evolution lectures 3/4

Question 1

What is the defintion of a population?

Answer 1

• localised group of interbreeding and interacting individuals

Question 2

how many populations make up a species?

Answer 2

one to many populations make up a species that can interbreed when they meet

Question 3

Genetic varibility

Answer 3

in most species, individuals are heterozygous at many loci/ places
- typically 2-10% heterozygousy

Question 4

source of genetic variability

Answer 4

new alleles arse by mutations to existing alleles

Question 5

most mutations that don’t meaningfully affect fitness are called what?

Answer 5

neutral alleles

Question 6

alleles that when mutated harm fitness?

Answer 6

harmful alleles

Question 7

alleles that mutate to help fitness?

Answer 7

beneficial alleles

Question 8

what is gene flow?

Answer 8

when alleles from one population are introduced to another population

Question 9

what is a gene pool?

Answer 9

all alleles at all gene loci in all individuals

Question 10

what are “fixed” alleles?

Answer 10

where the whole population is homozygous at locus (plural of loci)

Question 11

what are polymorphic loci?

Answer 11

2 or more alleles in a population,

have the some frequency

Question 12

microevolution

Answer 12

the change in the frequencies of different allele in the gene pool over generations

Question 13

how to calc allele frequencies

Answer 13

allele of interest/ total allele count

Question 14

what does the Hardy- Weinburg principle describe

Answer 14

expected relationships between alleles and genotype frequencies with NO EVOLUTION
- assumes random mating

Question 15

what are the assumptions of the Hardy Weingburg Principle

Answer 15

1) no net mutations
2) random mating
3) no natural selection
4) large (infinite) population size
5) no migration

Question 16

what do violations of the Hardy-weing burg principle assumptions indicate?

Answer 16

evolutionary change

Question 17

what are the three causes of microevolution?

Answer 17

natural selection
gene flow
genetic drift

Question 18

which of :
- natural selection
- gene flow
genetic drift 
result in adaptive evolution/ adaptation?

Answer 18

natural selection is the only one that results in adaptations

Question 19

what is gene flow?

Answer 19

dispersal of gametes or migration

gene flow can introduce new alleles to a population

Question 20

random genetic drift can lead too_______

Answer 20

fixation or extinction of alleles in absence of natural selection

Question 21

what is the rate of drift related to?

Answer 21

population size

- rate of drift faster in small populations than large

Question 22

a natural allele at 0.5 is equally likely to____

Answer 22

be fixed or go extinct

Question 23

what are genetic bottlenecks?

Answer 23

• breeding population is very small for a period of time

- because of this, genetic drift is very powerful

Question 24

what happens to the diversity of the population during genetic bottlenecks?

Answer 24

diversity goes down

- sometimes rare alleles up in frequency because diversity is generally donw

Question 25

how do captive breeding programs manage diversity?

Answer 25

by introducing others from different populations

Question 26

what is the founder effect?

Answer 26

a special case of genetic bottleneck - few individuals of population go form their own - when their new population is gornw, some rare alleles from the old population are more frequent in the new one

Question 27

what is polygenic inheritance?

Answer 27

phenotype influence by several different genes

Question 28

stabilizing selection

Answer 28

the outer most phenotypes are selected against

Question 29

disrupting selection

Answer 29

middle/ intermediate phenotypes selected against

Question 30

sexual selection

Answer 30

- competition for mating opprotunites | - results in adaptations that increase mating success

Question 31

is there any down fall to sexual selection?

Answer 31

sometimes the adaptations that increase mating sucess can reduce rate of survival

Question 32

intrasexual selection

Answer 32

competition within one sex for mating opprotunities | - usually within males

Question 33

intersexual selection

Answer 33

one sex choose mate from competing memebers of opposite sex | - usually female choose males

Question 34

preserving allelic variation

Answer 34

diploidy hides recessive alleles when they are rare | - dont see the recessive allele even thoght its there, because individual is heterozygous

Question 35

heterozygous advantage: sickle cell amneia

Answer 35

recessive - ss die young - SS resistance to malaria malaria absent: SS and Ss similar fitness malaria present: Ss higher fitness than SS

Question 36

inverse frequency-dependant selection

Answer 36

rarity increases relative fitness of a variant