U4 T2

Question 1

what is evolution?

Answer 1

the process of genetic change in living organisms that results in new forms and species over time

Question 2

what is microevolution?

Answer 2

small changes in allele frequency in a population that does not result in the creation of a new species

Question 3

what is macroevolution?

Answer 3

large changes in allele frequency over multiple generations that results in the creation of a new species

Question 4

what is allele frequency?

Answer 4

the rate at which an allele occurs in a population

Question 5

what is a species?

Answer 5

two or more organisms that can reproduce together to create offspring that is both viable and fertile

Question 6

why are multiple definitions of species needed?

Answer 6

some organisms such as bacteria reproduce asexually

Question 7

what is evolutionary radiation?

Answer 7

the appearance of new forms or taxa of a speices over time. Look at the U4T2 lesson 2 PPT for graphs for exam

Question 8

what is a mass extinction?

Answer 8

the dissappearance of a large number of species in a relatively short time frame. Graphs in U4T2 PPT

Question 9

what is speciation?

Answer 9

the evolution of a new species

Question 10

what is the difference between rooted and unrooted phylogenetic trees?

Answer 10

rooted show genetic distance including common ancestors, unrooted only show genetic distances. Graphs in U4T2 lesson 3 PPT

Question 11

what is natural selection?

Answer 11

The process by which individuals with the most favorable characteristics have an increased chance of surviving and reproducing (fecundity) compared to those that don’t. must understand alleles, genotypes and phenotypes from U4T1

Question 12

when does natural selection occur?

Answer 12

when environmental pressures confer a selective advantage to a specific phenotype to increase it’s survival (viability) and reproduction (fecundity)

Question 13

what is the equation for allele frequency?

Answer 13

allele frequency = 100(2no. of homozygotes with the allele + no. of heterozygotes)/(2*no. of individuals in the population). Answer ranges from 0 to 1. 0 means none have the allele, 1 means all have the allele (homozygous)

Question 14

what is positive selection of alleles?

Answer 14

promotes the spread of beneficial alleles. Allele frequency increases

Question 15

what is negative selection of alleles?

Answer 15

hinders the spread of detrimental alleles. Allele frequency decreases

Question 16

what are the types of selection?

Answer 16

stabilising, directional and disruptive

Question 17

what is stabilising selection?

Answer 17

intermediate phenotypes are favoured over extremes (e.g. instead of black or white fur, grey is preferred)

Question 18

what is directional selection?

Answer 18

one side of the bell curve is favoured over the rest (e.g. white fur is preferred over black or grey)

Question 19

what is disruptive selection?

Answer 19

both ends of the bell curve are favoured over the middle ground; favours extremes (e.g. white and black fur favoured over grey fur)

Question 20

look at U4T2 lesson 4 for graphs

Answer 20

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Question 21

what are the main processes of microevolutionary change

Answer 21

mutation, gene flow, genetic drift

Question 22

what is mutation

Answer 22

random variations in genetic sequences, can create new alleles. Can be beneficial or detrimental. Only passed on if gametes mutate

Question 23

how is mutation the ultimate sourvce of genetic varitation?

Answer 23

it introduces new alleles into a population

Question 24

what is gene flow

Answer 24

movement of genetic material between populations of a species. Caused when individuals join or leave a population

Question 25

what is genetic drift

Answer 25

random fluctuations in allele frequency in a population over time can occur due to bottle neck effect or founder effect

Question 26

what is the bottleneck effect

Answer 26

catastrophic events or periods of adverse conditions decrease the size of a population, potentially resulting in the loss of a number of alleles in the population

Question 27

what is the founder effect

Answer 27

a few individuals carry alleles to a new isolated area and a new population is established with different allele frequencies than the original population. Depends on the allele frequencies of the founders

Question 28

look at U4T2 lesson 5 for examples of gene flow and genetic drift

Answer 28

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