TAILIEUCHUNG - Linzey - Vertebrate Biology - Glossary
Glossary Abomasum. Fourth and last chamber of the ruminant stomach. Abyssopelagic zone. Region of the oceanic zone from approximately 4,000 to 6,000 m; almost constant physical environment; continually dark, cold (4°C), and virtually unchanging in chemical composition. | Linzey Vertebrate Biology Back Matter Glossary The McGraw-Hill Companies 2003 Gloss A Abomasum. Fourth and last chamber of the ruminant stomach. Abyssopelagic zone. Region of the oceanic zone from approximately 4 000 to 6 000 m almost constant physical environment continually dark cold 4 C and virtually unchanging in chemical composition. Accidental parthenogenesis. Development of a new individual from an unfertilized egg due to the physical or chemical stimulation of the egg. Acid rain. Precipitation with a pH value less than . Acinar. Cells in the pancreas that produce and secrete digestive enzymes. Acoelous. Describes a vertebra having the anterior and posterior articular surfaces of the centrum body flattened. Acrodont. Type of tooth attachment in which there are no sockets teeth are attached to the summit of the jaw. Adpressed limbs. In salamanders the situation in which the forelimbs are pushed backward and the hindlimbs are pushed forward along the sides of the body. Adipose fin. Fleshy fin without rays located behind the dorsal fin. Adrenal. Endocrine gland near or on the kidney secretes epinephrine norepinephrine aldosterone cortisone and gonadocorticoids. Adrenocorticotropic hormone ACTH . Hormone produced by the anterior pituitary gland that stimulates the secretion of hormones by the adrenal cortex. Adult. Mature individual capable of producing sex cells eggs sperm . Agnatha. Taxon of vertebrates comprising those without jaws. Aldosterone. Mineralocorticoid hormone produced by the adrenal cortex that induces sodium and water reabsorption and potassium excretion. Allantois. Extraembryonic saclike extension of the hindgut of amniotes aiding in excretion and respiration. Allen s Rule. Ecological principle describing a general trend among homeotherms for limbs to become longer and extremities such as ears to become less compact in warmer climates than in colder ones best applied within those species having wide north-south geographic ranges. Allopatric.
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