Category Archives for "Ecology"

Pollution and Pollutants: Causes, Effects and Control Measures

Today, environmental pollution is a major problem which affects humans and other life forms. The earth is a vast ecosystem within it. Green plants are the primary producer in every ecosystem and constitute the functional components. They take carbon dioxide and release oxygen during the process of photosynthesis and maintain equilibrium in the atmosphere. There are also other gases like sulfur dioxide (SO2), nitrogen oxides (NOx), ethylene, etc. in the atmosphere present in traces and are in a balanced proportion. 

Due to overpopulation and large scale of industrialization, some harmful components are released in the environment which disturbs the balance in nature and pollutes atmosphere and water bodies like ponds, lakes, river, etc. Other types of important environmental pollution are very frequently observed. They are commonly known as noise or sound pollution.

When the physical and biological components of the earth or atmosphere are contaminated by pollutants and adversely affect the normal environment, then it is known as pollution. In this case, naturally occurring substances are contaminated with harmful materials or foreign substances then they are considered as pollutants which cause an adverse change of natural environment.

According to Odum (1971), “pollution is an undesirable change in the physical, chemical, or biological characteristics of our air, land and water that may or will harmfully affect human life or that of desirable species, industrial processes, living conditions, and cultural assets or that may or will waste or determinate our raw material resources”.

Addition of accidental materials into the air, water or land in a concentration higher than that of the normal are detrimental to the natural quality of the environment thereby causing pollution is to make it unfit for use by undesirable elements.

Environmental pollution is the disadvantageous alteration of our surroundings, which directly affects the human being and other living organisms of the world.

Major forms of pollution include:

  • Air pollution
  • Water pollution
  • Noise pollution
  • Light pollution
  • Plastic pollution
  • Littering
  • Visual pollution
  • Radioactive contamination
  • Thermal pollution

Causes of Pollution

The major causes of pollution are:

  • Overgrowth of the population;
  • The building of cities and town in an unscientific way;
  • Using up of abundant natural resources and killing animals unscientifically;
  • Misuse of technological progress in different spheres;
  • Mining activities causes a release of dust and fumes into the atmosphere resulting in toxicity of air.
  • Certain agricultural activities such as using of chemicals causing to air pollution.
  • Poor waste disposal is a major cause of pollution.
  • Use of petroleum and coal causing heavy pollution in the environment.
  • Large quantities of Industrial emissions causing environmental pollution.

Effects of Pollution

  • Pollution causes different types of diseases such as typhoid, tuberculosis, cancer, nerve diseases, etc.
  • It causes economic loss and energy loss which results in the ultimate loss of wealth.
  • Adverse air pollution can cause various diseases killing many organisms including humans.
  • Decreases of various natural substances useful to human life.
  • Ozone pollution can also cause different types of diseases of man including respiratory disease, chest pain, cardiovascular disease, congestion, and throat inflammation, etc.
  • Water pollution causes dissuade and kill approximately 14,000 deaths per day in developing countries. In this case, it is occurred mostly due to contamination of drinking water.
  • Noise pollution causes hearing loss, stress, high blood pressure and sleep disturbance.
  •  Lead and other heavy metals pollution cause neurological problems.
  • Radioactive substances and other chemicals can cause cancer and as well as birth defects.
  • Release of greenhouse gases causes global warming which affects the ecosystems.
  • Soil can become infertile due to soil pollution which is unsuitable for plants and affect other organisms in the food web.
  • Sulfur dioxide (SO2) and nitrogen oxides (NOx) can cause acid rain which lowers the pH value of soil and water.
  • Organic pollution of water can reduce oxygen levels and finally lessen species diversity.


Pollution causes negative effects on the environment, wildlife, human health, and well-being. Substances which pollute the environment are known as pollutants. Odum (1971) divided pollutants into two major categories:

Non Degradable Pollutants: Substances which do not degrade or degrade very slowly in the natural environment are designated as the non-degradable pollutants such as mineral salts, aluminum cans, steel and long chain phenolic compounds, etc.

Degradable Pollutants: Those types of pollutants that break rapidly are known as degradable pollutants. The domestic wastages can be degraded by natural means or by the help of machines. Using proper methods the environment can be kept free from pollution. Some common degradable pollutants are smoke, smog, dust particles, coal tar, stored materials, metals like iron, lead, zinc, etc., nitrogen oxide, H2SO4, HCl, CO2, N2O, NH3, SO2, and other gaseous substances, different insecticides, DDT, Radioactive substances, etc.

Control Measures of Pollution

  • Introducing post-combustion measures to lessen the emission of various gaseous substances such as sulfur dioxide (SO2), nitrogen oxides (NOx) and particulate matters from power stations and in large-scale industry.
  • Introducing advanced emissions standards in various industries such as cement factories, glass and, chemical industry, iron and steel plants, etc.
  • Improving and strengthening emission standards for road vehicles such as light- and heavy-duty diesel vehicles.
  • Making compulsory checks and repairs for vehicles by vehicle inspector.
  • Suppressing construction and road dust; increasing green areas.
  • Open burning of agricultural crop residues should be strictly prohibited.
  • Open burning of residential and household waste should be strictly banned on.
  • Forest and peatland fires must be prevented using improved forest, land and water management and fire prevention strategies.
  • Livestock manure management strategies should be followed. In this case, you should encourage anaerobic digestion.
  • Use of private passenger vehicles should be discouraged to lessen CO2 emission. In this case, the public transport system should be encouraged.
  • Introducing well-managed wastewater treatment with biogas recovery.
  • You should use clean fuels like electricity, natural gas, liquefied petroleum gas (LPG) in cities.
  • Introducing LPG and advanced biomass cooking and heating stoves in rural areas;
  • For electricity generation, you should use of wind, solar and hydropower system. 
  • Encouraging the use of electric vehicles instead of diesel engines.
  • Improving and enforcing energy efficiency standards for households and industries.

Components of the Ecosystem

The region of the earth in which all organisms live is the biosphere. The nonliving features of the environment are abiotic factors and the organisms in the environment are biotic factors. Populations and communities make up an ecosystem. The ecosystem is the base of the biosphere which influences the wellbeing of the entire earth system. It includes living things and non-living environments in a given area where plants, animals and other organisms are the living things and weather, sun, earth, climate, soil, atmosphere, etc. form non-living environments.

Any ecosystem comprises of several factors which may be following two categories:

  • Abiotic components and
  • Biotic components

Abiotic Components

The environment is made up of living things or organisms that depend on one another for food and shelter but those organisms also depend on factors that surround them such as calcium, potassium, magnesium, sulfur, gaseous substances like oxygen, nitrogen, carbon dioxide, soil, sunlight, water or moisture, precipitation, temperature, and air. These factors form nonliving, physical features of the environment are known as abiotic factors. Besides all these, amino acid, humic acids, are present which adds into the abiotic factors. The producers such as green plants secure these substances from soil and air in order to prepare their foods. Abiotic factors actually control the functions, behavior, distribution, structure, and inter-relationship of organisms in an environment. Organisms cannot survive without the abiotic components.  Abiotic components can differ from one ecosystem to another ecosystem which mainly acts as a life supporter or limiting factors. They influence and control the growth of the population, number, and diversity of biotic factors. In the environment, if anyone factor changes slightly causing a disturbance.

The abiotic component is also divided into the following two categories:

  • Climatic factors: Climatic factors include rainfall, light, temperature, humidity, wind, and air, etc.
  • Edaphic factors: These factors include minerals, soil, topography, and pH, etc.

Light: Light is the primary source of energy in the living world. Various life processes are influenced directly or indirectly by this factor.

Temperature: It is of three types: such as minimum, optimum, and maximum. The temperature tolerance of a given species at different stages of its life history is variable. The optimum temperature lies towards the maximum limit of temperature and minimum temperatures. In the optimum temperature, life processes function smoothly and efficiently. The maximum temperature for some organisms is about 38 0C. The chemical constitutes of the protoplasm suffer considerable change at this temperature. The proteins, one of the chief constituent of the protoplasm, become denatured and coagulated at considerably high temperature. However, the average maximum temperature for living organisms lies between 40 and 45 0C. 

Atmospheric Pressure: It has its own influence on the living world. The atmospheric pressure varies inversely with the altitude. Lower atmospheric pressure results in lower pressure of oxygen and this condition are harmful as it leads to less oxygenation of the tissues. The above conditions along with humidity of the air, etc. fall under the climatic conditions of an environment.

Soil Factor:  The environmental condition of a place mainly depends on the nature of the soil, water holding capacity, percolation of water through the soil, amount of water under soil, soil air, soil temperature, nature of the soil-sap(whether it is acidic, basic or neutral, etc).

Physiographic or topographic Factors:  The altitude, undulating landscape, the amount of light falling on a place or wind blowing through the region, etc. add in to form the topographic factors of an ecosystem.

Image of Ecosystem components

Components of Ecosystem

From the functional point of view the living organisms of the ecosystem are divided into two components by Odum (1971):

Autotrophic Components: Those living organisms of a biotic community for the preparation of their own food depends on the environment for water, carbon dioxide and for fixation of light energy are regarded as autotrophic components. All chlorophyll-containing green plants come under this category.

Heterotrophic Components: Those living organisms utilizes, and decomposes the complex substances produced by autotrophic components as they cannot prepare their own food matters due to lack of chlorophyll are called heterotrophic components. Except for a few plants, most animals come under this category as they are directly or indirectly dependant on autotrophic components for food.

Biotic Community

Biotic factors are the living things which direct or indirect influence on other organisms in an environment. Organisms cannot depend only on abiotic factors for survival because they do not provide everything to live. Biotic factors depend on abiotic factors for their survival and they help to form of abiotic factors such as soil, nutrients, etc. Biotic factors such as plants offer food for other organisms while the abiotic factors such as soil support the growth of the plants by providing nutrients and other key components.

Mushrooms would not be able to grow without the decaying bodies of other organisms to feed on. Honeybees could not survive without pollen from flowers. Some species of owls and woodpeckers prefer to nest in the hollow trunks of dead trees. Organisms need help from other organisms to live. In this case, one organism provides food, shelter, protection, or reproduction to other organisms. Living or once-living organisms in the environment are known as biotic factors.

Biotic components are the constituents of a community. Each biotic community comprises of:

  • Producers
  • Consumers and
  • Decomposers


The green autotrophic plants are regarded as producers. They are able to synthesize carbohydrates, proteins, fats, etc. from certain inorganic constituents (CO2, H2O, mineral salts, etc.) of the surrounding environment with the help of chlorophyll in presence of sunlight. The producers prepare their food matters by the process of photosynthesis which is stated below:

Image of Photosynthesis reaction

Photosynthesis Equation

Proteins, amino acids, and other important minerals are also produced other than glucose. Autotrophic plants may be of two types such as (i) large rooted plants growing on lands or in shallow water and (ii) small floating algae constituting what is called phytoplankton. The later is more important of the two and they may grow up to that level of a sea or in a large lake where the sunlight can reach. Phytoplankton is the main source of food of the majority of the primary consumers.

There are certain bacteria which can prepare their own food even in darkness by a special process chemosynthesis. For example, some chemosynthetic bacteria (nitrifying bacteria) can convert ammonia to nitrite and nitrite to nitrate. Certain bacteria called photosynthetic bacteria can carry out photosynthesis. Both these types of bacteria are producer organisms. Finally, producers capture energy from non-organic sources and then store them for future use.


Consumers are heterotrophs organisms which cannot fix carbon from non-organic sources. Hence, they directly or indirectly depend on producers for their food. Consumers are a basic component of any ecosystem. Consumers are of three types:

  • Primary consumers
  • Secondary consumers and
  • Tertiary consumers.

Primary Consumers: The plant eaters are known as primary consumers or first-order consumers. The minute animals in the upper level of water constitute zooplankton such as Daphnia, Cyclops, etc. The primary consumers in a lower level of water are known as bottom fauna such as snails, small fishes, etc. Primary consumers of land are herbivorous animals such as grasshopper, rabbit, deer, cow, etc.

Secondary Consumers: The carnivorous animals feeding on the primary consumers are known as secondary consumers or second order consumers such as spiders, toad, frog, mole, etc.

Tertiary Consumers: The animals living on the secondary consumers are known as tertiary consumers or third order consumers such as tiger, lion, shark, eagle, etc.


It is also known as reducers or microorganisms. They are saprophytic organisms which act on dead matter and decompose them for their nutrition.

Certain heterotrophic bacteria and fungi break down the complex compounds of dead protoplasm, absorb some of the decomposed products and may release certain simpler substances for further utilization by the producers. These together form the decomposers.  They are very important to any ecosystem because the ecosystem could not perform very long without the presence of reducers.

Ecology and Ecosystem

The place where living organisms live with their surrounding forms its environment. Both physical and biotic environment together forms environment. Soil, water, air, light, temperature, topography, biogenic salt, pH, humidity, pressure, etc. form physical environment, whereas the plants, animals, microorganisms, food, parasites, enemies, etc. form the biotic environment. Living organisms and environments are interdependent.  With the combined interaction of these components, nature maintains a steady and stable continuity of life flow in the environment.


The branch of science which reveals the interrelationship between the living organism and the environment is known as ecology. German biologist Ernst Haeckel first proposed the term ecology in 1869. The term ‘Ecology’ is derived from the Greek word “Oikos” meaning ‘dwelling place’ or ‘house’ and “logos” meaning ‘knowledge.

Branches of Ecology


It is concerned with the study of the interactions of the individual organism or an individual species with the non-living and living factors of its environment. It is also known as species ecology or population ecology. The term “Autecology” was first established in the late 19th century by German Botanist. By studying the Autecology we understand the relationships between the environment and individual organism.


It is concerned with the study of groups of organisms of different species that are associated together as a unit in the form of a community. By studying the “Synecology”, we understand the relationships between the environment and communities. Synecology is also known as community ecology.

Importance of Ecology

The study of ecology is important because we understand the impact of natural resources on the earth and their interaction with biotic and abiotic factors. Here we make some reasons why ecology is important:

  • Ecology helps to conserve the environment.
  • Ecology helps to measure the damage of the environment that human being created.
  • Ecology provides information on how the world works.
  • It also provides facts on the interdependence between the people and the natural world.
  • By studying ecology, we can take part in the conservation efforts for ensuring the longevity of the planet.
  •  By studying ecology we understand how the planet works.
  • Ecology offers a helpful indication of the interdependence between the people and the natural world.
  • We can understand human activity on the environment.
  • Ecology provides the principal basis for nature conservation.
  • Ecology helps to identify ecological characteristics and how to preserve it.
  • It helps to predict the ecological effect of pollution by measuring the pollution levels.
  •  It helps to make predictions about future climate change.
  • Ecology makes easy to understand the communities and their interactions.
  • Ecology helps to monitor the threatened species more closely.
  • Ecology provides essential information about the benefits of the environment.
  • It helps to make ways for judicious use of earth`s natural resources.
  • It helps to make the environment healthy for future generations.
  • It provides information to understand the world around us.
  • It helps to improve our environment and protect human health.
  • The study of ecology offers to understand how pests and vectors behave and how aids in disease and pest control.
  • It makes people aware of their environment and encourages the adoption of a lifestyle that protects the ecology of life.


The ecosystem is the functional unit of ecology, which deals with the interrelation between the living and the non-living objects of the environment.  The term ecosystem was first used by Cristian Scientist Arthur Tansley in 1935. Almost all biotic community is formed from plants, animals, and microbes. The plants and animals of a particular area related to each other are called biotic community or simply community.

Important Terms Related to Ecosystem

Autotrophs: Chlorophyll-containing green plants are known as autotrophs. They act as producer in an ecosystem.

Homeostasis: It is the process during which the biological system tend to resist change and to remain in a state of equilibrium.

Biosphere: The parts of the earth i.e. the different strata of air, soil, and water, where living organisms survive or live together is known as the biosphere.

Plankton: The term “Plankton” was first introduced by German Ecologist Victor Hensen in 1887. The term plankton indicates any dead or living organism (plants and animals) that floats passively in water and which are more or less dependent on water currents or wind action for their movement. Plankton is of two types such as phytoplankton and zooplankton. Here autotrophic components are known as phytoplankton while heterotrophic components are known as zooplankton.

Benthos: The organisms attached with or resting on the bottom or living in the bottom sediments are known as benthos.

Nekton: Aquatic animals which can swim freely in water are known as nekton such as fish, whale, aquatic insects, etc.

Population: Population is defined as a group of organisms of the same species occupying a particular area. The term population is derived from the Latin word ‘populous’ meaning people. E.P. Odum (1971) defined the population as, “a population is a group of organisms of the same species occupying a specific area having characteristics, which are statistical measures that cannot be applied to individuals”.

Biotic Community: A biotic community is any assemblage of populations of living organisms in a prescribed area of habitat.

Types of Ecosystems

There are many types of ecosystems. Among them, some general types of ecosystems are described below:

Aquatic Ecosystem

Aquatic plants and animals form the aquatic ecosystem. It is the largest ecosystem because they represent 75% of the total ecosystem. It varies in size from an ocean to a pond or pool of water. The aquatic ecosystem can be further divided into two types such as Freshwater and saltwater ecosystem. The freshwater ecosystem includes ponds, lakes, streams, rivers, etc while the saltwater ecosystem includes seas.

Terrestrial Ecosystem

It is a certain terrestrial space or place where animals and plants live and develop. According to abiotic factors, terrestrial ecosystem comprises of the forest ecosystem, an ecosystem of grassland, desert regions, etc. It is one of the larger ecosystems which are also known as biomass or ecological regions.

Natural Ecosystem

It is a community of living and non-living beings, where every part cooperates together as a unit through a biological, physical and chemical process. The uniqueness of the natural ecosystem is that they are simply characteristic and their developments are not at all impacted by human activities. Forests, lakes, deserts, etc form the natural ecosystem.

Artificial Ecosystem

An artificial ecosystem is a man-made an ecosystem where animals, plants, and people live together in a specific area with their surroundings. Zoo parks, gardens, aquarium, etc create an artificial ecosystem because it is a human-made area where you keep animals and plants similar to their natural habitat.


The ecosystem which occurs in very small space that may be only a few centimeters with critical environmental factors such as temperature, nutrient supply,  chemical substances, solid substrates, gaseous substrates, etc. This type of ecosystem requires very exact conditions to exist.


The ecosystem occurs in a big space which encompasses huge amounts of flora and fauna associated with it. It is also called biomes and it has undergone changes throughout the history of the earth.  Examples: Lake of Maracaibo, the mountain range of the Andes or the Caribbean Sea, etc.

Conservation of Ecosystems

At present many ecosystems have faced risky conditions due to human activities. To make a better ecosystem, awareness about the conservation of the ecosystem is very important. They have intrinsic values because healthy ecosystems reduce global warming and provide food and medicines for our well-being.  In this case, the following points should be carefully kept in mind to make a better ecosystem.

  • Use of fuel energy should be reduced;
  • We should use environmentally friendly products that make safe environment;
  • We do not alter our surroundings;
  • Always we should respect our environment;
  • We try to make moderate use of water.
  • Limit all you can consumption and all waste. In this case, recycling would be best.