Evolution:%20How%20species%20change%20and%20how%20new%20species%20are%20created

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Evolution How species change and how new species
are created

• Why do species seem to be molded to their
  habitats?
• Fossil evidence tells us that species change over
  time. Some species disappear (go extinct) and
  other species appear. How does this happen?
• Why can the introduction of a new species into an
  ecosystem cause disruption?

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Important Terms
Evolution All the changes that have transformed
life on Earth from its earliest beginnings to the
diversity that characterizes it today. Natural
Selection Process by which a particular
beneficial gene or genes is reproduced more than
other genes in succeeding generations. Biodiversit
y Variety of different species.
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Jellybean experiment
Jellybeans are your favorite prey
The following slide contains a forest filled with
delicious jellybeans. See which ones you can
capture in 5 seconds. Record how many of each
color you can catch.
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Jellybean forest
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Results
Eaten
Blue Black Yellow Green





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Implications
Start
Survivors
(reproduction)
Next Generation
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Genetic variation
There must be genetic variation in traits
(characteristics) on which natural selection can
operate. For jellybeans it could be color or ???
versus
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Example of the Peppered Moth
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Example of natural selection Changes in moth
color due to changes in the color of tree trunks
in England in the 19th and 20th centuries
moths
pre-industrial tree trunks and moths
post-industrial tree trunks and moths
tree trunks
post-industrial pollution controls