- Different Resources on Earth are air, water, soil and living things.
- These basic resources are necessary to sustain life of all living things on Earth.
AIR- We are surrounded by air which we cannot see, taste or feel.
- Oxygen in the air is needed by all living things for respiration.
- In the body, oxygen is used to change food to energy. Energy is used by living things to carry out the various processes of life.
- Oxygen in air is needed for repiration
Food+ oxygen>>>carbon dioxide+ water+ energy. (glucose)
- Oxygen is also necessary for burning. Burning produces carbon dioxide, water vapour, heat energy and light energy.
Fuel+ oxygen>>>carbon dioxide+ water+ energy. - Carbon dioxide in the air is used by plants to make food via the process of photosynthesis with the help of sunlight.
- This food supplies energy to living things which feed on them.
Carbon dioxide+water >>> glucose+ oxygen
WATER- Water is a liquid at room temperature.
- Water is composed of two gases i,e, oxygen and hydrogen.
Oxygen+hydrogen >>> water. - Pure water has no taste and is colourless.
- Water contains minerals, microorganisms and other substances in solution together with oxygen, carbon dioxide, nitrogen and small amounts of other gases.
- Water is very important to living things for various reasons:
(a) The layer of moisture found on the surface of the alveolus in the lungs can dissolve gases and make it easier for the exchange of gases.
(b) Water is also a good solvent and this property enables water to dissolve, transport food and oxygen to the body cells and get rid of carbon dioxide and urea from the body.
(c) Water in the form of sweat is necessary for the control of body temperature.
(d) Besides this, water also functions as a medium for various chemical reactions that take place in the body. - Water is necessary for green plants to carry out the process of photosynthesis.
- Invertebrates, like the earthworm and caterpillar that have soft bodies, support their bodies by using their body fluids.
- Herbaceous plants like the sawi or mustard leaf and the balsam plant, use water pressure in the stem for support and cell turgidity.
SOIL- Soil is found in the upper layer of the Earth's surface.
- Soil is not a simple substance but is a mixture of mineral matter, water, air and humus.
- All green plants are dependent on soil for their supply of water and essential mineral salts, as well as the air needed for the respiration of their roots.
- Soil has resources that are necessary for supporting life.
MINERAL MATTER- Mineral matter is part of the soil formed by weathering, or breaking down, of the rocks of the Earth's crust.
- The soluble constituents of mineral matter dissolve in soil water, which occurs as films of moisture around the soil particles. This form a very dilute solution which the roots absorb.
- Mineral salts like nitrate and phosphate salts are necessary for the healthy growth of plants.
HUMUS- Humus is among the richest and darkest of soils.
- Humus is a kind of organic matter derived from plants and animals.
- Humus is necessary for the growth of healthy plants.
WATER AND AIR- When rainwater falls on soil, it fills most of the pore-spaces and moves downwards.
- The roots of plants absorb water from the soil for photosynthesis.
- Water and air in the soil make it a suitable habitat for soil organisms like termites and earthworms.
- Air in the soil helps the process of decay.
LIVING THINGS- Animals and plants are important resources in life.
- All living things need food in order to stay alive.
- Green plants contain a green pigment called chlorophyll which traps energy from sunlight, With this energy, plants make food from carbon dioxide and water.
- Since animals do not have chlorophyll, they cannot make their own food. Thus plants are the only food producers.
- Animals like goats, deers and cows eat plants as food. Animals like tigers, lions and leopards eat other animals.
- Animals are directly or indirectly dependent upon plants for food.
- Plants provide living places for certain animals.
