Table of Contents


Living organisms and their surroundings


Habitat-the surroundings in which a particular organism is found living in nature is called habitat.

Many plants and animals are found living in water and many plants and animals are found living on land, so we find two type habitats on earth :-

1. Aquatic habitats(living in water)-

In an aquatic habitat, water is the medium in which an organism or the organisms live through their life.

2.Terrestrial habitats(terrestrial means land) :-

Are the places on land, some organisms may be found living even in the soil, on the dead and decaying plant and animal matter.

On terrestrial habitat, air is the medium in which the organisms survive.

Components of habitat

Living or nonliving things together make a habitat or the environment.

In a habitat both biotic (living) and abiotic (non living) component interact with each other.

1. Biotic components :-

A. Plants

B. Animals

2. Abiotic components :-

A. Light

3. Temprature :- 

A. water

B. Air

C. Soil

D. Fire 

Biotic and abiotic components

Decomposers : organisms derive nutrition from dead and decaying plants and animals called decomposers .example-bacteria and fungi.

Saprotrophs(sapro means living on putrid) :- The organisms deriving nutrition from waste and dead decaying matter.

Scavengers :- animals that feed on decaying bodies of other animals leaving behind clean surroundings are called “scavengers”. example :- vulture, hawk, eagle, jackal, wolf.

Habitat and Adaptation

Adaptation :- The presence of specific features in the body which help a plant or animal to live or survive is called adaptation.

Adaptation may be with :-

1. Structural adaptation :- change in the body structure to match favourable conditions and combat the unfavourable once.

2. Bahavioural adaptaion :- with the change in season.

Adaptation for aquatic habitat

Adaptation in fishes :-

1. Body of fishes is covered with scales to protect it from decay under water.

2. Body is boat shaped to help in swim in water.

3. Eyes in fishes covered with a transparent membrane which protects their eyes from damage under water.

4. Fish breath through gills, which helps in  exchanges of gases.

Whales and dolphins breath through lungs, for breathing they need air. they come to the surface of water and breath air through nostrils or blow hole located on its snout.

Adaptation in aquatic plants

Plants growing in water are called hydrophytes(hydro-water, phytes-plant)adaptation in hydrophytes for aquatic life are-

1. Body covered with mucilage which protects their body from decay under water.

2. The surface of leaves is coated with a waxy layer to protect them from rotting in water.

3. Plants found in streams have long and narrow stem and ribbon like leaves to be able to float along with the current of water with out any damage.

4. Stem is full of air spaces.

Example :- lotus, water hyacinth(eichhornia)

Adaptation for terrestrial habitats

Terrestrial habitats are land habitats .

Land plant grow with their roots into soil and shoot in the air.

Land animals live on land and breath in air.

Some of the terrestrial habitats are

1.Grassland habitat(plains) :-

A. Plants :- Plants along grassland are herbs, shrubs and trees, these plant are called mesophytes, Most of them are garden plants, crop plants, fruit and vegetable yielding plants growing under normal conditions of air, water, warmth and airy humid soil.

B. Animals :- Animals along grassland are domestic and wild. All these plants and animals are distributed on land depending up on the availability of water, food, and suitable shelter at the place.

2. Desert habitat(dry and sandy habitat) :- Organisms in the desert have to develop habitats and structure to be able to live with whatever little water is available and they conserve maximum water in their body by reducing transpiration or perspiration.

Exa. Desert animal-camel, goat, lizard, Snake, Rats, Scorpion and mole.

Desert plant :- Acacia, Cactus, Euphorbia, Aloe, Calotropis, Argemone, Ziziphus.

Adaptation in camel

Camel is the most typical animal of the dry, hot and sandy desert. camel shows the following adaptation to desert habitat.

1. Camel drinks a large quantity of water when available and store in its body, utilize it sparingly so that it can live without taking water for long.

2. Indian camel has one hump, the hump stores fat as reserve food which is used by animal, while going with out food for long.

3. Camel has long feet with broad padded toes. this makes it easy for the camel to walk fast and cover long distance on hot sand in a short time, with out sinking its feet in lose as and for being able to walk easily and fast on hot sand so camel is called as the “ship of desert.”

4. Camel urinates a little and excretes dry and hard pallets,this helps camek

Adaptation in desert plants :- plants  growing in dry, hot desert conditions are called xerophytes. the xerophytes show following adaptation.

1. Deep growing roots to be able to reach sub-soil ground water.

2. The stem is hard,woody,thickned,may be spiny covered with thick bark.

4. Leaves are either absent or when present are small, covered with thick waxy coating to reduce the loss of water from the surface.

3. Under ground habitats(burrows) :- most of the desert animals do not come out during the hot and bright day and rest in burrows at night in search of food and water.

Example :- Moles, Rats, Hare, Snakes, Lizard, Insect, Earthworm.

Adaptation in plants to mountain habitat

Trees on hills are conical in shape with hard and woody main trunk growing straight to slide off the snow,save the branches from damage from the weight of the snow during snow fall.these conical threes are called “conifers”.

Most tress like pine and cedrus have small needle shaped leaves.

Needle shaped leaves are coated with a thick waxy layer of cuticle to reduce the loss of water due to transpiration.

Animals on mountain habitat

Presence of fur or thick long hair with fine hair under to keep the body warm.

A thick layer of flesh under the skin on their body protects them from severe cold.

They have strong lungs to breath heavily in low oxygen content air.

Snow covered polar regions

Arctic in the north and Antarctic in the south are the two polar regions of the earth which remain covered with snow all the year around.

There are no land plants in arctic and Antarctic region but some animals are present they are-

1. White bear/polar bear :To live in arctic region , it has a thick white fur and a thick layer of fat below the skin to be able to bear cold.

The hair fibres on its body are hollow which help in minimum heat loss from the body.

It has small ears and a small tail which do not get cool easily.

It has padded feet to help it walk on snow.

2. Arctic tern is the bird of the region of the north pole (in summer), it migrates from north polar region to south travelling hundred of miles a day, and back to live in the polar region during summer.

3. Penguin-the “coat bearing” bird, is inhabitant of Antarctic has black feathers at the back and white towards breast, giving the appearance of a black coat bearing bird.

It eats fish in huge quantity during summer and store fat in its body for cold period.

Arborial habitat

Arbor means “a tree”.so organisms living on trees are arboreal in habit.

Arboreal animals : Most birds and winged animals are arboreal.

Example- Squirrel honeybee, Spider, Grasshopper, Monkey, and bear.

Arboreal plants : algae, fungi, ferns and mosses.

Most orchids are arboreal bearing beautiful flowers in spike, hanging down. By habit, orchids grow on tree trunks and are called epiphytes.

Orchids are green autotrophs growing on tree trunks with a bunch of special roots suspended in air. the hanging roots are spongy, spongy tissue on the roots absorbs water for the plant from the moisture in the air.

Aerial habitat in birds

In birds body is light in weight and covered with waxy feathers all over body, to protect the body from sun, rain, and wind.

Bones are thin and hollow with air cavities to make them light in weight.

Shape of the body is streamlined to help smooth movement in the air while in flight.

Forelimbs are modified into wings and are supported with strong muscles.

Birds bear claws on their feet, claws help the bird in perching.


Acclimatization is the temporary adjustment of the body to the changed environment. It is temporary and reversible.