ADAPTIVE COLOURATION Archives

ADAPTIVE COLOURATION AND BEHAVIOURAL ADAPTATION ADAPTIVE COLOURATION This is the possession by an organism of a colour which enables it to catch its prey, avoid its predators or enemies, secure mates and ensure their survival. Adaptive colouration may be grouped into Concealing (cryptic) colouration to help organisms blend with their background and remain unnoticed by predators Colour blending with the environment e. g. green cuticles of grasshopper, green snakes etc. Counter shading by animals possessing a dark dorsal surface and light ventral surface as in tilapia fish to remain unnoticed by predator above and below. Colour change (camouflage) to match the environment as in chameleon, grasshopper etc. Disruptive colouration as patterns to break the body outline of animals against the dark and light shades of their background as in giraffe, leopard, tiger, lady bird beetle etc. Warning colouration to announce the presence of the organism(s) to potential predator to avoid them because they have some unpleasant features e. g. variegated grasshoppers, black and yellow bands of wasps. Mating colouration as in male agama lizard, peacock. Mimicry in harmless organisms resembling a distasteful or harmful one for the enemies to avoid such e.g. stick insects, swallow tail butterfly. Bright colouration of insect pollinated flowers and pitchers of insectivorous plants. BEHAVIOURAL ADAPTATION: Behaviour is basically adaptive, everything used by organisms to promote their survival. Examples include: Behavioural adaptation in predators e.g. Lion with high speed chases its prey; spider spins its webs for its prey Behavioural adaptation to protect prey from predators e.g bats hold tree branches with heads upside down (which is described as swaying in the air), Antelopes escape with speed, beetles secreate offensive odour, toad puffs itself up Behaviuoral adaptation for avoiding harsh weather conditions e.g. aestivation e. passive period of existence. It is practiced by crocodiles; Hibernation i.e. sleep period to survive food scarcity or winter (low temperature) exhibited by insect-eating bats; migration of certain animals (e.g cattle egrets) to favourable habitats Behavioural adaptation in plants: e.g some plants shed leaves in dry season (deciduous plants); some like yam tuber, potatoe die down and survive as underground stem; plant seeds can remain dormant, plant shoot moves towards light (Positive phototropism) Gregarious behaviour (movement in groups) is expressed by elephants zebra, birds, fishes, social animals (bees, termites) etc. See also arteries FACTORS AFFECTING TRANSPIRATION BIOLOGY SSS 2 SCHEME OF WORK Scheme of work DENTAL DISEASES