Science : The term science is derived from Latin word scientia which means knowledge. So, the term ‘science’ is used for knowledge gained by actual observation, found correct on verification and put in a systematic manner or science provides us information based on facts. There are several branches of science, each dealing with a specific subject.
Biology : It is the combination of two Greek words bios and logos. Bios mean life and logos means study. Thus, biology is the branch of science which deals with the study of life. The first major biological observations were made by ancient Greek naturalist Aristotle(384-322 B.C.). Aristotle has been designated as Father of biology. The term biology was given by French naturalist Lamarck(1744-1829). Biology has been further classified into,
(1) Botany (2) Zoology.
The science of plants is called Botany. The word botany has been derived from Greek word botane which means pasture or plants. Technically, botany is called Phytology (Gk. phyto = plants; logos = study). Theophrastus (370-287 B.C.) is known as Father of botany. Zoology is the study of animals (Gk. zoon = animals; logos = study). Aristotle is called Father of zoology. Being broad-based and with multi-disciplinary approach, the term biology has been replaced by Life Sciences or Biological Sciences.
Microbiology : It is the branch of biology which deals with different aspects of microorganisms. Leeuwenhock (1632-1723) is called Father of microbiology.
Some Branches of Biology
Anatomy : Study of internal structures of plants and animals after dissection.
Biochemistry : Study of chemistry of living matter (i.e., chemical composition, nature, mode of formation, functioning) in relation to life activities.
Cytology : Study of the structure and functions of cells and their organelles.
Ecology : Study of relationship between organisms and environment.
Embryology : Study of developmental stages of organisms upto hatching or birth.
Endocrinology : Study of endocrine glands and hormones action in animals.
Evolution : Study of the origin of life and the gradual differentiation or descent of species.
Histology : Study of tissues by microscopy.
Immunology : Study of resistance of organisms to infection.
Limnobiology : Study of fresh water lakes, ponds and streams.
Morphology : Study of form and structure of animals.
Palaeontology : Study of fossils and their distribution in time.
Palaeozoology : Study of fossil animals.
Physiology : Study of functions of various parts within the organisms.
Psychology : Study of related areas of psychology and biology.
Radiobiology : Study of effects of radioactivity on life.
Taxonomy : Study of classification of organisms and their evolutionary relationships with other organisms.
Zoogeography : Study of the distribution of animals over the earth.
Zoopathology : Study of diseases of animals.
Specified Branches of Biology
Acarology : Study of mites and ticks.
Actinobiology : Study of radiation effects on organisms.
Aerobiology : Study of flying organisms.
Agriology : Study of customs of primitive man.
Algology : Study of algae.
Anaesthesiology : Science for causing insensibility.
Angiology : Study of blood vascular system including veins and arteries.
Aphidology : Study of aphids (plant lice).
Araneology : Study of spiders.
Arthrology : Study of joints.
Bryology : Study of mosses and liverworts.
Carcinology : Study of crustaceans.
Carcinology : Study of malignant tissue, tumor and cancer.
Cardiology : Study of heart.
Chondriology : Study of cartilage.
Chorology : Study of the geographical distribution of organisms.
Cnidology : Study of coelenterates.
Conchology : Study of shells.
Craniology : Study of skulls.
Cryobiology : Study of effects on life at low temperature.
Ctetology : Study of acquired characters of organisms.
Dermatology : Study of body covering the skin.
Ecobiology : Study of problems of existence of life in the outer space.
Epidemiology : Study of infection of parasites or epidemic diseases.
Ethnology : Study of mankind.
Ethology : Study of behaviour of animals.
Etiology : Study of cause of disease.
Eugenics : Study of improvement of human race through laws of heredity
Euphenics : Study of improvement of human race by altering the proteins during mRNA synthesis i.e. protein synthesis process in cells. This is also called medical engineering.
Euthenics : Science of improvement of modern generation of man through better nutrition.
Exobiology : Study of possible life outside the earth.
Genecology : Study of genetical make up of species or populations in relation to their habitats.
Geology : Study of earth and life as recorded in rocks.
Gerontology : Study of growing old.
Gynaecology : Study of female reproductive organs.
Haematology : Study of blood.
Helminthology : Study of parasitic worms.
Hepatology : Study of liver.
Herpetology : Study of reptiles.
Hypnology : Study of sleep.
Ichnology : Study of fossil foot prints.
Kalology : Study of human beauty.
Karyology : Study of nucleus, particularly chromosomes.
Lepidoteriology : Study of moths and butter flies.
Leprology : Study of leprosy.
Limnology : Study of fresh water ecology and study of snails.
Malacology : Study of molluscs.
Malariology : Study of malaria.
Mammalogy : Study of mammals.
Mastology : Study of breast including teats.
Melanology : Study of pigments.
Molecular biology : Study of life sciences on molecular level (e.g, nucleic acids i.e., RNA & DNA and proteins).
Mycology : Study of fungi.
Myology : Study of muscles.
Myrmecology : Study of ants and anteaters.
Nematology : Study of nematodes.
Nephology : Study of clouds.
Neonatology : Study of newborns upto the age of two months.
Neontology : Science dealing with the life of recent organisms, just reverse to palaeontology.
Nephrology : Study of kidney.
Neurology : Study of nervous system including brain.
Nidology : Study of nests of birds.
Nosology : Study of classification of diseases.
Obstetrics : Science of midwifery.
Odonatology : Study of dragon flies and damsel flies.
Odontology : Study of teeth and gums.
Oncology : Study of tumors.
Oneirology : Study of dreams.
Ontogeny : Study of life history of organism through development.
Oology : Study of eggs of birds.
Ophiology : Study of snakes.
Ophthalmology : Study of eyes.
Organocology : Study of development of organs during embryonic period.
Organology : Study of organs.
Ornithology : Study of birds.
Osteology : Study of bones.
Otolaryngology : Study of ear and larynx.
Otorhinolaryngology : Study of ear, nose and throat (ENT).
Paediatrics : Science of medicine dealing with diseases and disorders of children.
Palaeontology : Study of fossils and their distribution.
Parasitology : Study of parasites.
Parazoology : Study of sponges.
Phenology : Study of periodic phenomena of organisms e.g. bird migration, time of flowering.
Phrenology : Study of mental faculties of brain including feeling.
Phycology : Study of algae.
Phytopathology : Study of plant diseases (their causes and symptoms).
Proctology : Study of hindgut including rectum and anus.
Protistology : Study of protists (a groups of protozoans such as Euglena, volvox etc.).
Protozoology : Study of unicellular organisms such as protozoans.
Psychiatry : Science of medical treatment of mental diseases.
Pteridology : Study of ferns.
Rhinology : Study of nose and olfactory organs.
Sarcology : Study of muscles.
Saurology : Study of lizards.
Serology : Study of serum, Study of antigen-antibody reactions.
Serpentology : Study of snakes.
Sitology : Study of regulation of diet.
Sonology : Study of hearing.
Space biology : Study of existence of life in the outer space.
Speciology : Study of species.
Splanchnology : Study of visceral organs.
Stomatology : Study of foregut including buccal cavity and stomach.
Syndesmology : Study of bony joints and ligaments.
Synecology : Study of environmental group of organisms such as communities.
Tactology : Study of structural organization of the body of organisms.
Taxidermatology : Study of skin and stuffing.
Teleology : Study of interpretations of structures in terms of purpose and utility.
Teratology : Study of monstrals and foetal malformations.
Termitology : Study of termites.
Torpedology : Study of skates and rays.
Toxicology : Study of toxic effects of drugs and harmful compounds.
Therapeutics : Science of healing.
Traumatology : Study of wounds.
Tricology : Study of hairs.
Trophology : Study of nutrition.
Urology : Study of urine and its diseases.
Venereology : Study of venereal diseases.
Virology : Study of viruses.
Zoophytology : Study of drifting organisms such as diatoms.
Zootechny : Science of breeding and domesticating animals.
Zymology : Study of fermentation.
Fathers of Various Sciences
Father of Zoology and Biology and Founder of Embryology : Aristotle
Father of Botany : Theophrastus
Father of Genetics : G.J. Mendel
Father of Evolutionary ideas : Empedocles
Father of Eugenics : Francis Galton
Father of Mutation : Hugo de Vries
Father of Modern Embryology : Karl Ernst Von Baer
Father of Palaeontology : Leonardo da vinci
Father of Taxonomy : Carolus Linnaeus
Father of Special Creation Theory : Father Saurez
Father of Blood groups : K.Landsteiner
Father of Blood circulation : William Harvey
Father of Comparative Anatomy : G. Cuvier
Father of Modern Genetics : T. H. Morgan
Father of Medicine : Hippocrates
Father of Microbiology : Louis Pasteur
Father of Immunology : Edward Jenner
Chronology of biological discoveries
460-377 Hippocrates : Used the plants in medicine (Father of
384-322 Aristotle : Initiated study of biology (Father of biology).
370-285Theophrastus : Described 480 kinds of plants in ‘Historia
Plantarum’ (Father of botany) and writer of ’cause of plants’.
1590 Invention of the first microscope by Jenssen and Zacharis Jenssen
1665 Discovery of the cellular structure (cells) in cork : Robert Hooke described in book ‘Micrographia’.
1675 Anatomia Plantarum : Book by Marcello Malpighi.
1683 Initial separation of bacteria : Antony Von Leeuwenhoek (of Holland) ‘animalcules’ named.
1694 Malpighi illustrated stomata and parenchyma.
1694 Camerarius described sexual reproduction of plants and importance of pollination.
1727 Stephan Hales discovered idea of manufacture of food by green plants in sunlight. Father of plant physiology.
1753 Species Plantarum and Genera Plantarum books (Linnaeus) Carl Van Linnae. Systema Naturae, Binomial nomenclature, father of taxonomy.
1759 C.F. Wolff established embryology, gave ‘epigenesis’ concept.
1761 Discovery of the sexuality of plants : Joseph Gottleib Koelreuter.
1779 Discovery of photosynthesis : Jan Ingenhousz.
1783 First studies of the biology of flowers : Christian Konard Sprengel.
1790 Metamorphosender pflanzen concept of plant metamorphosis : Johann Wolfgang Von Goethe.
1802 Lamarck and Treviranus proposed the term ‘Biology’.
1804 Researches chimiques surla vegetation, discovery of the gaseous exchange of plants : Nicolas Theodore de Saussure.
1809 J.B. Lamarck. Theory of inheritance of acquired characters ‘philosophie zoolozique’ book, use and disuse concept.
1809 Charles Darwin (England) voyage on ‘Beagle’ ship, ‘origin of species’ (1859) book. Theory of natural selection and survival of fittest influenced by Malthus.
1817 P. Caventon, discovery and naming of chlorophyll.
1824 Discovery of endosmosis by H.J. Dutrochet, also suggested that all plants and animals are made of cells.
1828 Brownian movement : Robert Brown.
1830 J.E. Purkinje studied movements and pollination.
1831 ‘Nucleus’ in plant cells : Robert Brown
1835 Nucleolus named by Bowman (1840) and first seen by Fontana (1781) but described by Schleiden M.J. (1835)
1835 Named Sarcode for cell fluid : Dujardin M. J.
1837 Named protoplasm : Purkinje J. E.
1838 T.R. Malthus : Suggested that human population increases much faster than food production.
1839 G.J. Mulder : Named proteins.
1839 Cell theory by German Scientists M.J. Schleiden (Botanist) and T. Schwann (Zoologist).
1840 Study of cell division : Hofmeister.
1840 Mineral nutrition of plants, established overthrow of the humus theory : Justus Von Liebig.
1842 R. Mayer : Light energy changed to chemical energy in photosynthesis.
1844 Properties of protoplasm : Hugo Von Mohl.
1845 Law of conservation of energy : Julius Robert Von Mayer.
1846 Plant cells arise from pre-existing cells : K. Nageli.
1851 Discovery of the homologies in plant reproduction : Wilheim Hofmeister.
1854 Thuret observed sexual union in algae Fucus.
1857 George Bentham and Joseph Dalton Hooker published ‘Genera Plantarum”.
1858 , ‘Omnis cellula e cellula’ (cells originate from pre-existing cells) R. Virchow.
1859 C. R. Darwin : Theory of Natural Selection, ‘Origin of species‘ book.
1861 ‘Protoplasmic Theory’ : Max Schultze.
1862 A. Kolliker introduced the term ‘cytoplasm‘
1863 Proposition of natural system of classification of angiosperms. George Bentham together with Sir Joseph Dalton Hooker.
1864 L. Pasteur : Proposed germ theory of diseases.
1865 ‘Plastid’ name given : E. Haeckel.
1866 Haeckel ‘Recapitulation theory, coined the term protista.
1866 G.J. Mendel Austrian monk : Laws of inheritance (Heredity). Father of genetics, worked on pea plant.
1868 T. H. Huxley : Protoplasm as the physical basis of life.
1869 Isolation of nuclein (DNA) from nuclei of pus cells : F. Meischer.
1870 W. His invented microtome.
1873 E. Strasburger observed cell division and nuclear division.
1875 Hertwig and Van Beneden both described fertilization between sperm and egg nuclei.
1876 Identification of the Anthrax bacillus as a pathogen of cattles : Robert Koch..
1878 J. Lister : obtained pure cultures of bacteria for the first time.
1878 W. Kuhne coined the term ‘enzymes’ for ‘ferment’ of yeast.
1880 Discovery of mitochondria : A. Kollicker.
1882 ‘Chromatin’ : W. Flemming, described chromosome splitting used the word ‘mitosis’.
1883 Schimper named chloroplasts, the special bodies of Sach (1865) and green granules of Comparatti (1791).
1884 E. Strasburger : Observed fertilization and cell division in plants, used terms cytoplasm and nucleoplasm.
1886 John Ray published ‘Historia Generalis Plantarum’.
1888 ‘Chromosome’ name W. Weldeyer but first seen by Hofmeister (1848)
1888 Centrosome and centriole : T. Boveri.
1892 D. Iwanowski (Russian) discovered T.M.V. virus.
1892 A. Weissman (1834–1914) : Theory of germplasm.
1892 D. Hertwig : Published monograph ‘The cells and tissues’ established ‘cytology’.
1893 Astral–rays : Fol.
1894 R. Altmann : Discovered mitochondria described as bioplast.
1895 Dixon and Jolly advocated cohesion tension theory for ascent of sap.
1897 ‘Mitochondrion’ : C. Benda.
1898 E. Buchner named ‘Zymase’ the enzymes of yeast.
1898 S. G. Nawaschin recorded double fertilization in angiosperms.
1898 Camilio Golgi discovered golgi apparatus in nerve cell of owl.
1899 Altmann : Introduced term ‘nucleic acids’ to replace nuclein.
1899 Adolf Engler and K. Prantl published ‘Die Naturlichem Pfianzenfamilen system’ of plant classification.
1900 Rediscovery of Mendel’s laws : Erich Tschermak; Carl Correns and Hugo de Vries.
1901 Die Mutations theory : Studies on Oenothera, theory of mutations– Hugo de Vries (1840–1935).
1901 Jule and Merbeck : Parthenogenesis.
1902 C. E. McClung : Identified sex chromosomes in grasshopper.
1902 ‘Chromosome theory’ : Sutton and Boveri.
1904 Blakeslee : Discovered ‘heterothallism‘ in Mucor.
1905 W. Bateson : Coined the term ‘genetics’.
1905 Robert Koch :’Microbiology’ term given; gave Koch’s postulates for germ theory.
1905 Name ‘meiosis‘ : Farmer and Moore.
1908 Winkler : Apomixis.
1909 W. L. Johansen coined the word ‘gene‘
1915 R. M. Willstater : Structure of chlorophyll.
1915 Twort and d’ Herelle : Bacteriophage.
1920 Garner and Allard : work on Photoperiodism.
1921 C.C. Bridges : Discovered duplication, deficiencies and translocations in chromosomes.
1924 Feulgen and H. Rossenbeck : Staining of DNA in cells.
1924 Oparin : Origin of life, materialistic theory.
1926 T. Svedberg : Invented ultra–centrifuge (Nobel Prize).
1926 Went : Carried out avena curvature test (auxins).
1928 Griffith : Transformation in pneumococcus bacteria.
1929 A. Fleming : Discovered Pencillin antibiotic from Penicillium notatum.
1930 Fuelgen and Behrens : RNA in cells.
1931 Zirnike : Phase contrast microscope.
1931 O.H. Warburg : Respiratory pigments and enzymes (Nobel Prize).
1931 Van Niel : Photosynthesis in sulphur bacteria, photolysis (origin from water).
1932 Electron microscope : M. Knoll and E. Ruska.
1933 T.H. Morgan was awarded Nobel Prize for development of gene theory, discovered linkage of genes.
1934 Kogl and Haagen Smit isolated IAA from human urine.
1934 John Hutchinson put forward phylogenetic system of plant classification.
1935 James Danielli and H. Davson proposed a molecular model of plasma membrane, showing trilamellar structure.
1935 Tensley : Ecosystem term given.
1935 Crystallization of the tabacco mosaic virus (TMV) : W.M. Stanley.
1937 Robin Hill : Demonstrated the release of molecular oxygen by illumination of isolated chloroplasts in photosynthesis.
1937 Hans Krebs explained citric acid cycle.
1938 Yabuta and Sumiki : Isolated the first Gibberellin from Gibberella fujikuroi.
1941 Ruben and Kamen : Used isotopes to prove photolysis of water in photosynthesis.
1944 Beadle and Tatum : One gene one enzyme concept (Neurospora).
1944 Claude : Microsomes.
1944 Avery, Mcleod, McCarthy proved DNA genetic material.
1945 S. Waksman : Streptomycin, used term antibiotic (Nobel Prize).
1945 Porter and Thompson : Endoplasmic reticulum.
1946 J. B. Sumner : Crystalized first enzyme urease.
1946 J. H. Northorp and W. M. Stanley : Enzymes and virus proteins purified.
1946 H.J. Muller : X–ray induced mutations (Nobel Prize).
1946 Lederberg and Tatum : First indication of sexuality in bacteria.
1951 M.H.F. Wilkins : X-ray diffraction studies of DNA.
1952 Hershey and Chase : DNA as infective part of bacteriophage.
1953 H. A. Kreb’s : ‘Citric acid cycle’ (Nobel Prize).
1953 J. D. Waston,, F.H.C. Crick and Wilkins gave DNA model and shared Nobel Prize 1962.
1953 F. A. Lipman : Coenzyme–A.
1953 Transduction in bacteria : Zinder and Lederberg.
1954 Arnon D. : Photophosphorylation in chloroplast.
1955 Ribosome : G. E. Palade.
1955 Christian de Duve discovered lysosomes and coined the term.
1955 Hoagland : Transfer RNA.
1956 S. Ochoa succeeded in invitro synthesis of polyribonucleotides (RNA) Nobel Prize.
1957 Fraenkel Conrat : RNA as genetic material in TMV (virus)
1958 Lederberg : Genetic recombination in bacteria, (Nobel Prize).
1959 Arthur Kornberg was awarded Nobel Prize for in vitro synthesis of DNA.
1959 Unit membrane : Robertson.
1959 Butle et al : Phytochrome.
1960 M. Calvin : Carbon fixation cycle (Nobel Prize).
1960 Jacob and Monod : Messenger RNA.
1961 Beevers : Glyoxysomes in plant cells.
1962 Menke : Thylakoid in chloroplasts.
1962 Kendrew and Perutz : Structure of proteins.
1963 Nass and Nass : DNA in mitochondria.
1963 Saffarman and Morris : Cyanophage virus with DNA.
1964 Osgoods et al : Multistranded chromosomes.
1964 Leninger : Oxysomes in mitochondria.
1964 Yanofsky : ‘One cistron one polypeptide theory’.
1964 Park and Biggins isolated quantosomes in the unit membrane of granum disc of chloroplast.
1965 Bernfield and Nirenberg : ‘Degeneracy’ in genetic code.
1965 F. Jacob and J. Monod : ‘Operon’ model (operator, regulator genes) Nobel Prize.
1965 Jacob and Wollman : Episome.
1967 M.D. Hatch and C.R. Slack: Dicarboxylic acid cycle (cycle).
1968 Tolbert et al : Peroxisomes.
1968 M.W. Nirenberg, H.G. Khorana and R.W. Holley were awarded Nobel Prize jointly for their discovery which led to breaking of genetic code.
1969 M. Delbruck, A.D. Hershey, S.E. Luria : Virus reproduction (Nobel Prize).
1969 Khorana synthesized ‘gene’ artificially in test tube, DNA ligase enzyme.
1970 Borlaug : Rust resistant high yield wheat varieties and peace (Nobel Prize).
1970 Crick and Klug : Nucleosome model of DNA.
1970 Dannielli : Test tube synthesis of cell.
1971 E.W. Sutherland : Role of cyclic AMP (Nobel Prize).
1972 R.R. Porter and G. M. Edelman : Chemical nature of antibodies. (Nobel Prize)
1974 A. Claude : Virus in cancer tumour cells, cell centrifugation technique (Nobel Prize).
1974 G.E. Palade : Nobel Prize for ribosome discovery.
1974 C. Duve : Nobel Prize for lysosome discovery.
1975 R. Dulbecco, H.M. Temin, D. Baltimore : Nobel Prize for RNA virus in cancer, and reverse transcriptase for coding DNA from RNA.
1976 Gajduseck and Blumenberg : Nobel Prize for cancer research.
1978 Arber, Smith and Nathans : Nobel Prize for DNA restriction enzymes.
1978 P. Steptoe and R. Edward : Work on 1st test tube baby.
1981 Sperry, Hubel and Weisel : Nobel Prize in medicine.
1982 S. Bergstroem, B. Samueleson and J. Vane : Nobel Prize for Prostoglandins role.
1983 B. McClintock : Nobel Prize for mobile genetic elements (transposons = jumping genes) in maize.
1984 K. J. Niels, G. E. Kochlar and C. Milstein : Nobel Prize for monoclonal antibodies.
Biology in Ancient India
References of classification of organisms are available in Upanishads and Vedas (1500 B.C. to 600 B.C.). However, earliest human activity can be traced back to early, middle and late stone age (400,000 B.C. – 200,000 B.C.).
About 740 plants and 250 animals have been mentioned in Vedic literature. Few significant references in old literature are,
(1) Chandyogya Upanishad : Here the animals have been classified into three categories –
(i) Jiraja (Viviparous) e.g. mammals.
(ii) Andaja (Oviparous) e.g. birds, reptiles, insects and worms.
(iii) Ubhija (Vegetal origin) e.g. small animals.
(2) Susruta Samhita (600 B.C.) : Here organisms were classified into,
(i) Sthavara in which immobile organisms like plants were kept.
(ii) Jangama in which mobile organisms like animals were placed.
Medical Science in Ancient India
Two Ashwini Kumars has been said to be practising medicine during Vedic times. Dhanwantrihas been called as ‘God of medicine’. Susruta has been called as ‘Father of surgery’. Few important references are,
(1) Susrutastudied human anatomy on dead bodies.
(2) Susruta carried plastic surgery on human nose (rhinoplasty).
(3) Ophthalmic surgery : Susruta carried an eye surgery like extraction of cataracts.
(4) Clotting of blood : Susruta used non-poisonous live leeches for checking clotting of blood in post operative conditions. Now its clearly established that heparin is released along saliva of leeches to produces this kind of effect.
(5) Charaka Samhita (100 B.C.) : It is said to be primarily written by Agnivasa under the guidance of Atreya(600 B.C.). Charakawas first to discuss the concepts of digestion, Metabolism and immunity.
(6) Taittiriya Upanishad (7–8 B.C.) : In this significant observations have been made about the process of evolution. According to this life originated in space.
(7) Manu Samhita or Manu Smriti (200 A.D.) : In this significant Sanskrit literature, evolution has been widely discussed.
Table : 1-1 Differences between Plants and Animals
|Photosynthesis||Show photosynthesis.||Do not show photosynthesis.|
|Chlorophyll||Contain chlorophyll.||Lack chlorophyll.|
|Dependence||Dependent upon inorganic substances like CO2 and H2O .||Feed on complex organic compounds.|
|Movement||Are fixed organisms but show bending, twisting etc.||They are capable of moving the whole body.|
|Branching||Have branched body.||Have compact body.|
|Sensitivity||Are comparatively less sensitive and respond slowly.||Are more sensitive and respond quickly.|
|Cell wall||Cellulose cell wall usually present.||Bear no cellulose cell walls.|
Serendipity and Science
(1) Serendipity is associated with scientific method and it refers to discoveries made unexpectedly or by chance.
(2) The term ‘serendipity’ was coined to Horace Walpolein 1754 from the title of the fairy-tale. ‘The Three Princes of Serendip (a former name for Sri Lanka)’, whose heroes were always making discoveries by accidents and sagacity.
(3) Louis Pasteur said that “chance favours the trained mind“. because an inquisitive, enthusiastic and intuitive mind may perceive the desired direction for a discovery.
(4) In 1922 while Alexander Fleming, the British bacteriologist has a cold, allowed few drops of his nasal mucus to fall on a bacterial culture.
(5) Fleming was excited to find sometime later that the mucus could dissolve away the bacteria and the enzyme lysozyme which dissolves bacterial cells could be discovered.
(6) One of the best known antibiotics, penicillin, was discovered by Fleming in 1928 as a result of a happy accident.
(7) Fleming had been working on Staphylococcus and it happened that some spores of a mould floated into his laboratory through an open window and landed on one of his Staphylococcus colonies.
(8) To Fleming’s surprise the bacteria were quickly destroyed.
(9) The mould was subsequently identified as Penicillium notatum; for this reason the active substance killing the bacteria was called penicillin.
(10) Edward Jenner, an English physician, could develop smallpox vaccine by observing that the dairymaids infected with milder cowpox are safer from infection of smallpox.
(11) In 1796, Jenner inoculated an 8-year old boy with fluid from cowpox blisters on the hand of a dairymaid, Sarah Nelms.
(12) To Jenner’s surprise, the boy had become immune to smallpox and this technique of inducing immunity became known as vaccination (Latin ‘
Biology is a Science of Exceptions
Exceptions are inherent in biology due to evolutionary divergence. Not only living organisms, but viruses and biomolecules also exhibit exceptional forms. A student of biology must be prepared to accept and enjoy this gesture of nature.
Some exceptions have been explained logically, while for others, the reasons are yet to be searched out. Following are noteworthy exceptions in zoology,
(1) Mammals are usually terrestrial, fossorial or arboreal but bat is only flying and whale and seals are aquatic mammals.
(2) Mature mammalian RBCs are devoid of nucleus except camel.
(3) The aquatic larval stage of some salamanders like Ambystoma is able to reproduce (paedogenesis) and attain sexual maturity. It is called neoteny. Total neoteny is found in Necturus, Siren and Proteus.
(4) Heart is three chambered in reptiles but four chambered in crocodiles. It is two chambered in fishes but three chambered in lung fishes like Protopterus which possess lung-like structure beside gills.
(5) DNA is double stranded in all cells and DNA viruses but single stranded in the bacteriophage and M-13. Likewise RNA is single stranded in all the cells and RNA viruses but double stranded in reovirus, rice dwarf virus and wound tumour virus.
Science and Technology
Scientific investigations may be basic or applied. Inventions of new technology extend new hopes and open avenues for the work and research which was not possible earlier. Discovery of radioactive isotopes enabled tracing metabolic pathways, development of microscope and then electron microscope provided useful tools to study biology. X-ray crystallography helped in the study of the structure of DNA, protein and many other biomolecules. Biotechnology and genetic engineering are fruitful due to accumulation of knowledge from different sources. It is note worthy that while information gathered from basic researches enriched the field of applied researches, the fruits of applied researches contribute to explore and widen the area of basic researches.