Hardy Weinberg Quiz

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Hardy Weinberg Quiz

• In 1909, in the state of Georgia 23 azalea bushes
  out of every 150 showed the recessive (mutation)
  phenotype of white flowers. In 2009, 99 out of
  every 220 azaleas in Georgia had white flowers.
  In a study researchers observed grazing animals
  preferred pink colored azalea flowers to eat.
• 1. List the 5 conditions of the Hardy Weinberg
  Theorem. List one that does NOT apply to this
  scenario.
• 2. Work the Hardy Weinberg Eq. for both years.
• a) 1909 q2, q, p, p2, 2pq
• b) 2009 q2, q, p, p2, 2pq
• 3. Did microevolution occur? Support your answer
  with data.
• 4. Is this example natural selection or genetic
  drift? Support your answer.

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Speciation

• The outcome of evolution
• THERE ARE ALWAYS NEW SPECIES BEING FORMED.
• WHY?!?!

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The 49th species of lemur in the rain forest
why so many?

• Competition
• Old species
• Stable climate

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Biological Species Concept

• Species are groups of interbreeding natural
  populations that are reproductively isolated from
  other such groups.
• Ernst Mayr

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What do you get when you cross a mouse with a
mango?
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Morphology Species

• Morphological traits may not be useful in
  distinguishing species
• Members of same species may appear different
  because of environmental conditions
• Morphology can vary with age and sex
• Different species can appear identical

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Variable Morphology
Grown in water
Grown on land
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Convergent Evolution
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Speciation Natural Selection

• Natural selection can lead to speciation
• Speciation can also occur as a result of other
  genetic drift
• Founder Effect
• Bottleneck effect

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Reproductive Isolation

• Speciation is the result of reproductive
  isolation
• Reproductive isolation arises as a by-product of
  gene pool changes

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Barriers to Gene Flow

• Whether or not a physical barrier deters gene
  flow depends upon
• Organisms mode of dispersal or locomotion
• Duration of time organism can move

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Genetic Divergence

• Gradual accumulation of differences in the gene
  pools of populations
• Natural selection genetic drift can contribute
  to genetic divergence
• Gene flow counters divergence

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Genetic Divergence
parent species
daughter species
time A
time B
time C
time D
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Reproductive Isolating Mechanisms

• Prezygotic isolation
• Mating or zygote formation is prevented
• Postzygotic isolation
• Takes effect after hybrid zygotes form
• Zygotes may die early, be weak, or be sterile

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Odd looking frog?!?
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Prezygotic Mechanisms

• Geographic Isolation
• Temporal Isolation
• Behavioral Isolation
• Gametic Mortality

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Postzygotic Mechanisms

• Zygotic mortality
• Hybrid inviability
• Hybrid sterility

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Types of Speciation

• Allopatric speciation
• Sympatric speciation
• Parapatric speciation

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Allopatric Speciation

• Speciation in geographically isolated populations
  
• Some sort of barrier arises and prevents gene
  flow
• Effectiveness of barrier varies with species

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Speciation in Darwins Finches
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NEW SPECIES DISCOVERED IN Isolated area of
INDONESIA

• What is this?
• New found KANGAROO SPECIES

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Extensive Divergence Prevents Breeding

• Species separated by geographic barriers will
  diverge genetically
• If divergence is great enough it will prevent
  breeding even if the barrier later disappears

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Speciation without a Barrier

• Sympatric speciation
• Species forms within the home range of the parent
  species
• Parapatric speciation
• Neighboring populations become distinct species
  while maintaining contact along a common border

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Speciation by Polyploidy - Sympatric

• Change in chromosome number (3n, 4n, etc.)
• Offspring with altered chromosome number cannot
  breed with parent population
• Common mechanism of speciation in flowering plants

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Parapatric Speciation

• Adjacent populations evolve into distinct
  species while maintaining contact along a common
  border

BULLOCKS ORIOLE
BALTIMORE ORIOLE
HYBRID ZONE
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Macroevolution

• Evolution over thousand/million/billion years
• Large scale, long term speciation events
• Ex birds from lizard ancestor
• Evidence fossil record, DNA, geology

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Macroevolution Punct. Eq. vs. Gradualism
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Patterns of Change in a Lineage

• Cladogenesis punct. eq.
• Branching pattern
• Lineage splits, isolated populations diverge
• Anagenesis - gradualism
• No branching
• Changes occur within single lineage
• Gene flow throughout process

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Gradualism Model

• Speciation model in which species emerge through
  many small morphological changes that accumulate
  over a long time period
• Fits well with evidence from certain lineages in
  fossil record

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Punctuation Equilibrium Model

• Stephan J. Gould
• Changes in morphology are compressed into brief
  period near onset of divergence
• Major catastrophies (extinction) ? Adaptive
  radiation (burst of speciation)

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Extinction

• Irrevocable loss of a species
• Mass extinctions have played a major role in
  evolutionary history
• Fossil record shows 6 MAJOR extinctions
• Reduced diversity is followed by adaptive
  radiation

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Who Survives?

• Species survival is to some extent random
• Asteroids have repeatedly struck Earth, other
  catastrophies destroying many lineages
• What is left has open niches and radiates
• Ex Mammals go from being appetizer for T-Rex
  (small and quick) to taking dominant role on
  earth 65MYA

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Adaptive Radiation

• Burst of divergence
• Single lineage gives rise to many new species
• New species fill vacant adaptive zone
• Adaptive zone is way of life explosion of
  niches being filled after vacancy

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Galapagos FinchesFrom 1 ancestor finch to many
species
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Adaptive Radiation
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Co-Evolution (AKA Co-speciation)

• Two species evolve in response to one another
• Ex Pollinating insects and flowering plants
• Usually associated with symbiosis

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Mystery Bee Disappearances Sweeping U.S.

• LIKE ORANGE JUICE?

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Co-Evolution of Parasite and Host
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CO-OPERATION A BEHAVIORAL ADAPTATION

• Altruistic genes hawk/dove experiments