Living organisms & their surroundings

HabitatThe surroundings where an organism lives is known as its habitat.

There are 2 components of ahabitat :

1. Biotic components.2. Abiotic components.

Biotic components :The living components of a habitat.

Eg : Plants, animals & other micro-organisms

Abiotic components :The non-living components of a habitat.

Eg : Air, water, soil, sunlight, temperature, rocks.

AdaptationsThe presence of certain specific features or habits which enables a plant or an animal to adjust and live in its surroundings is known as adaptations.

Types of Adaptations

1.Terrestrial adaptation : a) Desert

Adaptation b) Mountain Adaptation c) Grassland Adaptation

2. Aquatic Adaptation

Adaptation: Two rows of long eyelashes.Function: Protect against blowing sand and the sun

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Adaptation: Fat stored in hump(s)Function: Help it to survive long periods without food.

Adaptation: Broad, flat, leathery pads at the bottom of their hoovesFunction: Pads spread out when the camel places its feet on the ground thus preventing the camel from sinking into the sand

Adaptation: Thick leathery patches on kneesFunction: Protect it from getting burn when it kneels on the hot desert sand

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Adaptation: Long strong legsFunction: Help carry heavy loads over long distances and keep its body further away from the hot sand

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Animal Life in Mountain Habitat

Plant Adaptaion in Mountain Habitat

Animal Adaptaion in Grassland

Some animals are very small such as mice, dogs, snakes, lizards and insects. These animals can hide easily in the grasses.

There are also large animals such as elephants, lions, zebra, giraffes, cheetah, etc. These animals are too large to hide in the grasses, so they protect themselves in other ways, such as by speed or camouflage. Some animals like elephants, giraffes and rhinos are so large that predators cannot easily attack a healthy adult.

Many animals live in large groups. This gives protection from predators .There are more eyes to spot danger, & strong members surround weaker ones.

Grasses grow from the base. Creeping stems above the ground are called stolons, and those below the ground are called rhizomes..As these creeping stems spread out, shoots grow up and produce leaves. The deep, spreading root systems make sure that even in drought, the plants are able to get water. Long narrow leaves like grass do not lose as much water in the heat as big leaves do.Grass can be cut quite close to the ground, and new leaves sprout from the base of the plant. This means that grasses can be eaten and walked on by animals and are not killed.

If these plants are removed from the water, they hang limply. They are normally supported by water all around them and so have no need of mechanical strengthening.Roots are often reduced and their main function is anchorage. The submerged leaves are often highly dissected or divided. It also minimises water resistance .Air-filled cavities often extend throughout the stems.

Submerged Plants

They are of two types: those which are rooted with floating leaves (e.g. Water Lily) and those which are not rooted, but just float on the surface (e.g. Duckweed). Floating leaves are generally tough because they have to withstand the weather and water movement. Stomata are found only on the upper surface of the leaf. Upper surface has a thick waxy cuticle to repel water and help to keep the stomata open and clear.Weak stems produce a massive floating canopy of leaves Water provides all the necessary support

Floating Plants

Animal Adaptaion in Aquatic Habitat

vegetative propagation.Layering

Involves getting roots to grow from the stem. I.e., magnolia tree

Cutting Using a short section of plant stems for propagation.

BuddingTaking a bud from one plant and moving it to another.

GraftingPlacing a section of a stem of one plant onto another plant.

Tissue cultureTaking a group of cells or a single cell and growing it to a plant.

Layering

Cutting

Tissue Culture