Organism and population - Important revision notes for NEET/Jipmer/Board.

                           Ecology 

•  The term ecology was coined and described by – E.Haeckel
• Father of ecology – Reiter
• Father of Indian Ecology – Prof. Ram Deo Misra
• First of all term ecology was employed – Warming

Ecology is a branch of biology that deals with study of interaction between organisms and their environment.

Organism ~~ Environment

Organism and environment are organisation always interdependent, inter related or mutually reactive.

Branches of Ecology – It is based on organisation level

 1. Autecology – Study of the relation of a single species with its environment is known as autecology

 2. Synecology – Study of the relation of the group of different species with their environment is known as syncology.                                    

        ECOLOGICAL HIERARCHY

Organism --> Population (species) —> community --> Ecosystem --> Biome—> biosphere. 

size –> Increase

complexity –> Increases

                ORGANISM 

Organisms are the basic unit of ecology.

•  It may be small/large, unicellular/multicellular.
•  Fixed life span and organized life cycle (birth to death)
• Ecology at the organismic level is essentially physiological ecology.

                                POPULATION
A group of Individuals (members) of same species living at one place (specific geographical area) constitute a population.

•  Local Population or demes (Sub groups of population) – Population of organism inhabiting a particular area.

eg. Homosapiens inhabiting hills, plains

• Sister population – Different population of same species of organisms which are found in different places are known as sister population.
• Meta population – A group of local population which are interconnected by dispersing individuals.

 

                    Important gem  points 

1. Ecology at the organismic level also known as Physiological ecology.

2. The activities of key-stone species determine the structure of the community.

3. Stratification of lake and forest found according to the need of light.

4. The clear stratification is found in tropical rain forest.

5. In succession, climax community is always mesophytes.

6. Primary succession is slow while secondary succession is fast process.

Ecological Niche – Word is given by Grinnel. It is the functional role of any species in a ecosystem or community. In other words it is a occupational address or profession of a species it means it is a  functional position or status in an ecosystem.

•  Hyper parasitism —> A parasite living on another parasite

   e.g. Bacteriophages on bacteria.

•  Brood parasitism —> Parasitism in which the parasitic bird (cuckoo) lays its eggs in the nest of its host (crow) and lets the host incubate them, this relation is known as brood parasitism.
•  Holo parasite —> Parasite which are totally dependent upon the host for their requirement.          e.g. Rafflesia, (Total root parasite)          Cuscuta (Total stem parasite)

• Hemiparasite ® Parasite which partially depend on the host.              e.g. Viscum – on oak                 Loranthus – on mango

Note :

(1) Arceuthobium is the smallest parasitic angiosperm.

(2) Female Anopheles mosquito is not considered as parasite.

                   Golden points 

1.Mutualism is obligatory relationship, in which related species show co-evolution, co-extinction and co-existence.

2. In parasitism both host and parasite tend to co-evolve.

 

3. Predators help in maintaining species diversity in a community.

4. In competition fitness of one species is significantly lower in the presence of another species.

5. Gause's competitive exclusion principle states that two closely related species competing for thesame

resources cannot co-exist long period and the competitively inferior one will be eliminated.

6. Predation, parasitism and commensalism share a common characteristic - the interacting species live closely  together.

7. Herbivores and plants appear to be more adversely affected by competition than carnivores.

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