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Glossary: perforation

February 15th, 2012 — 3:40pm

A hole or pattern of holes made by, or seeming to be made by, piercing or boring, especially if occurring in a line or series.

Glossary: perianal

February 15th, 2012 — 3:40pm

Located around or close to the anus.

Glossary: periphyton

February 15th, 2012 — 3:40pm

Sessile, aquatic organisms that live attached to submerged surfaces in aquatic environments. Often complex in form and may comprise organisms from several groups including algae, cyanobacteria, other microbes, and detritus.

Glossary: peritoneum

February 15th, 2012 — 3:40pm

Membranous sac lining the abdominal cavity, the pigmentation of which is sometimes used in identification of fish larvae.

Glossary: pH

February 15th, 2012 — 3:40pm

Measure of the acidity or basicity of an aqueous solution. Pure water is said to be neutral, with a pH around 7.0, solutions with pH of less than 7.0 acidic and greater than 7.0 basic or alkaline. Measured on a logarithmic scale of 0.0-14.0 whereby a change of a single unit represents a ten-fold increase […]

Glossary: pH crash

February 15th, 2012 — 3:40pm

Sudden and rapid drop in pH, usually occurring in aquaria or ponds with poor buffering capacity. Can be fatal to fishes.

Glossary: pharyngeal

February 15th, 2012 — 3:40pm

Of, relating to, or located on the pharynx.

Glossary: pharyngeal teeth

February 15th, 2012 — 3:40pm

Opposing patches of teeth located on the upper and lower portions of the branchial arches in many fishes, e.g., cyprinids. Variable in structure and to an extent, function.

Glossary: pharynx

February 15th, 2012 — 3:40pm

Section of the alimentary canal connecting the mouth and nasal apparatus with the oesophagus.

Glossary: phenology

February 15th, 2012 — 3:40pm

Study of periodic events in the life cycle of organisms and their relationship with seasonal and interannual climatic changes, e.g., migration.

Glossary: phenotype

February 15th, 2012 — 3:40pm

The observable physical and biochemical traits of an organism, such as its behaviour, external morphology, colour pattern, phenology, etc. Influenced by both genetic and environmental factors.

Glossary: phenotypic plasticity

February 15th, 2012 — 3:40pm

Ability of an organism to change its phenotype in response to environmental change.

Glossary: pheromone

February 15th, 2012 — 3:40pm

Chemical secreted by an organism affecting the behaviour or physiology of other individuals of the same species which may function as an alarm or sexual stimulant, for example.

Glossary: phosphates

February 15th, 2012 — 3:40pm

Any salt or ester of phosphoric acid. The presence or addition of excessive phosphates in aquatic ecosystems can have significant ecological effects such as eutrophication, and they are one of the primary contributors to algal growth in aquaria if allowed to accumulate. Conversely, they may be actively added to heavily-planted set-ups in the form of liquid […]

Glossary: photoperiod

February 15th, 2012 — 3:40pm

The duration of an organism's daily exposure to light; the period of daylight in each 24-hour cycle.

Glossary: photophore

February 15th, 2012 — 3:40pm

Light-emitting organ found in some fishes.

Glossary: photosynthesis

February 15th, 2012 — 3:40pm

Chemical process occurring in the cells of plants, algae and certain other organisms by which carbon dioxide is converted into organic compounds, especially sugars, using the energy from sunlight.

Glossary: phylogenetic

February 15th, 2012 — 3:40pm

Of or relating to phylogeny.

Glossary: phylogenetic species concept

February 20th, 2012 — 9:48am

Species concept based on the evolutionary relationships among organisms, specifically using common ancestry and shared evolutionary history to define species. Under this concept a species is essentially the smallest group of organisms that share a common ancestor and can be distinguished from other such groups via phylogenetic analyses. Each such grouping constitutes a distinct branch on an evolutionary […]

Glossary: phylogenetics

February 15th, 2012 — 3:40pm

The study of evolutionary relatedness among species or other groups of organisms. May be based on morphology, molecular data, or both.