Results for “pH”

pH

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 in acidity or basicity/alkalinity, i.e., a solution with a pH of 4.0 is ten times more acidic than one of 5.0., and 100 times more acidic than one of 6.0. Some fishes require a relatively specific pH in aquaria, while others are more generalised, with the former requirement often-reduced in captive-bred examples.

Used in 397 profiles

phenotype

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.

Used in 7 profiles

phosphates

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 or other supplements in order to encourage plant growth.

pharyngeal

Of, relating to, or located on the pharynx.

Used in 30 profiles

pheromone

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.

Used in 2 profiles

phylogenetic

Of or relating to phylogeny.

Used in 488 profiles

phytoplankton

The photosynthesizing constituent of a planktonic community, consisting of algae, cyanobacteria and other microorganisms.

Used in 28 profiles

pH crash

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

phenotypic plasticity

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

Used in 2 profiles

phylogenetic species concept

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 tree. Subspecies tend not to be recognised and it is generally less restrictive than the biological species concept. Often abbreviated to PSC.

Used in 1 profile

pharyngeal teeth

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.

Used in 55 profiles

pharynx

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

Used in 4 profiles

phenology

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

photoperiod

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

photophore

Light-emitting organ found in some fishes.

Used in 1 profile

photosynthesis

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.

phylogenetics

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

Used in 3 profiles

phylogeny

The evolutionary development and history of a species or other taxonomic group. May be based on morphology, molecular data, or both.

Used in 52 profiles

phylogeography

The study of the relationships between organisms and their geographical location.

phylum

Taxonomic rank below kingdom and above class.