Habitat And Adaptations
The place where an organism lives is called its habitat. It may also refer to the place occupied by an entire biological community.
In order to live successfully in a particular habitat, plants and animals have special structures called adaptive characters, e.g. wings of birds, fins of fish and thorns in cacti. Such structural modifications facilitate them to adjust in a particular habitat. This is known as adaptation.
- Xerophytes occur in regions where the amount of water in the soil is very scarce. They show different types of adaptive features. The root system is well developed, profusely branched and extensively spread which can reach even up to water table and therefore are capable of absorbing water from deep soil, e.g. Alhagi. The leaf is reduced as inAcacia and Prosopis. In some plants, the leaves are covered with dense growth of small hair as in Calotropis and Nerium. They have sunken stomata, leathery leaf surfaces and waxy cuticle. In certain plants such as Opuntia and Euphorbia, the leaves are modified into spines. The stems are succulent and green and take over the function of photosynthesis.
- Mesophytes are plants that grow in areas where water is neither in excess nor deficient such as cultivated lands. They show well-developed roots with root hair. The stems are solid and freely branched. The leaves are generally large, broad, thin and variously shaped. They have numerous stomata, e.g. mango, maize, tomato, wheat etc.
- Plants which remain permanently immersed in water are called hydrophytes. They may be free floating, rooted and floating or submerged. Due to the availability of water in plenty, the root system is poorly developed as in Eichhornia or absent as in Ceratophyllum.
- Animals also show different structural and functional adaptations to the conditions in which they live. The adaptations seen in animals are of the following types: aquatic, terrestrial, arboreal and aerial.
- Terrestrial animals usually show adaptation in relation to (i) locomotion in a particular environment, and (ii) feeding and other habits. With regard to movement on land, animals are adapted in various ways and they are classified as cursorial (runners), fossorial (diggers and burrowers) etc.
- A great number of animals live in aquatic habitat. They include both fresh water and marine forms. Certain invertebrates are aquatic (e.g. prawn, octopus, jelly fish etc.) or semi-aquatic (e.g. insects).
- Some animals come to the trees for safety and shelter but live mainly on land. They are small in number and categorised as arboreal (e.g. chamaeleon, monkey, tree frog etc.)
- Aerial adaptation is termed as volant adaptation. Volant animals have certain adaptive features that enable them to fly in the air for a long time. Fore limbs are modified into wings for flying in air. Bones with air cavities to make body light. Flight muscles are present to provide additional strength for winged flight (e.g. birds).
- Two types of adaptations are prominent in animals living in arid region, namely lowering of water loss as much as possible and adapting to arid conditions. For example, the camels show unique adjustments to desert conditions being very economical in water use, tolerant to wide fluctuations in body temperature and are able to maintain blood stream moisture even during extreme heat stress.
- The habitat and adaptation have a very strong relationship and their balance is essential for the survival of organisms. There are many examples of animals extinction due to their non-adaptability.