In Singapore’s Primary School curriculum, the SEAB (Singapore Examinations and Assessment Board) syllabus for Science covers a wide range of topics, including “Living things need air”. This topic is crucial as it lays the foundation for understanding the importance of air for all living organisms on Earth.
Message us at +65 82226327 for our small groups Pri 5 Science tutorials.
For more Science guides, click here.
The SEAB syllabus for “Living things need air” begins by introducing students to the concept of respiration. Students learn that respiration is a process in which living organisms take in oxygen and release carbon dioxide. They also learn that respiration is essential for the survival of all living organisms, as it provides them with the energy they need to carry out their day-to-day activities.
The syllabus then goes on to discuss the different ways in which living organisms obtain oxygen. Students learn that animals, including humans, breathe in oxygen through their lungs, while plants obtain oxygen through small openings called stomata. The syllabus also covers the different ways in which living organisms release carbon dioxide, such as through breathing and photosynthesis.
Students are then introduced to the concept of the atmosphere and the importance of air for all living organisms. They learn that the atmosphere is a layer of gases that surrounds the Earth and that it is made up of mainly nitrogen, oxygen, and carbon dioxide. They also learn that air is essential for the survival of all living organisms, as it provides them with the oxygen they need for respiration.
The syllabus also covers the impact of air pollution on living organisms. Students learn that air pollution is caused by the release of harmful gases and particles into the atmosphere, such as carbon monoxide and sulfur dioxide. They also learn about the harmful effects of air pollution on living organisms, including respiratory problems and other health issues.
Air is essential for human life, as we rely on it for respiration, which is the process of taking in oxygen and releasing carbon dioxide. We use air for breathing, speaking, and the production of sound. In addition, air plays a critical role in regulating the temperature and climate of the planet, as well as in the water cycle, which is essential for sustaining life on Earth. However, human activities such as industrialization, transportation, and burning of fossil fuels have resulted in air pollution, which can have harmful effects on human health and the environment. To mitigate these effects, efforts are being made to reduce air pollution and promote sustainable practices that protect the quality of the air we breathe.
At the beginning, there was no air
The Earth’s atmosphere is the result of a complex series of processes that took place over billions of years during the formation of the planet. Scientists believe that the Earth formed about 4.6 billion years ago, from a cloud of gas and dust that surrounded the early sun. As the Earth grew and began to cool, it started to develop a primitive atmosphere.
The early Earth’s atmosphere was composed primarily of hydrogen and helium, along with small amounts of other gases such as methane and ammonia. However, this atmosphere was unstable and was gradually lost to space due to the weak gravitational field of the early Earth. Over time, volcanic activity on the early Earth released large amounts of gases, including nitrogen, water vapor, and carbon dioxide, which gradually built up to create the atmosphere that we have today.
One of the most important processes that contributed to the formation of the Earth’s atmosphere was the outgassing of the early Earth’s interior. Volcanic activity released large amounts of gases, including water vapor, carbon dioxide, and nitrogen, which gradually accumulated in the atmosphere over time. This outgassing process continued for billions of years, gradually building up the atmosphere to the composition that we see today.
Another important process that contributed to the formation of the Earth’s atmosphere was the impact of comets and asteroids. These objects, which were made up of ice and other volatile compounds, collided with the early Earth and released large amounts of water vapor and other gases into the atmosphere. This process helped to increase the overall mass of the atmosphere and contributed to the development of the water cycle, which is critical for sustaining life on Earth.
Overall, the Earth’s atmosphere is the result of a complex series of processes that took place over billions of years during the formation of the planet. These processes were influenced by a wide range of factors, including volcanic activity, impacts from comets and asteroids, and the overall temperature and composition of the early Earth. Together, these processes helped to create the atmosphere that we have today, which is essential for supporting life on the planet.
Composition of Air
Air is a colorless, odorless, and tasteless mixture of gases that surrounds the Earth. It is made up of a variety of different gases in varying proportions, as well as small amounts of other substances such as water vapor and dust particles. The composition of air can vary depending on location, altitude, and weather conditions. However, the following are the most common components of air:
- Nitrogen: Nitrogen is the most abundant gas in the Earth’s atmosphere, making up about 78% of the air. It is an essential element for life and is used by plants to make proteins.
- Oxygen: Oxygen is the second most abundant gas in the Earth’s atmosphere, making up about 21% of the air. It is essential for the survival of most living organisms, as it is used in the process of respiration to release energy from food.
- Argon: Argon is a noble gas that makes up about 0.93% of the air. It is used in some industrial processes and is also used to fill incandescent light bulbs.
- Carbon dioxide: Carbon dioxide is a gas that makes up about 0.04% of the air. It is an important component of the Earth’s atmosphere, as it helps to regulate the planet’s temperature by trapping heat from the sun.
- Neon, Helium, Krypton, and Xenon: These are noble gases that make up small amounts of the air, ranging from 0.001% to 0.0001%. They are used in a variety of applications, including lighting, cooling, and welding.
In addition to these gases, air also contains small amounts of other substances such as water vapor, dust particles, and pollutants. Water vapor makes up about 1-3% of the air, while dust particles and pollutants can vary in concentration depending on location and weather conditions.
Humidity, water vapour in the air
The percentage of water vapor in air varies depending on the location and weather conditions. The amount of water vapor in air is usually measured as relative humidity, which is the amount of water vapor in the air as a percentage of the maximum amount of water vapor that the air can hold at a given temperature and pressure.
At a comfortable room temperature of around 25°C (77°F), the air can hold a maximum of approximately 22 grams of water vapor per cubic meter of air. If the air contains 11 grams of water vapor per cubic meter of air, then the relative humidity would be 50%. This means that the air is holding 50% of the maximum amount of water vapor that it can hold at that temperature.
In tropical and humid regions, the percentage of water vapor in the air can be much higher, reaching up to 90% or more in some cases. In drier regions, such as deserts, the percentage of water vapor in the air can be much lower, sometimes as low as 10% or less.
The percentage of water vapor in the air is an important factor in determining the weather conditions and climate of a particular region. It can also have significant impacts on human health, as high levels of humidity can lead to discomfort and even heat stroke, while low levels of humidity can cause dry skin and respiratory problems.
Air=Atmosphere. Why?
The atmosphere is the layer of gases that surrounds the Earth and is held in place by gravity. It extends from the surface of the Earth up to a height of about 10,000 km, although the majority of its mass is concentrated in the lower part of the atmosphere.
The atmosphere is made up of a mixture of gases, including nitrogen, oxygen, carbon dioxide, and other trace gases. It also contains small amounts of water vapor, dust, and other particles. The composition of the atmosphere can vary depending on location and altitude, and it is constantly changing due to natural processes and human activities.
- Greenhouse effect: The atmosphere helps to regulate the temperature of the Earth by trapping some of the sun’s heat and preventing it from escaping back into space. This process is known as the greenhouse effect, and it is essential for maintaining the habitable temperature range that is required for life on Earth.
- Atmospheric circulation: The atmosphere helps to distribute heat and moisture around the planet through atmospheric circulation, which is responsible for the weather patterns and climate that we experience on Earth.
- Ozone layer: The ozone layer is a layer of ozone gas in the atmosphere that helps to absorb harmful ultraviolet radiation from the sun. This helps to protect life on Earth from the harmful effects of excessive UV radiation, such as skin cancer and other health problems.
- Air pressure: The atmosphere exerts a force on the Earth’s surface known as air pressure, which is essential for supporting life on the planet. Air pressure helps to maintain the shape of living cells, and it is also essential for respiration in animals.
- Water cycle: The atmosphere plays a crucial role in the water cycle, which is the process by which water evaporates from the Earth’s surface, forms clouds, and then falls back to the surface as precipitation. The water cycle is essential for sustaining life on Earth, as it provides freshwater for plants and animals to drink and for agriculture.
The atmosphere also helps to distribute heat and moisture around the planet through atmospheric circulation, which is responsible for the weather patterns and climate that we experience on Earth. The Earth’s atmosphere employs a range of strategies to protect and sustain life on the planet. These strategies are interconnected and work together to create a habitable environment that supports a diverse range of life forms.
Nitrogen, why so much?
Nitrogen is a chemical element that makes up approximately 78% of the Earth’s atmosphere. It is an important element in both science and engineering, with a wide range of uses across many different fields.
In science, nitrogen is used in many laboratory applications, such as in the production of ammonia, which is used as a fertilizer and in the production of nitric acid. Nitrogen is also used in the cryogenic preservation of biological samples, as it can be used to cool and preserve organic matter at very low temperatures.
In engineering, nitrogen is used in a variety of applications, such as in the production of steel and other metals. It is also used in the manufacturing of electronic components, as it can be used to create an inert atmosphere that helps to prevent the formation of oxides and other unwanted compounds.
One of the reasons why nitrogen is so abundant on Earth is due to the way that the Earth was formed. When the Earth was formed approximately 4.6 billion years ago, it was initially very hot and had a very thick atmosphere composed mostly of carbon dioxide, water vapor, and other gases. Over time, volcanic activity on the early Earth released large amounts of nitrogen gas into the atmosphere, which gradually built up over time to create the nitrogen-rich atmosphere that we have today.
In addition to its importance in science and engineering, nitrogen also plays a critical role in the Earth’s ecosystem. Nitrogen is an essential nutrient for plant growth, and it is often a limiting factor in agricultural production. The nitrogen cycle, which is the process by which nitrogen is converted between different forms in the soil and the atmosphere, is a crucial component of the Earth’s ecosystem and is responsible for maintaining the balance of nitrogen in the environment.
- Fertilizer: Nitrogen is a key component of fertilizers, which are used in agriculture to help plants grow. For example, ammonium nitrate is a commonly used nitrogen-based fertilizer that is used to increase crop yields and improve the quality of fruits and vegetables.
- Food and beverage industry: Nitrogen is used in the food and beverage industry to preserve food products and create an inert atmosphere for packaging. For example, nitrogen is used to preserve the freshness of coffee beans, prevent the growth of harmful bacteria in packaged food products, and create a creamy texture in whipped cream.
- Electronics industry: Nitrogen is used in the electronics industry to create an inert atmosphere that helps to prevent oxidation and other unwanted chemical reactions. For example, nitrogen is used in the production of computer chips and other electronic components to prevent contamination and ensure high quality.
- Cryogenic freezing: Nitrogen is used in cryogenic freezing to preserve biological samples, including sperm, eggs, and embryos. For example, nitrogen is used in the preservation of human sperm and eggs for fertility treatments, as well as in the storage of animal genetic material for breeding programs.
- Medical industry: Nitrogen is used in the medical industry to freeze and remove unwanted tissue, such as warts and skin tags. For example, liquid nitrogen is used in cryotherapy to treat certain skin conditions and to reduce pain and inflammation.
- Industrial applications: Nitrogen is used in a variety of industrial applications, including metal fabrication, welding, and heat treatment. For example, nitrogen is used in the production of stainless steel to prevent oxidation and to improve the quality of the finished product.
Nitrogen=Explosion
The Beirut explosion, which occurred on August 4, 2020, was a catastrophic event that rocked the city of Beirut, the capital of Lebanon. The explosion caused widespread damage and loss of life, with over 200 people killed and thousands more injured.
The cause of the explosion was determined to be the detonation of approximately 2,750 tons of ammonium nitrate, a highly explosive chemical compound commonly used as a fertilizer. The ammonium nitrate had been stored unsafely in a warehouse in the port of Beirut for several years, which led to its detonation and the devastating explosion that followed.
The explosion was one of the most powerful non-nuclear explosions in history, with a force equivalent to that of a small nuclear weapon. The blast was felt as far away as Cyprus, over 200 kilometers from Beirut.
The impact of the explosion was devastating. Buildings were destroyed, homes were leveled, and the city’s infrastructure was severely damaged. Hospitals were overwhelmed with the number of injured, and the death toll continued to rise in the days and weeks following the explosion.
The Beirut explosion has raised questions about the safety and regulation of the storage and handling of hazardous materials, such as ammonium nitrate, and the need for more effective safety measures to prevent such tragedies from occurring in the future.
In the aftermath of the explosion, there was an outpouring of support and aid from countries around the world, with many offering financial assistance, medical supplies, and other forms of aid to help Beirut recover from the devastation. While the recovery process will be long and difficult, the international community has shown its willingness to stand in solidarity with the people of Beirut and support them in their time of need.
Oxygen, something plants provide for free. Life as we know it.
Oxygen is thought to have first appeared on Earth around 2.5 billion years ago, during a period of Earth’s history known as the Great Oxygenation Event. This event was marked by the rapid accumulation of oxygen in the Earth’s atmosphere, which was largely the result of the photosynthetic activity of early bacteria and algae.
Photosynthesis is the process by which plants and other organisms use energy from the sun to convert carbon dioxide and water into organic compounds and oxygen gas. The first photosynthetic organisms were likely single-celled bacteria that used photosynthesis to produce food and release oxygen as a byproduct.
Over time, these photosynthetic organisms became more complex and diverse, eventually giving rise to the first plants and animals. As more and more oxygen was released into the atmosphere, it had a profound impact on the evolution of life on Earth, enabling the development of more complex organisms with higher energy requirements.
The buildup of oxygen in the atmosphere also had other important consequences, such as the formation of the ozone layer, which protects life on Earth from harmful ultraviolet radiation from the sun. The oxygen-rich atmosphere also helped to create the conditions necessary for the development of aerobic respiration, which is the process by which organisms use oxygen to extract energy from food.
Overall, the emergence of oxygen on Earth was a critical event in the history of life on the planet, and it has had profound and far-reaching consequences for the evolution of life as we know it.
Oxygen and relationship with us.
Oxygen is a colorless, odorless gas that makes up approximately 21% of the Earth’s atmosphere. It is one of the most important elements in chemistry, as it is involved in a wide range of chemical reactions and is essential for life on Earth. Oxygen plays a critical role in human respiration, as it is necessary for the production of energy in the body.
Oxygen is a highly reactive gas that readily forms compounds with other elements. In fact, many common chemical reactions involve oxygen in some way. For example, combustion, which is the process of burning a fuel to produce energy, requires oxygen. During combustion, oxygen reacts with the fuel to produce carbon dioxide, water, and heat. This reaction is used in many different applications, from burning wood in a fire to powering internal combustion engines in cars.
In addition to its role in chemical reactions, oxygen is also essential for human respiratory function. When we breathe in air, oxygen is transported to our lungs, where it diffuses into the bloodstream and is carried to the cells of our body. Once inside the cells, oxygen is used in a process called cellular respiration, which is the process by which our cells produce energy from food.
During cellular respiration, oxygen reacts with glucose, a type of sugar, to produce carbon dioxide, water, and energy. This process is essential for the proper functioning of our cells, and it is what allows us to perform physical activities, think, and grow.
Oxygen use for industrial and medical use
Oxygen is a versatile and essential gas that has numerous uses in human industry. Some of the key applications of oxygen in industry include:
- Steel production: Oxygen is used in the basic oxygen steelmaking process to remove impurities from molten iron and increase the temperature of the blast furnace. The high-purity oxygen reacts with the impurities to form slag, which can be removed from the molten metal. This process is used to produce high-quality steel for a wide range of industrial applications.
- Medical industry: Oxygen is widely used in the medical industry to treat patients with respiratory problems. Oxygen therapy is used to support breathing in patients with breathing difficulties or other medical conditions that require supplemental oxygen. Medical-grade compressed gas cylinders containing oxygen are also used to support respiration during surgery and other medical procedures.
- Chemical industry: Oxygen is used in the chemical industry for the production of a wide range of chemicals, including fertilizers, plastics, and textiles. For example, oxygen is used to produce ammonia, which is a key component of many types of fertilizers. It is also used in the production of ethylene oxide, which is a precursor to many types of plastics.
- Aerospace industry: Oxygen is used in the aerospace industry to support life on board spacecraft and other vehicles. In spacecraft, oxygen is used for breathing, as well as for combustion reactions in rocket engines. In addition, oxygen is used in aviation as a component of onboard breathing systems for pilots and other crew members.
- Welding and metal fabrication: Oxygen is used in welding and metal fabrication to support combustion reactions that create heat and energy. Oxygen is used as an oxidizer to help fuel and accelerate the welding process, resulting in a stronger and more durable weld. For example, in oxy-fuel welding, oxygen is used to create a flame that can melt and fuse metals together.
Oxygen is a critical gas that plays a vital role in many human industries, from steel production to aerospace to medicine. Its versatility and usefulness make it an essential component of modern life, and ongoing research and development will continue to uncover new applications for this important gas in the years to come.
Oxygen and Covid-19: Suddenly, there was a shortage
Covid-19 is a respiratory illness caused by the SARS-CoV-2 virus, which attacks the respiratory system and can cause severe respiratory distress in some cases. One of the main complications of Covid-19 is hypoxia, which is a condition in which the body is deprived of oxygen.
In severe cases of Covid-19, patients may require supplemental oxygen to support their breathing and maintain their oxygen levels. Oxygen therapy is an essential treatment for patients with Covid-19 who have low oxygen saturation levels or respiratory distress.
There are several different methods of delivering oxygen therapy, including nasal cannulas, face masks, and high-flow nasal cannula systems. The goal of oxygen therapy in Covid-19 patients is to improve oxygen saturation levels and reduce the risk of respiratory failure.
During the Covid-19 pandemic, the demand for oxygen has increased significantly, particularly in countries with high rates of infection. This has led to shortages of oxygen supplies in some areas, which has put additional strain on healthcare systems and made it more difficult to treat patients with Covid-19.
To address this issue, there have been various initiatives to increase the production and distribution of oxygen supplies, as well as efforts to improve the use of oxygen therapy in Covid-19 patients. These efforts have included the development of new oxygen delivery systems, the repurposing of industrial oxygen supplies, and the deployment of oxygen concentrators to remote and underserved areas.
Overall, oxygen therapy plays a critical role in the treatment of Covid-19 patients who are experiencing respiratory distress. The ongoing efforts to increase access to oxygen supplies and improve the use of oxygen therapy in Covid-19 patients will continue to be important in the fight against this global pandemic.
Carbon Dioxide
Carbon dioxide (CO2) is a versatile gas that has a wide range of uses in both home and industrial settings. Some of the key applications of carbon dioxide include:
- Home use: Carbon dioxide is used in many household applications, such as:
- Carbonated beverages: Carbon dioxide is used to create carbonated beverages, such as soda, sparkling water, and beer. In these drinks, carbon dioxide is dissolved in water under pressure to create carbonic acid, which gives the drinks their characteristic fizz and bubbles.
- Fire extinguishers: Carbon dioxide is used as a fire suppressant in some types of fire extinguishers. When released, the carbon dioxide displaces the oxygen in the air, which can help to smother the flames and prevent the fire from spreading.
- Industrial use: Carbon dioxide is used in many industrial applications, such as:
- Dry ice: Carbon dioxide is used to produce dry ice, which is a solid form of carbon dioxide that is used in a variety of applications, such as in shipping, refrigeration, and food preservation.
- Refrigeration: Carbon dioxide is used as a refrigerant in industrial refrigeration systems, such as those used in the food and beverage industry. Carbon dioxide has the advantage of being non-toxic and non-flammable, making it a safer alternative to other refrigerants.
- Welding and cutting: Carbon dioxide is used as a welding and cutting gas, where it is combined with other gases to create a shielding gas that protects the weld from atmospheric contamination and oxidation. Carbon dioxide is also used in plasma cutting, where it is used to create the plasma arc that cuts through metal.
- Environmental use: Carbon dioxide is also a key component of the Earth’s atmosphere and plays a critical role in the global carbon cycle. Plants use carbon dioxide in photosynthesis to produce oxygen and glucose, which is the basis for all life on Earth. Carbon dioxide is also a greenhouse gas, which can contribute to climate change when its levels in the atmosphere are too high.
Houston, we have a problem
The Apollo 13 mission was the seventh manned mission in the American Apollo space program and the third intended to land on the Moon. It launched on April 11, 1970, but suffered a major malfunction on its journey to the Moon when an oxygen tank in the service module exploded, causing significant damage to the spacecraft.
One of the major challenges faced by the Apollo 13 crew was the buildup of carbon dioxide in the Lunar Module, which was the only part of the spacecraft that could support the crew after the accident. The problem was caused by a failure in the carbon dioxide removal system in the Lunar Module, which was designed to scrub the carbon dioxide from the air using canisters filled with lithium hydroxide.
The damaged spacecraft had limited supplies of lithium hydroxide, which meant that the canisters needed to be conserved to ensure that there was enough to last for the remainder of the mission. To solve the carbon dioxide problem, the astronauts improvised a solution using materials that were available on board the spacecraft.
The crew members constructed makeshift carbon dioxide scrubbers using duct tape, plastic bags, and other materials, which they used to filter the carbon dioxide from the air. They also worked with mission control to develop a new system for distributing power and conserving water, which helped to prolong the life of the Lunar Module’s batteries and extend the mission.
Thanks to the quick thinking and ingenuity of the astronauts and mission control, the crew of Apollo 13 were able to overcome the carbon dioxide problem and safely return to Earth. The mission is widely regarded as a triumph of human ingenuity and a testament to the importance of teamwork and problem-solving skills in space exploration. The lessons learned from the Apollo 13 mission continue to inform the design and operation of spacecraft today.
Why is too much carbon dioxide dangerous to human?
Carbon dioxide is a gas that is produced by human respiration, and in the confined space of the Lunar Module, it can build up to dangerous levels if not removed.
The Lunar Module was equipped with a carbon dioxide removal system that used canisters filled with lithium hydroxide to scrub the carbon dioxide from the air. However, the explosion that occurred during the mission damaged the spacecraft and caused the system to fail. This meant that the carbon dioxide levels in the Lunar Module began to rise, and if left unchecked, it could have had serious health consequences for the astronauts.
Breathing air with too much carbon dioxide can cause a range of symptoms, including headache, dizziness, confusion, and even loss of consciousness. In extreme cases, it can lead to respiratory failure and death. In the case of the Apollo 13 mission, the carbon dioxide levels in the Lunar Module rose to dangerously high levels, and it was necessary to find a way to remove the gas from the air.
Global Warming
Carbon dioxide (CO2) is a greenhouse gas that plays a significant role in the Earth’s climate system. The Earth’s atmosphere contains a natural balance of gases, including CO2, which help to regulate the planet’s temperature and climate. However, human activities, such as the burning of fossil fuels, deforestation, and agriculture, have significantly increased the levels of CO2 in the atmosphere, leading to a range of environmental and social impacts.
Carbon dioxide is a greenhouse gas because it absorbs and re-radiates heat energy in the Earth’s atmosphere. When sunlight reaches the Earth’s surface, it warms the surface, which then radiates some of the energy back into the atmosphere in the form of infrared radiation.
Greenhouse gases, such as carbon dioxide, trap some of this heat energy in the atmosphere, which helps to regulate the planet’s temperature and climate. This is similar to how a greenhouse works – the glass walls of a greenhouse allow sunlight to enter and warm the air inside, but they also trap some of the heat energy inside, keeping the temperature warm even when it is cold outside.
Carbon dioxide is particularly effective at trapping heat energy because it is a long-lived gas that can persist in the atmosphere for many years. When carbon dioxide absorbs heat energy, it can re-radiate some of that energy back towards the Earth’s surface, which can cause the planet to warm up over time. This process is often referred to as the greenhouse effect.
The increase in atmospheric CO2 is the main driver of global warming, which is the long-term trend of rising temperatures on the Earth’s surface. As CO2 levels rise, the gas acts as a blanket, trapping heat in the Earth’s atmosphere and causing the planet’s temperature to rise. This rise in temperature has a wide range of impacts on the environment and human society, including:
- Rising sea levels: As global temperatures rise, the polar ice caps melt and sea levels rise. This can cause flooding in coastal areas, damage to infrastructure, and the loss of important habitats for wildlife.
- More frequent and severe weather events: Global warming can lead to more frequent and severe weather events, such as hurricanes, droughts, and heat waves. These events can cause significant damage to homes, businesses, and agricultural systems.
- Changes to ecosystems: As temperatures rise, ecosystems can shift and change, with some species migrating to new areas or going extinct. This can have ripple effects throughout the food chain and can impact human society through changes in crop yields and the availability of natural resources.
- Health impacts: Rising temperatures can also have significant impacts on human health, including increased rates of heat stroke, respiratory illness, and the spread of infectious diseases.
To address the problem of too much carbon dioxide in the atmosphere, it is important to take action to reduce greenhouse gas emissions and promote more sustainable practices. This can include transitioning to renewable energy sources, improving energy efficiency, reducing deforestation, and promoting sustainable agriculture. By taking action to address the issue of too much carbon dioxide, we can help to mitigate the impacts of global warming and ensure a more sustainable future for the planet and its inhabitants.
Photosynthesis: Bureau de change of life
Carbon dioxide is a key component of photosynthesis, as it provides the carbon atoms that are incorporated into the organic molecules that are produced. During the process, the carbon dioxide is absorbed by the leaves of the plant through small openings called stomata, and is then transported to the chloroplasts where it is converted into organic molecules.
Oxygen is also a byproduct of photosynthesis, and is released into the atmosphere as a waste product. The oxygen released by photosynthesis is essential for sustaining life on Earth, as it is used by animals and other organisms for respiration, which is the process by which they convert organic molecules into energy.
How living things breathe?
All living things need oxygen to live, including plants. We call this the “Respiratory System”.
Different living organisms have different respiratory systems, but below are some examples of the respiratory structures and organs used by plants, fish, animals, amphibians, and worms.
- Plants: Plants do not have lungs or specialized respiratory organs like animals. They use tiny pores called stomata located on their leaves to exchange gases with the atmosphere. The stomata open to allow the plant to take in carbon dioxide and release oxygen through a process called photosynthesis.
- Fish: Fish breathe through their gills, which are located on the sides of their heads. Water is drawn over the gills, where oxygen is extracted and carbon dioxide is released. Gills are made up of thousands of tiny filaments, which increase the surface area available for gas exchange.
- Animals: Many animals, including humans, have lungs as their primary respiratory organ. Lungs are large, spongy organs that are responsible for exchanging gases between the body and the atmosphere. When air is inhaled, it passes through the nasal cavity, pharynx, larynx, trachea, and bronchi, before reaching the lungs.
- Amphibians: Amphibians have a mixed respiratory system. They can breathe through their skin, which is moist and allows gases to diffuse in and out of the body. They can also use their lungs, which are less developed than those of mammals, to supplement their oxygen intake. Frogs, for example, breathe through their skin when they are in water and use their lungs when they are on land.
- Worms: Worms have a simple respiratory system that involves gas exchange through their skin. Like amphibians, their skin must be kept moist to allow gases to diffuse in and out of the body.
Overall, the respiratory structures and organs used by living organisms vary depending on the species, but they all serve the same fundamental purpose of exchanging gases between the body and the atmosphere.
Respiratory systems of plants
The stomata are small openings on the surface of the leaves that allow for the exchange of gases between the plant and the surrounding environment. During the process of photosynthesis, plants take in carbon dioxide and release oxygen through the stomata. The oxygen produced by photosynthesis is released into the atmosphere, while the carbon dioxide is used by the plant to produce organic molecules.
In addition to the stomata, plants also have internal structures that help with gas exchange. The leaves, stems, and roots of plants are composed of living cells that require oxygen for respiration. This oxygen is obtained through small openings in the cell walls, which allow gases to diffuse in and out of the cells.
Respiratory systems of fish
Fish have a respiratory system that is specialized for extracting oxygen from water. Unlike mammals, which breathe air using lungs, fish use gills to extract oxygen from water.
The gills of fish are made up of thousands of tiny filaments that increase the surface area available for gas exchange. As water flows over the gills, oxygen is extracted and carbon dioxide is released. The oxygen is then transported to the fish’s tissues, where it is used for respiration.
The filaments are covered in thin, plate-like structures called lamellae, which are richly supplied with blood vessels. The blood vessels in the gill filaments have thin walls that allow oxygen and carbon dioxide to easily diffuse across the membrane. As water flows over the gill filaments, oxygen molecules in the water come into contact with the blood vessels and diffuse across the membrane into the bloodstream. At the same time, carbon dioxide molecules in the blood diffuse out of the blood vessels and into the water, where they are carried away.
The flow of water over the gills is maintained by the movement of the fish through the water or by specialized muscles that create a current of water over the gills. The counter-current exchange system, in which water flows over the gills in the opposite direction to the flow of blood through the gill filaments, allows for efficient gas exchange and ensures that oxygen uptake is maximized.
This means that the blood is constantly exposed to water with a higher oxygen concentration, allowing for efficient gas exchange.
Fish also have a specialized structure called the operculum, which covers and protects the gills. The operculum allows fish to maintain a constant flow of water over their gills, even when they are not swimming.
Fish can suffocate both in and out of water. When a fish is out of water, it is unable to extract oxygen from the water through its gills, and it must rely on air to breathe.
When a fish is out of water, it faces two main challenges:
- Drying out: Fish are adapted to living in a watery environment, and their skin is permeable to water. When a fish is out of water, it can quickly lose water through its skin and gills, which can lead to dehydration and death.
- Lack of oxygen: Fish out of water are unable to extract oxygen from the surrounding environment, and they must rely on the small amount of oxygen stored in their bloodstream and tissues. This oxygen is quickly depleted, and the fish can suffocate if it is unable to return to water before its oxygen supply is exhausted.
When a fish is suffocating out of water, it may exhibit several symptoms, including gasping for air, lethargy, and disorientation. If the fish is unable to return to water, it may become unconscious and die.
Fish can also suffocate in water due to a lack of oxygen, blocked gills, or high levels of carbon dioxide in the water:
- Lack of oxygen in the water: If the water in which the fish is swimming has a low oxygen content, the fish may not be able to obtain enough oxygen to sustain its respiration. This can happen in water bodies that are polluted or stagnant, or during hot weather when the water temperature rises and the oxygen content decreases.
- Blocked gills: If the gills of the fish become blocked, the fish may not be able to extract enough oxygen from the water. Gills can become blocked by debris, parasites, or infections, which can interfere with the flow of water over the gill filaments.
- Too much carbon dioxide: If the water in which the fish is swimming has a high carbon dioxide content, the fish may not be able to release enough carbon dioxide from its bloodstream, which can lead to a buildup of carbon dioxide and a decrease in the oxygen-carrying capacity of the blood.
- Diseases: Fish can also suffocate due to diseases that affect their respiratory system or other organs that are essential for oxygen transport.
Respiratory systems of mammals/human
The respiratory system of mammals is responsible for exchanging gases between the body and the atmosphere, and it is composed of several structures, including the nose, nasal cavity, pharynx, larynx, trachea, bronchi, bronchioles, and lungs.
The process of respiration begins with the inhalation of air through the nose or mouth. The air enters the nasal cavity, where it is warmed, moistened, and filtered by tiny hairs called cilia and mucus. The air then passes through the pharynx and larynx, which are responsible for directing air into the trachea.
The trachea, or windpipe, is a tube that connects the larynx to the bronchi. The trachea is lined with cilia and mucus, which help to filter and clean the air before it reaches the lungs. The bronchi are two large tubes that branch off from the trachea and enter the lungs. The bronchi then branch into smaller tubes called bronchioles, which further divide into tiny air sacs called alveoli.
The alveoli are responsible for gas exchange between the lungs and the bloodstream. Oxygen from the inhaled air diffuses across the thin walls of the alveoli and into the bloodstream, while carbon dioxide, a waste product of cellular respiration, diffuses out of the bloodstream and into the alveoli to be exhaled.
The process of exhalation is the reverse of inhalation. The lungs and chest wall relax, causing the air to be forced out of the lungs and out of the body through the nose or mouth.
The nose. Not just for smelling the rose
The nose is a key component of the respiratory system in humans and other mammals, and it serves several important functions in respiration.
One of the primary functions of the nose is to warm, moisten, and filter the air that is inhaled through it. As air enters the nose, it passes over the nasal conchae, which are curved structures that help to increase the surface area of the nasal cavity. The nasal conchae are covered in a layer of mucus, which helps to trap and filter out dust, dirt, and other particles in the air.
The nasal cavity is also lined with a rich network of blood vessels, which helps to warm the air as it enters the body. This is important because cold air can be damaging to the sensitive tissues of the respiratory system, and warming the air helps to prevent this damage.
Of course, in addition to filtering and warming the air, the nose also plays a role in the sense of smell. The olfactory epithelium, which is located in the upper part of the nasal cavity, contains specialized cells called olfactory receptors that detect and respond to different odors in the air.
Breathe through nose or mouth? Which is better?
Breathing through the nose or mouth can be beneficial depending on the situation, but in general, breathing through the nose is considered to be better for several reasons.
When we breathe through the nose, the air is filtered, warmed, and moistened before it enters the respiratory system. This helps to remove dust, pollen, and other particles from the air, and it also prevents the air from drying out the tissues of the respiratory system. Breathing through the nose can also help to improve lung function, as it allows the body to better regulate the amount of air that is taken in.
Breathing through the mouth, on the other hand, can be useful in certain situations, such as during exercise or when we need to take in more air quickly. Mouth breathing allows us to take in larger volumes of air, which can be beneficial during intense physical activity. It can also be helpful for people with certain medical conditions, such as sleep apnea, who may have difficulty breathing through their nose at night.
However, chronic mouth breathing can have negative effects on health. It can increase the risk of respiratory infections, as well as dental problems such as dry mouth, bad breath, and gum disease. Chronic mouth breathing can also lead to a number of other health problems, including sleep apnea, snoring, and fatigue.
The Lungs
The lungs are a pair of spongy, cone-shaped organs located in the chest, on either side of the heart. They are an essential part of the respiratory system and play a key role in the process of breathing.
The lungs are made up of several components, including the bronchi, bronchioles, and alveoli. The bronchi are the two large tubes that branch off from the trachea and enter the lungs. The bronchi then branch into smaller tubes called bronchioles, which further divide into tiny air sacs called alveoli.
The alveoli are the primary site of gas exchange in the lungs. Oxygen from the inhaled air diffuses across the thin walls of the alveoli and into the bloodstream, while carbon dioxide, a waste product of cellular respiration, diffuses out of the bloodstream and into the alveoli to be exhaled.
The lungs are also surrounded by a thin, double-layered membrane called the pleura, which helps to protect and cushion the lungs as they move during breathing. The lungs are enclosed within the thoracic cavity, which is surrounded by the ribcage and is separated from the abdominal cavity by the diaphragm.
In addition to their role in gas exchange, the lungs also play a role in protecting the respiratory system from foreign substances and irritants. The airways of the lungs are lined with cilia and mucus, which help to trap and remove particles and bacteria from the air before it reaches the alveoli.
Trachea. The highways of breathing.
The trachea, also known as the windpipe, is a tube-like structure that connects the pharynx and larynx to the bronchi in the lungs. It is an important component of the respiratory system and plays a crucial role in the process of breathing.
The primary function of the trachea is to transport air to and from the lungs. When we inhale, air enters the nose or mouth and travels through the pharynx and larynx before entering the trachea. The trachea then directs the air to the bronchi in the lungs, where gas exchange occurs.
The trachea is lined with cilia and mucus, which help to filter and clean the air before it reaches the lungs. The cilia are tiny hair-like structures that beat in a coordinated motion to move mucus and trapped particles up and out of the trachea, where they can be coughed or swallowed.
In addition to transporting air to and from the lungs, the trachea also plays a role in protecting the respiratory system from foreign substances and irritants. The trachea is located in front of the esophagus and is surrounded by cartilage rings, which help to keep it open and prevent it from collapsing. This protects the trachea from external pressure, such as when we swallow, and helps to prevent foreign objects from entering the respiratory system.
Bronchi, off and on ramps to our lungs
The bronchi are two large tubes that branch off from the trachea and enter the lungs. They are an important component of the respiratory system and are responsible for directing air to and from the lungs.
The bronchi begin at the base of the trachea, just below the larynx, and extend into the lungs, where they branch into smaller tubes called bronchioles. The bronchi are lined with cilia and mucus, which help to filter and clean the air as it passes through.
The bronchi play a critical role in gas exchange, which is the process of exchanging oxygen and carbon dioxide between the lungs and the bloodstream. Oxygen from the inhaled air diffuses across the thin walls of the alveoli, tiny air sacs in the lungs, and into the bloodstream, while carbon dioxide, a waste product of cellular respiration, diffuses out of the bloodstream and into the alveoli to be exhaled.
The bronchi also play a role in protecting the respiratory system from foreign substances and irritants. Like the trachea, the bronchi are lined with cilia and mucus, which help to trap and remove particles and bacteria from the air before it reaches the lungs. The bronchi also have muscular walls that can contract and relax to help regulate the flow of air into and out of the lungs.
Bronchioles, backroads of our air passage
Bronchi and bronchioles are both part of the respiratory system and are responsible for directing air to and from the lungs. However, there are several differences between these structures in terms of their size, structure, and function.
Bronchi are the two large tubes that branch off from the trachea and enter the lungs. They are part of the conducting zone of the respiratory system and are responsible for directing air to and from the lungs. The bronchi are lined with cilia and mucus, which help to filter and clean the air as it passes through.
Bronchioles, on the other hand, are smaller tubes that branch off from the bronchi and extend into the lungs. They are part of the respiratory zone of the respiratory system and are responsible for carrying air to and from the alveoli, tiny air sacs in the lungs where gas exchange occurs. The bronchioles do not have cartilage rings, which makes them more flexible and allows them to constrict and dilate to regulate airflow into the lungs.
The bronchi and bronchioles also differ in their function. The bronchi are responsible for filtering and cleaning the air as it enters the lungs, while the bronchioles are responsible for delivering air to the alveoli, where gas exchange occurs.
Alveoli
The alveoli are tiny air sacs in the lungs where gas exchange occurs. They are the primary site of oxygen and carbon dioxide exchange between the lungs and the bloodstream.
The alveoli are surrounded by a network of small blood vessels called capillaries, which are responsible for carrying oxygen-poor blood to the alveoli and oxygen-rich blood away from the alveoli. When we inhale, air travels through the respiratory system and enters the alveoli, where oxygen from the inhaled air diffuses across the thin walls of the alveoli and into the capillaries. The oxygen-rich blood is then carried away from the alveoli and to the rest of the body, where it is used for cellular respiration.
At the same time, carbon dioxide, a waste product of cellular respiration, diffuses out of the bloodstream and into the alveoli. When we exhale, the carbon dioxide-rich air is expelled from the lungs and released into the atmosphere.
The walls of the alveoli are incredibly thin, allowing for efficient gas exchange between the lungs and the bloodstream. The alveoli also have a large surface area, which allows for a large volume of air to be exchanged during each breath.
In addition to their role in gas exchange, the alveoli also play a role in protecting the respiratory system from foreign substances and irritants. The alveoli are lined with a layer of fluid that helps to trap and remove particles and bacteria from the air before it reaches the capillaries.
Diaphragm
The diaphragm is a dome-shaped muscle that separates the thoracic cavity from the abdominal cavity. It plays a crucial role in the process of breathing and is an essential component of the respiratory system.
When we inhale, the diaphragm contracts and moves downward, creating a vacuum that draws air into the lungs. When we exhale, the diaphragm relaxes and moves upward, pushing air out of the lungs.
The diaphragm is controlled by the phrenic nerve, which originates from the spinal cord and passes through the chest and into the abdomen. The phrenic nerve is responsible for transmitting signals from the brain to the diaphragm, telling it when to contract and when to relax.
The diaphragm also plays a role in other bodily functions, such as helping to regulate intra-abdominal pressure and aiding in the process of defecation.
Birds just do it differently
Birds have a unique respiratory system that allows them to meet the high oxygen demands needed for flight. Unlike mammals, birds have a unidirectional system of airflow through their lungs.
The respiratory system of birds begins with the trachea, which is a tube-like structure that runs down the neck and into the chest. The trachea divides into two primary bronchi, which then divide into smaller tubes called secondary bronchi. The secondary bronchi then divide into even smaller tubes called tertiary bronchi.
Unlike the lungs of mammals, the lungs of birds do not have alveoli. Instead, the air sacs of birds are responsible for gas exchange. Birds have nine air sacs, which are connected to the lungs and extend into the abdomen, neck, and wings. The air sacs act as bellows, pumping air through the lungs and ensuring that oxygen-rich air is constantly available for gas exchange.
When a bird inhales, air flows through the trachea and into the posterior air sacs. When the bird exhales, the air flows through the lungs and into the anterior air sacs. When the bird inhales again, the air from the anterior air sacs is drawn into the lungs, while the air from the posterior air sacs is expelled.
This unidirectional flow of air through the respiratory system of birds allows for a more efficient exchange of oxygen and carbon dioxide. The constant flow of fresh air through the lungs ensures that oxygen-rich air is always available for gas exchange, even during high-energy activities like flight.
Insects too
Insects have a unique respiratory system that is very different from the respiratory systems of vertebrates. Unlike humans and other animals, insects do not have lungs or a circulatory system to transport oxygen throughout the body.
The respiratory system of insects consists of a network of small tubes called tracheae, which open to the outside through small holes called spiracles. The tracheae deliver oxygen directly to the cells of the body, and carbon dioxide is released through the same tubes.
Insects are able to move air in and out of the tracheae through a process called respiratory pumping. This involves the movement of abdominal and thoracic muscles, which create changes in air pressure that draw air in and out of the spiracles.
The tracheae are very efficient at delivering oxygen to the cells of the body, as they are highly branched and penetrate deeply into the tissues. The oxygen diffuses across the walls of the tracheae and into the cells, where it is used in cellular respiration to produce energy.
The respiratory system of insects is highly adapted to the unique requirements of their small size and active lifestyle. It allows them to extract oxygen from the air directly, without the need for complex organs like lungs or a circulatory system.