Timeline of biology and organic chemistry

Significant events in biology and organic chemistry:

Before 1600

• c. 520 B.C. — Alcmaeon of Croton distinguished veins from arteries and discovered the optic nerve.
• c. 450 B.C. — Sushruta writes the Sushruta Samhita, describing over 120 surgical instruments and 300 surgical procedures, classifies human surgery in 8 categories, and introduces cosmetic and plastic surgery.
• c. 450 B.C. — Xenophanes examined fossils and speculated on the evolution of life.
• c. 350 B.C. — Aristotle attempted a comprehensive classification of animals. His written works include Historion Animalium, a general biology of animals, De Partibus Animalium, a comparative anatomy and physiology of animals, and De Generatione Animalium, on developmental biology.
• c. 300 B.C. — Theophrastos (or Theophrastus) begins the systematic study of botany.
• c. 300 B.C. — Herophilos dissects the human body.
• c. 100 B.C. — Diocles wrote the oldest known anatomy book and was the first to use the term anatomy.
• c. 50-70 A.D. — Historia Naturalis by Pliny the Elder (Gaius Plinius Secundus) was published in 37 volumes.
• 130-200 — Claudius Galen wrote numerous treatises on human anatomy.

1600–1699

• ?? — Jan Baptist van Helmont performs his famous tree plant experiment in which he shows that the substance of a plant derives from water and air, the first description of photosynthesis.
• 1628 — William Harvey publishes An Anatomical Exercise on the Motion of the Heart and Blood in Animals
• 1651 — William Harvey concludes that all animals, including mammals, develop from eggs, and spontaneous generation of any animal from mud or excrement was an impossibility.
• 1658 — Jan Swammerdam observes red blood cells under a microscope.
• 1663 — Robert Hooke sees cells in cork using a microscope.
• 1668 — Francesco Redi disproves spontaneous generation by showing that fly maggots only appear on pieces of meat in jars if the jars are open to the air. Jars covered with cheesecloth contained no flies.
• 1672 — Marcello Malpighi publishes the first description of chick development, including the formation of muscle somites, circulation, and nervous system.
• 1676 — Anton van Leeuwenhoek observes protozoa and calls them animalcules.
• 1677 — Anton van Leeuwenhoek observes spermatozoa.
• 1683 — Anton van Leeuwenhoek observes bacteria. Leeuwenhoek's discoveries renew the question of spontaneous generation in microorganisms.

1700–1799

• 1767 — Kaspar Friedrich Wolff argues that the tissues of a developing chick form from nothing and are not simply elaborations of already-present structures in the egg.
• 1768 — Lazzaro Spallanzani again disproves spontaneous generation by showing that no organisms grow in a rich broth if it is first heated (to kill any organisms) and allowed to cool in a stoppered flask. He also shows that fertilization in mammals requires an egg and semen.
• 1771 — Joseph Priestley demonstrates that plants produce a gas that animals and flames consume. Those two gases are carbon dioxide and oxygen.
• 1798 — Thomas Malthus discusses human population growth and food production in An Essay on the Principle of Population.

1800–1899

• 1801 — Jean-Baptiste Lamarck begins the detailed study of invertebrate taxonomy.
• 1802 — The term biology in its modern sense is propounded independently by Gottfried Reinhold Treviranus (Biologie oder Philosophie der lebenden Natur) and Lamarck (Hydrogéologie). The word had been coined in 1800 by Karl Friedrich Burdach.
• 1809 — Lamarck proposes a modern theory of evolution based on the inheritance of acquired characteristics.
• 1817 — Pierre-Joseph Pelletier and Joseph-Bienaime Caventou isolate chlorophyll.
• 1820 — Christian Friedrich Nasse formulates Nasse's law: hemophilia occurs only in males and is passed on by unaffected females.
• 1824 — J. L Prevost and J. B. Dumas showed that the sperm in semen were not parasites, as previously thought, but, instead, the agents of fertilization.
• 1826 — Karl von Baer shows that the eggs of mammals are in the ovaries, ending a 200-year search for the mammalian egg.
• 1828 — Friedrich Woehler synthesizes urea; first synthesis of an organic compound from inorganic starting materials.
• 1836 — Theodor Schwann discovers pepsin in extracts from the stomach lining; first isolation of an animal enzyme.
• 1837 — Theodor Schwann shows that heating air will prevent it from causing putrefaction.
• 1838 — Matthias Schleiden proposes that all plants are composed of cells.
• 1839 — Theodor Schwann proposes that all animal tissues are composed of cells. Schwann and Schleinden argued that cells are the elementary particles of life.
• 1843 — Martin Barry reported the fusion of a sperm and an egg for rabbits in a 1-page paper in the Philosophical Transactions of the Royal Society of bunchie
• 1856 — Louis Pasteur states that microorganisms produce fermentation.
• 1858 — Charles R. Darwin and Alfred Wallace independently propose a theory of biological evolution ("descent through modification") by means of natural selection. Only in later editions of his works did Darwin used the term "evolution."
• 1858 — Rudolf Virchow proposes that cells can only arise from pre-existing cells; "Omnis cellula e celulla," all cell from cells. The Cell Theory states that all organisms are composed of cells (Schleiden and Schwann), and cells can only come from other cells (Virchow).
• 1864 — Louis Pasteur disproves the spontaneous generation of cellular life.
• 1865 — Gregor Mendel demonstrates in pea plants that inheritance follows definite rules. The Principle of Segregation states that each organism has two genes per trait, which segregate when the organism makes eggs or sperm. The Principle of Independent Assortment states that each gene in a pair is distributed independently during the formation of eggs or sperm. Mendel's trailblazing foundation for the science of genetics went unnoticed, to his lasting disappointment.
• 1865 — Friedrich August Kekulé von Stradonitz realizes that benzene is composed of carbon and hydrogen atoms in a hexagonal ring.
• 1869 — Friedrich Miescher discovers nucleic acids in the nuclei of cells.
• 1874 — Jacobus van 't Hoff and Joseph-Achille Le Bel advance a three-dimensional stereochemical representation of organic molecules and propose a tetrahedral carbon atom.
• 1876 — Oskar Hertwig and Hermann Fol independently describe (in sea urchin eggs) the entry of sperm into the egg and the subsequent fusion of the egg and sperm nuclei to form a single new nucleus.
• 1884 — Emil Fischer begins his detailed analysis of the compositions and structures of sugars.
• 1892 — Hans Driesch separates the individual cells of a 2-cell sea urchin embryo and shows that each cell develops into a complete individual, thus disproving the theory of preformation and showing that each cell is "totipotent," containing all the hereditary information necessary to form an individual.
• 1898 — Martinus Beijerinck used filtering experiments to show that tobacco mosaic disease is caused by something smaller than a bacterium, which he names a virus.

1900–1949

• 1900 — Two biologists independently rediscovered Mendel's paper on heredity.
• 1902 — Walter Sutton and Theodor Boveri, independently propose that the chromosomes carry the hereditary information.
• 1905 — William Bateson coins the term "genetics" to describe the study of biological inheritance.
• 1906 — Mikhail Tsvet discovers the chromatography technique for organic compound separation.
• 1907 — Ivan Pavlov demonstrates conditioned responses with salivating dogs.
• 1907 — Emil Fischer artificially synthesizes peptide amino acid chains and thereby shows that amino acids in proteins are connected by amino group-acid group bonds.
• 1909 — Wilhelm Johannsen coined the word "gene."
• 1911 — Thomas Hunt Morgan proposes that genes are arranged in a line on the chromosomes.
• 1922 — Aleksandr Oparin proposes that the Earth's early atmosphere contained methane, ammonia, hydrogen, and water vapor, and that these were the raw materials for the origin of life.
• 1926 — James Sumner shows that the urease enzyme is a protein.
• 1928 — Otto Diels and Kurt Alder discover the Diels-Alder cycloaddition reaction for forming ring molecules.
• 1928 — Alexander Fleming discovers the first antibiotic, penicillin
• 1929 — Phoebus Levene discovers the sugar deoxyribose in nucleic acids.
• 1929 — Edward Doisy and Adolf Butenandt independently discover estrone.
• 1930 — John Howard Northrop shows that the pepsin enzyme is a protein.
• 1931 — Adolf Butenandt discovers androsterone.
• 1932 — Hans Adolf Krebs discovers the urea cycle.
• 1933 — Tadeus Reichstein artificially synthesizes vitamin C; first vitamin synthesis.
• 1935 — Rudolf Schoenheimer uses deuterium as a tracer to examine the fat storage system of rats.
• 1935 — Wendell Stanley crystallizes the tobacco mosaic virus.
• 1935 — Konrad Lorenz describes the imprinting behavior of young birds.
• 1937 — Dorothy Crowfoot Hodgkin discovers the three-dimensional structure of cholesterol.
• 1937 — Hans Adolf Krebs discovers the tricarboxylic acid cycle.
• 1937 — In Genetics and the Origin of Species, Theodosius Dobzhansky applies the chromosome theory and population genetics to natural populations in the first mature work of neo-Darwinism, also called the modern synthesis, a term coined by Julian Huxley.
• 1938 — A living coelacanth is found off the coast of southern Africa.
• 1940 — Donald Griffin and Robert Galambos announce their discovery of sonar echolocation by bats.
• 1942 — Max Delbruck and Salvador Luria demonstrate that bacterial resistance to virus infection is caused by random mutation and not adaptive change.
• 1944 — Oswald Avery shows that DNA carries the hereditary information in pneumococcus bacteria.
• 1944 — Robert Burns Woodward and William von Eggers Doering synthesize quinine.
• 1945 — Dorothy Crowfoot Hodgkin discovers the three-dimensional structure of penicillin.
• 1948 — Erwin Chargaff shows that in DNA the number of guanine units equals the number of cytosine units and the number of adenine units equals the number of thymine units.

1950–1989

• 1951 — Robert Woodward synthesizes cholesterol and cortisone.
• 1952 — American developmental biologists Robert Briggs and Thomas King clone the first vertebrate by transplanting nuclei from leopard frogs embryos into enucleated eggs. More differentiated cells were the less able they are to direct development in the enucleated egg.
• 1952 — Alfred Hershey and Martha Chase show that DNA is the genetic material in bacteriophage viruses.
• 1952 — Fred Sanger, Hans Tuppy, and Ted Thompson complete their chromatographic analysis of the insulin amino acid sequence.
• 1952 — Rosalind Franklin concludes that DNA is a double helix with a diameter of 2 nm and the sugar-phosphate backbones on the outside of the helix, based on x ray diffraction studies. She suspects the two sugar-phosphate backbones have a peculiar relationship to each other.
• 1953 — After examining Franklin's unpublished data, James D. Watson and Francis Crick publish a double-helix structure for DNA, with one sugar-phosphate backbone running in the opposite direction to the other. They further suggest a mechanism by which the molecule can replicate itself and serve to transmit genetic information. Their paper, combined with the Hershey-Chase experiment and Chargaff's data on nucleotides, finally persuades biologists that DNA is the genetic material, not protein.
• 1953 — Max Perutz and John Kendrew determine the structure of hemoglobin using X-ray diffraction studies.
• 1953 — Stanley Miller shows that amino acids can be formed when simulated lightning is passed through vessels containing water, methane, ammonia, and hydrogen
• 1954 — Dorothy Crowfoot Hodgkin discovers the three-dimensional structure of vitamin B₁₂.
• 1955 — Marianne Grunberg-Manago and Severo Ochoa discover the first nucleic-acid-synthesizing enzyme (polynucleotide phosphorylase), which links nucleotides together into polynucleotides.
• 1955 — Arthur Kornberg discovers DNA polymerase enzymes.
• 1958 — Matthew Stanley Meselson and Franklin W. Stahl prove that DNA replication is semiconservative in the Meselson-Stahl experiment
• 1959 — Severo Ochoa and Arthur Kornberg receive a Nobel Prize for their work.
• 1959 — Max Perutz describes the structure of hemoglobin, the oxygen-carrying protein in blood.
• 1960 — John Kendrew describes the structure of myoglobin, the oxygen-carrying protein in muscle.
• 1960 — Four separate researchers (S. Weiss, J. Hurwitz, Audrey Stevens and J. Bonner) discover bacterial RNA polymerase, which polymerizes nucleotides under the direction of DNA.
• 1960 — Robert Woodward synthesizes chlorophyll.
• 1961 — J. Heinrich Matthaei cracks the first codon of the genetic code (the codon for the amino acid phenylalanine) using Grunberg-Manago's 1955 enzyme system for making polynucleotides.
• 1961 — Joan Oró finds that concentrated solutions of ammonium cyanide in water can produce the nucleotide adenine, a discovery that opened the way for theories on the origin of life.
• 1962 — Max Perutz and John Kendrew share a Nobel prize for their work on the structure of hemoglobin and myoglobin.
• 1965 — Genetic code fully cracked through trial-and-error experimental work.
• 1966 — Kimishige Ishizaka discovers a new type of immunoglobulin, IgE, that develops allergy and explains the mechanisms of allergy at molecular and cellular levels.
• 1966 — Lynn Margulis proposes the endosymbiotic theory, that the eukaryotic cell is a symbiotic union of primitive prokaryotic cells. Richard Dawkins called the theory "one of the great achievements of twentieth-century evolutionary biology."
• 1967 — John Gurdon uses nuclear transplantation to clone an African Clawed Frog; first cloning of a vertebrate using a nucleus from a fully differentiated adult cell.
• 1968 — Fred Sanger uses radioactive phosphorus as a tracer to chromatographically decipher a 120 base long RNA sequence.
• 1969 — Dorothy Crowfoot Hodgkin deciphers the three-dimensional structure of insulin.
• 1970 — Hamilton Smith and Daniel Nathans discover DNA restriction enzymes.
• 1970 — Howard Temin and David Baltimore independently discover reverse transcriptase enzymes.
• 1972 — Albert Eschenmoser and Robert Woodward synthesize vitamin B₁₂.
• 1972 — Stephen Jay Gould and Niles Eldredge propose an idea they call "punctuated equilibrium", which states that the fossil record is an accurate depiction of the pace of evolution, with long periods of "stasis" (little change) punctuated by brief periods of rapid change and species formation (within a lineage).
• 1972 — SJ Singer and GL Nicholson develop the fluid mosaic model, which deals with the make-up of the membrane of all cells.
• 1974 — Manfred Eigen and Manfred Sumper show that mixtures of nucleotide monomers and RNA replicase will give rise to RNA molecules which replicate, mutate, and evolve.
• 1974 — Leslie Orgel shows that RNA can replicate without RNA-replicase and that zinc aids this replication.
• 1977 — John Corliss and ten coauthors discover chemosynthetically based animal communities located around submarine hydrothermal vents on the Galapagos Rift.
• 1977 — Walter Gilbert and Allan Maxam present a rapid DNA sequencing technique which uses cloning, base destroying chemicals, and gel electrophoresis.
• 1977 — Frederick Sanger and Alan Coulson present a rapid gene sequencing technique which uses dideoxynucleotides and gel electrophoresis.
• 1978 — Frederick Sanger presents the 5,386 base sequence for the virus PhiX174; first sequencing of an entire genome.
• 1982 — Stanley B. Prusiner proposes the existence of infectious proteins, or prions. His idea is widely derided in the scientific community, but he wins a Nobel Prize in 1997.
• 1983 — Kary Mullis invents "PCR" ( polymerase chain reaction), an automated method for rapidly copying sequences of DNA.
• 1984 — Alec Jeffreys devises a genetic fingerprinting method.
• 1985 — Harry Kroto, J.R. Heath, S.C. O'Brien, R.F. Curl, and Richard Smalley discover the unusual stability of the buckminsterfullerene molecule and deduce its structure.
• 1986 — Alexander Klibanov demonstrates that enzymes can function in non-aqueous environments.
• 1986 — Rita Levi-Montalcini and Stanley Cohen receive the Nobel Prize in Physiology or Medicine for their discovery of Nerve growth factor (NGF).

1990–present

• 1990 — French Anderson et al. perform the first approved gene therapy on a human patient
• 1990 — Napoli, Lemieux and Jorgensen discover RNA interference (1990) during experiments aimed at the color of petunias.
• 1990 — Wolfgang Krätschmer, Lowell Lamb, Konstantinos Fostiropoulos, and Donald Huffman discover that Buckminsterfullerene can be separated from soot because it is soluble in benzene.
• 1995 — Publication of the first complete genome of a free-living organism.
• 1996 — Dolly the sheep is first clone of an adult mammal.
• 1999 — Researchers at the Institute for Human Gene Therapy at the University of Pennsylvania accidentally kill Jesse Gelsinger during a clinical trial of a gene therapy technique, leading the FDA to halt further gene therapy trials at the Institute.
• 2001 — Publication of the first drafts of the complete human genome.
• 2002 — First virus produced 'from scratch', an artificial polio virus that paralyzes and kills mice.

See also

• Timeline of medicine and medical technology
• History of biology
• History of chemistry