Results for “pH”

pecking order

Type of social hierarchy in which individuals within a given group or population are ranked by behavioural and/or physical dominance. Sometimes referred to as a dominance hierarchy.

Used in 106 profiles

planktonic bloom

A visble population explosion in plankton, typically involving phytoplankton, and normally resulting from an increase or excess of available nutrients.

polytomy

A section of a phylogeny in which the evolutionary relationships can not be fully resolved to dichotomies.

Used in 6 profiles

reproductive isolation

The inability of two or more groups of organisms to interbreed due to the existence of geographical, behavioral, physiological, or genetic barriers. These can be further separated into those being active pre- or post-copulation.

species

Taxonomic rank into which a genus is divided, but otherwise difficult to delineate precisely with a single definition satisfying all eventualities still lacking to date. There exist a number of concepts of which the most popular in vertebrate taxonomy include the biological species concept and phylogenetic species concept.

Used in 1,790 profiles

subspecies

Taxonomic rank below species, written in the form of a trinomen. Often applied to a geographically-separated population within a species that retains the capability to produce fertile offspring with other populations but may exhibit phenotypic differences.

Used in 78 profiles

territory

In biology, area occupied by an individual, pair or group of animals and often physically defended against others of the same sex or species. May be established on a permanent or temporary basis.

Used in 318 profiles

trace element

Any chemical element required in small proportions by a given organism in order for certain physiological and biochemical processes to function properly. Often added to marine aquaria using proprietary liquid products and require regular replenishment as they are used up.

visceral arch

One of the bony or cartilaginous arches situated on either side of the pharynx that form the branchial arches and lower jaw.

watershed

An ridge or otherwise elevated piece of land that physically separates areas drained by different river systems. Also used to refer to an area or region drained by a particular river, river system, or other water body.

Used in 165 profiles

zoology

Scientific study of animals, including their classification, structure, physiology, and history; the fauna native to a given area and its composition; the biological characteristics of a particular animal or group of animals.

Used in 3 profiles

Aeromonas

A genus of rod-shaped, gram-negative bacteria found in fresh and salt water, soil, and sewage. Various species affect fishes while others are pathogenic to amphibians, reptiles, and higher animals including humans.

algae shrimp

Somewhat misleading vernacular name for the freshwater shrimp Caridina multidentata Stimpson 1860, a popular addition to freshwater aquaria due to its reputation for consuming algae, though in reality it is unable to survive on a diet of algae alone. Formerly referred to as C. japonica De Man 1892 (that name is now regarded as a junior synonym of C. multidentata) and also known as the Amano shrimp. Exhibits an amphidromous life cycle in nature and is thus difficult to breed in captivity, though it has been achieved.

alimentary canal

The passage (including the oesophagus, stomach, and intestines when present) along which food passes through the body from mouth to anus.

allopatric

Occurring in separate, nonoverlapping geographic areas. Often used to refer to geographically-separated, reproductively-isolated populations of related organisms. Opposite of sympatric.

Used in 2 profiles

andropodium

Modified, flexible anal fin rays present in males of some fish species (families Hemirhamphidae and Goodeidae) giving the fin a 'notched' appearance. Not used for insemination like the gonopodium in members of the family Poecillidae but to clasp the female during mating.

Used in 5 profiles

biodiversity

The number, variety, and genetic variation of organisms found within a specified geographic region, both within and between species and ecosystems. Often used as a measure of overall ecosystem health.

Used in 16 profiles

carotenoid

Any of a category of yellow to red pigments occurring naturally in plants and animals and including the carotenes and xanthophylls. Animals obtain carotenoids in their diets and they're known to enhance colouration in some fishes.

Used in 4 profiles

cladistics

Taxonomical method used to classify species of organisms into clades, each of which contains an ancestor organism and all its descendants, based on synapomorphies (shared derived characters). Cladistic classifications are usually presented in the form of a cladogram.