Genetic Diversity in populations - Chapter 19 - Unit 6

Question 1

What makes up a population’s gene pool?

Answer 1

• sum of all the alleles for all the genes in a population
• a gene pool is the sum of all the genetic variation that can be passed on to the next generation
• the better the population can survive in a changing environment

Question 2

Distinguish among the genotype frequency, phenotype frequency, and allele frequency

Answer 2

• genotype - proportion of a population with a particular genotype
• Phenotype - proportion of a population with particular phenotype expressed as a decimal or percentage
• Allele frequency - rate of occurrence of particular allele in a population, with respect to a particular gene

Question 3

What are the conditions of the Hardy - Weinberg principle?

Answer 3

1. The population is large enough that chances events will not alter allele.
2. Mates are chosen on a random basis
3. There are no net mutations
4. There is no migration
5. There is no natural selection against any of the phenotypes

Question 4

Using the Hardy- Weinberg equation, distinguish between p and p2 as used to describe a population

Answer 4

Equation that can be used to determine the frequencies of different genotypes in a population

Question 5

How is it possible to find the number of heterozygotes in a sample population, given the allele frequencies?

Answer 5

• 2 possible way
• pq+pq= 2pq
• p2+2pq+q2 = 1.00

Question 6

How can you tell if a population is at genetic equilibrium or undergoing microevolution?

Answer 6

• genetic equilibrium - no change/ evolving in alleles frequencies
• Microevolution - gradual change in allele frequencies

Question 7

Describe how the two equation based on the Hardy- Weinberg principle can be used to detect gene pool changes over time.

Answer 7

• can be expanded to study genes with multiple alleles
• changes in the frequencies over time indicate that something is happening to cause microevolution in this vulnerable population

Question 8

What is the relationship between the conditions of the Hardy-Weinberg principle and gene pool change?

Answer 8

• Hardy-Weinberg principle represent an ideal situation that rarely, if ever occurs in natural population
• Hardy- Weinberg equation can be used to measure the amount of change in at the allele frequencies of a population overtime

1. genetic mutation
2. gene flow
3. non-random mating
4. genetic drift
5. natural selection

Question 9

Explain how inheritable mutations may add to the diversity of a gene pool.

Answer 9

• A mutation is a change that occurs in the DNA of an individual. An inheritable mutation, however has the potential to affect an entire gene pool.
• mutation are neutral, some are harmful and few are even beneficial
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Question 10

How does gene flow into a population affect the population’s gene pool?

Answer 10

Gene flow- describe the net movement of alleles from one population to another due to the migration of individuals

• It reduces genetic differences among population
• adjacent populations tend to share same alleles

Question 11

Describe the outcomes of two situations that result in gene flow between populations.

Answer 11

• Genetic diversity in the nearby population may increase having greater genetic diversity may help this population survive
• Gene flow between human population has increased
• Reduced genetic differences between local human population

Question 12

Why is most bathing in populations non-random?

Answer 12

• Random mating in a population means that there I no way to predict which makes will male with which females, or which females will mate with males
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Question 13

Describe one effect of non-random mating in plants and one effect in animals.

Answer 13

Animal - individuals may choose mates based on their physical and behavioural trait

Plants - inbreeding increases the frequency of homozygous genotypes.

Question 14

Why are small populations more susceptible to genetic drift than large populations are?

Answer 14

A small population is more likely to lose alleles from its gene pool than a large populations.

A change in allele frequencies due to change evens in small breeding population

Large population do not experience genetic drift, because change events are unlikely to affect overall allele frequencies

Question 15

Describe two possible gene pool changes that could result from the founder effect.

Answer 15

• Diversity in the new gene pool
• Alleles may in frequency
• Medical concern

Question 16

Why might the founder effect cause inbreeding?

Answer 16

• Human populations, and the lack of genetic diversity in these populations can be a medical concern

Question 17

Describe two situations that might result in the bottleneck effect.

Answer 17

• The edge of extinctions
• Fertility rates

Question 18

What is the relationship between mutations an natural selection?

Answer 18

Natural Selection occurs when a mutation produces a phenotype that gives one individuals a survival advantage over another

• Small and lack diversity of genetic drift - may be extinct

Question 19

Define heterozygote advantage.

Answer 19

Several alleles that are related to genetic health condition are thoughts to provide

Question 20

In what ways can habitat fragmentation affect gene pools of natural populations.

Answer 20

• Unregulated hunting, habitat removal and other human activities that cause population to decline abruptly can cause a bottle neck effect by genetic drift