Evolution and Agents of Evolution

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Evolution and Agents of Evolution

• Chapters 2 and 17

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Origin of Species

• Special creation- each of the different kinds of
  organisms were created in their present form.
• Inheritance of acquired characteristics- the
  modifications an organism acquires during its
  lifetime can be passed along to its offspring.

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Figure 17.1
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Charles Darwin- 1831 HMS Beagle
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Observations by Darwin in the Galápagos

• Two Important Observations
• 1) Plants and animals on the island were similar
  to those on the nearby mainland.
• 2) Phenotypic variation occured between organisms
  from island to island.

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Darwin repeatedly emphasized two points in his
book.

• Species evolve from other species. He termed this
  "descent with modification"
  Evolution
• The mechanism or driving force of evolution is
  Natural Selection

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Darwin cited the following in support of Natural
Selection

• Variation occurs in every group of plants and
  animals.
• All organisms have the potential to
  over-reproduce.
• Natural resources are limited.
• Only the most adapted to the local environment
  survive and pass along traits to the next
  generation.

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Darwin's own sketches of Galápagos finches. (1)
Large ground finch Geospiza magnirostris(2)
Medium ground finch Geospiza fortis(3) Small
tree finch Camarhynchus parvulus (4) Warbler
finch Certhidea olivacea
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Agents of Evolution

• Mutation
• Migration
• Genetic Drift
• Nonrandom Mating
• Selection

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Mutation- a change in the DNA sequence.
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Migration- the movement of individuals between
populations.
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Genetic Drift- the random change of allele
frequencies.
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Nonrandom mating- individuals with certain
genotypes mate with one another more commonly
than would be expected on a random basis.
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Natural Selection- the process by which
individuals that are better adapted than others
in meeting the challenges of their habitat
produce more offspring.

• Three Types of Natural Selection
• Stabilizing
• Disruptive
• Directional

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Stabilizing Selection
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Disruptive Selection
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Directional Selection
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Evolutions Critics

• Chapter 17

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Argument 1

• Evolution if not solidly demonstrated.
• Evolution is just a theory.

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Argument 2-There are no fossil intermediates.
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Argument 3

• The intelligent design argument.
• The organs of living creatures are too complex
  for a random process to have produced.

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Takechi Kuratani 2010.
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Argument 4

• Evolution Violates the 2nd Law of Thermodynamics.

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Argument 5

• Proteins are too improbable.

Oct. 5th
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Argument 6

• Natural Selection does not imply evolution.

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Argument 7

• Life could not have evolved in water.

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Irreducible Complexity- Michael Behe