Definitions

abdomen the posterior zone of a body divided into 3 regions, e.g. as in insects
abiotic a lifeless environment
abundance the total number of individuals of a given species in an area, population or community.
abyssal plain the flat part of the ocean floor lying beneath 4000 m or more of water.
acclimation/acclimatization the physiological adjustment to a change in an environmental factor
achromatic colourless, unpigmented
acid rain rainwater with a low pH, therefore high acidity. Caused by oxides of nitrogen and sulphur released during combustion of coal and oil.
acoelomates solid-bodied animals lacking cavities between the gut and the outer body wall, e.g. Platyhelminthes
aculeate hymenoptera Hymenoptera (bees, ants, wasps) armed with stings
adaptation a hereditary characteristic allowing an organism to develop in other than its usual niche
adaptive radiation the emergence of numerous species from a common ancestor introduced into an environment presenting a diversity of new opportunities and problems
adductor a muscle that draws 2 valves of a mollusc shell together, e.g. as in the Bivalvia
adventitious organ (botany) a bud, sprout, root, etc, which develops in unusual circumstances and conditions
aedeagus in beetles, the male genital structure
Aerobic describes an organism that can live only in the presence of oxygen
Aestivation prolonged summer torpor
Age structure the relative number of individuals of each age in a population
aggression A primary instinct, an offensive behaviour action
alarm pheromone A chemical substance exchanged among members of the same species that induces a state of alertness or alarm in the face of a common threat.
alarm recruitment system A communication system in social animals that rallies members of the group to some particular place to aid in defence of a member or resource.
alate having wings ( often used in reference to insects)
alimentary tract the passage from the mouth to the anus in which food is broken down and digested
allelochemical non-nutrients produced by one organism that affects the behaviour, health or ecological welfare of another
allometry the relative growth of a part of an animal, e.g. legs, ears, etc., in relation to the whole animal.
altruistic behaviour the aiding of another individual at one's own expense or risk
ammonite a group of fossil, spiral, chambered shells (similar to Nautilus), but the partitions between the chambers were waved in complicated pattern at their junction with the outer wall of the shell.
anaerobic an organism or biological process which occurs in the absence of free oxygen
anal towards the posterior end or side
analogy similarity of function, but not origin
anhydrobiosis dormancy induced by low humidity or desiccation, see tardigrada.
annelids Worms. The surface of the body has distinct divisions into rings or segments. Includes marine worms, earth worms and leeches.
antenna one of the paired sensory appendages on the heads of certain arthropods, etc., usually composed of numerous segments. Bumblebee antenna, insect antenna.
antennation touching or probing with antennae
antenniform shaped like antennae
anterior the head end of a bilaterally symmetrical animal
anthropocentric interpreting the activities of animals in relation to human values.
Anthropogenic Caused or produced by man
anus the posterior opening of the digestive tract
Aperture An opening, as in the first whorl of a gastropod shell
Apical pertaining to the tip or apex
Aposomatic colouration the bright colours of animals with effective physical and chemical defences that acts as a warning to predators, e.g. black and yellow of bumblebees.
Apparency obviousness, e. g. of prey to a predator
apterous wingless
Apterygote wingless, e.g. the insects are divide into apterygote and pterygote
Arboreal living in trees
Aristotle's lantern the mouth apparatus found in some urchins
Arteries vessels that carry blood away from the heart to the organs throughout the body
Arthropod a group of invertebrates which includes the insects, crustaceans and arachnids
Artificial selection the selective breeding of domesticated plants or animals to encourage the occurrence of desirable traits
Aschelminthes An old grouping of Rotifera, Gastrotricha, Kinorhyncha, Nematoda, and Nematomorpha. It is now considered a superphylum.
Asconoid The simplest form of sponge where the canals lead directly from the outside to the interior
Asexual reproduction Reproduction by a single female without the need for a male, e.g. in some aphids and stick insects
Autotroph An organism that makes its own organic nutrients from inorganic raw materials.
Axon a long outgrowth or process from a neuron that carries nerve impulses away from the cell body toward the target cells
Bacteria/Monerans Are the simplest fully-independent living things. They are prokaryotes, i.e. they lack the specialised structures found in eukaryotes. Energy is obtained from sunlight, organic and inorganic sources.
Ballooning In spiders, when a long strand of silk is caught by air currents enabling spiders to disperse over great distances
Basal near the point of attachment, opposite of apical
Batesian mimicry The close resemblance of a harmless or palatable species (the mimic) to a venomous or unpalatable species (the model) in order to deceive a predator. For example harmless hoverflies resembling stinging bees and wasps.
Bathymetry The measurement of ocean/lake depth and the study of floor topography.
Benthic living on the sea bottom
Bilateral symmetry Mirror image correspondence of opposite sides of the body.
Bilobed with 2 lobes
Binary fission Division into 2 parts. The commonest form of asexual reproduction in animals.
Binocular vision eyes face forwards to give overlapping fields of view and allow distance to an object to be judged.
Biogeochemical cycle The cyclic system through which a given chemical element is transferred between biotic and abiotic parts of the biosphere, e.g. the carbon and nitrogen cycles.
Biogeography The study of the geographical distributions of organisms, their habitats and the historical and biological factors which produced them.
Biological control The control of a pest by preservation, or facilitation of natural predators, parasites or other enemies, by sterilization techniques, or by the use of hormones or other biological means.
Biological magnification a trophic process in which retained substances become more concentrated with each link in the food chain, e.g. DDT and DDE magnified in the top predator
Biological monitoring using animals (often insects) or plants to detect changes in the environment
Bioluminescence Light produced by living organisms and the emission of such light. Most common in marine animals. Usually the protein luciferin reacting, in the presence of oxygen, with the enzyme luciferase to produce light.
Biomass the mass of living beings (animal and vegetable) present in a specific environment. It is usually expressed in weight of dry matter per unit of surface area.
Biomes the world's major communities which are classified according to the predominant vegetation and characterized by adaptations of organisms to that particular environment
Biosphere The global ecosystem. That part of the earth and atmosphere capable of supporting living organisms.
Biota the sum of all living organisms
Bivalve a mollusc with 2 shells
Bivoltine having 2 generations a year
Book lungs organs of gas exchange found in most spiders, made of stacks of tissues in an internal chamber
Boreal Pertaining to cool or cold temperate regions of the northern hemisphere
Brachiopod A phylum of animals encased in 2 valves, resembling some bivalves superficially, but unrelated to them. Commonly known as lamp shells.
Branchiopoda Small aquatic crustaceans, mainly freshwater, but some marine. Contains around 1000 species worldwide in 4 Orders: Notostraca (tadpole shrimps), Anostraca (fairy shrimps), Conchostraca (clam shrimps), Cladocera (water fleas).
Branchiura Fish lice. Ectoparasitic crustaceans attaching to their host (fish) by a pair of suckers. Feeds on the host's blood and mucus through its sucking, tubular mouth.
Brittle stars A type of starfish with long, flexible arms, abundant on the deep sea floor.
Broad spectrum insecticide An insecticide which acts on a range of insects, or even on all animals. Usually a nerve poison.
Brood The offspring of a single birth or clutch of eggs. A group of young animals that are being cared for together by an adult. To incubate eggs (see bumblebee queen).
Brood parasitism The use of a host species to brood the young of another species (the parasite), e.g. cuckoo bumblebees.
Bryozoa A phylum of animals usually found on stones or seaweeds, living in colonies and filter-feeding.
Budding A type of asexual reproduction in which a new individual develops as a direct outgrowth from the body of the parent, and may subsequently become detached. The division of one colony of social insects into two or more colonies.
Buffer species An animal or plant which is an alternative food supply for another organism, and so buffers the effect of predation on its animal prey.
Byssus Threads by which a bivalve attaches itself to the surface.
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