Comprehensive Environmental Topics: Wildlife, Pollution, Climate Change, Renewable Energy, and Conservation Initiatives

Understanding Ecology: Definition, History, and Environmental Components

Ecology comes from the Greek words ‘Oikos’ meaning home or place to live in, and ‘logos’ meaning study. Literally, it is the study of the home of nature.

Ecology is defined as the scientific study of the relationship of living organisms with each other and with their environment.

It deals with the ways in which organisms are moulded by their environment and how they make use of environmental resources, including energy flow and mineral cycling.

• History of Ecology

  The roots of ecology lie in Natural History, which is as old as human civilization itself. Since early history, humans have engaged with ecology practically, knowingly and unknowingly.

  In primitive societies, every individual was required to have an intimate knowledge of their environment for survival, such as understanding the forces of nature, plants, and animals around them.

  Our ancient Indian texts provide numerous references to ecological principles. Classical texts of the Vedic period such as the Vedas, Samhitas, Brahmanas, and Aranyakas-Upanishads contain detailed ecological concepts.

  The Charaka-Samhita and the Sushruta-Samhita show that people during this period had a good understanding of plant and animal ecology.

  These ancient texts classify animals based on habit and habitat, land types in terms of soil nature, climate, and vegetation.

  Charaka-Samhita states that air, land, water, and seasons are indispensable for life, and polluted air and water are injurious to health.

• Environment and Its Components

  The environment is defined as the sum total of living and non-living components, influences, and events surrounding an organism.

  All organisms, from viruses to humans, are obligatorily dependent on each other and on their environment for food, energy, water, oxygen, shelter, and other needs.

  The relationship between organisms and their environment is highly complex, involving both biotic (living) and abiotic (non-living) components.

  The environment is dynamic; both biotic and abiotic factors are continuously changing.

  • Abiotic Components

    • Energy
    • Radiation
    • Temperature and Heat Flow
    • Water
    • Atmospheric Gases and Wind
    • Fire
    • Gravity
    • Topography
    • Soil
    • Geologic Substratum

  • Biotic Components

    • Green Plants
    • Non-Green Plants
    • Decomposers
    • Parasites
    • Symbionts
    • Animals
    • Man

  For instance, considering the environment of a fish in a pond:

  • External Environment of Fish

    • Consists of abiotic components such as light, temperature, and water, containing dissolved nutrients, oxygen, other gases, and organic matter.
    • The biotic environment includes microscopic organisms called plankton, along with aquatic plants, animals, and decomposers.

  • Internal Environment of Fish

    • Enclosed by the outer body surface.
    • The internal environment is relatively stable compared to the external environment, although not absolutely constant.
    • Injury, illness, or excessive stress can upset the internal environment.
    • For example, if a marine fish is transferred to a freshwater environment, it will not be able to survive.

Levels of Organization in Ecology

Ecology operates across various levels of biological organization, with six primary levels that help understand the intricate web of life. These levels include:

• Individual

  An individual organism refers to a single living entity capable of independent functioning. It can belong to any category of life, such as plants, animals, bacteria, fungi, or others. The individual is composed of various organs and organelles that work in harmony to support vital life processes.

• Population

  A population consists of a group of organisms, typically from the same species, occupying a designated area during a specific time frame.

  The growth rate of a population measures the percentage change in the population size between two distinct times. This rate can be either positive (growth) or negative (decline).

  Factors contributing to population increase include reproduction and immigration, while factors such as death and emigration contribute to a decrease.

  The abiotic and biotic factors of the environment limit population growth, dictating the carrying capacity of the habitat.

  Population density is the relationship between the number of individuals in a given area and the space they occupy.

• Community

  In nature, populations of different species rarely exist in isolation. Species often depend on one another for resources and survival. For example, animals rely on plants for food and shelter, while plants depend on animals for pollination, seed dispersal, and nutrient cycling facilitated by microorganisms.

  Communities are generally identified based on the dominant plant species, such as a grassland community, which is primarily dominated by grasses, though it also includes shrubs, trees, and associated fauna.

  A community is dynamic and fluid; its composition can change based on environmental factors, and its size can vary from very large to small.

  Fun Fact: According to NASA research, the skies over North India are periodically filled with a dense layer of aerosol particles, especially around the southern Himalayas, Bangladesh, and the Bay of Bengal.

  • Types of Community

    Communities can be categorized into two primary types based on their size and the degree of independence:

    • Major Communities – These are large, well-organized communities that rely mainly on external energy, specifically the sun. They are self-sustaining and independent of neighboring communities' energy and nutrient cycles. An example is the tropical evergreen forests of the North-East.
    • Minor Communities – These communities rely heavily on the surrounding major communities and are often referred to as societies. They are secondary groups within a larger ecosystem and cannot fully function independently regarding energy and nutrient cycles. For example, a patch of lichen on a cow dung pad.

  • Structure of a Community

    Within a community, both the number of species and their population sizes can vary significantly. Communities may be dominated by a few species or host a broad variety of life.

    The environmental factors, including climate and available resources, shape the community's composition and the arrangement of its species.

    The structure of a community refers to the roles and interactions of its different populations, their distribution, the diversity of species, and the environmental features that govern the community's makeup.