3-3 Sources of Genetic Variability and Evolutionary Process

Question 1

Population

Answer 1

an interbreeding group of organisms

Question 2

What is a gene pool

Answer 2

all the different genes and various expressions (alleles) that exist in the DNA of a species or pop

Question 3

What is a genotype

Answer 3

genetic makeup of an individual. This can refer to entire genetic makeup or to the alleles found at specific gene locations

Question 4

What is phenotype

Answer 4

physical expression of an individual’s genotype

Question 5

What is evolution

Answer 5

“a change in allele frequency in a population from one generation to the next”

Question 6

What are the two components to evolutionary process

Answer 6

1. creation of genetic variability in individuals upon which the evolutionary process can act
2. external factors that act upon individuals’ genetic variability: the process of evolution

Question 7

sources of genetic variability upon which evolution can act:

Answer 7

1. Recombination
   a. random assortment of chromosomes
   b. crossing over
2. Random mutations

Question 8

Variability

Answer 8

• changes in allele frequencies
• new combos of alleles
• formation of new alleles

Question 9

what is random assortment

Answer 9

all 23 homologous pairs line up next to each other, which is on the left and which is on the right is random, line of homologous pairs separate into two daughter cells, each cell will get either father’s or mother’s version of each chromosome

Question 10

what is crossing over

Answer 10

during meiosis when double strands come together to form tetrad, and can swap section of DNA

Question 11

What is the only way new alleles can be introduced to gene pool

Answer 11

mutations

Question 12

what is mutation

Answer 12

random errors in transcription of base pairs in DNA replication

Question 13

are mutations needed for microevolution

Answer 13

no since there are already significant variability

Question 14

What are factors that act upon variability in allele frequency

Answer 14

• non random mating
• migration of gene flow
• random genetic drift
• natural selection

Question 15

what is sexual selection

Answer 15

type of non random mating that acts upon one sex or the other in a species

Question 16

what is mating competition

Answer 16

when a female chooses a mate from among multiple potential mates, based on her preference for specific traits

Question 17

What is positive assertive mating

Answer 17

tendency to select mates of a similar phenotype as own

Question 18

what is negative assertive mating

Answer 18

tendency to select mates of a different phenotype as own

Question 19

what is inbreeding

Answer 19

mating individuals that are genetically closely related
- increased chance offspring will inherit two recessive alleles for dangerous trait

Question 20

What did long term inbreeding do to neanderthals

Answer 20

• negative health conditions

Question 21

What is migration/gene flow

Answer 21

the exchange of genes between different populations

Question 22

examples of gene flow in humans

Answer 22

between Europeans and Indigenous 400-500 years ago

Question 23

gene flow prevented major speciation events with ancestors

Answer 23

true

Question 24

What is random genetic drift

Answer 24

• passive process
• random changes in gene pool towards greater proportions of specific gene expressions

Question 25

what is the founder effect

Answer 25

small group of individuals create gene pool - often from genetic bottlenecks