Our Environment Class 3 Notes Science

Environment

• The natural surroundings in which living things live is called the environment. 
• The environment includes soil, water, air, plants, animals and other living things.
• Animals and plants are living. They are known as the living components or biotic components of the environment.
• Air, water, soil and sunshine are non-living. They are known as the non-living components or abiotic components of the environment.
• Both living and non-living things depend on each other in an environment. This kind of dependence is called interdependence.

Dependence of Living Components on Non-Living Components

1. Air

• All living organisms use oxygen present in the air to breathe.
• Plants also need carbon dioxide from air to make food.

2. Water

• Water is important for both plants and animals. 
• Animals drink water. 
• Plants absorb minerals dissolved in water through their roots. 
• They also need water to prepare food.
• Our body is made up of 70% of water. 
• Blood, a flowing liquid present in our body is also made up of nearly 90% of water.

3. Soil

• Plants need soil to grow. 
• Fertile soil supports a rich variety of plants. 
• Plants get water and minerals from the soil. 
• Soil also provides them support.
• Soil provides shelter to animals such as rabbits, ants, earthworms and centipedes.

4. Heat and Light

• Plants need the energy of sun to make food. 
• Sunlight also provides warmth for the survival of plants and animals.
• There would be no food or oxygen in the air if there was no sunlight. 
• The heat from the sun keeps the Earth warm.

Interdependence Between Living Components Of Environment

Some ways in which living things depend on each other are as follows: 

1. Animals (including humans) Depend on Plants

• Animals are dependent on plants for food, oxygen and shelter.
• Herbivorous animals such as goat, cow and deer directly depend on plants for food. Carnivorous animals get their food by eating other animals. Therefore, they also indirectly depend on plants for food.
• Many animals live in trees. Birds build nest on trees to lay their eggs.

2. Plants Depend on Animals

• Plants depend on animals for carbon dioxide that animals give out during breathing.
• Plants depend on animals for providing nutrients in the soil. Animal wastes as well as their dead bodies provide nutrients to the soil.
• Birds and animals like squirrels eat fruits and throw away seeds. This helps plants to reproduce.
• Insects and birds suck nectar (a sweet liquid) from flowers and helps in producing fruits by the plants

Causes of Environment Pollution

• Cutting trees or deforestation is one of the reasons responsible for polluting the environment.
• Burning fossil fuels such as petrol or diesel pollutes the environment.         
• Throwing garbage here and there also pollutes the environment.
• Using plastic bags cause serious health hazards.
• Disposing chemical wastes in the rivers, pollutes the water bodies and thus causes serious threat to the environment.