Chapter 23

Question 1

Microevolution

Answer 1

The change in allele frequencies in a population over time.

Question 2

Populations

Answer 2

All the individuals of one species in a particular area.

Question 3

What is the medium ground finch an example of? And why?

Answer 3

Microevolution, they had smaller beaks before a drought. Because small soft seeds were short in supply so the birds with bigger beaks were able to survive.

Question 4

Genes

Answer 4

A discrete unit of hereditary information consisting of a specific nucleotide sequence in dna.

Question 5

Genotype

Answer 5

The genetic makeup, or set of alleles, of an organism.

Each gene has a genotype.

Question 6

How many alleles are there for each genotype?

Answer 6

2

Question 7

Aa is an example of

Answer 7

Heterozygous genotype

Question 8

BB is an example of

Answer 8

Homozygous dominant genotype

Question 9

cc is an example of

Answer 9

Homozygous recessive genotype

Question 10

What genotypes will give you the dominant phenotype?

Answer 10

Homozygous dominant and heterozygous genotypes

Question 11

Phenotype

Answer 11

Observable trait of an organism that are determined by genotype.

Question 12

Genetic variation

Answer 12

Differences among individuals in the composition of their genes or other dna segments.

Question 13

Phenotypic plasticity

Answer 13

Variation in appearance due to environmental differences

Question 14

What are the two ways to measure genetic variation?

Answer 14

1. Nucleotide variability - at the molecular level of dna

2. Gene variability- at the whole gene level , which is quantified by average heterozygosity.

Question 15

What is geographic variation?

Answer 15

Differences in the genetic composition of separate populations. (Separated by a natural disaster or mountains or something but the same species)

Question 16

Cline

Answer 16

A graded change in character along a geographic axis.

Question 17

What are the 4 sources of genetic variation?

Answer 17

1. formation of new alleles through mutation
2. altering the gene number or position through chromosomal changes that delete, disrupt, or rearrange loci.
3. Rapid reproduction can increase mutation rates.
4. Sexual reproduction due to
   - crossing over
   - independent assortment of alleles
   - fertilization

Question 18

What is the hardy Weinberg principle?

Answer 18

The hardy Weinberg principle suggests that the original proportion of genotypes within a population should remain constant, if the five following assumptions are met.

1. no mutations
2. No gene flow
3. Random mating occurs
4. Population size is large
5. No selection occurs

Question 19

What is an example of phenotypic plasticity?

Answer 19

Nemoria arixonaria these are the same caterpillar that look different because of what they eat.

Question 20

What is a mutation?

Answer 20

Dna is damaged and your body repairs it incorrectly.

Question 21

What is the allele frequency equation?

Answer 21

P+q=1

P= dominant allele
Q= recessive allele

Question 22

What is the genotype frequency equation?

Answer 22

P2+2pq+q2=1

P2 = homozygous dominant 
Q2 = homozygous recessive 
2pq = heterozygous

Question 23

What is genetic drift?

Answer 23

Chance events that can cause unpredictable fluctuation in allele frequencies from one generation to the next.
Example flower colors it’s by chance that this population of flowers ended up all red.

Question 24

What is the founder effect?

Answer 24

Occurs when a few individuals become isolated from a larger population.
Example, Amish people because they only mate with other Amish people.
The population size being small is key

Question 25

What is the bottleneck effect?

Answer 25

A reduction of population size due to a sudden change in environment.

Like a hurricane or a fire only a few individuals survive therefore the genotype frequencies will be different from the original population.

Example, prairie chickens.

Question 26

Gene flow

Answer 26

Movement of Alleles into or out of a population.
Immigration into the population
Emigration out of the population