Unit 1: Introduction to Ecology

 Unit 1:        Introduction to Ecology

Point to be Covered :1.     History of ecology  2.     Autecology 3.     Synecology

 

Ecology is the study of the interactions between living organisms and their environment.

or

Ecosystem is a community of organisms (biotic components) and their environment (abiotic components) interacting as an ecological unit.

Or

The branch of biology dealing with the relations and interactions between organisms and their environment, including other organisms.

Or

The branch of BIOLOGY that deals with the relations of organisms to one another and to their physical surroundings

In 1869, Earnst Haeckel coined the term “ecology”. It comes from the Greek word Oikos meaning “household” and logos meaning “study of”, therefore the “study of nature’s household”.

Thus, ecology deals with the organism and its environment

Levels of Ecological Organization

Ecology is the scientific study of the distribution and abundance of life along with the interactions between different organisms and their natural environment.

Ecosystems can be studied at small levels or at large levels. The levels of organization are described below from the smallest to the largest:

What are the 5 Levels of Ecology?

Organism → Population → Community → Ecosystem → Biosphere

 

Organism

It is the lowest level of organization, which includes both unicellular and multicellular organisms. All the living species in this level exhibits all the characteristics required for the existence of life.

Population

A population is a group of individuals of a single species living together within a particular geographic area. They interbreed and compete with each other for resources.

Community

It refers to the several populations that interact and inhabit a common environment and are interdependent.

Ecosystem

It is a set of all living species and abiotic components existing and interacting in a given area. There is an interaction with both living and nonliving components of the environment.

Biosphere

 It is the highest level of organization. It is the global ecological system which consists of all the living organisms and other factors which supports life. Biosphere mainly refers to the part of the earth’s crust.

 

Diagram showing interrelation between Biotic and abiotic Components

 

Biotic Components of Ecosystem

The living components of an ecosystem are called the biotic components. Some of these factors include plants, animals, as well as fungi and bacteria. These biotic components can be further classified, based on the energy requirement source. Producers, consumers, and decomposers are the three broad categories of biotic components.

 

Producers: Producers are the plants in the ecosystem, which can generate their own energy requirement through photosynthesis, in the presence of sunlight and chlorophyll. All other living beings are dependent on plants for their energy requirement of food as well as oxygen.

Consumers: Consumers include herbivores, carnivores, and omnivores. The herbivores are the living organisms that feed on plants. Carnivores eat other living organisms. Omnivores are animals that can eat both plant and animal tissue.

Decomposers: Decomposers are the fungi and bacteria, which are the saprophytes. They feed on the decaying organic matter and convert this matter into nitrogen and carbon dioxide. The saprophytes play a vital role in recycling the nutrients so that the producers i.e. plants can use them once again.

Abiotic Components of Ecosystem

Abiotic components are the physical and/or the chemical factors that act on the living organisms at any part of their life. These are also called as the ecological factors. The physical and chemical factors are characteristic of the environment.  Light, air, soil, and nutrients, etc. form the abiotic components of an ecosystem.

The abiotic factors vary from ecosystem to ecosystem. In an aquatic ecosystem, the abiotic factors may include water pH, sunlight, turbidity, water depth, salinity, available nutrients and dissolved oxygen. Similarly, abiotic factors in terrestrial ecosystems can include soil, soil types, temperature, rain, altitude, wind, nutrients, sunlight etc.

The sun is the energy source. Producers/plants use this energy to synthesize food in the presence of carbon dioxide and chlorophyll. The energy from the sun, through several chemical reactions, turns into chemical energy.