Lab 1: Evolution and Population Genetics

Question 1

List the 4 agents of Evolution

Answer 1

Natural Selection
Genetic Drift
Gene Flow
Mutation

Question 2

Name the 2 most important of the 4 Agents of Evolution

Answer 2

Natural Selection and Genetic Drift

Question 3

Genetic Drift

Answer 3

A process in which chance events cause unpredictable fluctuations in allele frequencies from one generation to the next.

Types of genetic drift include the founder effect and the bottleneck effect.

Question 4

Are the effects of genetic drift are most pronounced in small or large populations?

Answer 4

SMALL

Question 5

Gene Flow

Answer 5

The transfer of alleles from one population to another, resulting from the movement of fertile individuals or their gametes.

Gene Flow = immigration/emigration

Question 6

Hardy-Weinberg Principle

Answer 6

The principle that frequencies of alleles and genotypes in a population remain constant from generation to generation, provided that only Mendelian segregation and recombination of alleles are at work.

A null model.

Question 7

What are the 5 conditions for the Hardy-Weinberg Principle

Answer 7

1. The Population size must be Infinitely Large.
2. The Population is isolated from Gene Flow with other population (i.e., No Immigration or Emigration).
3. There is no net Mutation.
4. Individuals Mate Randomly
5. No Natural Selection occurs

Question 8

Natural Selection

Answer 8

A process in which individuals that have certain inherited traits tend to survive and reproduce at higher rates than other individuals because of those traits.

Question 9

Genotype

Answer 9

The genetic composition, or set of alleles, of an organism.

Question 10

Phenotype

Answer 10

The observable physical and physiological traits of an organism, which are determined by its genetic makeup. The expression of the genotype is influenced by the environment.

Question 11

Founder Effect

Answer 11

Genetic drift that occurs when a few individuals become isolated from a larger population and form a new population whose gene pool composition is not reflective of that of the original population.

Question 12

Bottleneck Effect

Answer 12

Genetic drift that occurs when the size of a population is reduced, as by a natural disaster or human actions. Typically, the surviving population is no longer genetically representative of the original population.

Question 13

Is Variation essential for Evolution?

Answer 13

Yes!!

Question 14

Microevolution

Answer 14

Evolutionary change below the species level; change in the allele frequencies in a population over generations.

Question 15

Macroevolution

Answer 15

Evolutionary change above the species level. Examples of macroevolutionary change include the origin of a new group of organisms through a series of speciation events and the impact of mass extinctions on the diversity of life and its subsequent recovery.

macroevolution=the evolution of species

Question 16

Evolution

Answer 16

Descent with modification; the idea that living species are descendants of ancestral species that were different from the present-day ones; also defined more narrowly as the change in the genetic composition of a population from generation to generation.

Question 17

Population

Answer 17

A group of individuals of the same species that live in the same area and interbreed, producing fertile offspring.

Question 18

Fitness

Answer 18

Fitness (often denoted w in population genetics models) is a central idea in evolutionary theory. It can be defined either with respect to a genotype or to a phenotype in a given environment. In either case, it describes the ability to both survive and reproduce, and is equal to the average contribution to the gene pool of the next generation that is made by an average individual of the specified genotype or phenotype. The term “Darwinian fitness” is often used to make clear the distinction with physical fitness. If differences between alleles of a given gene affect Darwinian fitness, then the frequencies of the alleles will change across generations; the alleles with higher fitness become more common. This process is called natural selection.

An individual’s fitness is manifested through its phenotype. The phenotype is affected by the developmental environment as well as by genes, and the fitness of a given phenotype can be different in different environments. The fitnesses of different individuals with the same genotype are therefore not necessarily equal. However, since the fitness of the genotype is an averaged quantity, it will reflect the reproductive outcomes of all individuals with that genotype in a given environment or set of environments.

Inclusive fitness differs from individual fitness by including the ability of an allele in one individual to promote the survival and/or reproduction of other individuals that share that allele, in preference to individuals with a different allele. One mechanism of inclusive fitness is kin selection.

Question 19

Survivability

Answer 19

?

Question 20

Descent with Modification

Answer 20

Evolution

Question 21

directional selection

Answer 21

Natural selection in which individuals at one end of the phenotypic range survive or reproduce more successfully than do other individuals.

Question 22

disruptive selection

Answer 22

Natural selection in which individuals on both extremes of a phenotypic range survive or reproduce more successfully than do individuals with intermediate phenotypes.

Question 23

Stabilizing selection

Answer 23

Natural selection in which intermediate phenotypes survive or reproduce more successfully than do extreme phenotypes.

Question 24

Many small changes in the gene pool of a population can lead to…

Answer 24

… the rise of a new species

Question 25

When allelic frequencies change, what is occurring?

Answer 25

Evolution.

Question 26

Do allelic frequencies change from generation to generation in diploid, sexually reproducing populations due only to sexual reproduction and recombination?

Answer 26

No