obj 21A, 21B, 22A, 24A

Question 1

microevolution

Answer 1

change in allele frequency of populations from one generation to the next

Question 2

contributions to genetic variation
- mutation
- altering gene #/position
- rapid reproduction
- sexual reproduction

Answer 2

• ultimate source of new alleles
• new gene combos
• increased chance of mutations occurring and being passed on
• combining 2 different genetic materials

Question 3

population
gene pool
gene frequency

Answer 3

• group of same species in particular area
• collection of all genes present within that population
• proportion of specific allele within that gene pool

Question 4

What does it mean for a population to be at Hardy-Weinberg equillibrium

Answer 4

the model shows a mathematical representation of the genetic variation of a large, unchanging population

Question 5

5 conditions for Hardy-Weinberg

Answer 5

• no mutation
• random mating
• no gene flow
• large population size
• no natural selection

Question 6

meaning of each
p
q
p^2
q^2
2pq

Answer 6

• freq. of dominant allele
• freq. of recessive allele
• freq of homozygous dom genotype
• freq. of homozygous recess. genotype
• freq. of heterozyg. genotype

Question 7

mutation

Answer 7

• change in DNA sequence
• increase evolution + fitness

Question 8

Genetic drift

Answer 8

• random changes in genetic makeup of a population from generation to generation
• signif. in small populations
• can lead to loss in genetic variability
• founder and bottleneck effect

Question 9

founder effect

Answer 9

• type of genetic drift
• small founding population does not reflect source gene pool
• ex: mars colony

Question 10

bottleneck effect

Answer 10

• population drastically reduced and surviving population doesn’t reflect original gene pool

Question 11

geneflow

Answer 11

• immigration /emigration: mvmt of alleles into/out of populations
• may increase or decrease variation in population

Question 12

natural selection

Answer 12

• population adapts to its environment
• heritable variation, more offspring born than can survive, competition for lim. resources, some survive and reproduce based on adaptation

Question 13

evolutionary fitness

Answer 13

beneficial adaptations that allow an organism to survive and reproduce

Question 14

sexual selection

Answer 14

• intersexual(within the same sex): male to male competition, structures, fighting
• intersexual (between sexes): mate choice, structures, dances

Question 15

directional selection

Answer 15

• type of natural selection
• one extreme favored
• horizontal shift

Question 16

disruptive selection

Answer 16

• type of natural selection
• both extremes favored
• 2 peaks that look like u

Question 17

stabilizing selection

Answer 17

• type of natural selection
• both extremes not favored
• horizontal compression (skinnier)

Question 18

balancing selection

Answer 18

• no single phenotype favored
• regular curve
• heterozygote advantage: existence of harmful alleles common, but usually hidden in heterozygotes

Question 19

frequency-dependent selection

Answer 19

fitness is dependent upon the frequency of a phenotype or genotype in a population
- pos: favors common and neg: favors rare

Question 20

sexual dimorphism

Answer 20

sexes of the same species exhibit diff morphological charachterstics
- ex: male vs female peacocks

Question 21

why do females tend to be more choosy in their mate selection

Answer 21

• invest more because they have fewer eggs
• genetic(offspring survival), resources, and parenting capabilities

Question 22

natural selection vs sexual selection

Answer 22

both face pressure that causes them to evolve over time
- natural: favors traits that enhance organism’s survival
- sexual: favors traits that increase chances of attracting mates and reproducing

Question 23

why can’t natural selection produce perfection

Answer 23

• only acts on existing genetic variations within population
• cannot create new traits or perfect adaptation
• environment also always changing

Question 24

microevolution vs speciation

Answer 24

• microevolution: small scale changes in gene frequencies within a population over time
• speciation: process by which a new species arises from an existing one

Question 25

biological species concept and reproductive isolationism

Answer 25

- population/group that can successfully interbreed - reproductive isolation: something that keeps 2 groups that would normally interbreed from doing so

Question 26

5 types of prezygotic barriers

Answer 26

temporal: time diff mechanical: cant have behavioral: mating gametic: gametes don't match and can't be fertilized habitat: diff loco

Question 27

3 types of postzygotic barriers

Answer 27

- hybrid: 2nd generation can't reproduce - reduced hybrid fertility: offspring are infertile - reduced hybrid viability: offspring weak and unhealthy

Question 28

allopatric speciation

Answer 28

- away from fatherlands - physical barrier divides one population into 2 - divergence in gene pool thru mutations, selection - w/ enough time, less likely to mate with each other if 2 populations reintroduced (isolated populations)

Question 29

sympatric speciation

Answer 29

- species evolved while alongside its fellow organisms - polypoidy: more than 2 sets of chromosomes - habitat differentiation - sexual selection

Question 30

Lake victoria light transmission leading to speciation

Answer 30

Hundreds of species in the Lake, feed differently based on environment, light sensitivity is heritable and keeps sexual selection within groups because the fish mate with certain colored fish

Question 31

4 major events in the evolution of life on earth

Answer 31

- small organic molecules synthesized - small molec. joined into macromolecules (proteins,nucleo.) - protocells form from lipids - replicating molecules evolve and begin to undergo natural selection

Question 32

conditions on surface if early earth

Answer 32

- incredibly hot - no ozone layer - highly volatile atmosphere - lots of meteors

Question 33

miller and Urey experiemtn

Answer 33

- created apparatus to stimulate early earth conditins - showed that organic molec, could have arisen spontaneously thru natural processes

Question 34

function of ribozymes and likely role in origin of life

Answer 34

- RNA catalysts that can catalyze rxns to copy itself - could have been template for DNA assembly

Question 35

formation of earth

Answer 35

4.56 bya

Question 36

fossil evidence for earliest life on earth

Answer 36

- 3.5 bya - bacteria in apex chert