Why Is Air Essential for Living Organisms?
Do you know why it becomes very difficult for us to breathe as we go to higher altitudes? It is because as we go to higher altitude, air pressure gets very less, and as a result, the amount of oxygen is reduced, and we start feeling altitude sickness. Do you know the composition of air? Which gas is present in a larger amount of air?
Air is a mixture of various gases. Nitrogen is present in large amounts of air, and some gases, such as helium and argon, are present in very few amounts.
What is Air?
Air is a mixture of various gases such as nitrogen, oxygen, other gases, water vapours, and dust particles. It is colourless and odourless. The movement of air from a high-pressure zone to a low-pressure zone is called wind.
Composition of Air
Air is a mixture of many gases. The percentage of these gases also varies. Percentages of gases present in the air are given below:
Nitrogen - 78% of air is made of nitrogen gas.
Oxygen - 21% of air made of oxygen.
Other gases - 1% of other gases made air. Other gases include carbon dioxide, argon, etc.
Importance of Air
Air has many importances. Some of the importance is given below:
Air helps maintain the temperature of the earth by circulating the hot and cold air.
The water cycle also maintain by the circulation of air.
Moving air also helps in the locomotion and flight of insects and birds.
Nitrogen gas is used by plants to make amino acids and proteins.
Seeds dispersed from one place to another place with the help of air.
Oxygen is inhaled from the air while breathing.
The ozone layer protects animals and plants from ultraviolet radiation.
Air is the most important element for sustaining life on earth.
Role of Air in Human Life
Oxygen is the most important gas for the survival of human beings, it assists in respiration, and oxygen helps in the combustion of food, from which ATP is released.
Ozone protects us from harmful radiation.
Air Pollution and Its Side Effects
Air pollution is defined as undesirable changes in the quality of air. It may be a physical, chemical, and biological change in the air quality.
There are various bad impacts of air pollution on human health.
It causes acid rain, which can damage monuments, plants, and animals.
It can also deplete the ozone layer, which leads to the entry of harmful ultraviolet radiation and cause various types of diseases in humans, such as cancer or skin diseases.
If the carbon monoxide level is high in the air, it can cause various harm to live organisms. It is a highly poisonous gas that binds to haemoglobin and reduces the oxygen-carrying capacity of the haemoglobin molecule.
It can cause various respiratory diseases such as asthma, shortness of breath.
It can also damage plants, and their chlorophyll.
Interesting Facts
Our lungs can hold up to seven litres of air.
Most oxygen in our atmosphere is obtained from oceans and seas.
Beijing cough is a disease in China caused due to increased pollution.
More than 65% of deaths in Asia caused due to air pollution.
Almost 80% of respiratory diseases occur due to air pollution.
Pollen grains of flowers can also contribute to air pollution.
Important Questions
Q1. Who discovered oxygen?
Ans: Oxygen was discovered by Joseph Priestley in 1774. It is used for breathing and is responsible for the burning of substances.
Q2. What gases do we inhale and exhale?
Ans: We inhale oxygen and exhale carbon dioxide while breathing. Air contains 21% oxygen, and less than 0.03% of carbon dioxide is present in the air.
Q3. What has caused air pollution?
Ans: Substances that cause air pollution are known as air pollutants. This pollutant is released into the air due to the burning of fossil fuel, from vehicles, or emitted from industries and agriculture.
Key Features
In this article, we have discussed air which is also regarded as the breath of life, the composition of air, etc.
The importance of air is maintaining the temperature of the earth, wind also blows due to the locomotion of air, and many other importances have been discussed in this article.
Air is composed of nitrogen, oxygen, carbon dioxide, argon, and helium.
Air pollution is defined as undesirable changes in the quality of air. It has many side effects, such as causing damage to buildings, monuments, plants, and animals.
Practice Questions
Q1. Which gas is regarded as the breath of life?
Q2. Is the breath of life energy?
Q3. Do we breathe the same air as our ancestors?
Q4. Why is the air we breathe so important?
Q5. Do we breathe to live?
FAQs on Breath of Life: Understanding Air in Biology
1. Why is air commonly referred to as the 'breath of life'?
Air is called the 'breath of life' because it contains gases essential for the survival of most living organisms. The most critical of these is oxygen, which is required for cellular respiration—the process that releases energy from food to power all metabolic functions in animals, plants, and microbes.
2. What is the atmosphere, and why is it crucial for life on Earth?
The atmosphere is the protective layer of gases enveloping the Earth. It is crucial for life because it provides oxygen for breathing, carbon dioxide for photosynthesis, and contains the ozone layer, which shields organisms from the sun's harmful ultraviolet (UV) radiation. It also helps regulate the planet's temperature, making it habitable.
3. What is the biological importance of air for plants?
Air is vital for plants for several reasons as per the CBSE syllabus for 2025-26. These include:
- Photosynthesis: Plants absorb carbon dioxide (CO₂) from the air to create their food (glucose).
- Respiration: Like animals, plants take in oxygen (O₂) from the air to break down glucose for energy, a process that occurs continuously.
- Nitrogen Source: While not used directly, atmospheric nitrogen is converted by soil bacteria into a usable form that plants absorb to build proteins.
4. How do aquatic animals like fish obtain oxygen to survive?
Aquatic animals obtain oxygen from the dissolved oxygen present in water, not directly from the air. Fish use specialised respiratory organs called gills, which are rich in blood vessels. As water passes over the gills, their thin membranes efficiently extract dissolved oxygen and release waste carbon dioxide into the water.
5. What is the key difference between the process of breathing and respiration?
Breathing is the physical process of inhaling air to take in oxygen and exhaling to remove carbon dioxide. In contrast, cellular respiration is a biochemical process that occurs inside the cells of an organism. It uses the oxygen obtained from breathing to chemically break down nutrients like glucose to release energy (ATP) for life activities.
6. How does air pollution interfere with air's role as the 'breath of life'?
Air pollution introduces harmful substances that compromise air's life-sustaining function. Pollutants like particulate matter can damage lung tissue, while toxic gases like carbon monoxide (CO) can bind to haemoglobin in the blood more effectively than oxygen, reducing the body's oxygen-carrying capacity. This directly impairs cellular respiration and can lead to severe health issues.
7. If plants are known for producing oxygen, why do they also need to take in oxygen from the air?
Plants produce oxygen as a byproduct of photosynthesis, which only happens in the presence of light. However, plants need to respire 24/7 to power their own life processes like growth and repair. Respiration requires oxygen to break down the food they created. Therefore, in the absence of light (at night), plants must take in oxygen from the atmosphere to survive.
