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Patterns In Evolution

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Title: Patterns In Evolution


1
Patterns In Evolution
2
Two Major Patterns Observed
MACROevolution And microevolution
3
Macroevolution
  • Macroevolution evolution of groups larger than
    an individual species. Takes a long period of
    time

4
Macro looking at bigger sections of evolution
5
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

6
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

7
Adaptive Radiation
  • A single species or a small group of species
    evolved into several different forms and live in
    different ways
  • Darwins Finches

8
Convergent Evolution
9
  • 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)

10
Convergent Evolution
11
Divergent Evolution
  • Because of different environments organisms begin
    to look more and more different over generations
  • Ex) Dog and Wolf

12
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

13
Coevolution
14
Macroevolution is also influenced by RATE
  • Rate how quickly the evolution occurs
  • Quick Punctuated Equilibrium
  • Gradual Gradualism

15
Punctuated Equilibrium
  • Pattern of long, stable periods interrupted by
    brief periods of rapid changes. Punctuated on the
    right

16
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

17
Gradualism
  • slow change in a population over a long period
  • of time

18
Microevolution
  • Quick change in gene frequency within a
    population.
  • Quicker then macroevolution.
  • observed over short periods of
  • time
  • Examples Antibiotic resistance,
  • Pesticide resistance

19
Microevolution
20
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

21
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.

22
What caused the microevolution?
  • Mutations in genes
  • Migration of organism
  • Genetic Drift of alleles
  • Natural Selection of the environment for a given
    trait
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