Tuesday, 12 November, 2019





  • Ecology is the branch of Biology that deals with the study of interactions between organisms and their environment.
  • Haeckel gave the term Ecology (1869)
  • Father of Indian Ecology – Ramdev Mishra.
  • Level of organisation – The level of ecology are divided in order from smallest in size to biggest.


Individual–>Population –>Species–>Biotic community (organisms)–>Ecosystem –> Biome–> Biosphere 


Organism –

  •  Organism are the basic unit of study in ecology. 


  • Population is group of individuals that belongs to same species.

Community –



  • Community is the sum of all different population found in a given area.
  • It constitutes biotic component (plants, animals, bacteria & fungi) of ecosystem.
    Species – A group of individuals with some morphology, anatomy and have the potential of breeding for producing fertile organisms of the come kind.
  • Ecosystem is system resulting from interaction of all living and non-living components of environment. Sun is the main source of energy.
  • A. G. Tansley, 1935 proposed the term ecosystem. All ecosystems are open system in the sense that energy and matter are transferred in and out.
  • Landscape have hetrogenous area composed of cluster of interacting ecosystem which are present in repeated manner.

Biome –

  • Bigger ecosystem of the world covering vast geographical areas.
    Biome is a biotic unit consist of both flora and fauna, But characterzed by particular type of Vegetational pattern. For ex – Tropical main ferest, Tundra.

Biosphere –


  • It is the largest unit of living systems.
  • Biosphere is earth crust or belt at which life is exist above and below the surface of earth is biosphere.
  • Biosphere consist of Hydrosphere, Lithosphere and Atmosphere


  • The abiotic components of an ecosystem include various physical and chemical factors. The physical factors having the greatest effect on the ecosystem are – light, temperature, precipitation, air, soil, fire and water.
  • However, chemical factors are pH, Salinity, Nutrient contents, Moisture contents (for terrestrial ecosystem), amount of toxic substances and level of “dissolved oxygen (in aquatic ecosystems).

Biotic Component –

  •  Biotic components include producers Consumer and detritus Producers are the autotrophic (self nourshing), generally chlorophyll – bearing organisms, which produce their own food.
  •  Consumers or phagotrophs are heterotrophic (other feeding) organisms. A consumer which derives nutrition by eating plants is called Primary consumer or herbivore (eg. grazing cattle).
  •  The secondary consumer or carnivore is an animal that devours the flesh of herbivore or other animals.
  • Decomposers or saprotrophs (Sapro – to decompose) are other hetertrophic organism, consisting mostly of bacteria and fungi which live on dead organic matter.


Food Chain


The transfer of food and energy from one organism to another organism in natural community is called food chain

Grass->rasshopper->Frog-> Snake->Hawk


  • Note – Any food chain started from producer and last in decomposer.
    Arrow of food chain indicates the direction of flow of energy. 90% energy is lost at every trophic level.
  • Trophic level refers to the organisms’ position in the food chain.
  • T1 is always producer.

Ecological Pyramid

  • Charles Elton first gave the concept of ecological pyramid.
    It is a graphic representation of trophic structure and function of producer, herbivors, primary carnivover, top carnivovers of a given ecosystem.
  •  The base of ecological pyramid is consist of producer (Green photosynthetic plant) and top is having carnivores.
types of pyramid nature
1.pyramid of number.

(Number of Individuals per unit area)
Upright is pond and grass lond ecosystem.
 Invested in tree ecosystem.
2.Pyramid of massUpright in grassland, and forest.,     
Inverted in aquatic ecosystem
3.Pyramid of energy It give true picture of Always upright   


Ecological Interaction


  •  Under natural conditions organisms live together influencing each other life directly or indirectly.

Table – Types of interaction between species

Interaction                        Species A Species B  Result
Neutralism      OONeither Population affected by the other.
Competition--  A & B compete for the some resource, each has a negative effect on the other.
Parasitism +-In this case species A is parasitic which is generally smaller than B, the host.
Predation-+ Spoon A is predator and species B is prey.
Amensalism-OSpecies A is inhibilted where as B is nor affected.
Commensalism       +OSpecies A becomes benefited where a B remains un affected
Protocoorporation ++   Ni fising bacteria
Mutualism                          ++Lichens   



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