💡 Important: This comprehensive list covers all chapters from NCERT Biology Class 11 & 12,
including key scientists, their years of discovery, and significant achievements relevant for NEET UG 2026 exam.
The Living World
Year
Scientist/Researcher
Significance/Achievement
1904-2004
Ernst Mayr
Evolutionary biologist known as "The Darwin of the 20th century"
1953
Ernst Mayr
Joined Harvard's Faculty of Arts and Sciences
1983, 1994, 1999
Ernst Mayr
Awarded the Balzan Prize, International Prize for Biology, and Crafoord Prize (Triple Crown of Biology)
N/A
Carolus Linnaeus
Proposed the Binomial Nomenclature system
Biological Classification
Year
Scientist/Researcher
Significance/Achievement
N/A
Aristotle
Earliest scientific classification; used simple morphological characters (Herbs, Shrubs, Trees; Red blood/No red blood)
N/A
Linnaeus
Developed the Two Kingdom system (Plantae and Animalia)
1892
Dmitri Ivanowsky
Recognized microbes causing tobacco mosaic disease; noted they were smaller than bacteria
1898
M.W. Beijerinck
Demonstrated extract of infected plants caused infection; coined Contagium vivum fluidum (infectious living fluid)
1935
W.M. Stanley
Showed that viruses could beized and crystals consist largely of proteins
1969
R.H. Whittaker
Proposed the Five Kingdom Classification (Monera, Protista, Fungi, Plantae, Animalia)
1971
T.O. Diener
Discovered Viroids (infectious agent smaller than viruses, free RNA, no protein coat)
N/A
George Bentham & Joseph Dalton Hooker
Gave the Natural Classification System for flowering plants based on internal and external features
Plant Kingdom
Year
Scientist
Significance/Achievement
N/A
George Bentham & Joseph Dalton Hooker
Natural Classification System for flowering plants
Morphology of Flowering Plants
Year
Scientist
Significance/Achievement
1898
Katherine Esau
Born in Ukraine; studied agriculture in Russia and Germany
1931
Katherine Esau
Received Doctorate from University of California
1954
Katherine Esau
Published Plant Anatomy
1960
Katherine Esau
Published Anatomy of Seed Plants (referred to as the "Webster's of plant biology")
1957
Katherine Esau
Elected to the National Academy of Sciences
1989
Katherine Esau
Received the National Medal of Science
Cell: The Unit of Life
Year
Scientist/Researcher
Significance/Achievement
1954
G.N. Ramachandran
Discovered the triple helical structure of collagen; published in Nature
1665
Robert Hooke
Discovered the cell
N/A
Anton Von Leeuwenhoek
First saw and described a live cell
1831
Robert Brown
Discovered the nucleus
1838
Matthias Schleiden
Observed that all plants are composed of different kinds of cells (Cell Theory)
1839
Theodore Schwann
Reported that cells have a thin outer layer (plasma membrane) and cell wall is unique to plants (Cell Theory)
1855
Rudolf Virchow
Explained that cells divide and new cells arise from pre-existing cells (Omnis cellula-e cellula)
1898
Camillo Golgi
First observed densely stained reticular structures (Golgi bodies) near the nucleus
1953
George Palade
Observed ribosomes as dense particles under the electron microscope
1972
Singer & Nicolson
Proposed the Fluid Mosaic Model of the cell membrane
Photosynthesis
Year
Scientist
Significance/Achievement
1770
Joseph Priestley
Performed experiments showing air is essential for growth of green plants
1774
Joseph Priestley
Discovered Oxygen
N/A
Jan Ingenhousz
Showed sunlight is essential; aquatic plants produce bubbles (oxygen) in light
1854
Julius von Sachs
Provided evidence for production of glucose (stored as starch) when plants grow
N/A
T.W. Engelmann
Described the first action spectrum of photosynthesis using Cladophora and aerobic bacteria
N/A
Cornelius van Niel
Demonstrated photosynthesis is a light-dependent reaction where hydrogen from an oxidizable compound reduces CO₂
N/A
Melvin Calvin
Used radioactive ¹⁴C in algal photosynthesis to discover the first CO₂ fixation product (PGA)
Respiration in Plants
Year
Scientist
Significance/Achievement
N/A
Gustav Embden, Otto Meyerhof, J. Parnas
Worked out the scheme of Glycolysis (EMP Pathway)
N/A
Hans Krebs
Elucidated the Citric Acid Cycle (Krebs Cycle)
Plant Growth and Development
Year
Scientist
Significance/Achievement
N/A
Charles Darwin & Francis Darwin
Observed phototropism in canary grass coleoptiles; concluded tip transmits influence
N/A
F.W. Went
Isolated Auxin from tips of coleoptiles of oat seedlings
1926
E. Kurosawa
Discovered Gibberellins (gibberellic acid) in rice seedlings infected with Gibberella fujikuroi (bakanae disease)
N/A
F. Skoog and co-workers
Observed that callus proliferation requires auxin + extract from vascular tissue/yeast/coconut milk/DNA
1955
Miller et al.
Crystallised Kinetin (a cytokinin) from autoclaved herring sperm DNA
1910
Cousins
Confirmed release of a volatile substance (Ethylene) from ripened oranges that hastened ripening of bananas
Proposed the Sliding Filament Theory of muscle contraction
Sexual Reproduction in Flowering Plants
Year
Scientist
Significance/Achievement
1904
Panchanan Maheshwari
Born in Jaipur; popularized the use of embryological characters in taxonomy; established the Department of Botany, University of Delhi
N/A
Panchanan Maheshwari
Honoured with the Fellowship of Royal Society of London (FRS), Indian National Science Academy, and others
Reproductive Health
Year
Scientist
Significance/Achievement
1951
Government of India
Family planning programmes were initiated in India
N/A
CDRI (Lucknow)
Developed 'Saheli', a new oral contraceptive for females
1971
Government of India
Legalised Medical Termination of Pregnancy (MTP) with some strict conditions
2017
Government of India
Enacted the Medical Termination of Pregnancy (Amendment) Act to reduce illegal abortions and maternal mortality
Principles of Inheritance and Variation
Year
Scientist
Significance/Achievement
1856-1863
Gregor Mendel
Conducted hybridisation experiments on garden peas
1865
Gregor Mendel
Published the results of his experiments
1900
de Vries, Correns, von Tschermak
Independently rediscovered Mendel's results on the inheritance of characters
1902
Sutton and Boveri
Noted that the behaviour of chromosomes was parallel to the behaviour of genes (Chromosomal Theory of Inheritance)
N/A
Thomas Hunt Morgan
Experimental verification of the chromosomal theory of inheritance using Drosophila melanogaster
N/A
Alfred Sturtevant
Used recombination frequency to map the position of genes on the chromosome (Genetic Maps)
1891
Henking
Traced a specific nuclear structure ('X body') in 50% of insect sperm; later identified as X chromosome
1866
Langdon Down
Described Down's Syndrome (Trisomy 21)
N/A
Reginald C. Punnett
Developed the Punnett Square
Molecular Basis of Inheritance
Year
Scientist
Significance/Achievement
1869
Friedrich Miescher
Identified DNA as an acidic substance in the nucleus and named it 'Nuclein'
1953
James Watson & Francis Crick
Proposed the Double Helix model for the structure of DNA
N/A
Maurice Wilkins & Rosalind Franklin
Produced X-ray diffraction data used to determine DNA structure
N/A
Erwin Chargaff
Observed that for dsDNA, ratios between A & T and G & C are constant and equal to one
1958
Francis Crick
Proposed the Central Dogma of molecular biology
1928
Frederick Griffith
Performed transformation experiments with Streptococcus pneumoniae (Transforming Principle)
1933-1944
Avery, MacLeod, McCarty
Determined the biochemical nature of the transforming principle to be DNA
1952
Alfred Hershey & Martha Chase
Proved unequivocally that DNA is the genetic material using bacteriophage
1958
Matthew Meselson & Franklin Stahl
Proved that DNA replication is semi-conservative using ¹⁵N isotopes
1958
Taylor and colleagues
Used radioactive thymidine in Vicia faba to prove semi-conservative replication in chromosomes
N/A
George Gamow
Physicist who proposed that the genetic code should be made of combinations of 3 bases (triplets)
N/A
Har Gobind Khorana
Synthesised RNA molecules with defined combinations of bases (homopolymers and copolymers)
N/A
Marshall Nirenberg
Developed a cell-free system for protein synthesis leading to code deciphering
N/A
Severo Ochoa
Discovered an enzyme (Polynucleotide phosphorylase) for polymerising RNA without a template
N/A
Francois Jacob & Jacques Monod
Elucidated the lac operon (Jacob was a geneticist, Monod a biochemist)
1990
N/A
The Human Genome Project (HGP) was launched
2003
N/A
The Human Genome Project was completed (Chromosome 1 completed in May 2006)
N/A
Frederick Sanger
Developed the method for automated DNA sequencing and amino acid sequencing in proteins
N/A
Alec Jeffreys
Developed the technique of DNA Fingerprinting
Evolution
Year
Scientist
Significance/Achievement
N/A
Louis Pasteur
Demonstrated that life comes only from pre-existing life (Swan-neck flask experiment)
N/A
Oparin & Haldane
Proposed that the first form of life could have come from pre-existing non-living organic molecules (Chemical Evolution)
1953
S.L. Miller
Created primitive earth conditions in a lab (CH₄, H₂, NH₃, water vapor at 800°C) forming amino acids
N/A
Charles Darwin
Proposed evolution by Natural Selection; journeyed on H.M.S. Beagle
N/A
Alfred Wallace
Naturalist in Malay Archipelago who came to similar conclusions as Darwin
N/A
Lamarck
Proposed evolution by use and disuse of organs (e.g., giraffe neck)
N/A
Thomas Malthus
Wrote 'Essay on the Principle of Population' which influenced Darwin
N/A
Hugo de Vries
Proposed Mutation Theory (Saltation) working on Evening Primrose
N/A
Hardy & Weinberg
Proposed principle of genetic equilibrium (allele frequencies remain constant)
1938
N/A
A Coelacanth fish was caught in South Africa (thought to be extinct)
Human Health and Diseases
Year
Scientist
Significance/Achievement
N/A
Hippocrates & Indian Ayurveda
Proposed the "Good humor" hypothesis of health (balance of humors)
N/A
William Harvey
Discovered blood circulation; demonstrated normal body temperature in "black bile" persons, disproving the good humor hypothesis
1981
N/A
AIDS was first reported
Microbes in Human Welfare
Year
Scientist
Significance/Achievement
1928
Alexander Fleming
Discovered Penicillin while working on Staphylococci bacteria
N/A
Ernest Chain & Howard Florey
Established the full potential of penicillin as an effective antibiotic
1945
Fleming, Chain, & Florey
Awarded the Nobel Prize for the discovery and development of penicillin
Biotechnology: Principles and Processes
Year
Scientist
Significance/Achievement
1963
N/A
Two enzymes restricting growth of bacteriophage in E. coli were isolated: one added methyl groups to DNA (methylase), the other cut DNA (restriction endonuclease)
1972
Stanley Cohen & Herbert Boyer
Constructed the first recombinant DNA (1972) by linking an antibiotic resistance gene with a plasmid of Salmonella typhimurium
1969
Herbert Boyer
Observed that restriction enzymes cut DNA at specific recognition sites in a precise manner
Biotechnology and its Applications
Year
Scientist
Significance/Achievement
1983
Eli Lilly (American Company)
first commercially available biosynthetic human insulin, known as Humulin
1990
French Anderson
First clinical gene therapy administered to a 4-year-old girl with ADA (Adenosine Deaminase) deficiency
1997
N/A
First transgenic cow, Rosie, produced human protein-enriched milk (2.4 grams of human alpha-lactalbumin per litre)
1997
N/A
An American company (RiceTec Inc.) obtained US patent rights on Basmati rice lines, sparking controversy over biopiracy
Organisms and Populations
Year
Scientist
Significance/Achievement
1937
Ramdeo Misra
Obtained Ph.D. in Ecology; revered as the "Father of Ecology in India"
1972 (Efforts)
Ramdeo Misra (Efforts)
Led to the Government of India establishing the National Committee for Environmental Planning and Coordination
1984 (Efforts)
Ramdeo Misra (Efforts)
Contributed to the establishment of the Ministry of Environment and Forests
N/A
Charles Darwin
Theory of Natural Selection; observed exponential growth potential in nature
1920s
N/A
Prickly pear cactus introduced into Australia; caused ecological havoc until controlled by a cactus-feeding moth (Cactoblastis cactorum)
N/A
G.F. Gause
Proposed the Competitive Exclusion Principle: two closely related species cannot coexist indefinitely when competing for the same limiting resources
N/A
Robert MacArthur
Demonstrated Resource Partitioning among five species of warblers coexisting on the same conifer tree
N/A
Joseph Connell
Field experiments on rocky sea coasts showing Balanus outcompetes Chthamalus in lower intertidal zones
Biodiversity and Conservation
Year
Scientist
Significance/Achievement
N/A
Edward O. Wilson
Sociobiologist who popularized the term "Biodiversity"
N/A
Robert May
Estimated global species diversity at approximately 7 million species
N/A
Alexander von Humboldt
Observed the Species-Area Relationship during explorations in South American jungles
N/A
David Tilman
Long-term ecosystem experiments showed that plots with higher species richness had greater stability (less year-to-year variation in biomass)
N/A
Paul Ehrlich
Proposed the 'Rivet Popper Hypothesis' comparing species loss to rivets popping from an airplane, threatening ecosystem integrity
1992
N/A
The Earth Summit (Rio de Janeiro); led to the Convention on Biological Diversity (CBD)
2002
N/A
World Summit on Sustainable Development (Johannesburg); 190 countries pledged to significantly reduce biodiversity loss
2004
IUCN
Published Red List documenting global extinctions and threatened species status
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