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									NATURAL SELECTION
 Prepared By: Miss Andrea Veira
      19th February, 2011.
                    Evolution
   Change over a long period of time.

   Darwin

   On the Beagle

   Variations favourable for survival accumulate
    from generation to generation; less favourable
    variations die out (extinct)
   What Is Natural Selection?
Scenario: white mice and brown mice are
  hunted by a hawk.

Q1. What happens to the brown mice?

Q2. What happens to the white mice?
Who Can Camouflage Better In A
    Natural Environment?




   http://www.danceswithreptiles.com/PG1/images/2mice.jpg
          Natural Selection Is:
   Process by which organisms remain well
    suited to their normal habitats.

   Those better adapted to environment
    have an increased chance of survival
    others dies before reproducing.

   SURVIVAL OF THE FITTEST!
                        Who Is Stronger?




http://4.bp.blogspot.com/-RFpoFqm5oxs/TVZx82rqc7I/AAAAAAAAAL4/UHP1xLSQY34/s1600/survival1.jpg
What Can Help Survival Of Species?
   Changing environments
    This often leads to adaptations which
    either kill you or help you survive.

   Genetic Variation—link to reproduction
    type being sexual vs asexual
    Examples Of Natural Selection
   Long neck giraffes
   Stretch necks to get
    food
   Selection Pressure:
    tall tree (food)
   Adaptation:stretch
    neck
   Result: long neck
    giraffes
                           http://image.wistatutor.com/content/organic-
                           evolution/lamarckism-in-giraffe.jpeg
    Examples Of Natural Selection
   Antibiotic Resistance in bacteria; those with resistance
    survive and reproduce while the others killed.

http://www.answersingenesis.org/articles/am/v2/n3/antibio
   tic-resistance-of-bacteria

   Mosquitoes resistant to DDT
    (dichlorodiphenyltrichloroethane insecticides)

http://www.blackwellpublishing.com/ridAley/tutorials/The_t
   heory_of_natural_selection__part_1_13.asp
    Examples Of Natural Selection
   Peppered Moth: Biston betularia

   England

   2 forms: pale and dark

   Speckled form (peppered) from countryside-
    lichen covers tree barks

   Black moth (melanic) from towns/cities- soot
    covers tree barks
           Find The Melanic And The
                Peppered Moths




http://users.rcn.com/jkimball.ma.ultranet/BiologyPages/K/Kettlewell.jpg
             Peppered Moth
   Birds prey on the moth

   Which one is likely to survive in the
    country side? And in the cities/towns?

What are the selection pressures in each
 location?
How Can Reproduction Type Affect
          Selection?
Asexual Reproduction     Sexual Reproduction


Stable Environment       Rapidly Changing
                         Environment

Selection Pressure Low   Selection Pressure High
                         (ability to change and
                         adapt greater)
    What Can Be A Result Of Natural
              Selection?

   Speciation: populations adapt to new
    environmental conditions

   Geographic speciation/isolation- Finches in
    Galapagos Islands
     Darwin’s Finches




http://www.galapagoscruises.be/darwins-finches.jpg
                Links To Explore
   http://www.galapagosonline.com/nathistory/wildlife/bird
    s/galapagosbirds.htm

   http://www.truthinscience.org.uk/site/content/view/53/6
    5/

   http://web.visionlearning.com/custom/biology/animation
    s/darwin_finches_working.shtml

   http://evolution.berkeley.edu/evolibrary/article/evo_25

   http://www.globalchange.umich.edu/globalchange1/curr
    ent/lectures/selection/selection.html

   http://www.churchofreality.org/opinion/evolve.htm

								
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