Ecology and Ecosystem

Ecology can be defined as a scientific study of the interactions of organisms with their physical environment and with each other.

A habitat in the ecological sense is the totality of the physical and chemical factors that constitute the general environment.

A system consisting of biotic and abiotic components is known as ecosystem. All these components in ecosystem are inter related and interact with each other. 

• Different types of ecosystems exist with varying ranges of environmental conditions where various plants and animal species have got adapted through evolution. This phenomenon is known as ecological adaptation.

All 

ecosystems consist of abiotic and biotic factors. 

• Abiotic factors include rainfall, temperature, 
  sunlight, atmospheric humidity, soil 
  conditions, inorganic substances (carbon 
  dioxide, water, nitrogen, calcium, phosphorus, 
  potassium, etc.). 
• Biotic factors include the producers, (primary, secondary, tertiary) the 
  consumers and the decomposers.

Ecosystems are of two major types: 

1. Terrestrial, and 
2. Aquatic 

"Terrestrial ecosystem" can be further be classified into ‘biomes’. 

• A biome is a plant and animal community that covers a large geographical area. 

The boundaries of different biomes on land are determined mainly by climate. Therefore, a biome can be defined as the total assemblage of plant and animal species interacting within specific conditions. 

• These include rainfall, temperature, humidity and soil conditions. 
• Some of the major biomes of the world are: forest, grassland, desert and tundra biomes.

"Aquatic ecosystems" can be classified as marine and freshwater ecosystems. 

• Marine ecosystem includes the oceans, coastal estuaries and coral reefs. 
• Freshwater ecosystem includes lakes, ponds, streams, marshes and bogs.