Download Darwin`s Theories

Change Over Time (Packet #2)
State Standard: H.2L.4 -- Explain how biological evolution is the
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consequence of the interactions of genetic variation (pg. 1), reproduction and
inheritance (pg. 3-7) , natural selection and time (pg. 2)
10
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Response
Exceeds
(excellent)
Meets
(proficient)
Nearly Meets
Does Not Meet
Incomplete
Scoring Rubric
Evaluate the impact of the interactions of genetic variation, reproduction and inheritance, natural
selection and time on biological evolution (change)
Explain how biological evolution is the consequence of the interactions of genetic variation,
reproduction and inheritance, natural selection, and time, using multiple lines of scientific evidence.
Describe the process of biological evolution through natural selection
Recognize that species have changed over time
Did not participate
Score
History's Mysteries
Science is a process of answering questions using the scientific method. Some questions have been
answered while others have not.
Answer the following:
1. Can spontaneous generation occur? Who were the scientists that disproved it? (p. 388-389)
2. Which experiment do you feel better disproves spontaneous generation?
3. What is biogenesis? (p. 389)
4. What 2 developments in primordial soup do some scientists believe preceded life on earth (p.
390)
5. Does this conflict with biogenesis? __________________
6. In 1953, what did Miller and Urey test? (p. 390)
7. What kind of organisms do some scientists believe were the first organisms to appear on Earth?
(p. 391)
8. Does this conflict with the cell theory (all cells come from pre-existing cells)? ________
9. What present day bacteria would they resemble (p. 392)
10. Can the process of science (the scientific method) be used to solve all problems? For
example: can science determine how matter was formed?
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Darwin’s Theories
What organisms impressed Darwin and why? (p. 402)
What are the 4 points of Natural Selection? (p.403)
a).
b).
c).
d).
What are homologous, analogous and vestigial structures? Provide examples (pg. 408-410)
Give an example of genetic drift in humans (pg. 414)
Label the graph Directional, Disruptive, or Stabilizing Selection and briefly explain each (p. 416).
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_________________
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Explain Geographic isolation, and reproductive isolation. Provide examples of each (p. 417-418)
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Change Over Time
First Name
Last Name
State Standard:
H.2L.4- Explain how biological evolution is the
consequence of the interactions of genetic variation, reproduction and inheritance,
natural selection, and time.
Response
Scoring Rubric
10 Exceeds
Evaluate the impact of the interactions of genetic variation, reproduction and inheritance, natural
(excellent)
selection and time on biological evolution (change)
8
Meets
Explain how biological evolution is the consequence of the interactions of genetic variation,
(proficient)
reproduction and inheritance, natural selection, and time, using multiple lines of scientific evidence.
6
Nearly Meets
Describe the process of biological evolution through natural selection
Does Not Meet
4
Recognize that species have changed over time
1
Incomplete
Did not participate
Score
Allelic Frequencies and Sickle- Cell Anemia
ickle-cell anemia, a potentially fatal disease, results from a mutant allele for hemoglobin, the
oxygen- carrying protein on red blood cells. There are two alleles for the production of
hemoglobin. Individuals with two Hemoglobin A alleles (AA) have normal red blood cells.
Those with two mutant Hemoglobin S alleles (SS) have abnormal sickle- shaped red blood cells and
suffer from sickle-cell anemia. Heterozygous (AS) individuals carry the mutant allele but do not suffer
from its debilitating effects. They have both normal and sickle-shaped red blood cells.
In the United Sates, about 1 in 500 African- Americans develops sickle-cell anemia. But in
Africa, about 1 in 100 individuals develops the disease. Why is the frequency of a potentially fatal
disease so much higher in Africa?
The answer is related to another potential fatal disease, malaria. Individuals with an AA
hemoglobin genotype have a significant greater risk of contracting malaria and may die from the
disease. This results in the removal of Hemoglobin A alleles from the gene pool. The SS genotype,
which results in sickle-cell anemia, is usually fatal before the age of twenty. This results in the
removal of Hemoglobin s alleles from the population. A person with an AS genotype does not develop
sickle-cell anemia and has less chance of contracting malaria. Such a person is better able to survive
and reproduce in a malaria-infected region. Therefore, both the individual’s A allele and S allele
remain in the population. The frequency of the Hemoglobin s allele in malaria-infected regions of
Africa is 16%. But in the United States, where malaria has been eradicated, the allelic frequency is
4%.
Simulate
You will now simulate the fusion of gametes and record the resulting genotypes of each
offspring, using all of the beans in the unlabeled container. You will also simulate the effect of being
homozygous or heterozygous for the hemoglobin gene in a malaria-infected region. One team member
will select two beans from the unlabeled container 50 times. After each selection, a second team
member will indentify and record the genotype of the “offspring” in Table 1 by making a slash under
the appropriate column head. The same team member then places each pair of beans in container AA,
AS, or SS, depending on the genotype. During the periods when the blindfold team member is making
a selection, the recorder will randomly call out the word “malaria” a total of 25 times. (This represents
a 50% malaria infection rate.) if the genotype of the selected pair of gametes is AA, that offspring will
contact malaria and die. Therefore, place that pair of alleles in the container labeled “Non-Surviving
Alleles” and put a circle around the slash (that is, the recorded genotype) in table 1. If the genotype is
AS, the individual will survive. Put a circle around the slash in Table 1, and place the pair of beans in
the container labeled AS. If the genotype is SS, the individual will die. As with the individual
homozygous for the normal Hemoglobin gene, place the beans in the container labeled “Non-Surviving
Alleles” and draw a circle around the recorded genotype.
S
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Procedure
1. Place 75 red beans in the unlabeled container (this is the 1st generation gene pool). These beans
represent gametes carrying the Hemoglobin A allele.
2. Add 25 white beans to the unlabeled container (this is the 1st generation gene pool). These
beans represent gametes carrying the Hemoglobin S allele.
3. Without looking, one partner should draw two beans out of the “gene pool”. The other partner
records in Table 1. REMEMBER: 1 TICK MARK = 1 BEAN or "Allele" !!!!!!!!!!!!!
4. If two reds are selected (AA), place them in the AA container and write two tick marks in
column AA in Table 1.
5. If one red and one white are selected (AS), place them in the AS container and write two tick
marks in column AS in Table 1.
6. If two whites are selected (SS), place them in the SS container and write two tick marks in
column SS in Table 1.
7. Randomly (every other time) the recorder should call “malaria” to simulate the malaria
infection rate of 50%. Circle the two tick marks in Table 1 showing a “bite”. AA's that are bit
show a high probability of death so let's put them in the non-surviving alleles container.
8. Count the number of surviving AA alleles (red beans) remaining in the population and record
that number below. Do the same for AS (remember to add all the surviving A's together and
the surviving S's together. The combined total represents the total number of alleles for
hemoglobin in the population. Calculate the allelic frequencies as shown and record your
results.
Table 1 “Second Generation
AA genotype
AS genotype
SS genotype
a. How many Red beans are remaining in the population?
alleles
(remember: 1 tick = 2 beans)
____________A
b. How many White beans are remaining in the population?
alleles
(remember: 1 tick = 2 beans)
____________S
c. What is the total number of alleles in the population? A+S=
_________________
d. What is the frequency (percent) of the A allele? _ A__ x 100 =
_________________
A+S
e. What is the frequency (percent) of the S allele?
_________________
_ S__ x 100 =
A+S
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9. After you have completed the cycle for one generation, you are ready to begin the next. All of
the beans in the containers labeled AA and AS should be emptied into the unlabeled container.
However, place all the beans from the container labeled SS into the container for “NonSurviving Alleles” (Since individuals who are homozygous SS will not usually live long
enough to have children, you will not use the SS gametes for tallying the next generation.)
10. To determine the 50% malaria infection rate for the generation of the population, take the total
number of A and S remaining in the population and divide it by 4. This is the number of times
you will randomly call out “malaria” in the next round of fusion of gametes. (For example, if
you had 47 A and 17 S alleles in part “c” above, you would have a total of 64 alleles in the
population. Divide this by 4 and you would get the number 16. This would be 50% of the next
generation of people produced by the gamete fusions.)
11. Repeat the procedures you followed in step 3 through 7. Use Table 2 to record your data.
12. Repeat the procedures you followed in step 8. Record your data and calculation in the spaces
provided under Table 2.
AA genotype
Table 2 Third Generation
AS genotype
SS genotype
f. How many Red beans are remaining in the population?
alleles
(remember: 1 tick = 2 beans)
____________A
g. How many White beans are remaining in the population?
alleles
(remember: 1 tick = 2 beans)
____________S
h. What is the total number of alleles in the population? A+S=
_________________
i. What is the frequency (percent) of the A allele?
_________________
_ A__ x 100 =
A+S
j. What is the frequency (percent) of the S allele?
_________________
_ S__ x 100 =
A+S
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Analysis
1. a. What was the frequency of the A allele in the original population?
___75 %_______
b. What was the frequency of the S allele in the original population?
_________________
c. What was the frequency of the A allele in the second population?
_________________
d. What was the frequency of the S allele in the second population?
_________________
e. What was the frequency of the A allele in the third population?
_________________
f. What was the frequency of the S allele in the third population?
_________________
g. Explain your findings.
2. Since few people with sickle-cell anemia are likely to survive to have children on their own,
why hasn’t the Hemoglobin S allele been eliminated by natural selection?
3. Why is the frequency of the Hemoglobin S allele so much lower in the United States than in
Africa?
4. Scientists are working on a vaccine against malaria. What impact would the vaccine have on
the frequency of the Hemoglobin S allele in Africa?
5. Using your chapter 15 notes, which one of the 3 types of natural selection pressures are
demonstrated in the lab?
Circle one:
Stabilizing
Directional
Disruptive
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Only answer the following if you’re going for a 10 
6. Gradualism is the idea that species originate through a gradual change of adaptations over time. For
this to work, some mutations must be favorable. What does “natural selection” say about favorable
traits?
7. Adaptive radiation is the idea that an ancestral species can evolve into an array of species to fit a
number of diverse habitats. Using the example of a donkey and a horse, why is the mule NOT a new
species?
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