Glossary

72 terms beginning with O · showing 1–40

1. oak leaf

   Leaf of the tree and shrub genus Quercus. Dried and used in aquaria to simulate certain natural conditions, especially those typical of blackwater habitats.

   Used in 43 profiles

2. objective synonym

   Each of two or more synonyms referring to nominal taxa with the same name-bearing type, or, in the cases of family-group and genus-group taxa, referring to nominal taxa with name-bearing types whose own names are themselves objectively synonymous.

3. obligate

   In biology, able to exist or thrive only under a certain set of environmental conditions, e.g., an obligate peat swamp-dweller.

   Used in 148 profiles

4. obtuse

   Having a blunt or rounded tip.

5. occipital

   Of or related to the back of the skull or head; occipital bone.

   Used in 5 profiles

6. occipital bone

   Median bone on the back of the head

7. occiput

   Back segment of the skull or head.

   Used in 2 profiles

8. ocellate

   Possessing or resembling an ocellus or ocelli; having a spotted colour pattern.

9. ocellus

   Element of colour pattern resembling an eye; an eyespot or 'false' eye, often present in order to disorient predators.

   Used in 39 profiles

10. ocular

    Of or related to the eye or sense of sight.

    Used in 82 profiles

11. od

    Abbreviation of the term original description, sometimes used in non-scientific literature.

12. odontode

    Rigid, dermal structure resembling a tooth or bristle found in certain fish taxa, notably many neotropical catfishes. Also known as a dermal tooth and has a structure comparable to that of an oral tooth, with dentine surrounding a central pulp cavity covered by a superficial layer of enamel or similar material. Often more pronounced or extensively-distributed in males than females.

    Used in 34 profiles

13. oedema

    Excess and subsequent accummulation of watery fluid in cells, tissues, or body cavities of an organism. Also spelled 'edema'.

14. oesophagus

    Muscular tube through which food passes from mouth to stomach in vertebrates; the gullet. Also spelled 'esophagus'.

15. oil globule

    Small, spherical droplet of oil found within the yolk sac of fish larvae. There may be one or more present and the size, positioning, and colour are also variable meaning they can be useful in terms of taxon identification.

16. olfactory

    Of, relating to, or contributing to the sense of smell.

    Used in 3 profiles

17. Oligochaeta

    Class of annelids that includes earthworms.

18. oligotroph

    An organism able to live in oligotrophic environments.

19. oligotrophic

    Refers to bodies of water containing few nutrients and supporting little in the way of plant life. Opposite of copiotrophic.

    Used in 2 profiles

20. omnivore

    An organism that consumes both plants and animals.

    Used in 148 profiles

21. omnivorous

    Consuming both plants and animals.

    Used in 241 profiles

22. ontogenesis

    See ontogeny.

23. ontogeny

    The origin and development of an individual from embryo to adult.

    Used in 15 profiles

24. oocyte

    Cell from which an egg or ovum develops.

25. Oodinium

    Genus of parasitic dinoflagellates occurring in marine and freshwater fishes and sometimes referred to as Piscinoodinium or 'velvet disease'.

    Used in 7 profiles

26. oophagy

    Feeding on eggs either inside or outside the mother's body

27. opercle

    Bone forming the upper, posterior portion of the operculum, sometimes bearing spines or spine-like structures. Normally the largest of the bones comprising the operculum.

    Used in 149 profiles

28. opercular

    Of or related to the operculum.

    Used in 53 profiles

29. opercular opening

    See gill opening.

30. operculum

    Flap composed of 4 bones that covers, supports and protects the gill opening in many fishes. Also known as gill flap or gill cover.

    Used in 64 profiles

31. oral

    Of or relating to the mouth.

    Used in 35 profiles

32. oral brooder

    See mouth brooder.

33. orbicular

    Circular or spherical in shape.

34. orbit

    Either of two dermal, bony structures in the skull, each of which houses an eye; eye socket.

    Used in 28 profiles

35. orbital

    Of or relating to the an orbit.

    Used in 61 profiles

36. organic

    Of, relating to, or derived from living organisms.

    Used in 583 profiles

37. organism

    An individual life form that can react to stimuli, reproduce, grow, and maintain homeostasis. There are five main groups, or kingdoms: prokaryotes, protists, fungi, plants, and animals.

    Used in 127 profiles

38. original description

    The description of a nominal taxon when it is established.

    Used in 51 profiles

39. ortho-

    Prefix meaning straight, upright, or vertical.

    Used in 1 profile

40. osmoregulation

    Active regulation of osmotic pressure, especially in the body of a living organism or cell, in order to prevent the body fluids from becoming too diluted or concentrated.