Ecology and Environment

Date: January 19, 2018

Ecology environment organisms interactions energy and matter flow

Ecology and Environment

Chapter 1: Introduction to ecology and terminology

Ecology by definition is the branch of science dealing with the interaction between organism and its environment.

The study of Ecology becomes important for various aspects regarding environment, its structure, functioning, regulation, and components as well as includes study of organisms, their hierarchy and their interaction amongst each other. This also helps us to understand the principles needed for sustainable use of resources, their maintenance and culmination of other ecological problems at local, regional and global levels.

Ecological hierarchy: Ecology can be understood as the spectrum of several levels of organization known as ecological hierarchy as explained Fig 1 with examples. In ecological hierarchy, organism are the basic unit of study in ecology, and when various organisms of same species (refer to the definition of species which is organisms capable of interbreeding and produce fertile offspring) are located at a place constitutes a population. When multiple populations of plants, animals, bacteria and fungi live at an area and interact amongst each other it constitutes a Biological community. Afterwards, components of biological community upon interacting with physical environment (comprising of temperature, water, air, soil, rainfall, sunlight, defoliation etc.) makes an ecosystem. On larger scale, Ecosystems with distinct vegetation type and climate is referred as a Biome. Some examples of terrestrial biomes are desert, temperate deciduous forest, tropical rain forest etc. On global scale, all earth’s terrestrial biomes and aquatic systems constitute a Biosphere which is actually the highest grade of ecological hierarchy. It can be said that planet earth is one big biosphere constituting many biospheres and ecosystems functioning.

Fig 1:

In this hierarchical organization, the place where an organism lives is called its habitat. This is characterized by various specific attributes possessed by that place only. For example, plants growing in saline soils would not by natural means grow in soils of natural pH and vice versa. Similarly, Ecological niche of an organism represents a range of conditions it can tolerate the resources it utilizes, and its functional role in the ecological system. Each species has a distinct niche and no two species are believed to occupy exactly the same niche.

Environment its structure and function:

Organisms perform various functions in any ecosystem and different organisms show varied forms, physiology, behavior, distribution and adaptations to their respective environment. Thus it can be stipulated that environment is the sum total of all biotic (living) and abiotic (non-living) factors that surround and potentially influence any organism (Fig 2). Some of these components serve as resources whereas others serve as regulatory factors and these are interlinked and interdependent. Organisms (their populations and the communities they form) constitute the biotic part of the environment whereas lithosphere (soil), hydrosphere (water) and atmosphere (air) constitute the physical or abiotic factors. Depending upon theses physical attributes properties of environment varies from place to place. The activities of organisms also influence the hydrosphere, lower atmosphere and near surface part of the lithosphere through exchange of energy and matter.

Fig 2:

The short term properties of atmosphere (rainfall, temperature, pressure, humidity, sunlight, cloud cover and wind intensity) at a given place and time is called as weather. Additionally, the average weather of an area is defined as its climate which represents seasonal patterns of the atmospheric conditions at that place. The climatic conditions of a certain area are solely responsible for determining the soil profile thus vegetation of that specific place.