Zoology glossary ~ P

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Pleiotropy
The control of more than one phenotypic characteristic by a single gene or set of genes. Pleiotropy occurs when a single gene controls multiple phenotypic traits.

Polymorphism
Polymorphism occurs in a population of the same species when two or more different phenotypes exist.

Phenotype
The observable characteristics of an organism.

Palearctic
The biogeographic region that includes Europe, North Africa (north of the Sahara), northern Arabia.

Paleoarchean
Paleoarchean

Paleoproterozoic
Paleoproterozoic

Paleozoic Era
Paleozoic Era

Pantropical
"Occurring throughout the tropical regions of the world."

Partial Molt
"The replacement of feathers in only some of the body's feather tracts."

Passerine
"A member of the order Passeriniformes, often referred to as a songbird."
Patagium
A membrane of double-sided skin that forms the wing material in bats.

PCBs
"Polychlorinated biphenyls, a class of chemicals used as lubricants and insulation materials and in printing ink."

Pectinate
"Having tooth-like projections similar to the teeth of a comb."

Peep
"General name for several small sandpiper species in the genus Calidris."

Pelagic
"Associated with deep waters of the open ocean."

Pellet
"A mass of indigestible material including fur, feathers, and bones regurgitated by hawks, owls, herons, and other predatory birds."

Pentaradial Symmetry
A type of radial symmetry, characteristic of echinoderms, in which body parts are arranged along five rays of symmetry.

Periostracum
The outermost layer of a snail's shell. Consists of conchin (a mixture of organic compounds), gives the shell color.

Phanerozoic Eon
Phanerozoic Eon

Phylogeny
The evolutionary history or pattern of kinship relationships among various groups of organisms.

Pineal Eye
Third eye in the forehead of tuataras and many lizards that can register light intensity and may help to regulate body temperature.

Plankton
Plankton are microscopic organisms that drift on the oceans' currents. They include organisms such as diatoms, dinoflagillates, krill, and copepods as well as the microscopic larva of crustaceans, sea urchins, and fish.

Plastron
The shell or shield on the ventral surface (belly) of tortoises and turtles.

Precambrian
Precambrian

Predator
An organism that feeds on other organisms (prey).

Preen Gland
"The source of the oil that a preening bird rubs on its feathers to maintain them in good condition; located on the lower back near the rump."

Proboscis
Long snout or mouthparts.

Prokaryote
Prokaryotes are organisms made up of cells that lack a cell nucleus or any membrane-encased organelles.

Proterozoic
Proterozoic

Pulmonate
Terrestrial snails belong to a group within the Order Stylommatophora called the 'pulmonates'.