Oxygen is also called the ‘life gas’. It is indispensable for the survival of the living beings.
Living things take in oxygen from the air. Oxygen helps release energy from the food they consume. Oxygen is often used together with carbon, hydrogen and nitrogen which in turn builds new molecules in the bodies. The process of photosynthesis that occurs in the leaves of green plants releases oxygen.
During the process of photosynthesis, plants take in carbon dioxide (CO2 and give out oxygen (O2).
Humans breathe oxygen (O2) and give out carbon dioxide (CO2).
All birds and animals take oxygen (O2)
Sun giveslight energy.
Water splits into hydrogen and oxygen.
Sugar and starch are produced.
Photosynthesis helps plants make their food.
Carbon is the element on which the bodies of all living things are based. It is, generally, obtained from carbon dioxide present in the air. Green plants and some bacteria consume carbon dioxide to make their own food.
When these plants are consumed by the animals, they get some part of carbon. Carbon dioxide is released back into the atmosphere when the animals exhale. Carbon is returned to nature when the animals die. Decomposers such as worms, bacteria and fungi feed on dead animal matter and release carbon dioxide as they respire.
Plants are the only source of converting CO2 to O2
Carbon dioxide in the atmosphere.
Plants gives CO2
Animal dung contains carbon.
Plants and animals remains decay.
Decomposes give out CO2, as they feed and respire.
Just like the other nutrients, water also goes through a never-ending process of recycling itself. Water is available in plenty on the Earth in the form of different water bodies such as lakes, rivers, ponds and seas.
With the heat generated by the Sun, water changes into water vapor and rises up in the atmosphere. As it rises, it cools down and condenses into water. The tiny water droplets combine together to constitute clouds. When clouds become heavy with water droplets, they fall back on Earth in the form of rain or snow.
Sun gives heat which helps water evaporate.
Water vapor cools ‘to form clouds.
Water falls back to Earth as rain or snow.
Water evaporates from the Earth’s surface
Water flows back into the rivers and seas.
Recycling in biosphere
Decomposers play a crucial role in the process of recycling. They eat away the dead remains of plants and animals. They have the capability of breaking down dead organic matter and converting them into simpler substances so that they could be used again and again.
Materials which can be broken down into simpler substances naturally are called biodegradable. But human activities have hampered the process of natural recycling. Certain products such as tin, plastic and glass are non-biodegradable. They cannot be broken down naturally and can remain in the environment for hundreds of years, thus posing a health hazard. So, we should replace non-hiodegradable products with biodegradable once.
When an animal dies, it is recycled by nature. Insects and their larvae are decomposing this dead rat.
Humansproduce huge quantities of non-biodegradable garbage. It could harm our environment.
