Module 2 (Evolution of Populations)

Question 1

__________ is a change in ALLELE FREQUENCIES in a population over generations

Answer 1

Microevolution

Question 2

T or F;

Organisms evolve during their lifetimes.

Answer 2

False

Question 3

What do you call the change of genetic composition of a population over time?

Answer 3

Evolution

Question 4

What two things would natural selection lead to?

Answer 4

1.Population changing over generations.

2. Evolutionary Adaptation.

Question 5

What is the only mechanism that consistently causes adaptive evolution?

Answer 5

Natural selection

Question 6

T or F;

Natural selection, genetic drift, and gene flow can alter allele frequencies in a population

Answer 6

True

Question 7

What is the use of the Hardy-Weinberg equation?

Answer 7

It is used to test whether a population is evolving or not

Question 8

T or F;

Genetic variation makes evolution possible

Answer 8

True

Question 9

Sources for Genetic Variation;

Answer 9

Mutation

Rapid Reproduction

Altering of gene number or position

Sexual Reproduction and Recombination

Question 10

Modified T or F;

Sensual Reproduction and Allele frequency produce the variation in gene pools that contribute to differences among individuals

Answer 10

False;
Sexual Reproduction and Recombination

Question 11

Give two types of variable traits in a population.

Answer 11

1. Polygenic traits
2. Single gene traits

Question 12

This trait results from the combined effects of several genes or determined by a single gene. Also, tend to produce phenotypes that vary more or less continuously.

Answer 12

Polygenic Traits

Question 13

This type of variable trait tends to produce only a few distinct phenotypes.

Answer 13

Single Gene Trait

Question 14

Modified T or F;

Variation in individual PHENOTYPE leads to variation in individual GENOTYPE

Answer 14

False;
Genotype leads to Phenotype variation

Question 15

T or F;

Not all phenotypic variation is heritable

Answer 15

True

Question 16

T or F;

Natural selection can only act on variation with a PHENOTYPIC component

Answer 16

False; genetic

Question 17

Describe discrete Characters.

Answer 17

determined by a single gene that produces a distinct phenotype

Question 18

Describe Quantitative Characters

Answer 18

Typically have a wide range and variation of phenotypes and are controlled by multiple genes

Question 19

It is a group of organisms, all of the same species, which interbreed and live in the same place and time.

Answer 19

Population

Question 20

T or F;

A population shares a common gene pool.

Answer 20

True

Question 21

How do population geneticists measure polymorphisms in a population?

Answer 21

By determining the amount of heterozygosity at the gene and molecular levels.

Question 22

What does average heterozygosity measure?

Answer 22

Average percent of loci that are heterozygous in a population.

Question 23

How is Nucleotide variability measured?

Answer 23

It is measured by comparing DNA sequences of pairs between individuals.

Question 24

In terms of variation between populations, most species exhibit what type of variation?

Answer 24

Geographic Variation

Question 25

Modified T or F; Genetic variation exists (or happens) within INDIVIDUALS.

Answer 25

False; populations

Question 26

What do you call a graded change in a trait along a geographic axis?

Answer 26

cline

Question 27

This word describe changes in the NUCLEOTIDE SEQUENCES of DNA.

Answer 27

Mutation

Question 28

T or F: Explain why if False. Mutations in ALL TYPES of cells can be passed to offspring

Answer 28

False; Only cells that produce gametes can pass mutations to offsprings.

Question 29

Define point mutation.

Answer 29

A change of ONE BASE in a gene. It can either be harmful or helpful in increasing fitness between organism and environment.

Question 30

Modified T or F; Chromosomal mutations that delete, disrupt, or rearrange SINGLE loci are typically BENEFICIAL.

Answer 30

False: Many (or multiple); Harmful

Question 31

T or False; Explain if False Mutation rates are LOW in animals and plants. Mutations rates are often LOWER in prokaryotes and higher in viruses

Answer 31

True

Question 32

This is a word that describes all the alleles for all loci in a population.

Answer 32

Gene pool

Question 33

Modified T or F; Locus is FLEXIBLE if all individuals in a population are homozygous for the same allele

Answer 33

False; fixed

Question 34

Modified T or F; Allele frequencies in a population will remain CONSTANT unless one or more factors cause those frequencies to CHANGE.

Answer 34

True

Question 35

What are the five conditions for Hardy-Weinberg equilibrium?

Answer 35

1. No Mutation (No genetic change) 2. No Gene Flow (no migration of species) 3. No Sexual selection 4. No Genetic Drift (large population size) 5. No Selection (Equal fitness)

Question 36

This type of genetic drift occurs when a few individuals become isolated from a larger population

Answer 36

Founder Effect

Question 37

This type of genetic drift is a sudden reduction in population size due to a change in the environment.

Answer 37

Bottleneck Effect

Question 38

Modified True or False; Allele frequencies in the small founder population can be COMPLETELY SIMILAR from those in the larger parent population

Answer 38

False; different

Question 39

Modified True or False; The resulting gene pool may NO LONGER BE REFLECTIVE of the original population’s gene pool

Answer 39

True

Question 40

This factor of evolution is a change in the allele frequency due to transfer of alleles into or out of the gene pool

Answer 40

Gene flow

Question 41

This factor of evolution is the only mechanism that consistently causes adaptive evolution

Answer 41

Natural Selection

Question 42

Modified T or F; Natural Selection brings about adaptive evolution by acting on an organism’s GENOTYPE.

Answer 42

False; Phenotype

Question 43

This word refers to the contribution an individual makes to the gene pool of the next generation, relative to the contributions of other individuals

Answer 43

Relative Fitness

Question 44

What are the three modes of Natural Selection? Explain each in your own words.

Answer 44

1. Directional Selection (favors individuals at one end of the phenotypic range) 2.Disruptive selection (favors individuals at both extremes of the phenotypic range) 3.Stabilizing selection (favors intermediate individuals of the phenotypic range)

Question 45

What is the Key Role of Natural Selection in Adaptive Evolution?

Answer 45

Natural selection INCREASES the frequencies of alleles that enhance survival and reproduction

Question 46

This concept of evolution occurs as the match between an organism and its environment increases

Answer 46

Adaptive evolution

Question 47

This factor of Evolution refers to natural selection in terms of MATING success.

Answer 47

Sexual Selection

Question 48

This word refers to MARKED DIFFERENCES between the sexes in their secondary sexual characteristics.

Answer 48

Sexual Dimorphism

Question 49

A type of Sexual selection where competition among individuals of ONE SEX (often males) for mates of the opposite sex

Answer 49

Intrasexual selection

Question 50

A type of Sexual selection, often called mate choice, occurs when individuals of one sex (usually females) are choosy in selecting their mates

Answer 50

Intersexual selection

Question 51

Modified True or False; Male showiness due to mate choice can DECREASE a male’s chances of attracting a female, while INCREASING his chances of survival

Answer 51

False; Increase then decrease

Question 52

What is this mechanism that maintains genetic variation in the form of hidden recessive alleles

Answer 52

Diploidy

Question 53

This is a concept that occurs when heterozygotes have a higher fitness than do both homozygotes

Answer 53

Heterozygote Advantage

Question 54

This concept of selection can favor whichever phenotype is less common in a population. The fitness of a phenotype declines if it becomes too common in the population

Answer 54

Frequency-Dependent Selection

Question 55

It is a type of genetic variation that appears to confer no selective advantage or disadvantage.

Answer 55

Neutral variation

Question 56

Why can't natural selection fashion perfect organisms?

Answer 56

1. Selection can act only on existing variations, favors the fittest 2. Evolution is limited by historical constraints [does not "occur" out of the blue] 3. Adaptations are often compromised 4. The interaction of Chance, natural selection, and the environment.

Question 56

Why can't natural selection fashion perfect organisms?

Answer 56

1. Selection can act only on existing variations, favors the fittest 2. Evolution is limited by historical constraints [does not "occur" out of the blue] 3. Adaptations are often compromised 4. The interaction of Chance, natural selection, and the environment.