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 🙂
| Scientist | Contribution |
|---|---|
| Gregor Johann Mendel | a) Father of genetics
b) Conducted experiments for the first time to understand the pattern of inheritance and variation. |
| Reginald C Punnett | Punnett square |
| Galton | Polygenic inheritance |
| De vries, Correns, Von Tschermark | Independently rediscovered Mendel’s work. |
| Walter Sutton and Theodore Boveri | Chromosomal theory of inheritance |
| Thomas Hunt Morgan (and his colleagues) | a) Experimental verification of chromosomal theory of inheritance.
b) Linkage and Recombination. |
| Alferd Sturtvant | Chromosomes maps or linkage maps |
| Henking | X-Body (Chromosome) |
| Friederich Miesher | Nuclein |
| Maurice Wilikins and Rasalind Franklin | X-ray diffraction data leading to the proposal of structure of DNA |
| James Waston and Francis Crick | Proposed the structure of double helix model for the DNA;
Semi conservative mode of DNA replication. |
| Erwin charagaff | Chargaff Rule: A+T/G+C=1 |
| Francis Crick | Central dogma in molecular Biology;
tRNA as adapter molecule |
| Frederick Grieffith | Transforming principle;
carried out a series of experiments with streptococcus pneumonia. |
| Oswald Avery, Colin Macleod and Maclyin Mc carty | Determined the biochemical nature of transforming principle. |
| Alferd Hershy and Martha Chase | The unequivocal proof that DNA is the genetic material |
| Matthew Meselon and Franklin Stahl | Experimented to prove DNA replicates semi-conservatively |
| George Gamaw | Genetic codon should be made up of 3 nucleotides |
| Hargovind Khuarana | Developed a chemical method for the synthesis of RNA molecule with defined base combination |
| Marshall Nirenberg | Put forward a cell free system for protein synthesis that help in deciphering the code |
| Severo Ochoa | Showed the polynucleotide phosphate also helped in polymerizing RNA with define sequence in a template in depend manners |
| Francois Jacob and Jacque Monad | Transitionally regulated system – lac operon |
| Frederick Sanger | a) 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 Haldane | Proposed 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 Pasteur | Disapproved Theory of Spontaneous Generation.
Experimentally demonstrated that life comes only from pre-existing life. |
| S L Miller | Miller’s experiment on the origin of life. He revealed that life originated from the nonliving components. |
| Charles Darwin | Father of Evolution
Concept of natural selection Concept of reproductive fitness Darwin finches – adaptive radiation |
| Alfred Wallace | Worked in Malay Archipelago and had a similar opinion as that of Mendel on the concept of reproductive fitness and natural selection. |
| Lamark | Evolution due to use and disuse of organs |
| Thomas Mathus | Proposed 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 Harvey | Discovered of blood circulation |
| Hugo deVries | Developed mutation theory – saltation |
| G. H. Hardy and Wilhelm Weinberg | Hardy-Weinberg principle – genetic equilibrium in a population. |
| Norman E Borlaug | He improved methods of cultivation and developed a robust strain of wheat. Semi-dwarf wheat. |
| Alexander Fleming | Discovery of first antibiotics- Penicillin |
| Ernest Chain and Howard Florey | Established the full potential of penicillin as an antibiotics. |
| Stanley Cohen and Herbert Boyer | Construction of the first recombinant DNA |
| Gause | Provided 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 Arthur | Resource 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 Wilson | Coined biodiversity to describe the combined diversity at all the levels of biological organization |
| Robert Constanza | He used to put price tags on nature’s life support services |
| Robert May | Made a more conservative and scientifically sound estimate which places the global species diversity at about 7 million. |
| Alexander von Humboldt | Observed that within a region species richness increased with increasing explored area, but only upto a limit |
| David Tilman | His long-term ecosystem experiments states that plots with more species showed less year-to-year variation in total biomass |
| Paul Ehrlich | Provided the ‘rivet popper hypothesis’ to show how quality of life is affected with reduction in organism. |