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List of Scientists and their Contributions | Class-12 Biology

Scientist and their contribution in Class-12 Biology NCERT Book

Dear students, here I have tried to compile all the scientists and their contributions given in the NCERT Class-XII Biology Textbook.

If you have any suggestions or additions, please do put in the comments section.

Happy Studying 🙂

ScientistContribution
Gregor Johann Mendela) Father of genetics
b) Conducted experiments for the first time to understand the pattern of inheritance and variation.
Reginald C PunnettPunnett square
GaltonPolygenic inheritance
De vries, Correns, Von TschermarkIndependently rediscovered Mendel’s work.
Walter Sutton and Theodore BoveriChromosomal theory of inheritance  
Thomas Hunt Morgan (and his colleagues)a) Experimental verification of chromosomal theory of inheritance.
b) Linkage and Recombination.
Alferd SturtvantChromosomes maps or linkage maps
HenkingX-Body (Chromosome)
Friederich MiesherNuclein
Maurice Wilikins and Rasalind FranklinX-ray diffraction data leading to the proposal of structure of DNA
James Waston and Francis CrickProposed the structure of double helix model for the DNA;
Semi conservative mode of DNA replication.
Erwin charagaffChargaff Rule: A+T/G+C=1
Francis CrickCentral dogma in molecular Biology;
tRNA as adapter molecule
Frederick GrieffithTransforming principle;
carried out a series of experiments with streptococcus pneumonia.
Oswald Avery, Colin Macleod and Maclyin Mc cartyDetermined the biochemical nature of transforming principle.
Alferd Hershy and Martha ChaseThe unequivocal proof that DNA is the genetic material
Matthew Meselon and Franklin StahlExperimented to prove DNA replicates semi-conservatively
George GamawGenetic codon should be made up of 3 nucleotides
Hargovind KhuaranaDeveloped a chemical method for the synthesis of RNA molecule with defined base combination
Marshall NirenbergPut forward a cell free system for protein synthesis that help in deciphering the code
Severo OchoaShowed the polynucleotide phosphate also helped in polymerizing RNA with define sequence in a template in depend manners
Francois Jacob and Jacque MonadTransitionally regulated system – lac operon
Frederick Sangera) developed method for determination of amino acid sequences in protein.
b) Developed a principle the automated DNA sequences worked on.
A.I Oparin and John HaldaneProposed that the first form of life could have come from pre-existing non-living organic molecules (e.g. RNA, protein, etc.) and that formation of life was preceded by chemical evolution.
Louis PasteurDisapproved Theory of Spontaneous Generation.
Experimentally demonstrated that life comes only from pre-existing life.
S L MillerMiller’s experiment on the origin of life. He revealed that life originated from the nonliving components.
Charles DarwinFather of Evolution
Concept of natural selection
Concept of reproductive fitness
Darwin finches – adaptive radiation
Alfred WallaceWorked in Malay Archipelago and had a similar opinion as that of Mendel on the concept of reproductive fitness and natural selection.
LamarkEvolution due to use and disuse of organs
Thomas MathusProposed Malthusian theory of population – this theory states that population growth will always tend to out run the food supply. This theory is thought to influence Darwin.
William HarveyDiscovered of blood circulation
Hugo deVriesDeveloped mutation theory – saltation
G. H. Hardy and Wilhelm WeinbergHardy-Weinberg principle – genetic equilibrium in a population.
Norman E BorlaugHe improved methods of cultivation and developed a robust strain of wheat. Semi-dwarf wheat.
Alexander FlemingDiscovery of first antibiotics- Penicillin
Ernest Chain and Howard FloreyEstablished the full potential of penicillin as an antibiotics.
Stanley Cohen and Herbert BoyerConstruction of the first recombinant DNA
GauseProvided competitive Exclusion principle: two closely related species competing for the same resources cannot coexist indefinitely and the competitively inferior one will be eliminated eventually
Mac ArthurResource partitioning: Showed that five closely related species of warblers living on the same tree were able to avoid competition and co-exist due to behavioral differences in their foraging activities
Edward WilsonCoined biodiversity to describe the combined diversity at all the levels of biological organization
Robert ConstanzaHe used to put price tags on nature’s life support services
Robert MayMade a more conservative and scientifically sound estimate which places the global species diversity at about 7 million.
Alexander von HumboldtObserved that within a region species richness increased with increasing explored area, but only upto a limit
David TilmanHis long-term ecosystem experiments states that plots with more species showed less year-to-year variation in total biomass
Paul EhrlichProvided the ‘rivet popper hypothesis’ to show how quality of life is affected with reduction in organism.

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