Presentation

Our Environment

Let’s Began

Our Environment

Atmosphere (or air)

Water Bodies

Land

PlantsAnimals

Waste Materials

Biodegradable Wastes.

Waste which can be decomposed by

by micro-organisms.

Non-biodegradable Wastes.

Waste which can not be decomposed by

micro-organisms.

Eco-System

Self-contained unit of living things, and their non-lining things.

E.g.:- grasslands, forests, deserts, mountains, lakes, river, pond and sea.

Components of Eco-system

Abiotic components of an Ecosystem.

Biotic components of an Ecosystem.

1. Producer organisms (Autotrophs).

2. Consumer organisms (Heterotrophs).

3. Decomposer organisms (Saprotrophs).

Producers

Organisms which produce food are called producers.

E.g.:- green plants.

Producers are the organisms upon which other organisms depend for food.

Consumers

Organisms which consumes food prepared by producers or depend on other organisms are called consumers.

All animals are consumers. E.g.:- man, goat, rabbit, fish, lion, etc.

Consumer organism are also called heterotrophs.

Consumers can be divided into three groups:

1. Herbivores.

2. Carnivores.

3. Omnivores.

Herbivores

Animals which eats only plants are called herbivores.

E.g. :- Cow, monkey, Turtle, etc.

Herbivores are primary consumers.

Carnivores

Animals which eat only other animal are called carnivores.

E.g.:- Lion, Tiger, lizard, Snake etc.

Carnivores are of two types:

1. Small Carnivores.

2. Large Carnivores.

The small carnivores which feed on herbivores (primary consumers) are called secondary consumers.

The large carnivores which feed on small carnivores are called tertiary consumers.

Omnivores

Animals which eat both, plants and animals, are called omnivores animals.

E.g.:- Human beings, Dog, Crow, etc.

Decomposers

Micro-organisms which breaks down the complex organic compounds present in dead organisms and their products into simpler substances.

The Decomposers help in decomposing the dead bodies of plants and animals, and hence act as cleaning agents of environment.

Due to the presence of decomposers that the various nutrient elements which were initially taken by plants from the soil, air and water are returned to the soil, air and water, after the death of plants and animals.

Importance of decomposers

Food Chain

The sequence of living organisms in a community in which one organism consumes other organism to transfer food energy, is called a food chain.

All the food chain begin with a green plant.

The food which we eat can be transferred from one organisms to the other through food chain.

Example of food chain

Food Web

The network of a large number of food chains existing in an ecosystem is called a food web.

Trophic levels The various steps in a food chain at which the transfer of

food takes place are called trophic levels.

Tertiary consumer

sSecondar

y consumer

sPrimary ConsumersProducers

Trophic level in food chain

Producers(1st Trophic level)

Primary Consumers(2nd Trophic level)

Secondary Consumers(3rd Trophic level)

Tertiary Consumers(4th Trophic level)

Eff ect of human activities towards the environment

There are two types of environmental problems caused by our activities :1. Depletion of ozone layer.

2. Disposal of domestic wastes.

Depletion of ozone layer

Ozone is a molecule made up of 3 atoms of oxygen combined together.

Ozone is a gas but it is poisonous in nature (if inhaled).

Ozone is formed high up in the atmosphere by the action of ultraviolet radiation on oxygen gas.

O2 UV radiation O(oxygen atom) + O(oxygen atom)

O2 (oxygen molecule) +O(oxygen atom) O3

(ozone molecule)

Ozone layer is important for the existence of life on earth because it absorbs most of the harmful UV radiations coming from the sun and prevents them from reaching the earth.

Ultraviolet rays can cause skin cancer or cataract.

The depletion of ozone layer is due to the use of chemicals called chlorofluorocarbons.

Disposal of domestic waste The household waste are called garbage.

E.g.:- left-over food, waste paper, unwanted plastics objects, old wooden objects.

Important modes of waste disposal are:

1. Recycling.

2. Preparation.

3. Incineration.

4. Landfill.

5. Sewage Treatment.

Thank You

By:-

Somen

Dey