Solved by a verified expert:Evolution and Natural Selection Lab (50 points)

Type your results and responses to

questions in this report and submit. Please answer all questions in full

sentences.

Materials:

Bag of 15 bean soup (dry beans), cup,

2 Paper lunch bags, paper and pencil.

1. We shall simulate genetic

drift and effects of a bottleneck on genetic drift in this simulation. (15 points)

Review “Evolution

Occurs in Several Ways”, Chapter 11.6 in your textbook.

Instructions:

Count out 25 speckled beans, 25 black beans, 25 white

beans and 25 red beans (it is easiest if you choose beans of the same size and

put in container. The beans represent different alleles (Unit 3). This means

each type of bean makes up 25% of the total number of beans (or alleles)

(25/100 = 0.25).

Write two hypotheses answering the two questions

below (5 points):

a.

How would the ratio of bean

phenotypes change if you randomly pick 40 beans from the container? Will the ratio change significantly in each

repetition (generation)?

b.

How would the ratio of bean

phenotypes change if you only pick 10 beans from the container? Will the ratio change significantly in each

repetition (generation)?

Method:

Now take 40 beans from the counter and count the

different phenotypes black, white, red and speckled. Write the results in the data

chart, then return the beans to the container, shake to mix, and repeat the

experiment two more times. Next, take only 10 beans from the container. Count

the different beans and add the data to the chart. Return the beans to the

container and repeat three more times. Complete the data chart below.

Results (5

points):

Large Sample (40 beans):

Bean

(Phenotype)

Original Population

Exp #1

Exp #2

Exp #3

#

%

#

%

#

%

#

%

Small Sample (10

beans):

BLR

(Phenotype)

Original Population

Exp #1

Exp #2

Exp #3

#

%

#

%

#

%

#

%

Were your hypotheses correct?

Answer the following questions (5 points):

I.

What was the range of ratios of

bean phenotypes in the large sample? In the small sample?

II.

How would genetic drift affect

the gene pool in a genetic bottleneck?

III.

Could genetic drift lead to

evolution of new species? Consider ratios of phenotypes of each small sample. Under

which condition would this change lead to speciation?

2. Simulation of Hardy

Weinberg Equilibrium (20 points)

Review “Evolution is Inevitable in Real Populations ”,

Chapter 11. 3 in your textbook.

Also, web site: http://www.nfstc.org/pdi/Subject07/pdi_s07_m01_02.htm

(click the glasses for more help)

We shall

simulate the frequency of two alleles in a population in Hardy Weinberg Equilibrium

over several generations.

Instructions:

This time the

beans will represent alleles (remember we carry two alleles for each trait or

gene, one from the father and one from the mother)

The red bean

represents a dominant allele and the white bean represents a recessive allele. The

homozygous dominant individual is represented by 2 red beans, the homozygous

recessive individual is represented by 2 white beans, and heterozygous

individuals are represented by one red bean and one white bean.

Method

Count and set

aside 60 red beans and 40 white beans. Label

one paper bag male and the other paper bag female. Divide beans evenly into

bags (30 red beans and 20 white beans into each bag). You will grab one bean

from each bag for the allele combination in the F1 generation, for a total of 50 pairs (50 individuals) in the

F1 generation.

Preparation (5 points):

Calculate the frequency of p (dominant allele – red) and

q (recessive allele – white) in population (see textbook chapter 11. 3B).

p=red beans/total # beans

q=white beans/total # beans

p+q=?

2pq = ?

P2= ?

q2= ?

What does p2, q2 and 2pq represent?

Write a hypothesis answering the following question:

a.

If the population is in Hardy

Weinberg equilibrium, what would be the frequency of both alleles in the F1, F2

and F3 generations?

Experiment 1 (5

points)

Remove one bean from each bag blindly and set the pair

aside. Repeat until all beans are paired. This represents one generation.

1.1 Count:

Red pairs (dominant homozygous ) = p2

White pairs (recessive homozygous) =q2

Red-white pairs (heterozygous) = 2pq.

P2 + 2pq + q2= 1

Calculate p = (2x red pairs + red-white pairs)/ total

number of alleles (beans) = ?

q = (2x white pairs + red-white

pairs)/total number of alleles (beans) = ?

p+q= ?

Return beans to bags and repeat the pairing two times, recording

p2, 2pq and q2each time.

1.2 Count:

Red pairs (dominant homozygous ) = p2

White pairs (recessive homozygous) =q2

Red-white pairs (heterozygous) = 2pq.

P2 + 2pq + q2= 1

Calculate p = (2x red pairs + red-white pairs)/ total

number of alleles (beans) = ?

q = (2x white pairs + red-white

pairs)/total number of alleles (beans) = ?

p+q= ?

1.3 Count:

Red pairs (dominant homozygous ) = p2

White pairs (recessive homozygous) =q2

Red-white pairs (heterozygous) = 2pq.

P2 + 2pq + q2= 1

Calculate p = (2x red pairs + red-white pairs)/ total

number of alleles (beans) = ?

q = (2x white pairs + red-white

pairs)/total number of alleles (beans) = ?

p+q= ?

Answer the

following questions:

I.

How much did your experimental

data differ from the calculated data?

II.

Do you accept or reject your

hypothesis?

Experiment 2 (5 points)

Remove one bean from each bag blindly and set the pair

aside. Repeat 10 times. This represents a loss of 10% of the population

(migration).

Now repeat steps of experiment 1.

2.1 Count:

Red pairs (dominant homozygous ) = p2

White pairs (recessive homozygous) = q2

Red-white pairs (heterozygous) = 2pq.

P2 + 2pq + q2= 1

alleles (beans) = ?

q =

(2x white pairs + red-white pairs)/total number of alleles (beans) = ?

p+q=

?

Repeat three times, each time removing 10% of the pairs,

so remove 9 and 8 pairs respectively. Keep the changing total number of beans in

mind when calculating allele (bean) frequencies.

2.2

Count

Red pairs (dominant homozygous ) = p2

White pairs (recessive homozygous) = q2

Red-white pairs (heterozygous) = 2pq.

Calculate p = (2x red pairs + red-white pairs)/ total

number of alleles (beans) = ?

q = (2x white pairs + red-white

pairs)/total number of alleles (beans) =?

p+q= ?

2.3

Count

Red pairs (dominant homozygous ) = p2

White pairs (recessive homozygous) = q2

Red-white pairs (heterozygous) = 2pq.

Calculate, p and q.

p + q = ?

Calculate p = (2x red pairs + red-white pairs)/ total

number of alleles (beans) = ?

q = (2x white pairs + red-white

pairs)/total number of alleles (beans) =?

p+q= ?

Answer the

following questions:

I.

How much did your experimental

data differ from the calculated data?

II.

Do you accept or reject your

hypothesis?

III.

Under what conditions is an

allele within a population in Hardy Weinberg equilibrium?

Experiment 3 (5 points)

Remove one bean from each bag blindly and set the pair

aside. Repeat until all beans are paired.

Remove all white pairs (lost to predation) This represents natural

selection.

3.1 Count

Red pairs (dominant homozygous ) = p2

White pairs (recessive homozygous) = q2

Red-white pairs (heterozygous) = 2pq.

Calculate p = (2x red pairs + red-white pairs)/ total number of

alleles (beans) = ?

q =

(2x white pairs + red-white pairs)/total number of alleles (beans) =?

p+q=

?

Write a

hypothesis answering the following question:

What will happen to p and q if this selective pressure

repeats in the next generation?

Work through another generation. Divide remaining beans

equally and return to bags, and repeat the experiment.

3.2

Count

Red pairs (dominant homozygous ) = p2

White pairs (recessive homozygous) = q2

Red-white pairs (heterozygous) = 2pq.

Calculate p = (2x red pairs + red-white pairs)/ total number of

alleles (beans) = ?

q =

(2x white pairs + red-white pairs)/total number of alleles (beans) =?

p+q=

?

Answer the

following questions:

I.

How much did your experimental

data differ from the calculated data?

II.

Do you accept or reject your

hypothesis?

III.

How does natural selection

affect allele frequencies?

3. Summary (15 points)

Answer the following question in full sentences, at least 150 to 200

words.

What did you

learn in this lab about the effects of population size, migration and natural

selection on allele frequencies in populations? How do allele

frequencies relate to evolution of

species?

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