microevolution

Question 1

What is microevolution?

Answer 1

It is the change in the gene pool of a population of organisms over time.

Question 2

What constitutes a population’s ‘gene pool’?

Answer 2

It is all alleles of all genes of all individuals in that population.

Question 3

What is the significance of the gene pool in evolutionary terms?

Answer 3

It represents all the genetic variation which is the ‘raw material’ of evolution.

Question 4

Define macroevolution.

Answer 4

It describes major evolutionary events that occur above the level of the species, such as the evolution of major animal groups.

Question 5

What are the two essential requirements for evolution by natural selection to occur?

Answer 5

Differential reproductive success and genetic differences between individuals (genetic variation).

Question 6

What is the primary distinction between microevolution and macroevolution?

Answer 6

Microevolution refers to evolutionary events within a species, whereas macroevolution refers to events above the species level.

Question 7

The study of microevolution, focusing on the genetic structure of populations, is called _____.

Answer 7

population genetics

Question 8

Population genetics represents a synthesis of Darwin’s theory of evolution and which other scientist’s theory?

Answer 8

Mendel’s theory of inheritance.

Question 9

Name the three scientists who were principal founders of population genetics.

Answer 9

John (JBS) Haldane, Sewall Wright, and Ronald Fisher.

Question 10

In what way can population genetics be applied to study evolving human pathogens like bacteria and viruses?

Answer 10

It can be used to track the development of resistance to antibiotics (e.g., MRSA) and antiviral drugs (e.g., HIV).

Question 11

The coronavirus most similar to SARS-CoV-2 (96% sequence identity) is found in which animal?

Answer 11

The horseshoe bat.

Question 12

What is the name of the sub-discipline that applies population genetics to the preservation of wild populations?

Answer 12

Conservation genetics.

Question 13

What are the two primary frequencies that population geneticists measure in a gene pool?

Answer 13

Allele frequency and genotype frequency.

Question 14

How is allele frequency calculated?

Answer 14

It is the number of alleles of one type divided by the total number of alleles in the population.

Question 15

How is genotype frequency calculated?

Answer 15

It is the number of individuals of one genotype divided by the total number of individuals in the population.

Question 16

What is the term for the state where allele and genotype frequencies in a population remain constant from generation to generation?

Answer 16

Hardy-Weinberg equilibrium.

Question 17

State the Hardy-Weinberg equation.

Answer 17

p^2+2pq+q^2=1

Question 18

In the Hardy-Weinberg equation, what do the variables p and q represent?

Answer 18

They represent the frequencies of the two alleles at a given gene locus.

Question 19

In the Hardy-Weinberg equation, what does the term p2
represent?

Answer 19

The frequency of the homozygous dominant genotype (e.g., RR).

Question 20

In the Hardy-Weinberg equation, what does the term 2pq represent?

Answer 20

The frequency of the heterozygous genotype (e.g., Rr).

Question 21

For the Hardy-Weinberg equilibrium to apply, the population size must be very _____.

Answer 21

large

Question 22

A key assumption of the Hardy-Weinberg equilibrium is that mating within the population is _____.

Answer 22

random

Question 23

For a population to be in Hardy-Weinberg equilibrium, there must be no _____ from other populations.

Answer 23

migration (gene flow)

Question 24

What assumption does the Hardy-Weinberg principle make about selection?

Answer 24

That there is no selection acting on the genotypes.

Question 25

A final assumption of the Hardy-Weinberg equilibrium is that there is no _____ occurring at the gene locus.

Answer 25

mutation

Question 26

What can be inferred if a gene in a population is found not to be in Hardy-Weinberg equilibrium?

Answer 26

That one or more of the five assumptions is being violated and evolution is likely occurring.

Question 27

Cystic fibrosis is caused by a recessive mutation. If the population is at H-W equilibrium, what term in the equation represents the frequency of affected individuals?

Answer 27

The q2 term.

Question 28

List the four main factors that can lead to changes in allele and genotype frequencies, causing microevolution.

Answer 28

Genetic drift, non-random mating, migration/gene flow, and selection.

Question 29

The force that causes random fluctuations in allele frequencies, especially in small populations, is known as _____.

Answer 29

genetic drift

Question 30

According to Charles Darwin, what is the 'raw material' upon which selection acts to produce new species?

Answer 30

Genetic variation (or variability of organic beings).

Question 31

What did molecular analysis by researchers like Richard Lewontin reveal about genetic variation in natural populations?

Answer 31

That there is a surprisingly large amount of genetic variation present.

Question 32

What is the name for a form of balancing selection where the heterozygote genotype has a selective advantage over both homozygotes?

Answer 32

Heterozygote advantage.

Question 33

What is a classic example of heterozygote advantage in human populations, related to malaria resistance?

Answer 33

Sickle-cell anaemia.

Question 34

What is frequency-dependent selection?

Answer 34

A type of balancing selection where the fitness of a phenotype depends on how common it is in the population.

Question 35

What is the central idea of Motoo Kimura's Neutral Theory of molecular evolution?

Answer 35

That many alleles are selectively 'neutral' and their frequencies change randomly over time due to genetic drift.

Question 36

A heritable change in the genetic code is called a _____.

Answer 36

mutation

Question 37

If allele A is dominant over allele a, which two genotypes will produce the same phenotype?

Answer 37

The homozygous dominant (AA) and heterozygous (Aa) genotypes.

Question 38

In a diploid organism, an individual with two different alleles for a particular gene (e.g., Rr) is called a _____.

Answer 38

heterozygote

Question 39

In a diploid organism, an individual with two identical alleles for a particular gene (e.g., RR or rr) is called a _____.

Answer 39

homozygote

Question 40

What statistical test is used to determine if observed genotype frequencies are significantly different from those expected under Hardy-Weinberg equilibrium?

Answer 40

The Chi-square test.

Question 41

In a hypothetical population of 10 plants with genotypes 5 RR, 4 Rr, and 1 rr, what is the genotype frequency of heterozygotes (f(Rr))?

Answer 41

0.4 (calculated as 4/10).

Question 42

Allele

Answer 42

An alternative form of a gene.

Question 43

When a mutation changes a codon that codes for an amino acid into one that codes for a stop signal, what is the likely effect on the protein?

Answer 43

The protein will be truncated or not produced at all.