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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?
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.
Biodiversity: Variety of different species.
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.
Jellybean forest
Results
#Eaten:
Blue
Black
Yellow
Green
Implications
Start
Survivors
(reproduction)
Next
Generation
Genetic variation
There must be genetic variation in
traits (characteristics) on which
natural selection can operate. For
jellybeans it could be color or ???
versus
Example of the Peppered Moth
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
pre-industrial tree
trunks and moths
post-industrial
tree trunks and
moths
post-industrial
pollution controls