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# Principle of Biology 1

By Mario Jones,2014-05-09 21:51
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Principle of Biology 1

General Biology 1

BIO 112

Exercise 17: Evolution - Natural Selection

The theory of ________________ describes _______________________ in populations.

Organisms that ________________ and __________________ successfully have

___________________ aiding survival and reproduction. These traits enhance an organism’s

____________ . The most _______ organisms transmit their traits to ________________ .

After many generations, the ________________ of these traits ________________ in the

population. This process is called _________________________.

Understanding Allelic and Genotype Frequencies

________________ is the proportions of individuals with a certain trait relative to the

________________ of individuals in a ________________ .

Procedure 17.1 parental population

Question 1:

How many of the total beads are black (yellow) and how many are white?

What color fur do Bb individuals have?

How many beads represent the population?

The Hardy-Weinberg Principle

Write out the allelic frequency and Hardy-Weinberg Principle formulas.

List the assumptions of the H-W Principle

Question 2:

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If the frequency of a recessive allele is 0.3, what is the frequency of the dominant allele?

If the frequency of the homozygous dominant genotype is 0.49, what is the frequency of the

dominant allele?

If the frequency of the homozygous dominant is 0.49, what is the frequency of the

homozygous recessive? Heterozygous?

Procedure 17.2 verify the Hardy-Weinberg Principle

Question 3:

The H-W Principle predicts that the genotypic frequencies of offspring will be the same as

those of the parental generation. Were they the same in your simulation?

If the frequencies were different, then one of the assumptions of the H-W Principle was

probably violated. Which one?

Effect of Selection

________________ is the ________________ reproduction of ________________ .

Procedure 17.3 100% negative selection

Question 4:

Did the frequency of white individuals decrease with successive generations?

Was the decrease in the frequency of white individuals from the first to the second generation

the same as the decrease from the second to the third generation? From the third to the fourth

generation?

How many generations would be necessary to eliminate the allele for white fur?

Procedure 17.4 20% negative selection

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Question 5:

Did the frequency of white individuals decrease with successive generations?

Was the rate of decrease for 20% negative selection similar to the rate fo 100% negative

selection? If not, how did the rates differ?

Questions for Further Thought

1) How would selection against the heterozygous individuals affect the frequencies of

homozygous individuals?

2) Is natural selection the only means of evolution? Explain.

3) Explain the concept of genetic drift. Distinguish between the bottleneck effect and the

founder effect.

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