topic 7

Question 1

smallest unit of evolutionary change

Answer 1

populations, evolve via natural selection

Question 2

microevolution

Answer 2

change in allele frequencies in populations

Question 3

allele

Answer 3

different forms of a gene (twoalleles in diploid)

Question 4

gene pool

Answer 4

alleles present in all individuals in population

Question 5

phenotype

Answer 5

the expression of genes, product of inheritance and environment

Question 6

mutations

Answer 6

changes in a dna sequence that occur randomly and create new alleles

Question 7

types of mutations

Answer 7

deletrious, neutral, or advantageous in their current environment

Question 8

harmful/less harmful mutations

Answer 8

chromosomal mutations are typically harmful, duplication of dna segments is less harmful, whole genome duplication is important for complexity

Question 9

how does sexual reproduction increase variation

Answer 9

new combindations of existing alleles

Question 10

recombination

Answer 10

switchup of homologous chromosmes to create new combinations in allleles

Question 11

factors that alter allele frequecies

Answer 11

natural selection, genetic drift, gene flow

Question 12

natural selection allele frequencies

Answer 12

adaptive evoltion

Question 13

non adaptive evolution

Answer 13

change in allele frequency that does not lead to better adaptation (gene flow and genetic drift)

Question 14

relative firness

Answer 14

contribution to the gene pool by one individual compared to the other

Question 15

directional selection

Answer 15

phenotype on an extreme is favored, shifts population in one direction (steady selective pressure)

Question 16

disruptive selection

Answer 16

favours individuals at the extremes, maintains genetic variationst

Question 17

stabilizing selection

Answer 17

favours intermediate phenotypes, reduces genetic variation, maintains mean phenotype

Question 18

genetic drift allele frequencies

Answer 18

non adaptive changes in allele frequencies, more likely in small populations, more likely to lose rare alleles, does not create adaptations

Question 19

bottleneck effect

Answer 19

sudden reduction in population size due to change in environment (prairie chicken), loss of genetic diversity

Question 20

founder effect

Answer 20

few individuals are isolated, allele frequency different than original population

Question 21

gene flow

Answer 21

movement of alleles between populations of a species,
new variation into recieving pop, reduces variation between populations

Question 22

gene flow advantages/disadvantages

Answer 22

could increase or decrease fitness, new genes might be maladaptive

Question 23

other factors that cause evolutionary changes

Answer 23

extirpation - reduction of species genetic diversity
extinction - loss of divbersity

Question 24

neutral variation

Answer 24

genetic varation that doesnt convey an advantage/disadvantage (no phenotypic expression)

Question 25

balancing selection

Answer 25

stable frequencies of multiple alleles favored

Question 26

mechanisms of balancing selection

Answer 26

temporal/spacial variation, heterozygote advantage, frequency-dependent selection

Question 27

temporal/spatial variation

Answer 27

different alleles favored at different time/location, best to maintain intermediate alleles

Question 28

heterozygote advantage

Answer 28

organism with different allels of a particular gene (sickle cell example with malaria)

Question 29

frequency dependent selection

Answer 29

fitness of an allele depends on the frequency in the population (negative if fitness devlines when its too common) - favors rare alleles

Question 30

why doesnt natural selection produce perfect organisms

Answer 30

adaptations just need to be good enough, no goals, only varying on existing variation, historical constraints, chance events