Natural Selection (15.3)
State Standard
SB5D. Relate natural selection to changes in
organisms
Chapter 15
Evolution
15.3 Natural Selection-Speciation-Resistance
Natural Selection
 Nature acts to
select the
individuals that
are best
____________
for survival and
reproduction in a
particular
____________
Chapter 15
Evolution
Principles of Natural Selection
Natural selection takes place when…
 Individuals in the population show ____________.
 The variations are ____________.
 Members of the population have more offspring
than can survive on available resources
(____________).
 Variations that increase reproductive
____________ have a greater chance of being
____________ on.
15.3 Natural Selection-Speciation-Resistance
• Industrialization
& the peppered
moths
Chapter 15
Evolution
15.3 Natural Selection-Speciation-Resistance
 ____________ selection operates to
____________ ____________ expressions
of a trait when the average expression leads
to higher fitness.
Ex: Peppered Moths before the Industrial Revolution
Chapter 15
Evolution
15.3 Natural Selection-Speciation-Resistance
 ____________ selection makes an organism
more fit by selecting ____________
____________ ____________.
Ex: Pollution from the Industrial Revolution caused
directional selection in the peppered moths.
Chapter 15
Evolution
15.3 Natural Selection-Speciation-Resistance
 ____________
selection is a process
that ____________ a
population into two
groups.
Ex: Different rock types in
the same biome will favor
different coat varieties of
these mice
Chapter 15
Evolution
15.3 Natural Selection-Speciation-Resistance
 ____________ selection operates in
populations where males and females
____________ significantly in appearance.
 Qualities of
sexual
attractiveness
appear to be the
____________
of qualities that
might enhance
survival.
Chapter 15
Evolution
15.3 Natural Selection-Speciation-Resistance
Adaptive Radiation – AKA Divergent Evolution/Speciation
 Can occur in a relatively short time when one species
gives rise to
many different
species in
response to the
creation of
____________
____________ or
some
other ecological
opportunity
Chapter 15
Evolution
15.3 Natural Selection-SpeciationResistance
Coevolution
 The relationship between two species might
be so close that the evolution of one species
____________ the evolution of the other
species.
 Associated with ____________
Chapter 15
Evolution
15.3 Natural Selection-Speciation-Resistance
Convergent Evolution
 ____________
species evolve
____________
traits because
of similar
environmental
pressures.
Chapter 15
Evolution
15.3 Natural Selection-Speciation-Resistance
Rate of Speciation
 Evolution proceeds in small, gradual steps
according to a theory called ____________.
 ____________ ____________ explains rapid
spurts of genetic change causing species to
diverge quickly.
Chapter 15
Evolution
15.3 Natural Selection-Speciation-Resistance