Final Study Guide: Part 2

Question 1

Define phenotype

Answer 1

a set of observable characteristics of an organism

Question 2

Define fitness

Answer 2

an organism’s ability to survive and reproduce in a particular environment

Question 3

The breeder’s equation

Answer 3

R = h^2 (S)

Question 4

What are some drivers of natural selection?

Answer 4

species interactions, environmental factors, mate choice

Question 5

Define sexual selection

Answer 5

selects for traits that enhance reproductive success

Question 6

Define altruism

Answer 6

a behavior that reduces individual fitness and increases the fitness of other individuals

Question 7

Define kin selection

Answer 7

selection that favors behaviors that increase the reproductive success of relatives

Question 8

Define inclusive fitness

Answer 8

the sum of an individual’s own fitness, and its contribution to the fitness of relatives

Question 9

Directional selection

Answer 9

phenotypes at one extreme have the highest fitness; mean trends toward the extreme phenotype

Question 10

Stabilizing selection

Answer 10

phenotypes nearest the mean have the highest fitness. The mean stays the same, variation is reduced

Question 11

Disruptive selection

Answer 11

phenotypes at both extremes have higher fitness than the mean. Variation is increased, pattern emerges.

Question 12

Balancing selection

Answer 12

selection maintains variation in a population

Question 13

Negative frequency dependent selection

Answer 13

rarer phenotype has the highest fitness. Frequency of a given phenotype oscillates (up and down)

Question 14

Intrasexual selection

Answer 14

competition among individuals of the same sex for mating opportunities

Question 15

Intersexual selection

Answer 15

mate choice by individuals of one sex (females) based on certain traits in individuals of the opposite sex

Question 16

Define genotype

Answer 16

the genetic makeup of an organism, consisting of the combination of alleles inherited from its parents

Question 17

Define allele

Answer 17

a variant form of a gene that determines specific traits

Question 18

Intramorph competition

Answer 18

competition among individuals of the same morph or form within a species for resources

Question 19

Intermorph competition

Answer 19

competition between individuals of different morphs or forms within a species for resources

Question 20

Root to shoot ratio

Answer 20

plant growth below ground (roots) compared to the growth above the ground (shoots)

Question 21

Define genome

Answer 21

all genetic material an individual carries

Question 22

Define gene

Answer 22

a section of DNA that codes for a particular protein

Question 23

Define nucleotides

Answer 23

organic molecules that makeup DNA and RNA

Question 24

Transcription

Answer 24

DNA into RNA

Question 25

Translation

Answer 25

RNA into proteins

Question 26

Substitution

Answer 26

a nucleotide is exchanged

Question 27

Insertion

Answer 27

a nucleotide in added

Question 28

Deletion

Answer 28

a nucleotide is removed

Question 29

Homozygous

Answer 29

Either fully dominant or fully recessive (BB or bb)

Question 30

Heterozygous

Answer 30

Has both one dominant and one recessive (Bb or bB)

Question 31

Law of segregation

Answer 31

when any individual produces gametes, the two copies of a gene separate so that each gamete receives only one copy

Question 32

Law of independent assortment

Answer 32

alleles of different genes assort independently of one another during gamete formation

Question 33

Simple/complete dominance

Answer 33

a single dominant allele produces the dominant phenotype; the homozygous dominant and heterozygous genotypes have the same phenotype; most commonly seen (BB: tall Bb: tall bb: short)

Question 34

Incomplete dominance

Answer 34

the heterozygote phenotype is intermediate between the two homozygous phenotypes aka blend (BB: red Bb: pink bb: white)

Question 35

Codominant

Answer 35

the heterozygote phenotype is both of the homozygous phenotypes expressed fully or equally (BB: red Bb: red and white bb: white)

Question 36

Pleiotropy

Answer 36

a situation where a single gene influences multiple, seemingly unrelated traits.

Question 37

Define epistasis

Answer 37

when multiple genes interact to determine the phenotype

Question 38

Define chromosome

Answer 38

a structure of DNA and proteins that contains genetic information

Question 39

Diploid

Answer 39

cells with two sets of chromosomes, one from each parent

Question 40

Haploid

Answer 40

cells with one set of chromosomes, found in gametes (sperm and egg)

Question 41

Define population

Answer 41

an interbreeding group of organisms of the same species

Question 42

Define gene pool

Answer 42

collection of all alleles that exist for a trait in a group

Question 43

Hardy-Weinberg Equilibrium (HWE)

Answer 43

In a non-evolving population, genotype and allele frequencies reach equilibrium after one generation and remains constant in the next generations

Question 44

HWE Assumptions

Answer 44

No mutation, no natural selection, no gene flow (migration), no genetic drift (infinite pop. size), random mating

Question 45

P, q, and 2Pq

Answer 45

P = A (homozygous dominant) q = a (homozygous recessive) 2Pq = Aa (heterozygous)

Question 46

P^2 and q^2

Answer 46

P^2 is AA (dominant alleles) and q^2 is aa (recessive alleles)

Question 47

True or false: p + q always equals 1

Answer 47

True

Question 48

A population is in HWE if...

Answer 48

observed genotype frequencies are equal to expected genotype frequencies

Question 49

Define gene flow

Answer 49

transfer of alleles through movement of individuals or their gametes (makes pop. more similar)

Question 50

Define migration

Answer 50

the movement of individuals from one population to another. A physical movement (not genetically).

Question 51

Define genetic drift

Answer 51

random events that cause allele frequencies to fluctuate unpredictably from one generation to the next

Question 52

True or false: Drift reduces genetic diversity

Answer 52

True

Question 53

True or false: Genetic drift is not stronger in smaller populations

Answer 53

False: genetic drift is stronger in smaller populations

Question 54

Genetic bottlenecks

Answer 54

when population size is severely reduced; descended from a few individuals

Question 55

Founder effect

Answer 55

new populations created from a few founders

Question 56

What are the consequences of genetic drift?

Answer 56

loss of overall genetic diversity (fixed or lost alleles), increase in homozygosity of the more common allele, increases in deleterious recessive conditions, increased susceptibility to future stressors