Transcript Natural Selection

Warm-up
1) What is the central dogma?
2) Put the following steps of protein synthesis in order.
___ Polypeptides (proteins) are formed as ribosomes move
along the messenger RNA strand.
DNA molecules serve as templates for making messenger
RNA molecules.
Transfer RNA molecules bring amino acids to ribosome.
Messenger RNA molecules move to the ribosome.
3) List as many factors as you can that make a protein different
from another protein
Evolution:
Science Department
Unit Review
#1-42
Science Standards:
7a-d, 8a-e
Charles Darwin
History of the Earth (8e)
1. What is a fossil?
History of the Earth (8e)
1. What is a fossil?

remains of ancient life
2. What is the fossil
record?
2. What is the fossil record?

all the information about past life
3. What is macroevolution?
Give an example.
3. What is macroevolution? Give an
example.

evolution over long periods of time
(millions of years)

ex Fossil Record
4. What is microevolution?
4. What is microevolution?
 all
of the small changes in genes
that happen in a few generations

ex Light and Dark Moths, England
5. What are the four Geologic Eras
(in order oldest – recent)?
5. What are the four Geologic Eras
(in order oldest – recent)?

Most Recent

Oldest
6. Which era was the longest?
6. Which era was the longest?

Precambrian
7. Which era are we currently in?
7. Which era are we currently in?

Cenozoic
8. Label the eras below.
A.
B.
C.
8. Label the eras below.
A.
B.
C.
Mesozoic
Paleozoic
Precambrian
9. What is a mass extinction?
9. What is a mass extinction?

a large number of unrelated species
quickly die
10. Why did life continue to exist
on Earth after each mass
extinction?
10. Why did life continue to exist
on Earth after each mass
extinction?

new habitats and resources were available
to them
11. Is there more or less diversity
before a mass extinction?
11. Is there more or less diversity
before a mass extinction?

More!!
Natural Selection (8a)
12. Define natural selection:
Natural Selection (8a)
12. Define natural selection:

how individuals who are better suited to
survive and reproduce successfully in
their environment
13. What happens to organisms
that are NOT well suited to
their environments?
13. What happens to organisms
that are NOT well suited to
their environments?

die or adapt
14. What does “survival of
the fittest” mean?
14. What does “survival of
the fittest” mean?

organisms with high levels of fitness
to survive, reproduce, and adapt)
(ability
15. Give one example of how
natural selection occurs:
15. Give one example of how
natural selection occurs:

Darwin’s Finches:
Finches in the
Galápagos Islands
have beaks
adapted to eat
the foods
available in the
birds’ habitats.
Diversity of Species (7c, 7d, 8b)
16. Define Species:
Diversity of Species (7c, 7d, 8b)
16. Define Species:

a group of similar organisms that can
breed and produce fertile offspring
17. Define Diversity:
17. Define Diversity:

a variety of something such as animals or
plants

(Pond A has more diversity)
Pond B
Pond A
18. Populations with (more or less)
diversity are more
likely to survive.
18. Populations with (more or less)
diversity are more
likely to survive.

MORE
19. Does asexual reproduction
increase or decrease diversity?
19. Does asexual reproduction
increase or decrease diversity?

DECREASE

Because (like cloning) all of its offspring would be the
same.
20. What is a mutation?
20. What is a mutation?

is any change in a DNA
sequence
21. Are mutations always harmful?
Do they always have some
effect?

Most mutations are harmless, and some are
helpful
22. Do mutations increase or
decrease diversity in a
population?
22. Do mutations increase or
decrease diversity in a
population?

INCREASE
23. Which group in
the diagram has
the most
biodiversity
during the
Cretaceous
period?
the Quaternary
Period?
23. Which group in the diagram
has the most biodiversity
during the Cretaceous
period?
the Quaternary Period?

Lizards and Lizards

How? Look at the WIDEST
band
24. Which of the ponds below has more
diversity?
Which has a higher chance of
survival?
Pond B
Pond A

Pond A contains 100
organisms - 30 algae, 15
frogs, 10 cattails, 5
ducks, 5 geese, 20
guppies, 13 bass, and 2
alligators.
Pond
B contains 100
organisms – 50 algae, 25
geese, 20 bass, and 5
alligators.
24. Which of the ponds below has more
diversity?
Which has a higher chance of
survival?


Pond B
Pond A

Pond A contains 100
organisms - 30 algae, 15
frogs, 10 cattails, 5
ducks, 5 geese, 20
guppies, 13 bass, and 2
alligators.
Pond
B contains 100
organisms – 50 algae, 25
geese, 20 bass, and 5
alligators.
Pond A --because
contains 8 types of
organisms
Pond A --because
contains 4 types of
organisms
Genetics and Natural Selection (7a, 7b)
25. Does natural selection work
directly on phenotypes or
genotypes of an individual?
Genetics and Natural Selection (7a, 7b)
25. Does natural selection work
directly on phenotypes or
genotypes of an individual?

Phenotype (physical characteristic)

ex leopards eat what they see…they don’t ask the prey what genotype they have!
26. The combined genetic
information of all members of a
population is called the
.
26. The combined genetic
information of all members of a
population is called the
.

Gene Pool
27. Explain why lethal alleles, such as sickleshaped blood cells, continue to show up
in the gene pool.
27. Explain why lethal alleles, such as sickleshaped blood cells, continue to show up
in the gene pool.

this disease is passed on by
heterozygous individuals
AND
natural selection works on
phenotype not genotype.
28. Why don’t carriers of these alleles
get eliminated through natural
selection?
28. Why don’t carriers of these alleles
get eliminated through natural
selection?

Natural selection acts on phenotype—they
are normal.
29. In England after the industrial revolution, dark
moths had an advantage over light moths. If
dark color in moths is dominant (D) why did
light moths (dd) continue to reappear?
29. In England after the industrial revolution, dark
moths had an advantage over light moths. If
dark color in moths is dominant (D) why did
light moths (dd) continue to reappear?

When heterzygous, dark moths mate (Dd
X Dd), they produce light moths (dd).
D
D
d
d
DD
Dd
Dd
dd
Genetic Drift (8c)
30. In genetic drift, changes in
allele (gene) frequencies
change due to
.
Genetic Drift (8c)
30. In genetic drift, changes in
allele (gene) frequencies
change due to
.

CHANCE!

Why? In small populations, Natural Selection is not the
only source of evolutionary change and the laws of
probability (genetics) don’t really work.
31. Genetic drift occurs in population
that are
in size.
31. Genetic drift occurs in population
that are
in size.

small
GENETIC DRIFT: In small populations, individuals that carry a particular allele may
have more descendants than other individuals. Over time, a series of chance occurrences of
this type can cause an allele to become more common in a population.
32. What is the bottleneck effect?
32. What is the bottleneck effect?

Is what
happens when
only a few
members
survive a major
catastrophe
and pass on
those
genotypes
33. Give an example of a situation
that could cause the bottleneck
effect?
33. Give an example of a situation
that could cause the bottleneck
effect?

Flood, fire,
earthquake,
meteorite,
worldwide disease
34. The type of genetic drift that
follows colonization of a new
habitat by a small group of
individuals is called
.
Original Popn.
New Popn.
34. The type of genetic drift that
follows colonization of a new
habitat by a small group of
individuals is called
.

Founder Effect
Original Popn.
New Popn.
35. The Amish people having an
unusually high occurrence of six
fingers are an example of
.
35. The Amish people having an
unusually high occurrence of six
fingers are an example of
.

Founder Effect
36. Label the 3 graphs below.
36. Label the 3 graphs below.
Graph A:
Directional
Selection
 Graph B.
Stabilizing
Selection
 Graph C:
Disruptive
Selection

Speciation (8d)
37. Define speciation:
Speciation (8d)
37. Define speciation:
is the evolutionary process by which new
biological species arise.
 is the result of reproductive isolation

38. Why are horses and donkeys considered
to be two different species?
(think about the definition of species)
Species:
a group of similar organisms that can breed
and produce fertile offspring
38. Why are horses and donkeys considered
to be two different species?
(think about the definition of species)


Species: a group of similar organisms that can breed and produce fertile
offspring
They usually don’t breed naturally. When
they do, they produce a mule; most mules
are sterile.
Mule
39. Define Reproductive Isolation.
Give 3 examples:
39. Define Reproductive Isolation:

Is when the members of different
populations cannot interbreed and new
species come up
ex
1. Behavioral Isolation
2. Geographic Isolation
3. Temporal Isolation
40. What happens when animals are
unable to reproduce for long
periods of time with another
population of the same animal?
40. What happens when animals are
unable to reproduce for long
periods of time with another
population of the same animal?

They become reproductively isolated and
gene pool differences increase
41. Define Geographic Isolation:
41. Define Geographic Isolation:

occurs when two
populations are
separated by
geographic barriers
such as rivers,
mountains, or bodies
of water
42. What happens two populations of
animals are geographically isolated for
long periods of time and as a result can
no longer reproduce with each other?
42. What happens two populations of
animals are geographically isolated for
long periods of time and as a result can
no longer reproduce with each other?

They become different species
STUDY!!!