Population, Genetics, And Evolution

Question 1

Three structural features of an evolutionary system

Answer 1

1. Variations- in the population
2. Reproduction- mechanism for those variations to reproduce
3. Differential Reproduction- environmental constraints that allow favorable variations to be reproduced more than others

Question 2

In biology, differential reproduction is accomplished by?

Answer 2

Natural selection

Question 3

Refers to the tendency of certain phenotypes to be favored in terms of reproduction. It is the mechanism through which evolution takes place.

Answer 3

Natural Selection

Question 4

ONLY refers to the chance of reproduction associated with a certain phenotype compared to baseline. It MUST be defined in terms of specific environmental constraints.

Answer 4

Fitness

Question 5

Natural selection could act on the level of the group, not the individual

Answer 5

Group Selection

Question 6

Expands the rigorous evolutionary definition of fitness to account not just for individuals but their relatives, who can be expected to share many of the same alleles

Answer 6

Inclusive fitness

Question 7

How can altruistic behavior be advantageous in the point of view of a gene?

Answer 7

If the altruistic behavior or even self-sacrifice can ensure the survival of more copies of the gene.

Question 8

The combined set of all genes/alleles in a population. It is often used to describe the genetic status of a population.

Answer 8

Gene pool

Question 9

Hardy-Weinberg equilibrium is used to model _________ gene pools

Answer 9

STABLE

Question 10

For Hardy-Weinberg equilibrium to apply to a population, it must meet the 6 characteristics

Answer 10

1. Organisms must be diploid and reproduce sexually
2. Mating is random
3. The population size is very large
4. Alleles are randomly distributed by sex
5. No mutations occur.
6. There is no migration into or out of the population

Question 11

Hardy-Weinberg equilibrium equations

Answer 11

1. p + q =1

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

Question 12

What does it mean when features are “polygenic“?

Answer 12

Multiple genes contribute to them

Question 13

Occurs if both extremes are selected against. For ex, very short and very tall have lower reproductive fitness, the height of the population will be maintained within a tight range

Answer 13

Stabilizing Selection

Question 14

Occurs if only one extreme phenotype is selected against and the other extreme is favored.

Answer 14

Directional Selection

Question 15

Occurs when median phenotype is selected against.

Answer 15

Disruptive selection

Question 16

Refers to the role of chance, in the absence of strong selective pressures, in determining the reproductive fitness of various alleles. A certain allele may randomly happen to be reproduced more or less often.

Answer 16

Genetic Drift

Question 17

Occurs when some external event dramatically reduces the size of a population in a way that is essentially random with regard to most if not all alleles. Ex. Tay-Sachs disease in Ashkenazi Jews

Answer 17

Evolutionary bottleneck

Question 18

How new species evolves through evolution

Answer 18

Speciation

Question 19

Term for when considerable phenotypic variation exist within a single species. Give an example.

Answer 19

Polymorphism- can help set the stage for speciation

Ex. ABO Blood type

Question 20

Anything that stops reproduction before the formation of a zygote, such as occupying different ecological niches, having different patterns of breeding, not engaging in reproductive behavior with members of the other species, etc.

Answer 20

Prezygotic barriers

Question 21

Various forms of reproductive isolation that can occur after a zygote is formed.

Answer 21

Postzygotic barriers

Question 22

Term for when hybrids are fertile but fertility breaks down in the second generation

Answer 22

Hybrid breakdown

Question 23

On the level of the gene pool, genes can sometimes travel between species, in what is known as?

Answer 23

Leakage

Question 24

Since random errors accumulate on the genome at a relatively fixed rate, the extent to which two genomes differ serves as a proxy for how long ago they had a shared common ancestor. What is the term that describes this?

Answer 24

Molecular clock

Question 25

Occurs when two species depend on each other and evolve together. Ex. Flowering plants and pollinators evolved together

Answer 25

Coevolution

Question 26

Two closely related species gradually become more genetically distinct

Answer 26

Divergent evolution

Question 27

Two closely related species independently evolve a similar trait

Answer 27

Parallel evolution

Question 28

Two species that do not have a recent common ancestor independently evolves similar trait

Answer 28

Convergent evolution

Question 29

One species benefit and the other is unaffected.

Answer 29

Commensalism