Lecture 20

Question 1

population level genetic data is expressed as … or … frequencies

Answer 1

gene; allele

Question 2

gene pool: total array of … and … in a population

Answer 2

genes; alleles

Question 3

within the gene pool, each allele is present in a certain …, or …, relative to the total number of alleles in the …

Answer 3

proportion; allele frequency; population

Question 4

genetic diversity = the genetic … within …, both among individuals within a … population and among … populations of a species

Answer 4

variation; species; single; geographically separate

Question 5

genetic variation within a species can allow the species to adapt to

Answer 5

environmental change

Question 6

genetic variation allows populations to survive in a … through …

Answer 6

changing environment; natural selection

Question 7

low genetic variability reduces the possibility for a popualtion to … and increases the chance that favorable … could be lost, or unfavorable traits could be …

Answer 7

adapt; traits; expressed

Question 8

large populations tend to have greater genetic diversity bc:

• generally, more individuals means a greater chance for additional alleles to be added to the gene pool through …
• … increases diversity, and the larger the population the more potential … (with different …)

Answer 8

random mutation; sexual reproduction; mates; alleles

Question 9

large populations dont always have greater genetic diversity:

• mating even in large populations can be … with certain traits being more attractive (..)
• mutations may be equally or even more important than …
• product of histoyr, large populations were very small in the past

Answer 9

nonrandom; sexual selection; population size

Question 10

any two humans differ, on average, at about … in … DNA base pairs-much lower … than many species, including our nearest relatives, chimpanzees

Answer 10

1; 1,000; genetic diversity

Question 11

small populations tend to have lower genetic diversity:
the bottleneck effect: a population forced through a bottleneck is likely to lose much … (especially in … populations)

Answer 11

genetic variation; smaller

Question 12

genetic bottlenecks occur when a population loses a large proportion of its members. bottlenecks are more consequential when the starting population is … in a large population, the reduced population is still likely to retain the same … present in the original population. in a small population, the loss of members is more likely to result in …, and therefore a dramatic change in the … and … of the “restored” population

Answer 12

small; alleles; loss of alleles; allele frequency; genetic diversity

Question 13

the founder effect: new populations are often founded by a small number of individuals with different … from the original population

Answer 13

gene frequencies

Question 14

when individuals colonize a new region, they often contain a … sample of the original population’s gene pool. Leads to further reduction in the … of populations. important in the … process of species which colonize oceanic islands

Answer 14

less-than representative; genetic diversity; diversification

Question 15

the founder effect is a type of …, in which chance events influence allele frequencies of a founding population. in this case, the chance event is the specific alleles that happen to be present in the small group of founders that leaves a large population. if by chance allelse from the original population are … from the founders, they will aslo be … from the new population

Answer 15

genetic drift; absent; absent

Question 16

tasmanian devils population declined severely twice int he past:
during the … 20,000 yrs ago
after a long and severe El Nino related … 5000 yrs ago

Answer 16

ice age; drought