Darwinism # ডারউইন এর মতবাদ
Postulates of Darwinism :
A. Fact: l :Prodigality of production
ll. Constancy of food and space
Deduction:
Struggle for existence
B. Fact l : Struggle for existence
ll : Omnipotence of variation among the individuals.
Deduction :
Survival of the fittest
C. Fact : l: Survival of the fittest
ll: Operation of Natural Selection among the surviving individuals
Deduction:
Origin of new species .
Explanation:
Prodigality of production: Reproduction rate in organisms is very high .
Constancy of food and space: Due to the Prodigality of production crowdedness results but space and food production remained constant .
Deduction: Over crowdedness with limited space and food create a sharp compitition which leads to the struggle for existence.
The struggle may be of intraspecific , Interspecific and environmental .
Omnipotence of variation among the individuals: Struggle for existence is universal & variations become the rule of nature . A few variations are benificial and rest harmful.
Deduction: If good variations are collected and transfered to the offspring , the species will survive and continue , insted of that the species will be extinct . It is called survival of the fittest .
Operation of Natural selection: Nature selects good varities among the fitest for continuity.
Deduction : The individuals which will be selected by nature and acumulate good variations in subsequent generations will appear as a new population and be quite different from the original population and will treat as a new species.
Adaptive radiation and Darwinism:
Darwin conjectured that Finches of Galapagos islands having different beak shape arose from same ancestral seed eating ground finch and probably due to trouble in main land migrated to newly formed islands where in course of time beaks altered by natural selection on the basis of availability of food pattern.
Comments
Post a Comment