Chapter 4

Hemoglobin altered so that it is less efficient in binding to and carrying oxygen. (page 86)

The exchange of genetic material between two or more populations. (page 96)

Refers to any effect caused by humans. (page 89)

Situation in which selection maintains two or more phenotypes for a specific gene in a population. (page 89)

Small blood vessels between the terminal ends of arteries and the veins. (page 87)

A local population of organisms that have similar genes, interbreed, and produce offspring. (page 74)

A population's movement into an area previously uninhabited by that group. (page 98)

Selection for one allele over the other alleles, causing the allele frequencies to shift in one direction. (page 83)

Selection for both extremes of the phenotypic distribution; may eventually lead to a speciation event. (page 83)

Refers to a population in which individuals breed only with other members of the population. (page 93)

A condition in which the system is stable, balanced, and unchanging. (page 76)

Refers to a population in which individuals breed only with nonmembers of their population. (page 93)

Average number of offspring produced by parents with a particular genotype compared to the number of offspring produced by parents with another genotype. (page 82)

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. (page 94)

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. (page 81)

An enzyme that aids in the proper functioning of red blood cells; its deficiency, a genetic condition, leads to hemolytic anemia. (page 91)

All the genetic information in the breeding population. (page 74)

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. (page 78)

A group of related genetic blood diseases characterized by abnormal hemoglobin. (page 89)

Conditions of insufficient iron in the blood due to the destruction of red blood cells resulting from genetic blood diseases, toxins, or infectious pathogens. (page 86)

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. (page 95)

Refers to those mutations in the DNA resulting from exposure to toxic chemicals or to radiation. (page 81)

A chromosomal trisomy in which males have an extra X chromosome, resulting in an XXY condition; affected individuals typically have reduced fertility. (page 81)

Large-scale evolution, such as a speciation event, that occurs after hundreds or thousands of generations. (page 76)

Refers to an individual with high concentrations of melanin. (page 84)

Small-scale evolution, such as changes in allele frequency, that occurs from one generation to the next. (page 76)

Substances, such as toxins, chemicals, or radiation, that may induce genetic mutations. (page 81)

Refers to an individual with low concentrations of melanin. (page 84)

A point mutation that creates a triplet coded to produce a different amino acid from that of the original triplet. (page 81)

Replacements of a single nitrogen base with another base, which may or may not affect the amino acid for which the triplet codes. (page 81)

Process in which advantageous genetic variants quickly increase in frequency in a population. (page 86)

Any circumstance that prevents two populations from interbreeding and exchanging genetic material, such as when two populations are separated by a large body of water or a major mountain range. (page 75)

A genetic blood disease in which the red blood cells become deformed and sickle-shaped, decreasing their ability to carry oxygen to tissues. (page 86)

Random changes in DNA that occur during cell division. (page 81)

Selection against the extremes of the phenotypic distribution, decreasing the genetic diversity for this trait in the population. (page 83)

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. (page 81)

A genetic blood disease in which the hemoglobin is improperly synthesized, causing the red blood cells to have a much shorter life span. (page 91)

Mobile pieces of DNA that can copy themselves into entirely new areas of the chromosomes. (page 81)