Basic Concepts of the Environment - EnvironReview (2023)

The term environment is derived from the French word “environ” and means everything that surrounds us. It is defined as the complex of physical, chemical, and biotic factors that act upon an organism or an ecological community and ultimately determines its form and survival.

The Element of Environment is constituted by the interacting systems of physical, biological, and cultural elements inter-related in various ways, individually as well as collectively.

Space, landforms, water bodies, climate, soils, rocks, and minerals are the physical elements which determine the variable character of the human habitat, its opportunities as well as limitations.

The biological environment consists of Plants (flora) and animals (fauna). All the organisms work to form their social groups and organizations at several levels. Thus, the social environment is formed. In this social environment, the organisms work to derive matter from the physical environment for their sustenance and development. This process leads to the economic environment.

The cultural elements of the environment are influenced by the level of development that humans have attained in the path towards progress. The level of development is manifested in economic, social, and political elements which are essentially man-made features, which make up the cultural background.

Types of Environment

The environment is divided into two types: the natural environment and the built environment. The natural environment encompasses all living and non-living things occurring naturally in the area while the built environment refers to the human-man made surroundings that provide the setting for human activities (e.g. buildings, parks, cities, and supporting infrastructures such as transport, water supply, and energy supply).

Components of Environment

The environment is divided into four major components which are lithosphere, hydrosphere, atmosphere, and biosphere; these correspond to rocks, water, air, and life respectively.

• Lithosphereis the outermost layer of earth called the crust, which is made of different minerals. Its depth can reach up to 100 kilometers and is found on both land (terrestrial crust) and oceans (oceanic crust). The main component of the lithosphere is the earth’s tectonic plates.
• Hydrospherecomprises all forms of water bodies on earth including oceans, seas, rivers, lakes, ponds, streams, etc. It covers 70% of the earth’s surface. 97.5% of water found on Earth is in the oceans in the form of saltwater. Only 2.5 % of the water on Earth is freshwater. Out of this, 30.8% is available as groundwater and 68.9% is in frozen forms as in glaciers. The amount of 0.3% is available in rivers, reservoirs, and lakes and is easily accessible to man.
• Atmosphereis a gaseous layer enveloping the Earth. The atmosphere with oxygen in abundance is unique to Earth and sustains life. It mainly comprises 78.08% nitrogen, 20.95% oxygen, 0.93% argon, 0.038% carbon dioxide, and traces of hydrogen, helium, and noble gases. The amount of water vapour present is variable.
• Biosphererefers to all the regions on Earth where life exists. The ecosystems that support life could be in the soil, air, water, or land. The term Biosphere was coined by Geologist Edward Suess who used this term for a place on Earth where life can be found. Biosphere refers to the sum total of all living matter, the biomass, or biota. It extends from the polar ice caps to the equator, with each region harboring some life forms suitable to the conditions there.

Environmental science is an interdisciplinary subject. It draws from a whole gamut of subjects like geography, geology, biology, chemistry, physics, botany, zoology, genetics, sociology, rural development, urban planning, policy development, politics, cultural studies, economics, ethics, law, education, health, communication, and philosophy. It is a science that will address the biggest challenges encountering the planet in this millennium. It studies the complex interaction of humans with nature and provides guidelines for the way forward.

Ecology and Ecosystem

The study and understanding of Ecology is an integral part of Environment Science learning. Every living being however small or big depends on the environment for its existence and also competes with others for essentials in life. For survival, living beings form groups and different groups compete with each other for survival. The study of interrelationships between organisms and the group of organisms is called the science of Ecology. The word ecology derived from the Greek word ‘Oikos meaning habitation, and logos meaning discourse or study, implies a study of the habitations of organisms. Ecology was first described as a separate field of knowledge in 1866 by the German Zoologist Ernst Haeckel, who invented the word Ecology for ‘the relation of the animal to its organic as well as its inorganic environment, particularly its friendly or hostile relations to those animals or plants with which it comes in contact. Ecology is hence the study of the interrelationship among plants and animals and their interactions with the physical environment.

An Ecosystem is defined as a group of plants, animals, or living organisms living together and interacting with the physical environment in which they live. An Ecosystem has a more or less a closed boundary and the flow of mass in and out of the system is very less as compared to the internal movement of the mass. Ecosystems can be large or small. Examples of large ecosystems are rain forests, deserts, salt marshes, coral reefs, lakes and ponds, Open Ocean, grasslands, etc. An ecosystem is made up of organisms, which established themselves in the given area and have continued to survive and have not become extinct. The species hence possess genes, which fit the environment and are tolerant of disturbances like a flood, fire, drought; and a reproductive rate that balances the natural catastrophes. The birth rate of organisms will have to be optimized to avoid overpopulation and hence starvation. The human population is a good example. As technological evolution brings down our normal death rate, social evolution lowers the birth rate to strike a balance. Biological evolution is however much slower than social or technological.

In ecosystems, organisms constantly adjust themselves to geologic or climatic changes and to each other. As an example, the bats developed sonar to find the moths and the moths developed ears sensitive to the bat’s frequency. The behavioral adaptations are also reflected in the anatomy or the body structure of the organisms. An ecosystem does not remain constant. Changes occur in it continuously in one form or the other. It is significant that even a small change in one part of an ecosystem is felt throughout the ecosystem. This establishes the importance of inter-linkages in an ecosystem. However, the system tries to maintain the stability of an ecosystem depends on its diversity. More the diversity more is interdependence and more is the resistance to change.

Functions of Ecosystem

1. The ecosystem performs the most important function of satisfying the requirements of the different aspects of the biotic component.
2. It is through an eco-system that the interaction, as well as the interdependence between the biological component and the physical component in the environment, takes place, this interdependence is between biotic and biotic components. For example, plants depend on solar energy and soil. The interdependence is also between different aspects within the biotic components. For example, carnivores depend on herbivores.
3. Eco-system leads to the transfer of food energy and nutrients from one source to another source.
4. The different forms of eco-system are beneficial because they lead to positive effects on the environment which in turn helps the living organisms.
5. Eco-systems have helped human beings by providing materials as well as services necessary for survival as well as development.

Ecosystem Integrity

Ecosystem integrity is the quality of a naturally unmanaged or managed ecosystem in which the natural ecological processes sustain the function, composition, and structure of the system. Ecosystem integrity provides a strong base for understanding the fundamental causes of environmental degradation and pollution, and linkages to human health; it also provides a strong justification needed to protect the environment and public health.

Ecological Balance

Ecological balance is a theory stipulating that natural conditions, including numbers of various animal and plant species, remain stable on their own through variations over time. The theory, also known as balance of nature, also holds that natural equilibrium can be changed significantly by new species entering an ecosystem, the disappearance of some species, man-made changes to the environment, or natural disasters.

Ecological Stress

Ecological stress is a disturbance in ecological balance or ecosystem equilibrium. The disturbance can be physical, chemical, and biological. It can be chronic or episodic and can occur when foreign substances or agents are introduced in concentrations large enough to affect some components of the ecosystem, thereby causing ecological change.

When the exposure to environmental stressors increases or decreases in intensity, ecological responses result. Stressors can be natural environmental factors, or they may result from the activities of humans. Some environmental stressors exert a relatively local influence, while others are regional or global in their scope. Stressors are challenges to the integrity of ecosystems and to the quality of the environment.

Species and ecosystems have some capacity to tolerate changes in the intensity of environmental stressors. This is known as resistance, but there are limits to this attribute, which represent thresholds of tolerance. When these thresholds are exceeded by further increases in the intensity of environmental stress, substantial ecological changes are caused.

Environmental Stressors can be grouped into the following categories:

1. Physical stress refers to brief but intense exposure to kineticenergy. This is a type of ecological disturbance because of its acute, episodic nature. Examples include volcanic eruptions, windstorms, and explosions.
2. Wildfireis also a disturbance, during which much of thebiomassof anecosystemis combusted, and the dominant species may be killed.
3. Pollutionoccurs when chemicals are present in concentrations large enough to affect organisms and thereby cause ecological changes. Toxic pollution can be caused by gases such assulfur dioxideandozone, by elements such as arsenic,lead, and mercury, and bypesticidessuch as DDT. Inputs ofnutrientssuch as phosphate and nitrate can influence productivity and other ecological processes, causing a type of pollution known aseutrophication.
4. Thermal stress occurs when releases ofheatinfluence ecosystems, as happened in the vicinity of natural hot-water vents on theoceanfloor, and near industrial discharges of heatedwater.
5. Radiationstress is associated with excessive loads of ionizing energy. This can occur on mountain tops where there are intense exposures to ultraviolet radiation, and in places where there are exposures to radioactive materials.
6. Climatic stress is associated with excessive or insufficient regimes oftemperature, moisture, solar radiation, and combinations of these.Tundraand deserts are examples of climatically stressed ecosystems, while tropical rainforests occur under a relatively benign climatic regime.
7. Biological stresses are associated with the diverse interactions that occur among organisms of the same or different species. Biological stresses can result fromcompetition, herbivory, predation, parasitism, anddisease. The harvesting and management of species and ecosystems by humans is a type of biological stress. The introduction of invasive, non-native species may be regarded as a type of biological pollution.

Environmental Problems

An environmental problem arises whenever there is a change in the quality or quantity of any environmental factor which directly or indirectly affects the health and well-being of man in an adverse manner. Environmental problems can be studied from two different viewpoints. One is simply to look for adverse effects without regard to their origin in order to detect trends that call for further investigation; the other is to try to understand the cause and effect relationships, which make a better prediction and proper management possible.

Environmental problems are consequences of pollution and degradation: they include but not limited to:

1. Pollution
2. Soil Degradation
3. Global Warming
4. Overpopulation
5. Natural Resource Depletion
6. Generating Unsustainable Waste
7. Waste Disposal
8. Deforestation
9. Polar Ice Caps
10. Loss of Biodiversity
11. Climate Change
12. Ocean Acidification
13. The Nitrogen Cycle
14. Ozone Layer Depletion
15. Acid Rain
16. Water Pollution

Environmental Pollution

As a result of over-population, rapid industrializations, and other human activities like agriculture and deforestation, etc., the earth became loaded with diverse pollutants that were released as by-products.

Environmental pollution is defined as the undesirable change in physical, chemical and biological characteristics of the air, land and water. It is the introduction of contaminants into the natural environment that cause adverse change.

Pollutants may cause primary damage, with direct identifiable impact on the environment, or secondary damage in the form of minor perturbations in the delicate balance of the biological food web that are detectable only over long time periods.

Pollutants are grouped under two classes:

• Biodegradable pollutants – Biodegradable pollutants are broken down by the activity of micro-organisms and enter into the biogeochemical cycles. Examples of such pollutants are domestic waste products, urine and faucal matter, sewage, agricultural residue, paper, wood, and cloth, etc.
• Non- Biodegradable pollutants have stronger chemical bonds. They do not break down into simpler and harmless products. These include various insecticides and other pesticides, mercury, lead, arsenic, aluminum, plastics, radioactive waste, etc.

Pollution is classified according to the components of the environment that are polluted. Examples are; Air pollution, Water pollution, Soil pollution (land degradation) and Noise pollution.

Environmental Degradation

It is a well-known fact that there is an interaction between various components of the environment. The atmosphere, the lithosphere, the hydrosphere, and the biosphere are interdependent on each other in a symbiotic manner. One component cannot function without the others. The inter-relationship between the various components is vital in the achievement of a dynamic equilibrium condition in the environment. The absence or extended disturbance of one component may render dynamic equilibrium unattainable and leads to environmental degradation.

Environmental degradation is described as the erosion of the natural environment through the depletion of resources, the destruction of ecosystems, and the extinction of plant and animal species. Environmental degradation is caused in a variety of ways, predominantly by human actions, however, natural events can also result in the deterioration of an environment. Earthquakes, volcanoes, and intense rainfall events can all affect the environment in negative ways. Environmental changes may be driven by many factors including economic growth, population growth, urbanization, intensification of agriculture, rising energy use, and transportation. The extraction of natural resources and the production of waste and other pollutants have severely degraded many of the planet’s ecosystems. Mining, deforestation, fossil fuel burning, and pollution are just some of the human activities that have led to environmental degradation.

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