Evolution of Populations - Ch. 19

Question 1

What is microevolution?

Answer 1

evolution on the smallest scale. change in allele frequency in a population. the likelihood or percentage of that allele in a population

Question 2

Darwin vs Mendel on genetic variation

Answer 2

Darwin could not explain how inherited variations are maintained in populations. It was not till Gregor Mendel proposed his hypothesis of inheritance. Parents pass on discrete heritable units (genes) that retain their identities in their offspring

Question 3

Mutations

Answer 3

only source of new genes and new alleles

Question 4

Gene flow

Answer 4

any movement of genes from one populations to another

Question 5

Sexual reproduction

Answer 5

shuffle existing alleles

Question 6

Gene pool

Answer 6

all alleles at all loci in all the members of a populations.
all alleles in all organisms in that population
change in time from gen to gen

Question 7

Population genetics

Answer 7

study of how populations change genetically over time

Question 8

Hardy Weinberg equilibrium

Answer 8

describe a population that is not evolving.
frequencies of alleles and genotype in a population’s gene pool remain constant over generations unless acted upon by agents other than sexual recombination

Question 9

Conditions for Hardy-Weinberg equilibrium

Answer 9

1. no mutations
2. random mating (no sexual selection)
3. extremely large population size (infinite)
4. no natural selection
5. no gene flow
   if any of these conditions are not met, then microevolution occurs

Question 10

HWE equation

Answer 10

p = frequency of A, dominant allele
p2 = phenotype or genotype, AA
q = frequency of a, recessive allele
q2 = phenotype or genotype, aa
2pq = heterzygous, Aa 
equation = p2 + 2pq + q2 = 1

Question 11

Natural selection

Answer 11

a mechanism of microevolution, differential and reproductive success. live long enough to contribute to the gene pool

Question 12

Directional selection

Answer 12

the population evolves

Question 13

Disruptive selection

Answer 13

original population turns into two

Question 14

Stabilizing selection

Answer 14

original population becomes an average

Question 15

Genetic variance

Answer 15

diversity of alleles and genotypes within a population

Question 16

Balancing selection

Answer 16

Diploidy: inherit 2 alleles
Recessive alleles hidden in heterozygotes
For example, heterozygotes have better survival. heterozygotes for sickle cell anemia protected against malaria

Question 17

Sexual selection

Answer 17

Certain individuals more likely to obtain mates based on size, color, behavior, etc.

Question 18

Genetic drift

Answer 18

unpredicatable genetic fluctuation of alleles from one generation to the next. Significant genetic drift occurs in small populations.
can lose genetic variations within a populations and can cause harmful alleles to become fixed

Question 19

Bottleneck effect

Answer 19

severe drop in population size. certain alleles may be over or under represented. happens environmentally

Question 20

Founder effect

Answer 20

a few individuals migrate, they become isolated from a larger population, causing alleles to be over or under represented

Question 21

Gene flow

Answer 21

population loses or gains alleles due to immigration or emigration. constant inflow and outflow of genes