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EVOLUTION



origin of species is written by Charles Darwin in 1859


Herbert Spencer coined the term 'survival of the fittest.'


Lamarck gave the theory of progressive use and disuse of organs and believed in the inheritance of acquired characters.


an experiment to prove that organic compounds were the basis of life was performed by Stanley Miller.


nucleoproteins gave probably the first sign of life.


a single chromosome contains hundred to thousands of genes.


genetics is the study of inheritance.


Y chromosome does not have any allele linked to it


Three botanists - Hugo DeVries, Carl Correns and Erich von Tschermak ,independently rediscovered Mendel's work in the same year, a generation after Mendel published his papers.


Evolution can be described as generation and shaping of diversity by environmental selection


extinct species must have existed at some time:- this statement describes evolution


java man, peking man and heidelberg man are the fossils of "homo erectus".


crow magnon is the fossil of an early homo sapien that lived about 40000 years ago.


allopatric speciation is speciation that happens when 2 populations of same species become isolated from each other due to geographical changes.

it is also known as geographic speciation.


the swan neck experiment by louis pasteur disapproved the spontaneous generation theory which stated that life was generated from inanimated matter.


this theory was set up to prove that particles in the air(germ theory) rather than the air itself(spontaneous generation) led to fermentation.


bar eye character in "DROSOPHILA" is by duplication in X-chromosome.


monohybrid ratio is 3:1

dihybrif ratio is 9:3:3:1


Planaria has rudimentary eyes.


primitive earth had a reducing atmosphere because of the absence of free oxygen.

free oxygen first evolved due to the presence  of blue green alga and later on plants which release free oxygen as by product which made the atmosphere oxidizing later on


blood group O is a recessive trait.


adaptations can either be temporary or permanent.


analogous organs indicate convergent evolution.


PARAPATRIC SPECIATION:- in this type of speciation,2 subpopulation of a species evolve reproductive isolation from each other while continuing to exchange genes.


PERIPATRIC SPECIATION:- in this type of speciation, 2 subpopulations are geographically isolated from each other.its primary characteristic is that one of the populations is much smaller than the other one.genetic drift takes place.





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