CH.4-Microevolution/genetic changes

Question 1

Natural selection acts on —- but —- do not evolve during their lifetime

Answer 1

individuals - individuals

Question 2

What is a population?

Answer 2

A group of same species living is same area

Question 3

What is the smallest unit of evolution?

Answer 3

A population

Question 4

Natural selection can only happen if:

Answer 4

1) Members of a pop have variations in genetic characteristics
2) Environmental pressures to produce more
3) Lots of time

Question 5

What are genes?

Answer 5

Section of DNA on a chromosome that has the information to make specific proteins. These proteins have a certain trait

Question 6

How many pairs of chromosomes does a human have?

Answer 6

23 pairs (46 total) –> 23 from ch/ parent

Question 7

What are homologous chromosomes?

Answer 7

Copies of the same chromosome (have same gene)

Question 8

Are homologous chromosomes identical?

Answer 8

NO - they have same genes but different versions (alleles)

Question 9

What are alleles?

Answer 9

Different version of same gene (characteristic). Will code for different trait of characteristic.

Question 10

Eye color is a — and brown/blue/green eyes is a —

Answer 10

Gene - Alleles

Question 11

Is eye color a characteristic or a trait?

Answer 11

Characteristic

Question 12

Are blue eyes a characteristic or a trait?

Answer 12

Trait

Question 13

How many alleles for every gene?

Answer 13

2 (1 allele from each chromosome from each parent)

Question 14

— alleles for a gene are always expressed as a trait when present

Answer 14

Dominant

Question 15

—- alleles for a gene are only expressed when an individual has 2 copies of it

Answer 15

Recessive

Question 16

What’s a genotype?

Answer 16

Combination of alleles an individual has for a particular gene

Question 17

What are the 3 possible genotypes for a gene that has 2 alleles versions (e and E)

Answer 17

EE, Ee, ee

Question 18

What is homozygous? E and e

Answer 18

Individual’s genotype has 2 alleles the same EE, ee

Question 19

What’s heterozygous?

Answer 19

Individual’s genotype has 2 different alleles Ee

Question 20

What is a phenotype?

Answer 20

The trait that is expressed for particular characteristic (end result)

Question 21

EE, Ee, ee are —

Answer 21

Genotypes

Question 22

EE = Brown eyes, Ee = Brown eyes, ee = blue eyes are —-

Answer 22

Phenotypes

Question 23

What is a gene pool?

Answer 23

A population’s genetic makeup. Quantifies how many of ch/ type of allele for a given gene can be found withing the population

Question 24

How does microevolution affect the gene pool?

Answer 24

Changes in the ALELLE FREQUENCIES within the gen pool can occur over generations

Question 25

What is the formula for GENOTYPE FREQUENCY?

Answer 25

of individuals with a particular genotype/Total # of individuals in the population

Question 26

What's the formula for allele frequency?

Answer 26

of copies of a specific allele for a gene in the population/ Total # of alleles for a gene in the population

Question 27

When do we apply the Hardy-Weinberg Principle?

Answer 27

When the population isn't evolving (Equilibrium)

Question 28

What is Genetic Equilibirum?

Answer 28

1) No gene flow 2) No mutation 3) Random mating 4) No natural selection 5) Large population size

Question 29

Hardy-Weinberg: what is p and q?

Answer 29

p = freq of dominant allele q = freq of recessive allele

Question 30

Hardy-Weinberg: What is p^2 and q^2? What is 2pq?

Answer 30

p^2 = freq of homozygous dominant genotype q^2: = freq of homozygous recessive genotype 2pq = freq of heterozygous genotype

Question 31

What causes microevolution?

Answer 31

1) Natural selection 2) Genetic drift 3) Gene flow

Question 32

What are the 3 modes that natural selection can act on a population?

Answer 32

1) Directional selection 2) Disruptive selection 3) Stabilizing selection

Question 33

What is directional selection?

Answer 33

1 extreme variant in phenotype is favored

Question 34

What is disruptive selection?

Answer 34

2 extreme variants in phenotype are favored

Question 35

What is stabilizing selection?

Answer 35

Intermediate variant in phenotype is favored (average phenotype)

Question 36

What is Genetic drift?

Answer 36

Random fluctuations in allele frequencies from 1 generation to the next

Question 37

Is a genetic drift more substantial to a small or large population?

Answer 37

Small - If large, most likely to be similar to previous population

Question 38

What are the special cases of Genetic Drift?

Answer 38

1) Founder Effect 2) Bottle neck effect

Question 39

What is the Founder effect? Is the gene pool necessarily the same?

Answer 39

When very few individuals get isolated and start their own population - Gene pool differs bc very few (bigger effect)

Question 40

What is the Bottle neck Effect?

Answer 40

Population's number lowers drastically because of disaster (surviving population)

Question 41

What is Gene flow?

Answer 41

Transfer of alleles in/out of population bc of immigration/emigration of fertile individuals or gametes