Glossary

125 terms beginning with A · showing 41–80

1. algal bloom

   A population explosion of unicellular algae, normally resulting from an increase or excess of available nutrients.

   Used in 3 profiles

2. alien species

   See exotic species.

3. alimentary canal

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

4. alkali

   A substance which neutralises an acid.

   Used in 2 profiles

5. alkaline

   Relating to or containing an alkali; having a pH greater than 7.0; having a relatively low concentration of hydrogen ions; able to neutralise an acid.

   Used in 94 profiles

6. alkalinity

   Measure of the buffering capacity of a given water body, i.e. its capacity to neutralize acids and bases thereby maintaining a fairly stable pH. Water containing compounds, such as bicarbonates, carbonates, and hydroxides has a stronger such capacity and is referred to as hard water, while water lacking or deficient in them is termed soft water. Soft water aquaria tend to be susceptible to pH crashes if not maintained correctly.

   Used in 6 profiles

7. allelopathy

   A biological phenomenon by which an organism produces one or more biochemicals that affect the growth, survival, and reproduction of others. Typical in certain plants, algae, bacteria, coral, and fungi.

8. allometry

   The growth of body parts at different rates, resulting in a change of body proportions; the study of this phenomenon.

9. 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

10. allopatric speciation

    Speciation event driven by some form of physical separation, e.g., the formation of new mountain ranges, followed by development of new genotypes and/or phenotypes.

    Used in 2 profiles

11. alluvial

    Refers to sediment deposited by flowing water.

    Used in 2 profiles

12. altruism

    Behaviour benefitting other individuals of the same species, whether or not they are the offspring of the individual concerned. Frequently detrimental to the individual but favouring the spread or survival of its genes.

13. altruistic behaviour

    Behaviour which benefits other organisms. May be expressed at the level of the individual, group, or more extensive social system.

    Used in 2 profiles

14. ammonia

    The chemical compound NH3, which is toxic to fish. The main source in aquaria is the breakdown of protein by a fish's metabolism.

    Used in 4 profiles

15. amphibian

    A class of cold-blooded vertebrates, generally requiring water for reproduction.

    Used in 32 profiles

16. amphibious

    Living or able to live both in water and on land.

    Used in 3 profiles

17. amphidromous

    Migrating from fresh to salt water or from salt to fresh water at some stage of the life cycle other than the breeding period.

    Used in 34 profiles

18. amphidromy

    A form of diadromy in which fishes migrate between fresh and marine water as part of their life cycle for some purpose other than spawning, e.g., newly-hatched, arvae may be swept downstream into the sea where they spend a period of time before migrating back into fresh water to mature and eventually reproduce.

    Used in 15 profiles

19. amphipod

    A crustacean of the order Amphipoda, most of which are small and have a laterally-compressed shape. The suborder Gammaridea contains all freshwater species.

    Used in 1 profile

20. ampullae

    Used in ichthyology to describe dilations in the semicircular ear canals of some fishes.

21. anadromous

    Migrating from marine to freshwater environments in order to spawn, as many salmonids do for example.

22. anaerobic

    Living or occurring in the absence of oxygen.

23. anal-fin

    A median, unpaired, ventral fin located between the anus and caudal fin, usually in the posterior portion of the body. Used to maintain equilibrium and stability.

    Used in 764 profiles

24. anal-fin origin

    Anteriormost point at which the anal fin base is attached to the body.

    Used in 108 profiles

25. analogous

    Similar in function but not structure or evolutionary origin i.e. evolved independantly.

26. anastomose

    To undergo the process of anastomosis.

    Used in 5 profiles

27. anastomosis

    The connection of separate parts of a branching system to form a network. Sometimes used to describe the process by which a relatively regular, e.g. striped, patterning in juveniles of certain fishes breaks up as they mature.

    Used in 6 profiles

28. anchor worm

    Member of the copepod crustacean genus Lernaea. Adult females are parasitic on freshwater fishes.

29. 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

30. anguloarticular

    A compound bone formed by the fusion of the dermal angular and the cartilaginous articular and comprising the posterior part of the lower jaw.

    Used in 5 profiles

31. annelid

    Member of the phylum Annelida which comprises a large group of segmented, usually elongate, worm-like invertebrates. Contains both earthworms and leeches among others.

    Used in 1 profile

32. annual fish

    A fish species which naturally completes its life cycle within a year at the end of which it dies leaving behind fertile eggs which typically survive in the soil and hatch during the next rainy season. Often used in reference to certain South American and African killifishes.

    Used in 4 profiles

33. anoxia

    Absence of oxygen.

34. anoxic

    Depleted of oxygen..

35. anterior

    Located near or towards the head; forward in position.

    Used in 401 profiles

36. anterior margin

    Used to refer to the margin of a fin from its origin to its apex.

    Used in 22 profiles

37. anterolateral

    Refers to the position or direction between the front and side of an object.

38. anthelmintic

    See antihelmintic.

39. anthropogenic

    Caused by humans. Often applied to the environment.

    Used in 18 profiles

40. antihelminthic

    Substance or medication that destroys or expels parasitic worms from the body. Same meaning as anthelmintic.

    Used in 1 profile