Everything that a man needs comes from his surrounding environment, viz., food, fuel, water, shelter, energy, etc. It is the same for other living beings. But Man, over the periods to quench his thirst, exploited nature so much that now the environment is not able to reach its homeostasis.

Homeostasis is the tendency of organisms to auto-regulate and maintains its internal environment in a stable state.
If homeostasis is successful, life continues; if unsuccessful, disaster or death ensues. The stability attained is actually a dynamic equilibrium, in which continuous change occurs yet relatively uniform conditions prevail.

There is widespread degradation of the environment, extinction of animals and plant species, loss of forests, pollution of air, water, and sound. All this had been done without the proper assessment of the consequences of the acts of humans on the environment.

Thus, it is important to understand the environment before we make further damage to the earth which is our Home.

What is the Environment?

The word environment is derived from the French word “Environer / Environner”, which refers to the neighbourhood.
Everything that surrounds or affects an organism during its lifetime is collectively known as its environment, which comprises both living (biotic) and nonliving (abiotic) components. Each part of the environment is called an ecological factor.
In a biological sense, environment constitutes the physical (nutrients, water, air) and biological factors (biomolecules, organisms) along with their chemical interactions (chemical cycles – carbon cycle, nitrogen cycle, etc.) that affect an organism or a group of organisms.
All organisms (from viruses to humans) are obligatorily dependent on the environment for food, energy, water, oxygen, shelter, and other needs.
The environment is defined as ‘the sum total of living, non-living components, influences and events, surrounding an organism’.
And we can say that this environment constitutes two components, viz., abiotic and biotic components. These both are not static but are in flux and keep on changing continuously.
- Biotic components are living. Example plants, animals, parasites, decomposers, Man, etc.
- Abiotic components are non-living. Example energy, radiation, heat flow, water soil, air, etc.
The relationship and interaction between organisms and the environment are highly complex. No organism can live alone without interacting with other organisms. So, each organism has other organisms as a part of its environment. Each and everything with which we interact or which we need for our sustenance forms our environment.

Types of Environment:

The environment can be classified into two broad types:

Natural environment: Consists of all naturally occurring living and non-living things, such as forests, oceans, deserts, and the atmosphere. Natural ecosystems form organically without significant human intervention.
Human-made environment (or Anthropogenic environment): Refers to areas created or modified by human activities. This includes urban environments like cities and towns, as well as agricultural lands, industries, and built infrastructure like roads and bridges.

Functions of the environment:

The environment performs several vital functions for all living organisms:

Provides resources: Supplies essential renewable (like sunlight) and non-renewable (like fossil
fuels) resources used for survival and economic development.
Sustains life: Provides the fundamental conditions necessary for life, including food, water, air, and suitable temperatures.
Assimilates waste: Absorbs and processes waste products from consumption and production
through natural processes.
Enhances quality of life: Offers aesthetic value through natural landscapes, which is important for human physical and mental well-being.

What `Ecology’ Really Is?

‘Ecology may be defined as the scientific study of the relationship of living organisms with each other and with their environment.’ Ecology is the study of organisms and how they interact with the environment around them.
The term ecology was first coined in 1869 by the German biologist Ernst Haeckel. It has been derived from two Greek words, ‘Oikos’, meaning home or estate, and ‘logos’ meaning study.
The emphasis is on relationships between organisms and the components of the environment namely abiotic (non-living) and biotic (living).
It deals with the ways in which organisms are molded by their environment, how they make use of environmental resources including energy flow and mineral cycling.

Types of Ecology

Organism Ecology
- This is the study of organisms’ responses to stimuli caused by the physical environment. The organisms adapt to the environment either happily or ignore its effects. A physical change in the environment will show a change in behaviour or physical attributes.
Population Ecology
- The natural process is that all organisms will grow and die. The factors by which they will populate are the size of the colony, birth and death rates, and population growth rate.
Community Ecology
- The association of populations of two or more different species occupying the same geographical area.
- Competition and mutualisms are key interactions to maintaining a community.
Ecosystem Ecology
- This is the community of living organisms, along with non-living environments like air, water, and soil.
Landscape Ecology
- The exchange of energy, materials, organisms and other products between the ecosystems is known as landscape ecology.
Global Ecology
- The effect of change in energy and matter exchange on the function and distribution of organisms in the environment.

When and how the ecology started?

The genesis ecology is as old as human civilisation. In primitive societies, every individual was required to have an intimate knowledge of his environment for their survival, i.e., about the forces of nature and of plants and animals around him.
The ancient Indian classical texts have references to the principles of ecology. The ancient Vedas, the Samhitas, the Brahmanas, and the Aranyakas-Upanishads contain many references to ecological concepts.
The Indian treatise on medicine, the Charaka Samhita, and the surgical text Susruta Samhita show that people during this period had a good understanding and knowledge of plant and animal ecology.
We came to know that ecology is the ‘scientific study of the relationship of living organisms with each other and their environment’.