Ecology/ Nitrogen cycle

Ecology/ Nitrogen cycle

• Study of inter relationship between living organisms and their environment.
• Environment include both biotic and abiotic factors.
• Various population of living in a definite geographical region is called Biotic Community.
• Ecosystem or Ecological system word was first coined by the scientist namely Tansley.

Every ecosystem is made up of two components –

(A) Biotic component – Living part

(B) Abiotic component – Non living part

A. Biotic components:

It is divided into three parts –

1. Producer 2. Consumer 3. Decomposers

1. Producer:

Those components that make their own food. Like – green plants.

2. Consumer:

Those components that consumes the food made by plant. Consumers are of three types –

a. Primary consumers:

In this category those organisms are included that lives on green plants or some parts of them.

b. Secondary consumers:

In this category those organisms are included that depends on the primary consumers as their food. Like – fox, wolf, peacocks etc.

c. Tertiary consumers:

In this category those organism are included that depends on the secondary consumers. Like – Tiger, lion, cheetah etc.

3. Decomposers:

Mainly fungi and bacteria are included in this category. These decomposes dead producers and consumers and changes them into physical elements.

B. Abiotic component:

Abiotic components are as follows –

1. Carbonic substance, 2. Non-carbonic substance, 3. Climatic factor

Example: water, sun-light, temperature, air, humidity, soil, minerals etc.

• Food chain: transfer of energy from the producer through a series of organisms.

Ex: Grass → Goat →Human.

Where grass is producer while goat and human are primary and secondary consumer. Man is primary as well as secondary consumer.

• The term steppe is associated with bio-region grass lands.
• About 2 % of the world’s land area is tropical rainforest.
• Beef is the world growing appetite for food product which is the leading cause of tropical deforestation.
• Two components of ecosystem are biotic and abiotic.
• The resources which are obtained by biosphere and have life called Biotic resources.
• B-Diversity is also known as ecosystem diversity.
• Biosphere reserve: An ecosystem with plants and animals protected by law to support conservation of natural resources and help in learning as well as research for sustainable development.
• Dr. Dhrubajyoti Ghosh is associated with ecology, who work on the east Kolkata wetland and its wise use.
• Red Data Book deals with plants on the verge of extinction.
• Thermosphere lies above the mesosphere in which region temperatures increases with height.
• The sphere of living matter together with water and soil on the surface of earth is called lithosphere.

Nitrogen Cycle

• Nitrogen fixation is a process in which free atmospheric nitrogen is converted by living
• Organism into nitrogenous compound that can be used by plant.
• Ammonification : Formation of ammonia from organic compound like proteins and nucleic acid by micro organism.
• Nitrification : A process in which ammonia is converted into nitrites and nitrates by Nitrobacteria.
• Plants use nitrogen mostly in the form of nitrate.
• Denitrification : It is the process of converting fix nitrogen like nitrates, nitrites and ammonia into free nitrogen by denitrifying bacteria eg Pseudomonas.