Study guide

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Study guide

• What is biological evolution?
• What was Darwins contribution to evolution and
  who were his mentors?
• Explain natural selection.
• Explain the evidence that supports the theory of
  evolution.
• What are analogous, homologous and vestigial
  structures? Give examples of each.

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Biological evolution

• Biological evolution change in population or
  species over time
• Evidence to support
• 1. Direct observation
• 2. Fossil record
• 3. Biogeographical evidence
• 4. Anatomical evidence
• 5. Embryological evidence
• 6. Biochemical evidence

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Linnaeus
Hutton
Lamarck
Malthus
Cuvier
Lyell
Darwin
Wallace
American Revolution
French Revolution
U.S. Civil War

• Who were Darwins biggest influences?
• Why were Darwins ideas revolutionary?

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Observation 1 Members of a population often
vary greatly in their traitsWhere do these
variations come from?
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• Observation 2 Traits are inherited from parents
  to offspring
• Observation 3 All species are capable of
  producing more offspring than the environment can
  support

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Observation 4 Owing to lack of food or other
resources, many of these offspring do not survive

• Inference 1 Individuals whose inherited traits
  give them a higher probability of surviving and
  reproducing in a given environment tend to leave
  more offspring than other individuals
• Inference 2 This unequal ability of individuals
  to survive and reproduce will lead to the
  accumulation of favorable traits in the
  population over generations

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Lamarck vs. Darwin

• Large biceps muscle of a blacksmith will be
  passed down to his offspring.
• The appendix (vestigial organ) has gotten smaller
  because it is not used.

• Biceps muscles may increase in strength, but this
  does not change the genes passed down to
  offspring.
• Natural selection has favored organisms with a
  reduced version of the appendix.

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Contrasting theories of evolution
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1. Direct ObservationPredation and Coloration
Predator Killifish preys mainly on
juvenile guppies (which do not express the color
genes)
Experimental transplant of guppies
Pools with killifish, but no guppies prior to
transplant
Guppies Adult males have brighter colors than
those in pike-cichlid pools
Predator Pike-cichlid preys mainly on adult
guppies
Guppies Adult males are more drab in color than
those in killifish pools
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2. Fossil record

• The deeper the layer, the older the fossil
• Prokaryotes came first, followed by eukaryotes.

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3. Biogeographical evidence

• Is the study of the distribution of plants and
  animals throughout the world
• Supports the hypothesis that organisms originate
  in one locale and then may spread out
• Different life forms are expected whenever
  geography separates them
• Why are the Galapagos Islands still an ideal
  place to study evolution?

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4. Anatomical evidence Homologous structures
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Analogous structures
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5. Embryological evidence
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6. Biochemical evidence

• Almost all living things use the same
  biochemicals (e.g. DNA and ATP)
• Living things use the same genetic code
• Living things use the same 20 amino acids in
  their proteins
• Living things share many of the same genes
• Genome projects have allowed comparisons

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Natural selection does not create new traits, but
edits or selects for traits already present in
the population. How do new traits arise?
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Study guide

• How are modern humans classified?
• What characteristics do primates have in common?
• Explain the evolution of hominids.
• Explain the evolution of humans.

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The arrival of humans on earth

• D
• K
• P
• C
• O
• F
• G
• S

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Order Primates

• Characteristics
• Opposable thumb
• Stereoscopic vision (depth perception)
• Well-developed brain
• Reduced of offspring (usually a single birth)
  with an increased period of parental care
• Emphasis on learned behavior and social
  interactions
• Two suborders
• Prosimians includes lemurs, tarsiers and
  lorises
• Anthropoids includes monkeys, apes and humans

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Evolution of primates
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Family hominids

• Hominids human lineage on the evolutionary tree
• Characteristics
• Bipedal
• Flatter face with more pronounced chin
• Brain size
• Suggested fossils of the first hominids ( 6-7
  MYA)
• Central African fossil 7 MYA (Sahelanthropus
  tchadensis)
• Eastern African fossil 6 MYA (Orrorin
  tugenensis)
• Eastern African fossil 5.8-5.2 MYA
  (Ardipithecus ramidus)
• Hominids split from the ape line of descent 7
  MYA

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Australopithecines

• A group of hominids that evolved and diversified
  in Africa 3 MYA
• Some had slight frames and others were robust
  with massive jaws that fed on plant materials
• Walked upright
• Small brain
• Famous skeleton named Lucy is from this group
• Australopithecus africanus has a large brain- the
  most likely ancestral candidate for early Homo
• (but it was not alone)

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Australopithecines
What other recent findings do we have?
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Genus Homo

• Brain size is 600 cm3 or greater
• Evidence of tool use
• Jaw and teeth resemble humans
• Early Homo representatives
• Homo habilis
• Homo erectus
• Later Homo representatives
• Neandertals
• Cro-Magnons

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Human evolution
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Early Homo Homo habilis

• Lived 2.0-1.9 MYA
• Large brain with enlarged speech area
• Omnivorous (hunters and gatherers)
• Primitive tools
• Culture may have existed

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Early Homo Homo erectus

• Lived 1.9-0.3 MYA
• Larger brain than H. habilis
• Flat face with the nose projected
• Tall and stood erect
• May have migrated from Africa to Europe and Asia
• Advanced tools and fire (systematic hunters)
• Language may have evolved

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Homo sapiens

• What characteristics will be used to describe us
  in the future?
• Are we still evolving?
• What is the force? Is it natural selection or
• human intervention?