EVOLUTION
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Students know and understand the
characteristics and structure of living things,
the processes of life, and how living things
interact with each other and their
environment.
Benchmark 3.18: Organisms change over
time in terms of biological evolution and
genetics.
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Darwin, the Beagle and Finches: 3:59
Darwin’s Discoveries: 10:10
Gene frequency, natural selection, speciation:
29:00
What do you get when you cross a mouse
with a mango? 4:15
Why did the woolly mammoth become
extinct? 2:17
Total time: 49:41 min. (approximately)
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The modern theory
of evolution began
when Charles
Darwin presented
evidence that
evolution happens
and offered an
explanation of how
evolution happens.
Darwin, the Beagle
and Finches (3:59)
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In natural selection,
individuals that have
traits that better suit
their environment are
more likely to
survive.
Artificial selection
occurs when humans
breed offspring to
promote desirable
traits like different
breeds of dogs.
QuickLab pg. 378.
Darwin’s discoveries (10:00)
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In Darwin’s time, the
science of geology
was born.
By studying fossils in
rock formations such
as the Burgess shale
formation in Yoho
Park, Canada,
scientists eventually
deduced that species
evolve gradually over
long periods of time.
Gene frequency, natural selection,
speciation (29:00)
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1. Overproduction: Every population is capable
of producing more offspring than can possibly
survive.
2. Variation exists within every population.
Much of this variation is in the form of inherited
traits.
3. Selection: In a given environment, having a
particular trait can make individuals more or less
likely to survive and have successful offspring.
So, some individuals leave more offspring than
others do.
4. Adaptation: Over time, those traits that
improve survival and reproduction will become
more common.
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The link between
microevolution and
macroevolution is
speciation.
Speciation is the
formation of a new
species as a process
of genetic change or
as a pattern of
change in the form of
organisms.
QuickLab pg. 387
What do you get when you cross
a mouse with a mango? (4:15)
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Natural selection
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Migration
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Mate Choice
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Mutation
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Genetic Drift
◦ Causes an increase or decrease in certain alleles in a
population.
◦ The movement of individuals into, out or between
populations. Changes the types of alleles in a population.
◦ Random pairing of mates increases the assortment of traits.
◦ Changes the numbers and types of alleles from generation
to generation.
◦ Random effects of everyday life can affect the survival and
reproduction in populations, thus some alleles can become
more or less prevalent.
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Convergent
evolution is
strongly directed by
environment—
species living in the
same type of
environment should
evolve similar
adaptations.
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Coevolution:
Species that live
close together can
affect one another’s
evolution.
Species that live in
close contact often
have clear
adaptations to one
another’s existence.
Coevolution between the yucca moth
and the yucca plant. A female yucca
moth (Tegeticula yuccasella) pushing
pollen into the stigma tube of the
yucca flower while visiting the flower
to deposit her eggs.
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Over time, species
may split into two
or more lines of
descendants or
lineages. As the
splitting repeats,
one species can
give rise to many
new species.
Darwin’s finches
Adaptive Radiation (13:04)
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If all members of a
lineage die off or
fail to reproduce,
the species is said
to be extinct.
Evolution and
Sexual
Reproduction
Why did the Wooly Mammoth
become extinct? (2:17)
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Gradualism is a model
used to describe the
formation of a new
species through small,
gradual changes as
opposed to large-scale
changes.
Punctuated equilibrium
is where new species
“suddenly” appear in
response to
environmental
changes.
Chapter 16 Lab pg. 391