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Patterns of Evolution
Standards and Essential
Question
Standard
O SZ2b. Explain the
concepts evolution,
adaptation, natural
selection,
convergence, and
speciation.
Essential Question
O Has evolution really
taken place?
I will be able to…
O Explain the four major patterns of evolution
O Differentiate between punctuated
equilibrium and gradualism
O Differentiate between Microevolution and
Macroevolution
Microevolution
O Change in the
frequency of alleles
in populations over
time.
O Over a long period of
time microevolution
results in large-scale
changes.
Macroevolution
O Large-scale changes
that result in
extinction and the
formation of new
species.
O Difficult to observe in
progress due to the
change over the
geological time
scale.
Adaptive Radiation
O Also known as
divergent evolution
O Is when one species
gives rise to many
different species.
O Occurs in a relatively
short time span.
O Usually occurs in
response to the
creation of a new
habitat.
Coevolution
O When the
relationship between
two species is
extremely close, the
evolution of one
species affects the
evolution of the other
species.
O One species can
evolve a parasitic
dependency on
another species.
O Also known as
coevolutionary arms
race.
Coevolution
Convergent evolution
O Unrelated species
evolve similar traits
even though they live
in different parts of
the world.
O This may be due to
the organisms
inhabiting similar
niches.
O When organisms
inhabit similar
niches they usually
evolve similarities in
morphology,
physiology, and
behavior.
Convergent Evolution
Rate of Speciation
Gradualism
O The belief that
evolution occurs in
small, gradual steps
over time.
Punctuated Equilibrium
O Rapid spurts of genetic
change that cause a
species to diverge
quickly.
O These periods
punctuate much longer
periods when the
species exhibit little
change.
Rate of Speciation
Gradualism
Punctuated
Equilibrium