Chapter 23.1 : The evolution of populations

Question 1

MICROEVOLUTION

Answer 1

.Evolution defined on the smallest scale

. it is the change in allele frequencies in a population over generations

Question 2

3 main mechanisms of microevolution

Answer 2

. Natural selection
. Genetic Drift
.Gene flow

Question 3

What 3 factors must exist for Natural selection to occur

Answer 3

. Variation ( individuals differed in their inherited traits and selection acted on such differences)
. Heritability ( These differences should be heritable)
. Fitness

Question 4

GENETIC VARIATION

Answer 4

Differences among individuals in the composition of their genes or other DNA segments.
. Genetic variation provides the raw material for evolutionary change .
. Without genetic variation, evolution can not occur

Question 5

PHENOTYPE

Answer 5

Is the product of an inherited genotype and many environmental influences
. Only the genetically determined part of phenotypic variation can have evolutionary consequences

Question 6

CHARACTERS THAT VARY IN A POPULATION MAYBE

Answer 6

. Discrete

. Quantitative

Question 7

DISCRETE characters

Answer 7

e.g. flower colors
. can be classified on an either or basis
.determined by a single gene locus with different alleles that produce distinct phenotype

Question 8

QUANTITATIVE Characters

Answer 8

.vary along a continuum within a population

. Usually results from the influence of two or more genes on a single character ( polygenic inheritance,

Question 9

GENE VARIABILITY

Answer 9

Genetic variation on the whole gene level

. Can be quantified as the AVERAGE HETEROZYGOSITY

Question 10

2 ways to measure how much genetic variation there is in a population

Answer 10

. Genetic variability

. nucleotide variability

Question 11

AVERAGE HETEROZYGOSITY

Answer 11

The average percentage of loci that are heterozygous

Question 12

HETEROZYGOUS

Answer 12

Individuals has two different alleles for a given locus

Question 13

HOMOZYGOUS

Answer 13

Individual has 2 identical alleles for that locus

Question 14

To measure NUCLEOTIDE VARIABILITY

Answer 14

Biologist compare the DNA sequences of 2 individuals in a population and then average the data from many such comparisons

Question 15

GEOGRAPHIC VARIATION

Answer 15

differences in genetic composition of separate populations

Question 16

CLINE

Answer 16

a graded change in character along a geographic axis

Question 17

egs of sources of genetic variation

Answer 17

the genetic variation on which evolution depend originates when
mutatation
gene duplication
sexual reproduction

Question 18

MUTATIONS

Answer 18

a change in the nucleotide sequence of an organisim’s dna

Question 19

POINT MUTATION

Answer 19

a change in one base in a gene

Question 20

The 3 mechanisms that make sexual reproduction a source of genetic variation

Answer 20

. Crossing over
. Independent assortment of chromosomes
.Random fertilization