Appendix F Biological Terms

audiogram

—graph showing an animal’s absolute auditory threshold (threshold in the absence of much background noise) versus frequency.

Behavioral audiograms

are determined by tests with trained animals. Cf. evoked potential.*

A-weighting

—a frequency response characteristic with the same sensitivity to frequency as that of the human ear. An A-weighted sound-level meter will have the same sensitivity (response) to sound at different frequencies as the average human ear.

baleen whale

—whales in the order of Mysteceti that possess plates of dense, hair-like material (keratin) that hang side by side in rows from the roof of the mouth. These plates are for filter feeding on surface plankton and were formerly known as “whalebone” but have no actual resemblance to true bone.

beaked whale

—members of the family Ziphiidae, which includes five genera: Berardius, Hyperoodin, Mesoplodon, Tasmacetus, and Ziphius.

catecholamine

—any of various amines (as epinephrine, norepinephrine, and dopamine) that function as hormones or neurotransmitters or both.

cephalopod

—a member of a group of mollusks including squids, cuttlefish, and octopuses.



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Appendix F Biological Terms audiogram —graph showing an animal’s absolute auditory threshold (threshold in the absence of much background noise) versus frequency. Behavioral audiograms are determined by tests with trained animals. Cf. evoked potential.* A-weighting —a frequency response characteristic with the same sensitivity to frequency as that of the human ear. An A-weighted sound-level meter will have the same sensitivity (response) to sound at different frequencies as the average human ear. baleen whale —whales in the order of Mysteceti that possess plates of dense, hair-like material (keratin) that hang side by side in rows from the roof of the mouth. These plates are for filter feeding on surface plankton and were formerly known as “whalebone” but have no actual resemblance to true bone. beaked whale —members of the family Ziphiidae, which includes five genera: Berardius, Hyperoodin, Mesoplodon, Tasmacetus, and Ziphius. catecholamine —any of various amines (as epinephrine, norepinephrine, and dopamine) that function as hormones or neurotransmitters or both. cephalopod —a member of a group of mollusks including squids, cuttlefish, and octopuses.

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cetacean —any member of the order Cetacea of aquatic, mostly marine mammals that includes whales, dolphins, porpoises, and related forms; among other attributes they have a long tail that ends in two traverse flukes. critical band (CB) —frequency band within which background noise has strong effects on detection of a sound signal at a particular frequency.* critical ratio (CR) —difference between sound level for a barely audible tone and the spectrum level of background noise at nearby frequencies.* echolocation† —a physiological process for locating distant or invisible objects (as prey) by means of sound waves reflected back to the emitter (as a bat) by the objects. ecosystem† —the complex of a community of organisms and its environment functioning as an ecological unit. elasmobranchs† —any of a subclass (Elasmobranchii) of cartilaginous fishes that have five to seven lateral to ventral gill openings on each side and that comprise the sharks, rays, skates, and extinct related fishes. glucocorticoid —steroids such as cortisol and corticosterone produced by the adrenal cortex and affecting a broad range of metabolic and immunologic processes. habituation (behavioral) —gradual waning of behavioral responsiveness over time as animals learn that a repeated or ongoing stimulus lacks significant consequences for the animal (cf. sensitization).* hair cell —a special kind of cell that has tiny hairs projecting from its surface into the intercellular space. Movement of the hairs is registered by neurons that contact the hair cell. Hair cells are found in the inner ear of mammals. haulout —the act of a seal leaving the ocean and crawling onto land or ice. homeostasis —a relatively stable state of equilibrium or a tendency toward such a state among the different but interdependent elements or groups of elements of an organism, population, or group. hyperplasia —an abnormal or unusual increase in the elements composing a part (as cells composing a tissue). hypertrophy —excessive development of an organ or part; specifically an

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increase in bulk (as by thickening of muscle fibers) without multiplication of parts. hydrophone —transducer for detecting underwater sound pressures; an underwater microphone.* invertebrate —lacking a spinal column; also of or relating to invertebrate animals. Level A harassment —any act of pursuit, torment, or annoyance that has the potential to injure a marine mammal stock in the wild. Level B harassment —any act of pursuit, torment, or annoyance that has the potential to disturb a marine mammal or marine mammal stock in the wild by causing disruption of behavioral patterns, including, but not limited to, migration, breathing, nursing, breeding, feeding, or sheltering. masking —obscuring of sounds of interest by interfering sounds, generally at similar frequencies.* mysticete —member of the suborder Mysticeti, the toothless or baleen (whalebone) whales, including the rorquals, gray whales, and right whales; the suborder of whales that includes those that bulk feed and cannot echolocate. Their skulls have an antorbital process of maxilla, a loose mandibular symphysis, a relatively small pterygoid sinus, and the maxillary bone telescoped beneath the supraorbital process of the frontal, or baleen whales, composed of four families: Eschrichtiidae, Balaenidae, Neobalaenidae, and Balaenoptidae. odontocete —member of the toothed-whale suborder Odontoceti, which contains nine families and includes dolphins and porpoises: Physeteridae, Kogiidae, Monodontidae, Ziphiidae, Delphinidae, Pontoporiidae, Platanistidae, Iniidae, and Phocoenidae. The toothed whales, including sperm and killer whales, belugas, narwhals dolphins, and porpoises; the suborder of whales including those able to echolocate. Their skulls have premaxillary foramina, a relatively large pterygoid sinus extending anteriorly around the nostril passage, and the maxillary bone telescoped over the supraorbital process of the frontal. Otarid —the eared seals (sea lions and fur seals), which use their foreflippers for propulsion.

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Phocid —a family group within the pinnipeds that includes all of the “true” seals (i.e., the “earless” species). Generally used to refer to all recent pinnipeds that are more closely related to Phoca than to otariids or the walrus. pinniped —one of a group of acquatic, mostly marine, carnivorous animals; includes seals, sea lions, and walruses; all their limbs are finlike and they spend at least some time on land or ice. Permanent Threshold Shift (PTS) —prolonged exposure to noise causing permanent hearing damage. sensitization —an increased behavioral (or physiological) responsiveness occurring over time, as an animal learns that a repeated or ongoing stimulus has significant consequences. Cf. habitutation. *   Richardson et al., 1995. †   Webster.com