Explain the concept of struggle for existence.

Explanation

Struggle for exitence is one of the principles in the theory of nutural selection as proposed by Drawin.Individuals multiply in geometric ratio but the spce and food remain constant.This leads to competition for survival of life.This competition is called struggle for exitence.The struggle may be intraspecific,interspecific or environmental.(1)Intraspecific struggle:Intraspecific struggle is the competition among the individuals of the same species.This is a severe struggle because the need and approach of all competing organisms is similar,e.g.,struggle between two herbivore animals for getting grass.(2)Interspecific struggle: Interspecific struggle is the struggle between the organisms of different species living together,Individuals of one species compere with the other species for food shelter and breeding places,e.g., a parasite and host or a predator and prey show interspecific struggle.(3):Environmental struggle:Environmental struggle is struggle shown by all living forms aganist adverse environmental condition or against natural calamities like extreme heat or cold,drought,stroms,earthquakes,volcanic eruptions,etc.