Transcript Natural Selection

TAKS OBJECTIVE 3
TEKS OBJECTIVE 7(B)
NATURAL SELECTION AS A PROCESS OF
EVOLUTION
The student knows the theory of
biological evolution. The student is
expected to (B) illustrate the results of
natural selection in speciation, diversity,
adaptation, behavior, and extinction.
Focus Question: Discuss and record
your answer in your packet.
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Explain how changes in an environment
may change a population of organisms.
TAKS Practice:
Characteristics of Some Lizards
•Live mainly in hot, dry climates
•Release very little water
•Excrete wastes in the form of solid
uric acid, which contains very little
water.
Which of the following is supported by the
information shown above?
F These lizards evolved in arid habitats.
G Modern lizards drink more water than their
ancestors.
H These lizards cool themselves by evaporation.
J Modern lizards excrete more water than their
ancestors.
Common Descent with
Modification
Natural Selection
is THE driving
force of
evolution
 During the
struggle for
resources only
the strongest
will survive &
reproduce.
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What
happens to
those that
aren’t the
strongest???
Consider this situation…
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The idea that
organisms change
with time, diverging
from a common
ancestor caused
evolution of new
species
What will happen to
the descendents of
#2 when the same
insecticide is used?
What will happen to
the genes of those
killed by the
insecticide?
If You Can't Run You've Got to
Hide! Where’s Waldo???
What if you
aren’t the
fastest or
strongest?
Physical Adaptations: CAN YOU
FIND THE US?
Behavioral adaptations for survival
HERD
SOLITARY
Is there
safety in
numbers?
Why would
some sharks
be solitary?
Think about
how each of
these
behaviors
might help an
organism
survive?
SCHOOL
Speciation: all of these finches descended from
a common ancestor
Each of these
modern
finches has
found a
specific niche
to survive in
based on its
beak shape
and size.
Leads to
biodiversity in
nature
Natural variation in one plant species
EXPLANATION
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NECESSARY VOCABULARY:
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Evolution –
Biodiversity –
Natural Selection –
Survival of the Fittest –
Speciation –
Behavior –
Adaptation –
Extinction -
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Evolution
Change over time
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Biodiversity
The vast assortment of life forms on earth
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Natural Selection
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Survival of the Fittest
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Speciation
The formation of new species resulting
from reproductive isolation.
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Behavior
The way an organism reacts to changes
in its internal or external environment.
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Adaptation
Ability to adjust to new environment.
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Extinction
The survival and reproduction of organisms
that have inherited the most desirable
characteristics.
Organisms that are fit for that
environment will survive & reproduce.
Cessation of existence of a species or
group of taxa.
The guppy is a species of small freshwater
fish. Scientists observed that the average
size of guppies in a pond decreased over a
few years after a guppy predator was
introduced into the pond. Which of the
following best explains the change in
guppy size?
F
Speciation
G
Convergent Evolution
H
Inbreeding
J
Natural Selection
Birds and reptiles are similar in that they are
vertebrates and lay eggs. They differ in that
reptiles have teeth and birds have beaks. Some
birds do possess teeth. However, these teeth are
present only in the embryonic stage. Which
conclusion is best supported by the presence of
teeth in bird embryos?
A
Birds and reptiles share a common
ancestor
B
Modern reptiles are the ancestors of modern
birds
C
Birds and reptiles eat similar types of food
D
Ancestors of reptiles had beaks similar to that
of birds
Because of this animal’s adaptations, it
would be most successful at —
F competing with birds
G making its own food
H hiding from predators
J running very rapidly
The diagram illustrates how some characteristics of the horse
have changed over time. Along with the difference in size,
what is another anatomical difference between the modern
horse and its ancestors?
A. The structure of the tooth has been adapted for eating
meat.
B. The size of the molars has decreased.
C. The length of the forefoot has decreased.
D. The number of toes has decreased.
The maps below show the geographic ranges of four
species of the order Lagomorpha, which includes
rabbits and hares. In which range would developing
white fur in winter most likely not be an advantage for a
member of this order?
What I need to remember…
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Write down the 3 most important things
about this topic.