Results for “species”

peat swamp forest

Type of tropical moist forest lying over a thick bed of acidic peat, over 60% of which occur in Indonesia and Malaysia. Typically contain water with very low pH (<4.0) that is stained brown due to the release of various organic compounds from the decaying peat and thus often referred to as blackwater swamps. Usually contain some permanent water but also flood seasonally. Highly biodiverse when in pristine condition, with many species found nowhere else on earth, though increasingly subjected to intensive drainage, burning and subsequent conversion to agriculture in recent decades.

Used in 89 profiles

pelagic phase

Period of time during the life cycle spent floating freely in the water column, usually as a larval constituent of plankton. Relatively common in marine fishes but also typical of amphidromous and diadromous species.

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

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

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

planaria

Generic term applied to numerous non-parasitic flatworms of the class Turbellaria. Also a genus within that class, Planaria. Various species occur in aquaria where they're most often associated with accumulation of uneaten food or organic material and normally considered pests.

polymorphism

The occurrence of different forms, stages, or types in individuals or multiple organisms of the same species independent of sexual variation.

Used in 2 profiles

population

Group of individuals of a given taxon occupying a particular geographic area or specified habitat.

Used in 487 profiles

pseudotympanum

Translucent, triangular area in the humeral region, behind the opercle, without muscle and where the anterior part of the gas bladder is in direct contact with the skin. It is hypothesised to function as a hearing aid in many juvenile characoids and is present in adults of certain species, notably members of the family Cheirodontidae.

Used in 2 profiles

redescription

New, updated, corrected or more complete version of a species description.

Used in 13 profiles

refractometer

Instrument used to measure salinity or specific gravity via the refractive index (basically, the degree that light bends when shined through something) of a liquid. Most models are designed to measure sodium chloride or brine solutions and not seawater which contains a more complex range of salts and minerals, but usually more accurate than a hydrometer nevertheless.

refugium

A region that has remained unaltered by a climatic change event and provides an area where relict species are able to survive; in aquaria the term is used to describe an aquarium or other container maintained within a larger system, usually displayed alongside or beneath it, where certain organisms that would not survive in the main aquarium can be maintained.

reintroduction

Deliberate release of an organism or group of organisms into an area or habitat previously inhabited by the taxon but from where it has been lost. Primarily carried out for conservation purposes using specimens taken from captivity or relocated from a different area.

Used in 5 profiles

relict

An organism or group of organisms that exists as a remnant, typically belonging to a formerly abundant group in an environment much changed from that in which it originated; a surviving species from an otherwise extinct taxon.

Used in 5 profiles

resource partitioning

Form of niche differentiation by which two species partition (divide) a resource based on behavioral or morphological variation in order to ensure their mutual survival by reducing competition.

Used in 11 profiles

Rhodophyta

Division of eukaryotic algae containing thousands of species, most of which are multicellular and inhabit marine environments, e.g., many seaweeds.

Used in 3 profiles

sample

In ichthyology, a collection of fishes made from a particular locality or specified area.

Used in 8 profiles

saprolegnia

Genus of aquatic fungi, some species of which attack fishes. Normally a secondary pathogen attacking previously damaged tissue and causing cellular necrosis alongside other epidermal damage. Generally visible as a whitish or greyish filamentous fungus and thus commonly referred to as cotton-wool disease.

school

Tightly-aggregated group of fishes, normally of the same species, which tends to orient and move in the same direction; the act of schooling. Often confused with shoal.

Used in 135 profiles