Glossary

72 terms beginning with R · showing 1–40

1. race

   Genealogical line or lineage. Sometimes used as an infrasubspecific category, i.e., below the subspecies level, to refer to populations or individuals which are not given taxonomic names.

   Used in 1 profile

2. radial

   In ichthyology, a bony or cartilaginous support for a fin ray or spine.

   Used in 15 profiles

3. ramified

   Split or divided into branches or constituent parts; with branches or extensions.

   Used in 1 profile

4. ramify

   To split into branches or constituent parts; to send forth branches or extensions.

5. rapacious

   Aggressively greedy or ravenous; feeding on live prey.

   Used in 3 profiles

6. rare

   Uncommon; occurring infrequently.

   Used in 178 profiles

7. rarity

   The state or quality of being rare.

   Used in 35 profiles

8. ray

   Any of the bony spines supporting the membrane of a fish's fin including both spines and soft rays.

   Used in 793 profiles

9. rear

   To breed an organism and play some part in caring for the young.

   Used in 62 profiles

10. red algae

    Any member of the division Rhodophyta.

11. redescription

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

    Used in 13 profiles

12. redox

    Abbreviation of reduction-oxygenation. Used in reference to a chemical process whereby one substance or molecule undergoes reduction and another oxidation.

13. reduction

    Chemical process whereby an atom or ion gains electrons and undergoes a subsequent increase in valence; the act or process of being reduced. Opposite of oxidation.

    Used in 60 profiles

14. 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.

15. 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.

16. 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

17. rejected name

    In zoological nomernclature, any name, available, unavailable, or vernacular, for a taxon other than its valid name. Also referred to using the Latin term nomen rejiciendum (nom. rej.).

18. 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

19. replacement name

    In zoological nomenclature, an available name used to replace an older available name.

    Used in 57 profiles

20. reproduction

    Production of offspring via a sexual or asexual process.

    Used in 111 profiles

21. 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.

22. reservoir

    Natural or artificial pond, lake or tank used for the collection and storage of water.

    Used in 61 profiles

23. 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

24. respiration

    The process by which an organism acquires the oxygen necessary for metabolism and expels excess carbon dioxide formed during energy-yielding reactions.

    Used in 7 profiles

25. reticulate

    Resembling a network or net, or having a network of parts, as seen in the colour pattern of many fishes.

    Used in 3 profiles

26. reticulated

    Constructed, arranged, or marked like a net or network; having a reticulate pattern consisting of interconnected lines.

    Used in 34 profiles

27. reticulation

    Arrangement or pattern in the form of a network or net.

    Used in 11 profiles

28. retrorse

    Directed or curved backwards or inwards; opposite of atrose.

29. reverse osmosis

    Form of purification, often abbreviated to RO, that removes dissolved salts and other impurities from water by applying pressure to it on one side of a semipermeable membrane. Pure water molecules are able to pass through the membrane while the majority of others are not, with more-or-less pure water the result. Sometimes used in combination with deionisation to remove additional mineral ions. Pure water can be harmful to fishes and is normally remineralised to some degree using proprietary products.

    Used in 2 profiles

30. reverse osmosis unit

    Device used to purify water via the process of reverse osmosis. Some units combine both reverse osomosis and deionisation functions.

    Used in 56 profiles

31. revision

    In taxonomy, a paper or study concerned with changes, amendments or corrections to a particular taxonomic group.

    Used in 113 profiles

32. rheophile

    An organism living or thriving in running water.

    Used in 71 profiles

33. rheophilic

    See rheophile.

34. rheophilous

    Living or thriving in running water.

35. rheotaxis

    Movement or orientation of an organism towards, into (positive rheotaxis) or away from (negative rheotaxis) a current of air or water

36. rhizoid

    Rootlike, filamentous structure used for attachment to a substrate and uptake of nutrients in mosses, ferns, and related plants, plus certain algae and fungi.

37. rhizoidal

    Of or relating to a rhizoid or rhizoid-bearing organism.

38. rhizome

    Horizontally-orientated plant stem growing under or along the ground surface from which new roots and shoots often arise.

39. 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

40. rhomboid

    Parallelogram with adjacent sides of unequal lengths; shaped like a rhombus or rhomboid.

    Used in 8 profiles