Evidence of Biological Evolution

• Morphology
• Homologous organs dog and human hand basically
  the same
• Organ Systems become more complex
• Vestigial organs useless organs
• ex appendix, coccyx, wisdom teeth.
• Biochemistry similarity in all organisms (DNA
  and amino acids)
• Cells
• Embryology

4

• Fossil Record
• Radioactive Dating radioactive elements decay
  into stable products at specific constant rates
• example uranium to lead has a half life of 4.5
  billion years, when igneous rocks are formed from
  lava they contain uranium. Therefore by
  measuring the ratio of U to Pb in the rock the
  age of the fossil is discovered.
• Oldest Fossil found 3.4 billion years old

5

• Biogeography
• animals and plants are NOT found everywhere they
  could survive
• example alligators found only in rivers of SE
  U.S. and in China, kangaroos only found in
  Australia.
• Because each species originates only once and
  that place where it originated is its center of
  origin. Then they spread out until halted by a
  barrier.

6

• Convergent Evolution when unrelated or
  distantly related organisms possess similar
  adaptations
• examples
• eyes evolved separately 8 times
• plants unrelated to cacti have similar
  characteristics to reduce water loss
• Divergent Evolution each group spreads out and
  occupies as many different habitats and niches as
  possible.
• Ex Galapogos finches
• 9. Co Evolution Mutual evolution of two
  different species interacting with each other.
  Example fruit bat and flower

7
The Evolving Earth

• Why did no life exist on Earth in the very
  beginning?
• Before the increase in atmospheric ozone, what
  did early bacterial life use to protect itself
  from the damaging UV radiation?
• Before life could successfully exist on land,
  what significant change in Earths atmosphere had
  to occur?
• At the end of the Mesozoic Era a massive asteroid
  impact occurred on Earth. Did the impact result
  in a mass extinction of all life on Earth?

8

• When do you see greater biological diversity?
• Why do complex organisms appear so late in our
  biologic and geologic history?