lecture 19- evolution of populations

Question 1

what is the smallest unit that can evolve

Answer 1

populations

Question 2

what is the variability in populations due to

Answer 2

the environment and genetics

Question 3

what is genetics the basis of

Answer 3

evolution

Question 4

what is microevolution

Answer 4

change in the genetic makeup of a population from generation to generation
can lead to macroevolution

Question 5

what is the gene pool

Answer 5

all the alleles for all the loci present in the population

Question 6

what is genotype frequency

Answer 6

the proportion of a particular genotype in the population

Question 7

how do you calculate the genotype frequency

Answer 7

by dividing the genotype number by the number of individual (490 AA out of 1000 individuals = 0.49)

Question 8

what is allele frequency

Answer 8

the proportion of a specific allele in a population

Question 9

how do you calculate allele frequency

Answer 9

count alleles separately and divide by 2x individuals (600 Aa = 600 A and 600 a divided by 2x 1000 individuals (2 alleles each) = 0.3 each) technically should add up to 1

Question 10

how do you see the evolution of a population

Answer 10

you compare the allele frequencies of the first generation with the second generation

Question 11

how do allele frequencies change

Answer 11

from environmental changes/outside factors

Question 12

what happens when the population is in genetic equilibrium

Answer 12

the allele and genotype frequencies are not changing from generation to the next

Question 13

what does HW principle/equilibrium stand for

Answer 13

Hardy-Weinberg

Question 14

what are the characteristics of HW equilibrium

Answer 14

in large population where mating is random and likely the allele frequency will not change

Question 15

what are the formulas for allele and genotype frquencies

Answer 15

allele: p + q = 1
genotype: p^2 + 2pq +q^2 = 1
where
p: dominant allele freq.
q: recessive allele freq.
p^2: homozygous dominant genotype freq.
2pq: heterozygous genotype frq.
q^2: homozygous recessive freq.

Question 16

HW equilibrium equations meaning

Answer 16

any population that conforms to p^2 + 2pq + q^2 = 1 is at genetic equilibrium
wont tell us anything about evolving populations

Question 17

what are the conditions for genetic equilibrium

Answer 17

random mating
no mutation
no natural selection
extremely large pop. size
no migration

Question 18

factors that cause microevolution

Answer 18

mutations
sexual recombination
natural selection
genetic drift
gene flow

Question 19

mutations effects and characteristics

Answer 19

only way of getting new genes and alleles
most occur in somatic cells
can only be transmitted if it occurs in gametes
low rate in animals and plants
little effect on population

Question 20

sexual recombination effects

Answer 20

genetic variability
little effect from generation to generation
mostly just reshuffling

Question 21

natural selection effects and characteristics

Answer 21

certain alleles are passed to the next gen. in greater proportions
major factor in changing allele frequencies

Question 22

wha are the three types of genetic drift

Answer 22

bottleneck
founder effect

Question 23

what is genetic drift

Answer 23

random evolutionary changes in a population
how allele frequencies can change unpredictably from one gen. to the next
alleles can be eliminated by chance
major factor affecting allele frequencies

Question 24

effects of genetic drift

Answer 24

decrease in genetic variation in a population (smaller size)
increase in genetic differences between different populations

Question 25

bottleneck effect

Answer 25

large population reduced to nothing because of a disaster
genetic drift continues to affect the gene pool until pop. becomes large enough to eliminate the effect of chance fluctuations

Question 26

founder effect

Answer 26

few individuals becoming isolated from a larger population
bring only a small fraction of genetic variability with them
allele frequency is different than the parent population’s

Question 27

what is gene flow

Answer 27

the gain or loss of alleles from the movement of fertile individuals
one loses alleles the other gains
will reduce differences between populations over time
counters gene flow and natural selection
major factor altering allele frequencies

Question 28

what makes natural selection different than other factors than cause microevolution

Answer 28

only one that can lead to an adaptation to the environment
increases the frequencies of certain genotypes (survival of the fittest)
only adaptive and non-random mechanism

Question 29

types of natural selection

Answer 29

directional selection
disruptive selection
stabilizing selection

Question 30

what is directional selection

Answer 30

favors individuals at one end of the phenotypic range

Question 31

what is disruptive selection

Answer 31

favors individuals at both extremes of the phenotypic range

Question 32

what is stabilizing selection

Answer 32

favors intermediate individuals (against extremes phenotypes)

Question 33

what creates the most genetic variation in a population

Answer 33

sexual reproduction
(crossing over, independent assortment, random fertilization)
original differences originated from mutations

Question 34

is sexual reproduction a handicap and why

Answer 34

yes because its much slower and and results in less reproductive offsprings

Question 35

what is sexual selection

Answer 35

natural selection for mating success
can result in sexual dimorphism

Question 36

what is sexual dimorphism

Answer 36

differences between sexes in secondary sexual characteristics (colorful males)

Question 37

what is intrasexual selection

Answer 37

direct competition among individuals of one sex for mates of the opposite sex (males fighting with other males)

Question 38

what is intersexual selection

Answer 38

when one sex (usually females) are choosy in selecting their mates in the other sex (birds singing so female choose him)