Patterns In Evolution

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Patterns In Evolution
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Two Major Patterns Observed
MACROevolution And microevolution
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Macroevolution

• Macroevolution evolution of groups larger than
  an individual species. Takes a long period of
  time

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Macro looking at bigger sections of evolution
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The 6 Patterns that influence how macroevolution
occurs are

• 1-Mass Extinctions -
• 2-Adaptive Radiation
• 3-Convergent or Divergent Evolution
• 4-Co-evolution
• 5-Punctuated Equilibrium
• 6-Gradualism

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Mass Extinction

• Loss of complete huge number of species and
  ecological systems
• Causes could be
• large asteroid during the Cretaceous period l
  throwing huge amonts of dust and vapor? altering
  global climate? affects organismslike dinosaurs
• Volcanic eruptions, continental shifts, changing
  sea levels, other major environmental changes

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Adaptive Radiation

• A single species or a small group of species
  evolved into several different forms and live in
  different ways
• Darwins Finches

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Convergent Evolution
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• Unrelated organisms come to resemble each other
• This effect is due to different organisms
  undergoing adaptive radiation in different places
  BUT in ecologically similar environments
• Face similar environmental demands
• Examples streamlined bodies and flippers of
  water organism ( shark, dolphin, seals,
  penguins)

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Convergent Evolution
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Divergent Evolution

• Because of different environments organisms begin
  to look more and more different over generations
• Ex) Dog and Wolf

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Coevolution

• Two species evolve in response to each other due
  to ecological interactions
• Flowers and insects(Madagascar orchid and hawk
  moth)
• Plants and plant eating insects plants have
  developed poisons to prevents plant eating
  insects from feeding on them. Natural selection
  in insect eating plant favored variants that
  could alter, inactivate, or eliminate the
  poisons? both organisms change in response to
  each other

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Coevolution
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Macroevolution is also influenced by RATE

• Rate how quickly the evolution occurs
• Quick Punctuated Equilibrium
• Gradual Gradualism

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Punctuated Equilibrium

• Pattern of long, stable periods interrupted by
  brief periods of rapid changes. Punctuated on the
  right

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When does this type of evolution occur?

• Small populations become isolated from the main
  part of the population .Population changes
  quicker because genetic changes can spread more
  quickly among fewer organism
• Small group of organisms migrate to a new
  environment? GALAPAGOS FINCHES

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Gradualism

• slow change in a population over a long period
• of time

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Microevolution

• Quick change in gene frequency within a
  population.
• Quicker then macroevolution.
• observed over short periods of
• time
• Examples Antibiotic resistance,
• Pesticide resistance

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Microevolution
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Antibiotic resistance

• Bacteria can evolve quicker when they are
  resistant to the antibiotic. This is because of
  genetic shuffling due to their quick reproduction
  rates?which means more chances for mutation
  (changes)? less likely to be killed by
  antibiotics if they have changed their genes? SO
  SMART!!
• http//www.pbs.org/wgbh/evolution/library/11/2/qui
  cktime/e_s_6.html

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Microevolution example

• Imagine that you go to the mountaintop this year,
  sample these beetles, and determine that 80 of
  the genes in the population are for green
  coloration and 20 of them are for brown
  coloration. You go back the next year, repeat the
  procedure, and find a new ratio 60 green genes
  to 40 brown genes.
• You have detected a micro evolutionary pattern a
  change in gene frequency. A change in gene
  frequency over time means that the population has
  evolved.

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What caused the microevolution?

• Mutations in genes
• Migration of organism
• Genetic Drift of alleles
• Natural Selection of the environment for a given
  trait