ADAPTATION FOR SURVIVAL
Competition is the process by which living organisms in the habitat struggle with one another for limited essential needs in the environment. Such scarce resources in plants include; light, space, nutrient and water while animals complete for food, space or mate.
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Competition finally results in survival of the fittest and elimination of the unfit.
Types of competition
- Intraspecies competition: competition between organisms of the same species. e.g. many maize seedlings grown in a small area.
- Interspecies competition: that between different species of organisms. e.g. many maize and pepper seedlings growing in a small area.
Relationship between competition and succession
Succession is the change in a population caused by the replacement of the old members with new ones as a result of competition. The newly formed habitat is gradually colonized by different species of plants in a stepwise manner until a relatively stable community is established and later the habitat will be inhabited by animals. As soon as a habitat is established, competition sets in. The early inhabitant modify the habitat by their activities while the later arrivals compete and outgrow the previous inhabitants which gradually loss out.
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.
There are three modes of adaptation:
- Structural Adaptation
- Adaptive colouration
- Behavioural Adaptation
This is a special modification of structures which help organisms to survive better in their environment. Examples include;
- Structural adaptation to obtain foodg. 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 matesg. 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 temperatureg. 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.