alleles: Specific locations on DNA carrying information for contrasting forms of the same trait (e.g., blue eyes and brown eyes) (I.1.4.2).
allopatric: Living in different areas (I.1.5.1).
anaerobic cell:A cell that grows only in the absence of oxygen, i.e., it derives its energy by fermenting nutrients in the absence of oxygen (I.3.3.l.b).
archosaurian reptiles:Ruling reptiles that are specialized toward bipedal life; the dinosaur is the famous example. They were the dominant land reptiles in the Mesozoic era. Today they survive only in the form of aberrant crocodiles and alligators (I.2.2.2).

cataclysmic flood:The flood recorded in Genesis 6-9. It was a universal, sudden, and violent deluge that covered the whole earth and wiped out all the land animals (II.6.1.1).
Cavendish balance:A device invented by Rev. John Mitchell but first used by Sir Henry Cavendish in 1798 to measure the force of gravitational attraction between two bodies. It consists of alight, rigid T-shaped member supported by a fine vertical fiber. Two spheres with known mass are mounted at the ends of the horizontal portion of the T, and a small mirror fastened to the vertical portion reflects a beam of light onto a scale. To use the balance, two large spheres with gravitational attraction to the small spheres mounted on the balance are brought to juxtaposition with the latter. The forces of gravitational attractions between the large and small spheres result in the twisting of the system through a small angle, thereby moving the reflected light beam along the scale (I.3.1).
clone: A group of cells with identical genetic make-up (I. 1.3).
colinearity: The exact correspondence between the nucleotide sequence on the DNA with the amino acid sequence on the polypeptide encoded by the DNA; e. g., a mutation on the DNA code will change the amino acid to be inserted into a corresponding site on the polypeptide (I.3.3.1.d).
colony: An area of bacterial growth on an agar plate containing millions of bacterial cells of the same genetic make-up (I.1.3).
cornified: Hardened (I.2.5.2.c).

dimorphism: Distinctness in structure and appearance usually associated with the different sex role of male and female; e.g., differences between man and woman, both being in the same species (I.1.2).

echinoderm: A member of the phylum Echinodermata (spiny-skinned animals such as sea stars, sea urchins, and sea cucumbers) (I.2.5.3)
endemic: Regularly found in a particular locality (I.2.4).

fidelity: Accuracy, exactness (I.2.6.1).
formal: Having to do with form (I.2.3.3).

genetic polymorphism:The existence of two or more forms of individuals in the same species. These forms have detectable differences that are controlled genetically; e.g., the human blood groups (I.1.2).
geological column:A geological timetable that divides the earth's history into the Precambrian, Paleozoic, Mesozoic, and Cenozoic eras characterized by various fossilized plants and animals. The age of the rocks found in each era was estimated by both radiometric and nonradiometric methods (I.2.1.2).
geological time scale:Each geological stratum in the earth's crust (geological column) has been correlated with quantitative measurements of radiometric data, resulting in the construction of a geologic time scale (I.1.5; 2.1.2.b.4).

haploid: Having a single set of chromosomes per individual or cell, as in gametes (I.1.2).
heliocentric: Referring to the view that the sun is the center of the solar system. This view challenged the medieval belief that the earth was the center of the universe. It was first promulgated by Copernicus and later elaborated by Galileo and Kepler (II.4.2.1).
homology: A similarity of specific organs of living members of an animal group, albeit with slight or marked modification, to corresponding organs in their presumed common ancestor (I.2.3.1).

lymphocytes: White blood cells of a certain type produced in the bone marrow that are involved in the immune system of the body (I.2.5.2.d).
lymphoid tissue:Tissue that is rich in lymphocytes. Some of the lymphoid tissues in the body are the thymus, the lymph nodes, the spleen, and the bone marrow (I.2.5.2.d).

macrogenesis (saltation): A sudden change in the genetic make-up of an organism leading to a new species (I.1.5.1).
manus: The proximal part of the hand below the radius and ulna bones (I.2.2.2).
marsupial: Pertaining to mammals whose young are born quite early in development and complete their development attached to a nipple in the mother's marsupium, or pouch (I.2.4).
mechanistic: Referring to the theory that everything in the universe is produced by matter in motion; materialism (I.4.3.3).
meiosis: A process involved in sexual reproduction in which the number of chromosomes is reduced by half (I.1.4.2).
musculature: The muscular system (I.2.3.3).
mutator locus:A region of DNA in certain bacteria and bacteriophage (virus) that has been known to produce DNA polymerase, the enzyme responsible for the replication process of DNA. Mutations in this region of the DNA alter the behavior of this enzyme, leading to an increase in the spontaneous mutation rate for all detectable genetic loci due to base mispairing (I.2.6.3.[3]).

neonatal thymectomy:The surgical removal of the thymus from a newborn (I.2.5.2.d).
neontologist:A developmental biologist (I.2.2.2).

occipital: Pertaining to the back part of the head or skull (I.2.3.3).
organic infusions:Liquid extracts (of meat vegetable, or any other kind of organic matter) that contain an abundance of nutrients for growth of microorganisms (I.3.3.1.a).
outcrossing: Outbreeding, mating with genetically unrelated individuals (I.2.6.5).

phagocytic cells:Cells that are capable of phagocytosis (I.3.2.1.c). (See definition of phagocytosis, I.2.6.)
phagocytosis:The process by which certain cells such as the leukocytes (white blood cells) engulf large particles into a sac or membrane-bound vacuole in the cell (I.2.6.1).
phenotypic: Pertaining to the structural and functional appearance of an organism that results from the interaction of genes with one another and with the environment (I.3.2.2.c).
phylogenetic:Pertaining to the presumed evolutionary relationship (I.2.2.1. b).
placental: Pertaining to mammals that carry their young in the mother's uterus where they receive food and oxygen via the placenta until a fairly advanced stage of development (I.2.4).
point-mutations:Changes in the DNA molecules that are confined to single base (i.e., adenine, guanine, cytosine, or thymine) (I.1.5).
polyploidy: Possession of more than two complete sets of chromosomes (I.1.5.1).

sagittal: Vertical and lengthwise from snout to tail in the body as in sagittal section (I.2.3.3).
saltation (macrogenesis): Sudden change in the genetic make-up of an organism leading to a new species (I.1.4.1; I.5.1).
spatial: Pertaining to space (I.2.3.3).
sympatric: Living in the same area (I.1.5.1).
synapse: The pairing up of homologous chromosomes during meiosis (see I.2.66, Figure 2.62) (I.3.3.1.c).

taxon (pl. taxa): One of the hierarchical categories in which organisms are classified, i.e., species, order, class, etc. (I.2.2.1.b).
temporal: Pertaining to time (I.2.3.3).
thymus: A lymphocyte-rich organ located in the chest behind the top of the breast bone; important in the production and maintenance of immune cells (I.2.5.3).
tundra: A treeless terrestrial communi8ty north of the arctic circle (I.2.4, Figure 2.25).

universal cataclysm:A world-wide, sudden, and violent flood (Genesis 6?9) that covered the whole earth and wiped out all land animals (II.7.1.l).
enous blood: Blood that flows from the peripheries of the body toward the heart via the veins; it is usually deoxygenated (I.2.5.2.c).

young earth: The view that the universe was created in six solar days so that the earth is only 10,000 to 20,000 years old (II.6.1.1).