FlashcardsChapter04

Question 1

Term

Answer 1

Description

Question 2

Abnormal hemoglobin

Answer 2

Hemoglobin altered so that it is less efficient in binding to and carrying oxygen.

Question 3

Admixture

Answer 3

The exchange of genetic material between two or more populations.

Question 4

Balanced polymorphism

Answer 4

Situation in which selection maintains two or more phenotypes for a specific gene in a population.

Question 5

Capillaries

Answer 5

Small blood vessels between the terminal ends of arteries and the veins.

Question 6

Deme

Answer 6

A local population of organisms that have similar genes, interbreed, and produce offspring.

Question 7

Demic diffusion

Answer 7

A population’s movement into an area previously uninhabited by that group.

Question 8

Directional selection

Answer 8

Selection for one allele over the other alleles, causing the allele frequencies to shift in one direction.

Question 9

Disruptive selection

Answer 9

Selection for both extremes of the phenotypic distribution; may eventually lead to a speciation event.

Question 10

Endogamous

Answer 10

Refers to a population in which individuals breed only with other members of the population.

Question 11

Equilibrium

Answer 11

A condition in which the system is stable, balanced, and unchanging.

Question 12

Exogamous

Answer 12

Refers to a population in which individuals breed only with nonmembers of their population.

Question 13

Fitness

Answer 13

Average number of offspring produced by parents with a particular genotype compared to the number of offspring produced by parents with another genotype.

Question 14

Founder effect

Answer 14

The accumulation of random genetic changes in a small population that has become isolated from the parent population due to the genetic input of only a few colonizers.

Question 15

Frameshift mutation

Answer 15

The change in a gene due to the insertion or deletion of one or more nitrogen bases, which causes the subsequent triplets to be rearranged and the codons to be read incorrectly during translation.

Question 16

Gene pool

Answer 16

All the genetic information in the breeding population.

Question 17

Glucose-6-phosphate dehydrogenase (G6PD)

Answer 17

An enzyme that aids in the proper functioning of red blood cells; its deficiency, a genetic condition, leads to hemolytic anemia.

Question 18

Hardy-Weinberg law of equilibrium

Answer 18

A mathematical model in population genetics that reflects the relationship between frequencies of alleles and of genotypes; it can be used to determine whether a population is undergoing evolutionary changes.

Question 19

Hemoglobinopathies

Answer 19

A group of related genetic blood diseases characterized by abnormal hemoglobin.

Question 20

Hemolytic anemias

Answer 20

Conditions of insufficient iron in the blood due to the destruction of red blood cells resulting from genetic blood diseases, toxins, or infectious pathogens.

Question 21

Huntington’s chorea

Answer 21

A rare genetic disease in which the central nervous system degenerates and the individual loses control over voluntary movements, with the symptoms often appearing between ages 30 and 50.

Question 22

Induced mutations

Answer 22

Refers to those mutations in the DNA resulting from exposure to toxic chemicals or to radiation.

Question 23

Klinefelter’s syndrome

Answer 23

A chromosomal trisomy in which males have an extra X chromosome, resulting in an XXY condition; affected individuals typically have reduced fertility.

Question 24

Macroevolution

Answer 24

Large-scale evolution, such as a speciation event, that occurs after hundreds or thousands of generations.

Question 25

Melanic

Answer 25

Refers to an individual with high concentrations of melanin.

Question 26

Microevolution

Answer 26

Small-scale evolution, such as changes in allele frequency, that occurs from one generation to the next.

Question 27

Mutagens

Answer 27

Substances, such as toxins, chemicals, or radiation, that may induce genetic mutations.

Question 28

Nonmelanic

Answer 28

Refers to an individual with low concentrations of melanin.

Question 29

Nonsynonymous point mutation

Answer 29

A point mutation that creates a triplet coded to produce a different amino acid than that of the original triplet.

Question 30

Point mutations

Answer 30

Replacements of a single nitrogen base with another base, which may or may not affect the amino acid for which the triplet codes.

Question 31

Positive selection

Answer 31

Process in which advantageous genetic variants quickly increase in frequency in a population.

Question 32

Reproductive isolation

Answer 32

Any mechanism that prevents two populations from interbreeding and exchanging genetic material.

Question 33

Sickle-cell anemia

Answer 33

A genetic blood disease in which the red blood cells become deformed and sickle-shaped, decreasing their ability to carry oxygen to tissues.

Question 34

Spontaneous mutations

Answer 34

Random changes in DNA that occur during cell division.

Question 35

Stabilizing selection

Answer 35

Selection against the extremes of the phenotypic distribution, decreasing the genetic diversity for this trait in the population.

Question 36

Synonymous point mutation

Answer 36

A neutral point mutation in which the substituted nitrogen base creates a triplet coded to produce the same amino acid as that of the original triplet.

Question 37

Thalassemia

Answer 37

A genetic blood disease in which the hemoglobin is improperly synthesized, causing the red blood cells to have a much shorter lifespan.

Question 38

Transposable elements

Answer 38

Mobile pieces of DNA that can copy themselves into entirely new areas of the chromosomes.