Natural Selection
BIO 241
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Life on Earth- A Group Portrait
How did all of these groups and these organisms emerge?2
Evolution
• Evolution is the change in
inherited traits of a
population over time
• Process that can be
caused by many different
factors:
– genetic drift
– Mutation
– sexual selection &
non-random mating
– natural selection
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Natural Selection
• First proposed by Darwin in 1859 as a
mechanism of evolutionary change
• Changes in the environment act on physical
characteristics within a population, selecting
more successful, better adapted traits over
time
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Natural Selection
• Acts on inherited physical
characteristics within a
population
• Selects more successful traits
to move on to future
generations
• Often coined “survival of the
fittest”
• Only evolutionary force that
can cause adaptive evolution
Classic Example: Darwin’s Finches
• Discovered a variety on
small birds on the
Galapagos islands off the
coast of Ecuador
• Noted the diversity in
their beak sizes and
shapes
• Later concluded that they
were all closely related
•
Given the birds’ isolation away from competition with other birds,
they were able to quickly adapt their physical characteristics (beaks)
and behavior in order to occupy different ecological niches
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This week’s lab
• Natural selection virtual lab simulation
– Explores the survival of prey based on their
coloring and the environment
– You will be the predator trying to eat the prey!
– 3 environment simulations to perform
– Fill in the tables and answer the questions (which
are included in the lab itself-not a separate
document)
• Submit in CANVAS using the submission link
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