Air Supports Life In Plants And Animals
We all need air to survive. Air contains oxygen and carbon dioxide useful to plants and animals. Plants use carbon dioxide of the air to make their own food by a process called photosynthesis. Let us see how air supports life in plants and animals.
In Plants
Plants have tiny pores called stomata, found on the underside of a leaf. Air containing carbon dioxide and oxygen enters the plant through these openings where it gets used in photosynthesis and respiration.
In Animals
All animals need to respire, be it a cockroach, a fish, or an elephant. It is just that they use different organs and mechanisms for respiration.
Sometimes, we wrongly use the terms breathing and respiration interchangeably. Breathing is a physical act of taking in oxygen and giving out carbon dioxide, whereas respiration is a chemical process by which glucose in the body breaks down to give energy.
In Aquatic Animals and Plants
Most aquatic animals like fish, tadpole, crab, and shrimp have special organs for respiration called gills. Gills help to take in oxygen and give out carbon dioxide. Some aquatic animals like dolphin and whale come to the surface of the water regularly to take in air, since they breathe with the help of lungs. Aquatic plants like Hydrilla also breathe in oxygen dissolved in water through their stomata.
In Amphibians
Amphibians like frog, newt, and salamander need breathing systems for both air and water. Crocodile and alligator swim through water with part of their snout above the water surface to breathe easily through nostrils.
In Birds
Birds have an efficient respiratory system as they need high levels of oxygen during flight. Birds have a pair of lungs with air sacs that remain open all the time, so that air can easily pass through them.
In Mammals
Most mammals breathe with the help of lungs. They take in oxygen and give out carbon dioxide.
BALANCE OF OXYGEN AND CARBON DIOXIDE IN THE AIR
The balance of oxygen and carbon dioxide in the atmosphere is maintained through respiration in plants and animals and by photosynthesis in plants. Plants produce oxygen during photosynthesis and utilize oxygen during respiration. They produce much more oxygen during photosynthesis than they consume, during respiration This is how the oxygen consumed by plants and to a large extent by animals is replenished in the air through photosynthesis.
Activity
Aim: To show the presence of air in soil
Materials needed: A jar, some soil, and a jug of water
Method:
1. Take some soil in a jar.
2. Pour water into it. Can you see bubbles coming out? What does it suggest?
Observation: The bubbles show the presence of air in soil.
Conclusion: Animals living inside the soil take in air present in soil.