Transcript environmental pressure

Putting It All Together
HW on your desk.
Write in complete sentences!
Don’t talk during the Catalyst!
Catalyst
Owls have a gene that makes them brown or
black. Mice (owl’s prey) can see brown owls
better.
1. What is the environmental pressure?
2. What will happen to the gene that causes owls
to be brown?
3. EXPLAIN your answer to #2.
4. What causes the difference in owl color?
Agenda
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Catalyst Review
What did we learn?!
Poker Face
QQT
Review Sheet
EQ
Owls have a gene that makes them brown or black.
Mice (owl’s prey) can see brown owls better.
1.
What is the environmental pressure?
GOOD answer: The environmental pressure is
how well the mice can see the brown owls.
(May be due to the amount of light, the
background, etc.)
INCORRECT: Color of the owl. Owl’s gene.
Owls have a gene that makes them brown or black.
Mice (owl’s prey) can see brown owls better.
2.
What will happen to the gene that causes
owls to be brown?
GOOD answer: The gene that causes owls to be
brown will decrease in frequency.
Owls have a gene that makes them brown or black.
Mice (owl’s prey) can see brown owls better.
3.
EXPLAIN your answer to #2.
GOOD answer: The gene for brown owls will
decrease in frequency because their prey can
see them better, so they will not be as good at
getting food. If they have trouble getting food,
their chance of survival decreases and their
chance of having offspring decreases.
Therefore, the amount of genes passed on
decreases.
Owls have a gene that makes them brown or black.
Mice (owl’s prey) can see brown owls better.
4.
What causes the difference in owl color?
GOOD answer: Mutations cause the variation
in owl color!
EVOLVE
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http://www.5min.com/Video/How-EvolutionHappens-4804307
Evolution Theories
LAMARK SEZ…
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Organisms can force
themselves to adapt
Acquired characteristics
are inherited
DARWIN SEZ…
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Random mutation
Environmental pressure
Natural selection
Evolution
Natural Selection
SURVIVAL rate
Chance of
OFFSPRING
GENE
FREQUENCY
SURVIVAL rate
Chance of
OFFSPRING
GENE
FREQUENCY
Natural Selection
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GOOD mutations
INCREASE fitness.
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Become MORE common.
BAD mutations
DECREASE fitness.
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Become LESS common.
THINK ABOUT:
Environmental Pressure
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Prey/Food source
Population change
 Mutations
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Predators
Population change
 Mutations
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Physical Environmental
Amount of light
 Background
 Weather
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Evidence for Evolution
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All living organisms contain DNA that is made of the
same 4 bases.
 COMMON
ANCESTOR!
 More DNA they share = More closely related
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If an organism shares 50% of its DNA with Animal A
and 77% of its DNA with Animal B.
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It is more related to animal
B
Fossils
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Where is the oldest fossil?
Where is the most
complex fossil?
Where would you find a
transitional fossil between a
fossil found in layer A and C?
Where would you find a
transitional fossil between a
fossil found in layer D and B?
Compare the fossils in layer D
to the fossils in layer B.
A
B
C
D
E
Homologous Structure
What it is: Same structure, same position.
What it proves: Recent common ancestor.
Animal Embryos
What it is: Beginning stage of organism development.
All have gill slits and tails.
What type of structure: Homologous.
What it proves: Common ancestor.
Analagous Structure
What it is: Same structure.
What it proves: Adaptations evolved in response to
similar environments with similar environmental
pressures. (No recent common ancestor.)
Vestigial Structure
What it is: Useless structure.
What it proves: Ancestors used to live in a different
environment. (Structure took up too much energy
and didn’t increase fitness, so it’s role was
decreased.)
Quiz-Quiz-Trade
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Find a partner. Quiz them with your question on
your flashcard. If they can’t get it right, coach them
(coaching is not telling them the answer).
Then your partner quizzes you.
Once you have each successfully answered your
question, trade your flashcards. Then raise your
hand.
High-five someone with a raised hand. BAM! You’re
now partners.
Poker Face
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The team with the most people standing gets to
answer the question.
Ms. Sanacore will call on the team member who will
answer the question.
 If
THE PERSON CALLED ON gets it right, the team earns
one point for each person standing.
 If THE PERSON CALLED ON gets it wrong, the question
goes to the other team.
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If someone is talking or calls out, their team will lose
one point for each person standing.
GET GOING ON THE REVIEW SHEET!
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NOW is the time to ask questions.
Write in complete sentences!
Exit Questions
Sharks in the Gulf have
big or small fins. They eat
fish, which also have fins.
Sharks and fish do not
share a recent common
ancestor. Since June, the
number of fish has
decreased.
Don’t talk during the Exit Question!
1.
2.
3.
4.
What is the environmental
pressure?
What will happen to the
gene frequency of the
sharks with small fins?
SUPPORT your answer.
What type of structure are
the fins?
EXPLAIN how this structure
supports evolution.