Chapter 10: Population Genetics and Evolution

Question 1

evolution

Answer 1

the change in a population’s gene pool from one generation to the next

Question 2

quantitative characteristics

Answer 2

traits in a population that vary along a continuum

Question 3

gene pool

Answer 3

all the collective genes of a population

Question 4

population

Answer 4

all the members of the same species within a given area

Question 5

non-evolving population

Answer 5

a hypothetical collection of individuals in a given area whose gene pool does not change from generation to generation

Question 6

genotype

Answer 6

the allelic composition for a particular trait

Question 7

alleles

Answer 7

different forms of a given gene

Question 8

homozygous

Answer 8

having two identical alleles for a given trait

Question 9

Tay-Sachs disease

Answer 9

a genetically based disease characterized by a dysfunctional enzyme that fails to break down brain lipids, and is expressed in the homozygous recessive condition

Question 10

sickle-cell anemia

Answer 10

a disease characterized by defective red blood cells that are inefficient in carrying oxygen

Question 11

microevolution

Answer 11

changes in genetic structure (genotype) of a population

Question 12

genetic drift

Answer 12

changes in the gene pool of a small population due to chance

Question 13

mutation

Answer 13

a change in an organism’s DNA that can result in a permanent change in the allele

Question 14

natural selection

Answer 14

differential success in the reproduction of different phenotypes resulting from the interaction of organisms with their environment

Question 15

gene flow

Answer 15

changes in the gene pool due to migration of fertile individuals or gametes

Question 16

non-random mating

Answer 16

when an individual chooses a mate based on specific criteria

Question 17

polymorphism

Answer 17

the occurrence of two or more distinct forms of members of a population

Question 18

dimorphism

Answer 18

two different morphs

Question 19

stabilizing selection

Answer 19

extremes are selected against, and the average is selected for

Question 20

directional selection

Answer 20

one extreme is selected for, and the opposite extreme is selected against

Question 21

diversifying selection

Answer 21

extremes are selected for, and the average is selected against

Question 22

natural selection

Answer 22

the process where organisms of differing phenotypes interact with their environment which results in differential reproductive success

Question 23

biological species concept

Answer 23

two organisms are in the same species when they can produce fertile, viable offspring in free-ranging conditions

Question 24

morphological species concept

Answer 24

classifies species based on anatomical differences

Question 25

recognition species concept

Answer 25

classifies species based upon their courtship rituals (genetic, morphological, and behavioral) and mate selection

Question 26

cohesion species concept

Answer 26

classifies species based upon the mechanisms they use to maintain the phenotypic integrity of the population (ex: reproductive barriers such as pre and post-zygotic isolation)

Question 27

polyploid

Answer 27

having more than two complete sets of chromosomes (2n)

Question 28

ecological species concept

Answer 28

classifies species based on their ecological niche or role in the environment (where they live, what they do, and how they look)

Question 29

allopatric speciation

Answer 29

physical isolation resulting from a geographic barrier separates a splinter population from a main population

Question 30

marsupial

Answer 30

mammals characterized by embryonic development in a pouch

Question 31

placental

Answer 31

mammals characterized by embryonic development in a uterus

Question 32

adaptive radiation

Answer 32

a great increase in species diversity over a relatively short time, each variation adapting to a new or unused resources or habit

Question 33

sympatric speciation

Answer 33

formation of a new species from a subpopulation while physically located amongst the parent population

Question 34

autopolyploidy

Answer 34

having more than 2n sets of chromosomes, all of which derived from the same species, and can occur through self-fertilization

Question 35

nondisjunction

Answer 35

a mistake during cell division in which either pairs of homologous chromosomes or sister chromatids fail to separate properly

Question 36

allopolyploidy

Answer 36

having more than 2n sets of chromosomes which are derived from two different species

Question 37

meiotic errors

Answer 37

mistakes that occur during gamete formation that result in cells with an incorrect number of chromosomes

Question 38

transition fossils

Answer 38

preserved, extinct life forms that show the link between a new species and its parent species

Question 39

balanced polymorphism

Answer 39

the ability of natural selection to promote diversity in a population