Showing Page:
1/15
Q.1 Ecosystem
Definition
“An ecosystem is defined as a community of lifeforms in concurrence with non-living components,
interacting with each other.”
Types of Ecosystem
An ecosystem can be as small as an oasis in a desert, or as big as an ocean, spanning thousands of miles.
Montreal Protocol was proposed in 1987 to unite the world to cut out production and import of ozone-
depleting substances. The are two types of ecosystem:
1Terrestrial Ecosystem
2Aquatic Ecosystem
Terrestrial Ecosystems
Terrestrial ecosystems are exclusively land-based ecosystems. There are different types of terrestrial
ecosystems distributed around various geological zones. They are as follows:
Forest ecosystems
Grassland Ecosystems
Tundra Ecosystems
Desert Ecosystem
Forest Ecosystem
A forest ecosystem consists of several plants, animals and microorganisms that live in coordination with
the abiotic factors of the environment. Forests help in maintaining the temperature of the earth and are
the major carbon sink.
Grassland Ecosystem
In a grassland ecosystem, the vegetation is dominated by grasses and herbs. Temperate grasslands,
savanna grasslands are some of the examples of grassland ecosystems.
Tundra Ecosystem
Showing Page:
2/15
Tundra ecosystems are devoid of trees and are found in cold climates or where rainfall is scarce. These
are covered with snow for most of the year. The ecosystem in the Arctic or mountain tops is tundra
type.
Desert Ecosystem
Deserts are found throughout the world. These are regions with very little rainfall. The days are hot and
the nights are cold.
Aquatic Ecosystem
Aquatic ecosystems are ecosystems present in a body of water. These can be further divided into two
types, namely:
1Freshwater Ecosystem
2Marine Ecosystem
Freshwater Ecosystem
The freshwater ecosystem is an aquatic ecosystem that includes lakes, ponds, rivers, streams and
wetlands. These have no salt content in contrast with the marine ecosystem.
Marine Ecosystem
The marine ecosystem includes seas and oceans. These have a more substantial salt content and greater
biodiversity in comparison to the freshwater ecosystem.
Structure of the Ecosystem
The structure of an ecosystem is characterised by the organisation of both biotic and abiotic
components. This includes the distribution of energy in our environment. It also includes the climatic
conditions prevailing in that particular environment.
The structure of an ecosystem can be split
into two main components, namely:
Biotic Components
Abiotic Components
Showing Page:
3/15
The biotic and abiotic components are interrelated in an ecosystem. It is an open system where the
energy and components can flow throughout the boundaries.
Biotic Components
Biotic components refer to all life in an ecosystem. Based on nutrition, biotic components can be
categorised into autotrophs, heterotrophs and saprotrophs (or decomposers).
Producers include all autotrophs such as plants. They are called autotrophs as they can produce food
through the process of photosynthesis. Consequently, all other organisms higher up on the food chain
rely on producers for food.
Consumers or heterotrophs are organisms that depend on other organisms for food. Consumers
are further classified into primary consumers, secondary consumers and tertiary consumers.
Primary consumers are always herbivores that they rely on producers for food.
Secondary consumers depend on primary consumers for energy. They can either be a carnivore or an
omnivore.
Tertiary consumers are organisms that depend on secondary consumers for food. Tertiary consumers
can also be an omnivore.
Quaternary consumers are present in some food chains. These organisms prey on tertiary consumers for
energy. Furthermore, they are usually at the top of a food chain as they have no natural predators.
Decomposers include saprophytes such as fungi and bacteria. They directly thrive on the dead and
decaying organic matter. Decomposers are essential for the ecosystem as they help in recycling
nutrients to be reused by plants.
Abiotic Components
Abiotic components are the non-living component of an ecosystem. It includes air, water, soil, minerals,
sunlight, temperature, nutrients, wind, altitude, turbidity, etc.
Functions of Ecosystem
The functions of the ecosystem are as follows:
It regulates the essential ecological processes, supports life systems and renders stability.
It is also responsible for the cycling of nutrients between biotic and abiotic components.
It maintains a balance among the various trophic levels in the ecosystem.
Showing Page:
4/15
It cycles the minerals through the biosphere.
The abiotic components help in the synthesis of organic components that involves the exchange of
energy.
So the functional units of an ecosystem or functional components that work together in an ecosystem
are:
Productivity It refers to the rate of biomass production.
Energy flow It is the sequential process through which energy flows from one trophic level to another.
The energy captured from the sun flows from producers to consumers and then to decomposers and
finally back to the environment.
Decomposition It is the process of breakdown of dead organic material. The top-soil is the major site
for decomposition.
Nutrient cycling In an ecosystem nutrients are consumed and recycled back in various forms for the
utilisation by various organisms.
Q.2 Atmosphere
Definition
“Atmosphere is a protective layer of gases that shelters all life on Earth, keeping temperatures within a
relatively small range and blocking out harmful rays of sunlight.”
Features of the Atmosphere:
Helps retain the sun’s heat and prevents it from escaping back into space.
Protects life from harmful radiation from the sun.
Plays a major role in Earth’s water cycle.
Helps keep the climate on Earth moderate.
There is no boundary between the atmosphere and outer space. The atmosphere gets less dense and
denser until it “blends” into outer space.
Layers of Atmosphere
Showing Page:
5/15
The atmosphere has five distinct layers that are determined by the changes in temperature that happen
with increasing altitude. Layers of Earth’s atmosphere are divided into five different layers as:
Exosphere
Thermosphere
Mesosphere
Stratosphere
Troposphere
Troposphere
The troposphere is the lowest layer in the atmosphere. It extends upward to about 10kms above sea
level starting from ground level. The lowest part of the troposphere is called the boundary layer and the
topmost layer is called the tropopause. The troposphere contains 75% of all air in the atmosphere. Most
clouds appear in this layer because 99% of the water vapour in the atmosphere is found here.
Temperature and air pressure drop as you go higher in the troposphere. When a parcel of air moves
upwards it expands. When air expands it cools. Due to this reason, the base of the troposphere is
warmer than its base because the air in the surface of the Earth absorbs the sun’s energy, gets heated
up and moves upward as a result of which it cools down.
Stratosphere
Above the troposphere lies the stratosphere which extends from the top of the troposphere to about 50
km (31 miles) above the ground. The ozone layer lies within the stratosphere. Ozone molecules in this
layer absorb high-energy ultraviolet (UV) light from the Sun and convert it into heat. Because of this,
unlike the troposphere, the stratosphere gets warmer the higher you go!
Mesosphere
Above the stratosphere is the mesosphere and it extends to a height of about 85 km (53 miles) from the
ground. Here, the temperature grows colder as you rise up through the mesosphere. The coldest parts
of our atmosphere are located in this layer and can reach 90°C.
Thermosphere
Thermosphere lies above the mesosphere and this is a region where the temperature increases as you
go higher up. The temperature increase is caused due to the absorption of energetic ultraviolet and X-
Ray radiation from the sun. However, the air in this layer is so thin that it would feel freezing cold to us!
Satellites orbit Earth within the thermosphere. Temperatures in the upper thermosphere can range
from about 500° C to 2,000° C or higher. The aurora, the Northern Lights and Southern Lights, occur in
the thermosphere.
Showing Page:
6/15
Exosphere
Exosphere is the final frontier of the Earth’s gaseous envelope. The air in the exosphere is constantly but
gradually leaking out of the Earth’s atmosphere into outer space. There is no clear cut upper boundary
where the exosphere finally fades away into space.
Ionosphere
The ionosphere isn’t a distinct layer unlike other layers in the atmosphere. The ionosphere is a series of
regions in parts of the mesosphere and thermosphere where high-energy radiation from the Sun has
knocked electrons loose from their parent atoms and molecules
Composition of Atmosphere Gases in the Atmosphere
The atmospheric composition of gas on Earth is largely conducted by the by-products of the life that it
nurtures
Dry air from earth’s atmosphere contains 0.038% of carbon dioxide, 20.95% of oxygen, 78.08% of
nitrogen and 0.93% of argon.
Traces of hydrogen, neon, helium, nitrous oxide, ozone and other “noble” gases, but generally a variable
amount of water vapour is also present, on average about 1% at sea level.
What is the greenhouse effect?
The process of gases in the Earth’s atmosphere trapping the Sun’s heat is known as the greenhouse
effect. Due to this process, the Earth is much warmer than it would be without an atmosphere. The
greenhouse effect is one of the things that makes Earth a comfortable place to live.
Q.3 Ozone depletion
Ozone layer depletion: Cause, effects, and solutions
The Ozone layer reduces harmful UV radiation reaching the Earth's surface. The Ozone layer is present in
Earth’s atmosphere (15-35km above Earth) in the lower portion of the stratosphere and has relatively
high concentrations of ozone (O3).
Ozone layer depletion is the gradual thinning of the earth’s ozone layer present in the upper
atmosphere. Ozone depletion also consists of a much larger springtime decrease in stratospheric ozone
around Earth's polar regions, which is referred to as the ozone hole.
Cause of ozone depletion
Showing Page:
7/15
main cause of ozone depletion and the ozone hole is manufactured chemicals, especially manufactured
halocarbon refrigerants, solvents, propellants, and foam- blowing agents (chlorofluorocarbons (CFCs),
HCFCs, halons). Since the early 1970's, scientists observed reduction in stratospheric ozone and it was
found more prominent in Polar Regions. ODS substances have a lifetime of about 100 years.
Effects Of Ozone Layer Depletion
depletion of the ozone layer has harmful effects on the human health, animals, environment and marine
life.
Studies demonstrate that an increase in UV-B rays causes a higher risk of skin cancer, plays a major role
in malignant melanoma development, sunburns, quick ageing, eye cataracts, blindness and weekend
immune system.
Direct exposure to ultraviolet radiations also leads to skin and eye cancer in animals.
UV-B rays negatively affect plants, crops. It may lead to minimal plant growth, smaller leaf size,
flowering and photosynthesis in plants, lower quality crops for humans. And decline in plant productivity
would in turn affect soil erosion and the carbon cycle.
Planktons and zooplankton are greatly affected by the exposure to UV-B rays. These are higher in the
aquatic food chain. If the planktons declines, it would likely have wide-reaching effects for all marine life
in the lower food chain.
Solutions to Ozone Layer Depletion
Montreal Protocol was proposed in 1987 to unite the world to cut out production and import of ozone-
depleting substances. The Montreal Protocol phases down the consumption and production of the
different ozone depleting substances (ODS) in a step-wise manner, with different timetables for
developed and developing countries.
Every individual should also take steps to prevent the depletion of the ozone layer. One should avoid
using pesticides and shift to natural methods to get rid of pests instead of using chemicals. The vehicles
emit a large amount of greenhouse gases that lead to global warming as well as ozone depletion.
Therefore, the use of vehicles should be minimized as much as possible. Most of the cleaning products
have chemicals that affect the ozone layer. We should substitut that with eco-friendly products.
Maintain air conditioners, as their malfunctions cause CFC to escape into the atmosphere.
Q.4Pollution
Showing Page:
8/15
Pollution is defined as "An unwanted change in the environment which involves the physical, biological
and chemical changes involving air, water and land which affects the human life in one way or the
other". Pollution is in any form like noise, water and air.
What are the causes of Pollution?
The major types of pollutions and their causes are denoted as below:
causes of Pollution
Air Pollution: Discharge of chemicals and particulates like carbon monoxide, sulfur dioxide,
chlorofluorocarbons and Nitrogen oxides produced by industries and motor vehicles in to the
environment.
Light Pollution: It is caused due to over illumination and astronomical interference.
Noise Pollution: This occurs due to roadway noise, aircraft noise, industrial noise as well as high-
intensity sonar.
Soil Contamination: It occurs due to releasing of chemicals through underground leakage. Among the
most significant soil contaminants are hydrocarbons, heavy metals, MTBE, herbicides, pesticides and
chlorinated hydrocarbons.
Radioactive Contamination: It occurs due to radioactive activities like nuclear power generation and
nuclear weapons research, manufacture and deployment.
Thermal Pollution: It occurs due to change in temperature and natural water bodies due to coolant in a
power plant.
Visual Pollution: It occurs due to overhead power lines, motorway billboards, and scarred landforms,
open storage of trash or municipal solid waste.
Water Pollution: Release or discharge of commercial and industrial wastewater into surface waters;
discharge of untreated domestic sewage, and chemical contaminants, such as chlorine, from treated
sewage; release of waste and contaminants into surface runoff flowing to surface waters, waste disposal
and leaching into groundwater; eutrophication and littering.
Effects of Air Pollution:
Impact on Lung functioning
Asthma
Itching of eyes, mouth and throat
Showing Page:
9/15
Respiratory disorders
Cough and wheezing
Reduced energy levels
Headache
Negative impact on reproductive and immune systems
Neurological disorders
Cancer
II. Effects of Water Pollution:
Causes waterborne diseases like Typhoid, Amoebiasis, Giardiasis, Ascariasis and Hookworm diseases
Rashes, earache and pink eye
Hepatitis, encephalitis, gastroenteritis and vomiting, stomach aches and diarrhea
Prostate cancer
Lack of developmental growth
Liver and kidney damage
DNA damage
Exposure to mercury causes Parkinson's disease
III. Effects of soil pollution:
Leukemia
Effects children's brain and causes developmental damage
Kidney damage
Damage to central nervous system
Headache, fatigue, skin rash and eye irritation
Contamination of crop brings up problems like food security
IV. Effects of Noise pollution
Noise pollution decreases the human efficiency
Showing Page:
10/15
Reduced concentration
Fatigue
Fertility problems in women
Increased blood pressure
Temporary/Permanent deafness
IV. What are the measures to be taken to prevent pollution?
Prevention and control of pollution: Pollution control is an approach to eliminate the release of
pollutants into the environment. It is regulated by various environmental agencies that establish limits
for the discharge of pollutants into the air, water, and land. A wide variety of devices and systems have
been developed to control air and water pollution and solid wastes. Pollution is prevented by using the
below strategies:
Recycling
Reusing
Reducing
Mitigating
Q.5 Air Pollution
Air Pollution is the release of pollutants such as gases, particles, biological molecules, etc. into the air
that is harmful to human health and the environment.”
Types of Air Pollutants
There are two types of air pollutants:
Primary Pollutants
The pollutants that directly cause air pollution are known as primary pollutants. Sulphur-dioxide emitted
from factories is a primary pollutant.
Secondary Pollutants
Showing Page:
11/15
The pollutants formed by the intermingling and reaction of primary pollutants are known as secondary
pollutants. Smog, formed by the intermingling of smoke and fog, is a secondary pollutant.
Causes of Air Pollution
Following are the important causes of air pollution:
Burning of Fossil Fuels
The combustion of fossil fuels emits a large amount of sulphur dioxide. Carbon monoxide released by
incomplete combustion of fossil fuels also results in air pollution.
Automobiles
The gases emitted from vehicles such as jeeps, trucks, cars, buses, etc. pollute the environment. These
are the major sources of greenhouse gases and also result in diseases among individuals.
Agricultural Activities
Ammonia is one of the most hazardous gases emitted during agricultural activities. The insecticides,
pesticides and fertilizers emit harmful chemicals in the atmosphere and contaminate it.
Factories and Industries
Factories and industries are the main source of carbon monoxide, organic compounds, hydrocarbons
and chemicals. These are released into the air, degrading its quality.
Mining Activities
In the mining process, the minerals below the earth are extracted using large pieces of equipment. The
dust and chemicals released during the process not only pollute the air, but also deteriorate the health
of the workers and people living in the nearby areas.
Domestic Sources
The household cleaning products and paints contain toxic chemicals that are released in the air. The
smell from the newly painted walls is the smell of the chemicals present in the paints. It not only
pollutes the air but also affects breathing.
Effects of Air Pollution
The hazardous effects of air pollution on the environment include:
Diseases
Showing Page:
12/15
Air pollution has resulted in several respiratory disorders and heart diseases among humans. The cases
of lung cancer have increased in the last few decades. Children living near polluted areas are more
prone to pneumonia and asthma. Many people die every year due to the direct or indirect effects of air
pollution.
Global Warming
Due to the emission of greenhouse gases, there is an imbalance in the gaseous composition of the air.
This has led to an increase in the temperature of the earth. This increase in earth’s temperature is
known as global warming. This has resulted in the melting of glaciers and an increase in sea levels. Many
areas are submerged underwater.
Acid Rain
The burning of fossil fuels releases harmful gases such as nitrogen oxides and sulphur oxides in the air.
The water droplets combine with these pollutants, become acidic and fall as acid rain which damages
human, animal and plant life.
Ozone Layer Depletion
The release of chlorofluorocarbons, halons, and hydro chlorofluorocarbons in the atmosphere is the
major cause of depletion of the ozone layer. The depleting ozone layer does not prevent the harmful
ultraviolet rays coming from the sun and causes skin diseases and eye problems among individuals.
Effect on Animals
The air pollutants suspend on the water bodies and affect the aquatic life. Pollution also compels the
animals to leave their habitat and shift to a new place. This renders them stray and
has also led to the extinction of a large number of animal species.
Air Pollution Control
Following are the measures one should adopt, to control air pollution:
Avoid Using Vehicles
People should avoid using vehicles for shorter distances. Rather, they should prefer public modes of
transport to travel from one place to another. This not only prevents pollution, but also conserves
energy.
Energy Conservation
Showing Page:
13/15
A large number of fossil fuels are burnt to generate electricity. Therefore, do not forget to switch off the
electrical appliances when not in use. Thus, you can save the environment at the individual level. Use of
energy-efficient devices such CFLs also controls pollution to a greater level.
Use of Clean Energy Resources
The use of solar, wind and geothermal energies reduce air pollution at a larger level. Various countries,
including India, have implemented the use of these resources as a step towards a cleaner environment.
Q.6 Water Pollution
WHAT IS WATER POLLUTION
The World Health Organisation (WHO) says that polluted water is water whose composition has been
changed to the extent that it is unusable. In other words, it is toxic water that cannot be drunk or used
for essential purposes like agriculture, and which also causes diseases like diarrhoea, cholera, dysentery,
typhoid and poliomyelitis that kill more than 500,000 people worldwide every year.
The main water pollutants include bacteria, viruses, parasites, fertilisers, pesticides, pharmaceutical
products, nitrates, phosphates, plastics, faecal waste and even radioactive substances. These substances
do not always change the colour of the water, meaning that they are often invisible pollutants. That's
why small amounts of water and aquatic organisms are tested to determine water quality.
MAIN CAUSES OF WATER POLLUTION
It is sometimes caused by nature, such as when mercury filters from the Earth's crust, polluting oceans,
rivers, lakes, canals and reservoirs. However, the most common cause of poor quality water is human
activity and its consequences, which we will now go on to explain:
Global warming
Rising global temperatures caused by CO2 emissions heat the water, reducing its oxygen content.
Deforestation
Felling forests can exhaust water resources and generate organic residue which becomes a breeding
ground for harmful bacteria.
Industry, agriculture and livestock farming
Chemical dumping from these sectors is one of the main causes of eutrophication of water.
Rubbish and faecal water dumping
The UN says that more than 80% of the world's sewage finds its way into seas and rivers untreated.
Showing Page:
14/15
Maritime traffic
Much of the plastic pollution in the ocean comes from fishing boats, tankers and cargo shipping.
Fuel spillages
The transportation and storage of oil and its derivatives is subject to leakage that pollutes our water
resources.
EFFECTS OF WATER POLLUTION
Deteriorating water quality is damaging the environment, health conditions and the global economy.
The president of the World Bank, David Malpass, warns of the economic impact: "Deteriorating water
quality is stalling economic growth and exacerbating poverty in many countries". The explanation is that,
when biological oxygen demand the indicator that measures the organic pollution found in water
exceeds a certain threshold, the growth in the Gross Domestic Product (GDP) of the regions within the
associated water basins falls by a third. In addition, here are some of the other consequences:
Destruction of biodiversity. Water pollution depletes aquatic ecosystems and triggers unbridled
proliferation of phytoplankton in lakes eutrophication .
Contamination of the food chain. Fishing in polluted waters and the use of waste water for livestock
farming and agriculture can introduce toxins into foods which are harmful to our health when eaten.
Lack of potable water. The UN says that billions of people around the world have no access to clean
water to drink or sanitation, particularly in rural areas.
Disease. The WHO estimates that about 2 billion people have no option but to drink water contaminated
by excrement, exposing them to diseases such as cholera, hepatitis A and dysentery.
Infant mortality. According to the UN, diarrhoeal diseases linked to lack of hygiene cause the death of
about 1,000 children a day worldwide.
PREVENTION OF WATER POLLUTION
Half of the world's inhabitants will live in water-scarce areas by 2025, so every drop of polluted water
today is an irreparable loss for tomorrow. That's why we must prevent water pollution with measures
like the following:
Reduce CO2 emissions to prevent global warming and acidification of the oceans.
Reduce the use of chemical pesticides and nutrients on crops.
Reduce and safely treat waste water so that, as well as not polluting, it can be reused for irrigation and
energy production.
Showing Page:
15/15
Restrict the use of single-use plastics that end up floating in rivers, lakes and oceans, many as
microplastics.
Encourage sustainable fishing to ensure the survival of species and avoid depletion of the seas.

Unformatted Attachment Preview

Q.1 Ecosystem Definition “An ecosystem is defined as a community of lifeforms in concurrence with non-living components, interacting with each other.” Types of Ecosystem An ecosystem can be as small as an oasis in a desert, or as big as an ocean, spanning thousands of miles. Montreal Protocol was proposed in 1987 to unite the world to cut out production and import of ozonedepleting substances. The are two types of ecosystem: 1Terrestrial Ecosystem 2Aquatic Ecosystem Terrestrial Ecosystems Terrestrial ecosystems are exclusively land-based ecosystems. There are different types of terrestrial ecosystems distributed around various geological zones. They are as follows: Forest ecosystems Grassland Ecosystems Tundra Ecosystems Desert Ecosystem Forest Ecosystem A forest ecosystem consists of several plants, animals and microorganisms that live in coordination with the abiotic factors of the environment. Forests help in maintaining the temperature of the earth and are the major carbon sink. Grassland Ecosystem In a grassland ecosystem, the vegetation is dominated by grasses and herbs. Temperate grasslands, savanna grasslands are some of the examples of grassland ecosystems. Tundra Ecosystem Tundra ecosystems are devoid of trees and are found in cold climates or where rainfall is scarce. These are covered with snow for most of the year. The ecosystem in the Arctic or mountain tops is tundra type. Desert Ecosystem Deserts are found throughout the world. These are regions with very little rainfall. The days are hot and the nights are cold. Aquatic Ecosystem Aquatic ecosystems are ecosystems present in a body of water. These can be further divided into two types, namely: 1Freshwater Ecosystem 2Marine Ecosystem Freshwater Ecosystem The freshwater ecosystem is an aquatic ecosystem that includes lakes, ponds, rivers, streams and wetlands. These have no salt content in contrast with the marine ecosystem. Marine Ecosystem The marine ecosystem includes seas and oceans. These have a more substantial salt content and greater biodiversity in comparison to the freshwater ecosystem. Structure of the Ecosystem The structure of an ecosystem is characterised by the organisation of both biotic and abiotic components. This includes the distribution of energy in our environment. It also includes the climatic conditions prevailing in that particular environment. The structure of an ecosystem can be split into two main components, namely: Biotic Components Abiotic Components The biotic and abiotic components are interrelated in an ecosystem. It is an open system where the energy and components can flow throughout the boundaries. Biotic Components Biotic components refer to all life in an ecosystem. Based on nutrition, biotic components can be categorised into autotrophs, heterotrophs and saprotrophs (or decomposers). Producers include all autotrophs such as plants. They are called autotrophs as they can produce food through the process of photosynthesis. Consequently, all other organisms higher up on the food chain rely on producers for food. Consumers or heterotrophs are organisms that depend on other organisms for food. Consumers are further classified into primary consumers, secondary consumers and tertiary consumers. Primary consumers are always herbivores that they rely on producers for food. Secondary consumers depend on primary consumers for energy. They can either be a carnivore or an omnivore. Tertiary consumers are organisms that depend on secondary consumers for food. Tertiary consumers can also be an omnivore. Quaternary consumers are present in some food chains. These organisms prey on tertiary consumers for energy. Furthermore, they are usually at the top of a food chain as they have no natural predators. Decomposers include saprophytes such as fungi and bacteria. They directly thrive on the dead and decaying organic matter. Decomposers are essential for the ecosystem as they help in recycling nutrients to be reused by plants. Abiotic Components Abiotic components are the non-living component of an ecosystem. It includes air, water, soil, minerals, sunlight, temperature, nutrients, wind, altitude, turbidity, etc. Functions of Ecosystem The functions of the ecosystem are as follows: It regulates the essential ecological processes, supports life systems and renders stability. It is also responsible for the cycling of nutrients between biotic and abiotic components. It maintains a balance among the various trophic levels in the ecosystem. It cycles the minerals through the biosphere. The abiotic components help in the synthesis of organic components that involves the exchange of energy. So the functional units of an ecosystem or functional components that work together in an ecosystem are: Productivity – It refers to the rate of biomass production. Energy flow – It is the sequential process through which energy flows from one trophic level to another. The energy captured from the sun flows from producers to consumers and then to decomposers and finally back to the environment. Decomposition – It is the process of breakdown of dead organic material. The top-soil is the major site for decomposition. Nutrient cycling – In an ecosystem nutrients are consumed and recycled back in various forms for the utilisation by various organisms. Q.2 Atmosphere Definition “Atmosphere is a protective layer of gases that shelters all life on Earth, keeping temperatures within a relatively small range and blocking out harmful rays of sunlight.” Features of the Atmosphere: Helps retain the sun’s heat and prevents it from escaping back into space. Protects life from harmful radiation from the sun. Plays a major role in Earth’s water cycle. Helps keep the climate on Earth moderate. There is no boundary between the atmosphere and outer space. The atmosphere gets less dense and denser until it “blends” into outer space. Layers of Atmosphere The atmosphere has five distinct layers that are determined by the changes in temperature that happen with increasing altitude. Layers of Earth’s atmosphere are divided into five different layers as: Exosphere Thermosphere Mesosphere Stratosphere Troposphere Troposphere The troposphere is the lowest layer in the atmosphere. It extends upward to about 10kms above sea level starting from ground level. The lowest part of the troposphere is called the boundary layer and the topmost layer is called the tropopause. The troposphere contains 75% of all air in the atmosphere. Most clouds appear in this layer because 99% of the water vapour in the atmosphere is found here. Temperature and air pressure drop as you go higher in the troposphere. When a parcel of air moves upwards it expands. When air expands it cools. Due to this reason, the base of the troposphere is warmer than its base because the air in the surface of the Earth absorbs the sun’s energy, gets heated up and moves upward as a result of which it cools down. Stratosphere Above the troposphere lies the stratosphere which extends from the top of the troposphere to about 50 km (31 miles) above the ground. The ozone layer lies within the stratosphere. Ozone molecules in this layer absorb high-energy ultraviolet (UV) light from the Sun and convert it into heat. Because of this, unlike the troposphere, the stratosphere gets warmer the higher you go! Mesosphere Above the stratosphere is the mesosphere and it extends to a height of about 85 km (53 miles) from the ground. Here, the temperature grows colder as you rise up through the mesosphere. The coldest parts of our atmosphere are located in this layer and can reach –90°C. Thermosphere Thermosphere lies above the mesosphere and this is a region where the temperature increases as you go higher up. The temperature increase is caused due to the absorption of energetic ultraviolet and XRay radiation from the sun. However, the air in this layer is so thin that it would feel freezing cold to us! Satellites orbit Earth within the thermosphere. Temperatures in the upper thermosphere can range from about 500° C to 2,000° C or higher. The aurora, the Northern Lights and Southern Lights, occur in the thermosphere. Exosphere Exosphere is the final frontier of the Earth’s gaseous envelope. The air in the exosphere is constantly but gradually leaking out of the Earth’s atmosphere into outer space. There is no clear cut upper boundary where the exosphere finally fades away into space. Ionosphere The ionosphere isn’t a distinct layer unlike other layers in the atmosphere. The ionosphere is a series of regions in parts of the mesosphere and thermosphere where high-energy radiation from the Sun has knocked electrons loose from their parent atoms and molecules Composition of Atmosphere – Gases in the Atmosphere The atmospheric composition of gas on Earth is largely conducted by the by-products of the life that it nurtures Dry air from earth’s atmosphere contains 0.038% of carbon dioxide, 20.95% of oxygen, 78.08% of nitrogen and 0.93% of argon. Traces of hydrogen, neon, helium, nitrous oxide, ozone and other “noble” gases, but generally a variable amount of water vapour is also present, on average about 1% at sea level. What is the greenhouse effect? The process of gases in the Earth’s atmosphere trapping the Sun’s heat is known as the greenhouse effect. Due to this process, the Earth is much warmer than it would be without an atmosphere. The greenhouse effect is one of the things that makes Earth a comfortable place to live. Q.3 Ozone depletion Ozone layer depletion: Cause, effects, and solutions The Ozone layer reduces harmful UV radiation reaching the Earth's surface. The Ozone layer is present in Earth’s atmosphere (15-35km above Earth) in the lower portion of the stratosphere and has relatively high concentrations of ozone (O3). Ozone layer depletion is the gradual thinning of the earth’s ozone layer present in the upper atmosphere. Ozone depletion also consists of a much larger springtime decrease in stratospheric ozone around Earth's polar regions, which is referred to as the ozone hole. Cause of ozone depletion main cause of ozone depletion and the ozone hole is manufactured chemicals, especially manufactured halocarbon refrigerants, solvents, propellants, and foam- blowing agents (chlorofluorocarbons (CFCs), HCFCs, halons). Since the early 1970's, scientists observed reduction in stratospheric ozone and it was found more prominent in Polar Regions. ODS substances have a lifetime of about 100 years. Effects Of Ozone Layer Depletion depletion of the ozone layer has harmful effects on the human health, animals, environment and marine life. Studies demonstrate that an increase in UV-B rays causes a higher risk of skin cancer, plays a major role in malignant melanoma development, sunburns, quick ageing, eye cataracts, blindness and weekend immune system. Direct exposure to ultraviolet radiations also leads to skin and eye cancer in animals. UV-B rays negatively affect plants, crops. It may lead to minimal plant growth, smaller leaf size, flowering and photosynthesis in plants, lower quality crops for humans. And decline in plant productivity would in turn affect soil erosion and the carbon cycle. Planktons and zooplankton are greatly affected by the exposure to UV-B rays. These are higher in the aquatic food chain. If the planktons declines, it would likely have wide-reaching effects for all marine life in the lower food chain. Solutions to Ozone Layer Depletion Montreal Protocol was proposed in 1987 to unite the world to cut out production and import of ozonedepleting substances. The Montreal Protocol phases down the consumption and production of the different ozone depleting substances (ODS) in a step-wise manner, with different timetables for developed and developing countries. Every individual should also take steps to prevent the depletion of the ozone layer. One should avoid using pesticides and shift to natural methods to get rid of pests instead of using chemicals. The vehicles emit a large amount of greenhouse gases that lead to global warming as well as ozone depletion. Therefore, the use of vehicles should be minimized as much as possible. Most of the cleaning products have chemicals that affect the ozone layer. We should substitut that with eco-friendly products. Maintain air conditioners, as their malfunctions cause CFC to escape into the atmosphere. Q.4Pollution Pollution is defined as "An unwanted change in the environment which involves the physical, biological and chemical changes involving air, water and land which affects the human life in one way or the other". Pollution is in any form like noise, water and air. What are the causes of Pollution? The major types of pollutions and their causes are denoted as below: causes of Pollution Air Pollution: Discharge of chemicals and particulates like carbon monoxide, sulfur dioxide, chlorofluorocarbons and Nitrogen oxides produced by industries and motor vehicles in to the environment. Light Pollution: It is caused due to over illumination and astronomical interference. Noise Pollution: This occurs due to roadway noise, aircraft noise, industrial noise as well as highintensity sonar. Soil Contamination: It occurs due to releasing of chemicals through underground leakage. Among the most significant soil contaminants are hydrocarbons, heavy metals, MTBE, herbicides, pesticides and chlorinated hydrocarbons. Radioactive Contamination: It occurs due to radioactive activities like nuclear power generation and nuclear weapons research, manufacture and deployment. Thermal Pollution: It occurs due to change in temperature and natural water bodies due to coolant in a power plant. Visual Pollution: It occurs due to overhead power lines, motorway billboards, and scarred landforms, open storage of trash or municipal solid waste. Water Pollution: Release or discharge of commercial and industrial wastewater into surface waters; discharge of untreated domestic sewage, and chemical contaminants, such as chlorine, from treated sewage; release of waste and contaminants into surface runoff flowing to surface waters, waste disposal and leaching into groundwater; eutrophication and littering. Effects of Air Pollution: Impact on Lung functioning Asthma Itching of eyes, mouth and throat Respiratory disorders Cough and wheezing Reduced energy levels Headache Negative impact on reproductive and immune systems Neurological disorders Cancer II. Effects of Water Pollution: Causes waterborne diseases like Typhoid, Amoebiasis, Giardiasis, Ascariasis and Hookworm diseases Rashes, earache and pink eye Hepatitis, encephalitis, gastroenteritis and vomiting, stomach aches and diarrhea Prostate cancer Lack of developmental growth Liver and kidney damage DNA damage Exposure to mercury causes Parkinson's disease III. Effects of soil pollution: Leukemia Effects children's brain and causes developmental damage Kidney damage Damage to central nervous system Headache, fatigue, skin rash and eye irritation Contamination of crop brings up problems like food security IV. Effects of Noise pollution Noise pollution decreases the human efficiency Reduced concentration Fatigue Fertility problems in women Increased blood pressure Temporary/Permanent deafness IV. What are the measures to be taken to prevent pollution? Prevention and control of pollution: Pollution control is an approach to eliminate the release of pollutants into the environment. It is regulated by various environmental agencies that establish limits for the discharge of pollutants into the air, water, and land. A wide variety of devices and systems have been developed to control air and water pollution and solid wastes. Pollution is prevented by using the below strategies: Recycling Reusing Reducing Mitigating Q.5 Air Pollution Air Pollution is the release of pollutants such as gases, particles, biological molecules, etc. into the air that is harmful to human health and the environment.” Types of Air Pollutants There are two types of air pollutants: Primary Pollutants The pollutants that directly cause air pollution are known as primary pollutants. Sulphur-dioxide emitted from factories is a primary pollutant. Secondary Pollutants The pollutants formed by the intermingling and reaction of primary pollutants are known as secondary pollutants. Smog, formed by the intermingling of smoke and fog, is a secondary pollutant. Causes of Air Pollution Following are the important causes of air pollution: Burning of Fossil Fuels The combustion of fossil fuels emits a large amount of sulphur dioxide. Carbon monoxide released by incomplete combustion of fossil fuels also results in air pollution. Automobiles The gases emitted from vehicles such as jeeps, trucks, cars, buses, etc. pollute the environment. These are the major sources of greenhouse gases and also result in diseases among individuals. Agricultural Activities Ammonia is one of the most hazardous gases emitted during agricultural activities. The insecticides, pesticides and fertilizers emit harmful chemicals in the atmosphere and contaminate it. Factories and Industries Factories and industries are the main source of carbon monoxide, organic compounds, hydrocarbons and chemicals. These are released into the air, degrading its quality. Mining Activities In the mining process, the minerals below the earth are extracted using large pieces of equipment. The dust and chemicals released during the process not only pollute the air, but also deteriorate the health of the workers and people living in the nearby areas. Domestic Sources The household cleaning products and paints contain toxic chemicals that are released in the air. The smell from the newly painted walls is the smell of the chemicals present in the paints. It not only pollutes the air but also affects breathing. Effects of Air Pollution The hazardous effects of air pollution on the environment include: Diseases Air pollution has resulted in several respiratory disorders and heart diseases among humans. The cases of lung cancer have increased in the last few decades. Children living near polluted areas are more prone to pneumonia and asthma. Many people die every year due to the direct or indirect effects of air pollution. Global Warming Due to the emission of greenhouse gases, there is an imbalance in the gaseous composition of the air. This has led to an increase in the temperature of the earth. This increase in earth’s temperature is known as global warming. This has resulted in the melting of glaciers and an increase in sea levels. Many areas are submerged underwater. Acid Rain The burning of fossil fuels releases harmful gases such as nitrogen oxides and sulphur oxides in the air. The water droplets combine with these pollutants, become acidic and fall as acid rain which damages human, animal and plant life. Ozone Layer Depletion The release of chlorofluorocarbons, halons, and hydro chlorofluorocarbons in the atmosphere is the major cause of depletion of the ozone layer. The depleting ozone layer does not prevent the harmful ultraviolet rays coming from the sun and causes skin diseases and eye problems among individuals. Effect on Animals The air pollutants suspend on the water bodies and affect the aquatic life. Pollution also compels the animals to leave their habitat and shift to a new place. This renders them stray and has also led to the extinction of a large number of animal species. Air Pollution Control Following are the measures one should adopt, to control air pollution: Avoid Using Vehicles People should avoid using vehicles for shorter distances. Rather, they should prefer public modes of transport to travel from one place to another. This not only prevents pollution, but also conserves energy. Energy Conservation A large number of fossil fuels are burnt to generate electricity. Therefore, do not forget to switch off the electrical appliances when not in use. Thus, you can save the environment at the individual level. Use of energy-efficient devices such CFLs also controls pollution to a greater level. Use of Clean Energy Resources The use of solar, wind and geothermal energies reduce air pollution at a larger level. Various countries, including India, have implemented the use of these resources as a step towards a cleaner environment. Q.6 Water Pollution WHAT IS WATER POLLUTION The World Health Organisation (WHO) says that polluted water is water whose composition has been changed to the extent that it is unusable. In other words, it is toxic water that cannot be drunk or used for essential purposes like agriculture, and which also causes diseases like diarrhoea, cholera, dysentery, typhoid and poliomyelitis that kill more than 500,000 people worldwide every year. The main water pollutants include bacteria, viruses, parasites, fertilisers, pesticides, pharmaceutical products, nitrates, phosphates, plastics, faecal waste and even radioactive substances. These substances do not always change the colour of the water, meaning that they are often invisible pollutants. That's why small amounts of water and aquatic organisms are tested to determine water quality. MAIN CAUSES OF WATER POLLUTION It is sometimes caused by nature, such as when mercury filters from the Earth's crust, polluting oceans, rivers, lakes, canals and reservoirs. However, the most common cause of poor quality water is human activity and its consequences, which we will now go on to explain: Global warming Rising global temperatures caused by CO2 emissions heat the water, reducing its oxygen content. Deforestation Felling forests can exhaust water resources and generate organic residue which becomes a breeding ground for harmful bacteria. Industry, agriculture and livestock farming Chemical dumping from these sectors is one of the main causes of eutrophication of water. Rubbish and faecal water dumping The UN says that more than 80% of the world's sewage finds its way into seas and rivers untreated. Maritime traffic Much of the plastic pollution in the ocean comes from fishing boats, tankers and cargo shipping. Fuel spillages The transportation and storage of oil and its derivatives is subject to leakage that pollutes our water resources. EFFECTS OF WATER POLLUTION Deteriorating water quality is damaging the environment, health conditions and the global economy. The president of the World Bank, David Malpass, warns of the economic impact: "Deteriorating water quality is stalling economic growth and exacerbating poverty in many countries". The explanation is that, when biological oxygen demand — the indicator that measures the organic pollution found in water — exceeds a certain threshold, the growth in the Gross Domestic Product (GDP) of the regions within the associated water basins falls by a third. In addition, here are some of the other consequences: Destruction of biodiversity. Water pollution depletes aquatic ecosystems and triggers unbridled proliferation of phytoplankton in lakes — eutrophication —. Contamination of the food chain. Fishing in polluted waters and the use of waste water for livestock farming and agriculture can introduce toxins into foods which are harmful to our health when eaten. Lack of potable water. The UN says that billions of people around the world have no access to clean water to drink or sanitation, particularly in rural areas. Disease. The WHO estimates that about 2 billion people have no option but to drink water contaminated by excrement, exposing them to diseases such as cholera, hepatitis A and dysentery. Infant mortality. According to the UN, diarrhoeal diseases linked to lack of hygiene cause the death of about 1,000 children a day worldwide. PREVENTION OF WATER POLLUTION Half of the world's inhabitants will live in water-scarce areas by 2025, so every drop of polluted water today is an irreparable loss for tomorrow. That's why we must prevent water pollution with measures like the following: Reduce CO2 emissions to prevent global warming and acidification of the oceans. Reduce the use of chemical pesticides and nutrients on crops. Reduce and safely treat waste water so that, as well as not polluting, it can be reused for irrigation and energy production. Restrict the use of single-use plastics that end up floating in rivers, lakes and oceans, many as microplastics. Encourage sustainable fishing to ensure the survival of species and avoid depletion of the seas. Name: Description: ...
User generated content is uploaded by users for the purposes of learning and should be used following Studypool's honor code & terms of service.
Studypool
4.7
Trustpilot
4.5
Sitejabber
4.4