The following points highlight the top eight chronological events in the progress of biology. The chronological events are: 1. Tools and Techniques 2. Systematics 3. Cells and Tissues 4. Embryology 5. Distribution.
Chronological Event # 1. Tools and Techniques:
1590—Dutch spectacles makers Janssen and Janssen are credited with building first successful microscope.
1665—Robert Hooke improvised the microscopes (Fig. 6.2) and drew attention to the world of minute organisms.
1878—Brandt demonstrated that certain stains or dyes have the property of being incorporated in the living cells. He called them vital stains.
1895—Rontgen discovered the X-rays. Application of X-rays made advances in Physiology, Anatomy and Genetics.
1911— Carrel developed tissue culture technique by growing live tissue outside the body of the animal.
1912— Kite began microsurgical studies by devising micromanipulators.
1923—Hevesay utilised isotopes of chemical elements for tracing fate of molecules in living system.
1932—Construction of emission type of electron microscope by Knoll and Ruska.
1938—Svedberg developed ultra-centrifuge.
Chronological Event # 2. Systematics:
1665—Discovery of protozoa Leeuwenhoek. It enlarged the concept of animal kingdom.
1693—Concept of genus and species on similarity of form was advocated by John Ray.
1758—Binomial system of nomenclature was introduced by Linnaeus.
1848—Status of protozoa and its unicellular nature was determined by Sie- hold.
1864—Modern zoological classification and development of basic divisions were introduced by Haeckel.
Chronological Event # 3. Cells and Tissues:
1658—Description of cell (RBC of frog) was given by Swammerdam.
1665—Robert Hooke first used the term cell.
1800—Classification of tissue (21 different types) was made by Bichat.
1824—Cell division was first described by Prevost from cleavage division in frog’s egg.
1831—Nucleus of plant cells was named and described by Robert Brown.
1835—Description of Sarcode (protoplasm) as the basis of life was made by Dujardin.
1838-39—Schwann and Schleiden advocated the cell doctrine.
1846—The name protoplasm was given by Hugo von Mohl.
1848—First description of chromosomes and drawings of pollen mother cell was done by Hofmeister.
1858-—Doctrine of germinal continuity was expressed by Virchow in his motto— Omnis cellula e cellula.
1875-—Mitosis was described by Strats- burger.
1882—Counts of chromosomes were done by Flemming.
1887—Meiosis was predicted by Weiss- mann.
1898—Mitochondria and Golgi apparatus was named by Benda and Golgi respectively.
1934—^Isolation and analysis of mitochondria was done by Bensley and Hoerr.
1952— Detailed structure of mitochondria with the aid of electron microscope was done by Palade.
1953— DNA as a double helix was proved by Watson and Crick.
1953—Detailed structure of endoplasmic reticulum was given by Porter.
1956—Revision of the count of human chromosome, i.e., diploid-46 in place of 48 was done by Tijo and Levan.
Chronological Event # 4. Embryology:
1651—Concept of continuity of life was given by Harvey—Omne vivum ex ovo (All life from egg).
1672—Description of ovarian follicle was made by Graff.
1745—Parthenogenesis was described by Bonnet.
1759—Theory of epigenesis was advocated by Wolff overthrowing the concept of preformation.
1817—Recognition of three germ layers in chick was made by Pander which later was extended by Von Baer to all vertebrates.
1827—Mammalian ovum was discovered by Von Baer.
1854—Description of entrance of sperm into ovum was given by Newport.
1875—Union of male and female nuclear material in fertilization was shown by O. Hertwig.
1885—Cleavage dividing the zygote of frog into cells was described by Roux.
1885—Germplasm theory was advocated by Weismann.
1897—Influence of the, yolk present in an egg was demonstrated by O. Hertwig.
1897—Successful heteroplastic grafting was conducted by Born.
1900—Artificial fertilization was conducted by Loeb.
1911—Axial gradient theory was proposed by Child.
1914—Role of fertilizin in fertilization was established by Lillie.
1921—Organiser concept was introduced by Spemann.
1933—Embryological inductor concept was presented by Holtfreter.
1936—Artificial parthenogenesis in rabbit was done by Pincus.
Chronological Event # 5. Distribution:
1858—Zoogeographical realms were recognised by Sclater.
1860—Line of faunal delimitation between the Oriental and Australian zoogeographical realm was made by Wallace.
1894—Life zone concept was advocated by Merriam.
1935—The concept of ecosystem was proposed by Tansley.
Chronological Event # 6. Palaeontology:
1669—Fossils as organic remains was recognised by Stensen.
1791—Correlation between geological strata and fossils was made by Smith.
1796—Vertebrate palaeontology was started by Cuvier.
1830—Lyell’s book ‘The principle of Geology’ brought relation between Zoology and Geology
1923—Discovery of fossilized eggs of Dinosaurs from Mongolia was made by Chapman.
Chronological Event # 7. Genetics:
1866—Mendel’s laws of genetics came to light.
1866—Nuclear control of inheritance was foreshadowed by Haeckel.
1883—Chromosome control of inheritance was proposed by Roux without any experimental verification.
1900—Rediscovery of Mendel’s laws was made by De Vries, Gorrens and Tshermark.
1902—Discovery of X-chromosome was made by McClung and its significance in sex-determination was hinted at.
1506—Linkage groups in sweet pea was discovered by Bateson and Punnet.
1909—Origin of terms—gene, genotype and phenotype was made by Johannsen.
1909— Crossing over as a genetic process was observed by Janssens. Twenty years later Morgan proposed the theory of crossing over.
1910- 1920—Morgan established the gene theory of inheritance.
1910—Discovery of sex-linked inheritance was made by Morgan.
1913—First chromosome map was made by Sturtevant.
1925—Sex-determination by environmental factor was demonstrated by Baltzar in Bonellia.
1927—Artificial increase in mutation rate was demonstrated by Muller in Drosophila.
1931—Exchange of genes during crossing over was demonstrated by Stern.
1933—Giant salivary gland chromosomes were rediscovered in Drosophila by Painter and others.
1935—Target theory of mechanism of gene mutation was established by Ressovsky.
1941—Biochemical mutation was produced in Neurospora by Beadle and Tatum. They were awarded Nobel Prize in 1958.
1943—Plasmagenc inheritance in Para- moecium was demonstrated by Sonneborn.
1949—Genetic control of protein structure in animals was shown by Pauling.
Chronological Event # 8. Evolution:
1693—Concept of a species was provided by John Ray.
1809—Theory of use and disuse by Lamarck.
1830—Biogenetic law of Von Baer.
1859— Theory of natural selection of Darwin.
1860— Spontaneous generation was disproved by Pasteur.
1874—Gastrea theory of metazoan ancestry and recapitulation theory of Haeckel.
1901—Mutation theory of De Vries.
1932— Effect of genetic drift on small population was outlined by Swell Wright.
1933— Heterotroph theory of origin of life of Haldane and Oparin.
1953—Laboratory demonstration of formation of organic substances by Urey and Miller.