Class 7 Unit-4 (Biodiversity and Environment)

 

Unit-4 (Biodiversity and Environment)

Introduction

Biodiversity is the variety of all living things on Earth. It includes different plants, animals, fungi, and microorganisms, as well as the ecosystems they live in.

 

The environment is everything that is around us, including all the living things and non-living things.

 

Natural resource

All the materials available in nature which are needed to support life and meet demands of human beings are called natural resources.

-Natural resources include water, air, soil, rocks, minerals, coal, petroleum, natural gas, solar energy, including humans and plants.

Types of Natural Resources

1. Nonrenewable natural resources

-Non-renewable resources are natural things that can be used only once and cannot be made again quickly.
Once they are finished, they take millions of years to form again.

-Energy obtained from non-renewable sources is called non-renewable energy.

-For example: Natural gas, petroleum, coal, nuclear energy.

 

2. Renewable natural resources

-Renewable natural resources are resources that can be

  used again and again. They do not run out easily

  because nature replaces them in a short time.

-Energy obtained from non-renewable sources is called

  renewable energy.

-For example: Solar energy, wind energy,

  hydroelectricity,  geothermal energy, wood, biomass.

 

Importance of Natural Resources:

• They provide food, water, and shelter.
• They give raw materials for making things.
• They help in producing energy.
• They support life on Earth.

 

Water resource

Water resources are the sources of water that are useful to humans, animals, and plants. This water can be used for drinking, farming, industry, and generating electricity. The sources of water as given below:

a. Water reserve

A water reserve is a region where water is collected from various sources. It is one of the main sources of water.

Importance of water reserve

a.      It recharges soil, maintains environmental balance, balances the climate and water cycle.

b.      It provides habitat for various organisms.

c.      It provides irrigation facility for agriculture.

d.      It can generate hydroelectricity.

 

b. Wetland

A wetland is an area where land is saturated with water permanently or seasonally.

Importance of Wetlands:

·   Wetlands provide homes for many animals, birds, and plants.

·   They help control floods by holding extra water.

·   Wetlands clean water by removing dirt and harmful substances.

·   They give resources like fish, reeds, and plants for people to use.

·   Wetlands help keep the environment balanced and healthy.

 

c. Watersheds

A watershed is an area of land where all the rainwater and melting snow drain into a single river, lake, or other water body.

·   Watersheds provide water for drinking, farming, and industries.

·   They help prevent floods by controlling water flow.

·   Watersheds support plants, animals, and fish by providing habitats.

·   They help in maintaining soil fertility and reduce soil erosion.

 

Depletion of natural resources

·   Overuse of resources like water, forests, and minerals.

·   Pollution of air, water, and soil.

·   Deforestation and loss of wildlife.

·   Overpopulation and increased demand for resources.

·   Industrialization and urbanization.

·   Natural disasters

·   Political instability and weak laws to manage wetlands

 

Solid waste management

Solid waste management is the process of collecting, storing, and disposing of solid waste in proper way to keep the environment clean and healthy.

Types of solid waste:

1. Biodegradable waste: Solid waste that decays easily by microbs is called biodegradable waste.  It is derived from living organisms.

Examples: Peels or fruits and vegetables, plants, animal excrete, etc.

2. Non-biodegradable waste: Solid waste that does not decay easily by microbs is called non-biodegradable waste.  It remains in solid form for the long time and causes serious environmental pollution.

Examples: Plastic bags, broken glasses, bottles, metal cans, etc. 

 

Methods of waste disposal

Some methods for disposing waste disposal:

a. Incineration: Burning waste at high temperatures to reduce its volume. It can also produce energy.

b. Sanitary landfill: Waste is buried in a specially prepared area of land. Layers of soil are added to cover the waste, which prevents pollution.

c. Preparation of compost: Biodegradable waste like food scraps and leaves are turned into compost, which can be used as natural fertilizer for plants.

d. Reduce: Using fewer resources and producing less waste to protect the environment.

e. Reuse: Using items again instead of throwing them away, like old jars, bottles, and bags.

f. Recycle: Processing waste materials like paper, plastic, and metal to make new products, reducing the need for new resources.