Adaptation is the possession of special features which improve the chances of an organism to survive in its environment. All organisms have adaptive structures which could be structural or morphological and behavioural in nature. These enable them to live successfully in their habitat.
Modes of Adaptation:
- Structural Adaptation
- Adaptive Colouration
- Behavioural Adaptation
Structural Adaptation
This is a special modification of structures which help organisms to survive better in their environment. Examples include;
Structural adaptation to obtain food e.g. a toad has a long tongue to catch its prey; birds have sharp, strong and curved claws for catching their prey; Insects have modified mouth parts for feeding; Insectivorous plants (e.gutriculariaspi.e. bladderwort, Droseriasp i.e. sundew, etc) have special structural adaptive features.
Structural adaptation for escape and defence. Escape adaptation can be grouped into camouflage (concealing ccolouration), individual and group responses e.g. caterpillars taking the colour of leaves. Defence adaptation may be inform of physical structure e.g. spines and shell, scales etc, chemical defence e. g. snakes attack their enemies by spitting venom, bees and scorpion have stings and mimicry (looking like an uninteresting objects) e. g. stone plant.
Structural adaptation to attract matese.g. Adult male agama lizard displays its bright colour to attract its mates, flowering plants attract insects for pollination, bright coloured feathers of male domestic fowls and peacock etc. Structural adaptation to regulate body temperature e.g. mammals have fat layer, sweat gland, feathers and subcutaneous fat in birds in birds etc. All serve to regulate heat loss.
Structural adaptation for water conservation: e.g. some plants have small needle like leaves (conifers), thick bark (acacia), waxy cuticles etc to reduce the rate of transpiration. Likewise some animals possess scales, exoskeleton, feathers etc. to reduce water loss.
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 blendingwith 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(camouflague)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 backgroung 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 i.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:
Variation, Competition & Succession of Organisms
GENETIC: HEREDITARY, TERMINOLOGY, MENDEL’S WORK, GENOTYPE & PRINCIPLES OF HEREDITARY
Reproductive Behaviours: Courtship Behaviour, Display of Colours & Seasonal Migration
Fruits : Types, Structure, Dispersal of Fruits, Agents of Dispersal of Fruits
The Eyes | Anatomy, Functions, Problems, Solutions, Symptoms or Signs, Care For Eyes