HOME

TheInfoList



OR:

Wilhelm Johannsen (3 February 1857 – 11 November 1927) was a Danish pharmacist,
botanist Botany, also called , plant biology or phytology, is the science of plant life and a branch of biology. A botanist, plant scientist or phytologist is a scientist who specialises in this field. The term "botany" comes from the Ancient Greek wo ...
, plant physiologist, and
geneticist A geneticist is a biologist or physician who studies genetics, the science of genes, heredity, and variation of organisms. A geneticist can be employed as a scientist or a lecturer. Geneticists may perform general research on genetic processe ...
. He is best known for coining the terms
gene In biology, the word gene (from , ; "...Wilhelm Johannsen coined the word gene to describe the Mendelian units of heredity..." meaning ''generation'' or ''birth'' or ''gender'') can have several different meanings. The Mendelian gene is a ba ...
,
phenotype In genetics, the phenotype () is the set of observable characteristics or traits of an organism. The term covers the organism's morphology or physical form and structure, its developmental processes, its biochemical and physiological proper ...
and
genotype The genotype of an organism is its complete set of genetic material. Genotype can also be used to refer to the alleles or variants an individual carries in a particular gene or genetic location. The number of alleles an individual can have in a ...
, and for his 1903 "pure line" experiments in
genetics Genetics is the study of genes, genetic variation, and heredity in organisms.Hartl D, Jones E (2005) It is an important branch in biology because heredity is vital to organisms' evolution. Gregor Mendel, a Moravian Augustinian friar wor ...
.


Biography

Johannsen was born in Copenhagen. While very young, he was apprenticed to a
pharmacist A pharmacist, also known as a chemist (Commonwealth English) or a druggist (North American and, archaically, Commonwealth English), is a healthcare professional who prepares, controls and distributes medicines and provides advice and instructi ...
and worked in
Denmark ) , song = ( en, "King Christian stood by the lofty mast") , song_type = National and royal anthem , image_map = EU-Denmark.svg , map_caption = , subdivision_type = Sovereign state , subdivision_name = Danish Realm, Kingdom of Denmark ...
and Germany beginning in 1872 until passing his pharmacist's exam in 1879. In 1881, he became assistant in the chemistry department at the
Carlsberg Laboratory The Carlsberg Research Laboratory is a private scientific research center in Copenhagen, Denmark under the Carlsberg Group. It was founded in 1875 by J. C. Jacobsen, the founder of the Carlsberg brewery, with the purpose of advancing biochemica ...
under the chemist
Johan Kjeldahl Johan Gustav Christoffer Thorsager Kjeldahl ( 16 August 1849 – 18 July 1900), was a Danish chemist who developed a method for determining the amount of nitrogen in certain organic compounds using a laboratory technique which was named the Kjel ...
. Johannsen studied the
metabolism Metabolism (, from el, μεταβολή ''metabolē'', "change") is the set of life-sustaining chemical reactions in organisms. The three main functions of metabolism are: the conversion of the energy in food to energy available to run cell ...
of
dormancy Dormancy is a period in an organism's life cycle when growth, development, and (in animals) physical activity are temporarily stopped. This minimizes metabolic activity and therefore helps an organism to conserve energy. Dormancy tends to be clo ...
and
germination Germination is the process by which an organism grows from a seed or spore. The term is applied to the sprouting of a seedling from a seed of an angiosperm or gymnosperm, the growth of a sporeling from a spore, such as the spores of fungi, fer ...
in
seed A seed is an embryonic plant enclosed in a protective outer covering, along with a food reserve. The formation of the seed is a part of the process of reproduction in seed plants, the spermatophytes, including the gymnosperm and angiospe ...
s,
tuber Tubers are a type of enlarged structure used as storage organs for nutrients in some plants. They are used for the plant's perennation (survival of the winter or dry months), to provide energy and nutrients for regrowth during the next growing ...
s and
bud In botany, a bud is an undeveloped or embryonic shoot and normally occurs in the axil of a leaf or at the tip of a stem. Once formed, a bud may remain for some time in a dormant condition, or it may form a shoot immediately. Buds may be spec ...
s. He showed that
dormancy Dormancy is a period in an organism's life cycle when growth, development, and (in animals) physical activity are temporarily stopped. This minimizes metabolic activity and therefore helps an organism to conserve energy. Dormancy tends to be clo ...
could be broken by various
anesthetic An anesthetic (American English) or anaesthetic (British English; see spelling differences) is a drug used to induce anesthesia ⁠— ⁠in other words, to result in a temporary loss of sensation or awareness. They may be divided into two ...
compounds, such as
diethyl ether Diethyl ether, or simply ether, is an organic compound in the ether class with the formula , sometimes abbreviated as (see Pseudoelement symbols). It is a colourless, highly volatile, sweet-smelling ("ethereal odour"), extremely flammable liq ...
and
chloroform Chloroform, or trichloromethane, is an organic compound with chemical formula, formula Carbon, CHydrogen, HChlorine, Cl3 and a common organic solvent. It is a colorless, strong-smelling, dense liquid produced on a large scale as a precursor to ...
. In 1892, he was appointed lecturer at
Royal Veterinary and Agricultural University The Royal Veterinary and Agricultural University ( da, Kongelige Veterinær- og Landbohøjskole, abbr. KVL) was a veterinary and agricultural science university in Denmark. It was founded in 1856 and operated until 2007, when it became a part of t ...
and later became professor of
botany Botany, also called , plant biology or phytology, is the science of plant life and a branch of biology. A botanist, plant scientist or phytologist is a scientist who specialises in this field. The term "botany" comes from the Ancient Greek w ...
and
plant physiology Plant physiology is a subdiscipline of botany concerned with the functioning, or physiology, of plants. Closely related fields include plant morphology (structure of plants), plant ecology (interactions with the environment), phytochemistry (bi ...
. He taught plant physiology. His best-known research concerned so-called ''pure lines'' of the self-fertile
common bean ''Phaseolus vulgaris'', the common bean, is a herbaceous annual plant grown worldwide for its edible dry seeds or green bean, green, unripe pods. Its leaf is also occasionally used as a Leaf vegetable, vegetable and the straw as fodder. Its Pla ...
. He was able to show that even in
population Population typically refers to the number of people in a single area, whether it be a city or town, region, country, continent, or the world. Governments typically quantify the size of the resident population within their jurisdiction using a ...
s
homozygous Zygosity (the noun, zygote, is from the Greek "yoked," from "yoke") () is the degree to which both copies of a chromosome or gene have the same genetic sequence. In other words, it is the degree of similarity of the alleles in an organism. Mo ...
for all traits, i.e. without genetic variation, seed size followed a
normal distribution In statistics, a normal distribution or Gaussian distribution is a type of continuous probability distribution for a real-valued random variable. The general form of its probability density function is : f(x) = \frac e^ The parameter \mu ...
. This was attributable to resource provision to the mother plant and to the position of seeds in pods and of pods on the plant. This led him to coin the terms ''
phenotype In genetics, the phenotype () is the set of observable characteristics or traits of an organism. The term covers the organism's morphology or physical form and structure, its developmental processes, its biochemical and physiological proper ...
'' and ''
genotype The genotype of an organism is its complete set of genetic material. Genotype can also be used to refer to the alleles or variants an individual carries in a particular gene or genetic location. The number of alleles an individual can have in a ...
''. Johannsen's findings led him to oppose contemporary Darwinists, most notably
Francis Galton Sir Francis Galton, FRS FRAI (; 16 February 1822 – 17 January 1911), was an English Victorian era polymath: a statistician, sociologist, psychologist, anthropologist, tropical explorer, geographer, inventor, meteorologist, proto- ...
and
Karl Pearson Karl Pearson (; born Carl Pearson; 27 March 1857 – 27 April 1936) was an English mathematician and biostatistician. He has been credited with establishing the discipline of mathematical statistics. He founded the world's first university st ...
, who held the occurrence of normal distributed trait variation in
population Population typically refers to the number of people in a single area, whether it be a city or town, region, country, continent, or the world. Governments typically quantify the size of the resident population within their jurisdiction using a ...
s as proof of gradual genetic variation on which selection could act. Only with the
modern synthesis Modern synthesis or modern evolutionary synthesis refers to several perspectives on evolutionary biology, namely: * Modern synthesis (20th century), the term coined by Julian Huxley in 1942 to denote the synthesis between Mendelian genetics and s ...
, was it established that variation needed to be
heritable Heredity, also called inheritance or biological inheritance, is the passing on of traits from parents to their offspring; either through asexual reproduction or sexual reproduction, the offspring cells or organisms acquire the genetic informa ...
to act as the raw material for
selection Selection may refer to: Science * Selection (biology), also called natural selection, selection in evolution ** Sex selection, in genetics ** Mate selection, in mating ** Sexual selection in humans, in human sexuality ** Human mating strategie ...
. He created the terms ''
phenotype In genetics, the phenotype () is the set of observable characteristics or traits of an organism. The term covers the organism's morphology or physical form and structure, its developmental processes, its biochemical and physiological proper ...
'' and ''
genotype The genotype of an organism is its complete set of genetic material. Genotype can also be used to refer to the alleles or variants an individual carries in a particular gene or genetic location. The number of alleles an individual can have in a ...
'', first using them in his book in German as ''Elemente der exakten Erblichkeitslehre'' (Elements of the exact theory of heredity). This book was based in large part on ''Om arvelighed i samfund og i rene linier'' ("On heredity in society and in pure lines") and in his book ''Arvelighedslærens Elementer''. It was in this book Johannsen also introduced the term ''
gene In biology, the word gene (from , ; "...Wilhelm Johannsen coined the word gene to describe the Mendelian units of heredity..." meaning ''generation'' or ''birth'' or ''gender'') can have several different meanings. The Mendelian gene is a ba ...
''. This term was coined in opposition to the then common ''pangene'' that stemmed from Darwin's theory of
pangenesis Pangenesis was Charles Darwin's hypothetical mechanism for heredity, in which he proposed that each part of the body continually emitted its own type of small organic particles called gemmules that aggregated in the gonads, contributing herita ...
. The book became one of the founding texts of genetics. Also in 1905, Johannsen was appointed professor of
plant physiology Plant physiology is a subdiscipline of botany concerned with the functioning, or physiology, of plants. Closely related fields include plant morphology (structure of plants), plant ecology (interactions with the environment), phytochemistry (bi ...
at the
University of Copenhagen The University of Copenhagen ( da, Københavns Universitet, KU) is a prestigious public university, public research university in Copenhagen, Copenhagen, Denmark. Founded in 1479, the University of Copenhagen is the second-oldest university in ...
, becoming vice-chancellor in 1917. In December 1910, Johannsen was invited to give an address before the
American Society of Naturalists The American Society of Naturalists was founded in 1883 and is one of the oldest professional societies dedicated to the biological sciences in North America. The purpose of the Society is "to advance and diffuse knowledge of organic evolution and o ...
. This talk was printed in the
American Naturalist ''The American Naturalist'' is the monthly peer-reviewed scientific journal of the American Society of Naturalists, whose purpose is "to advance and to diffuse knowledge of organic evolution and other broad biological principles so as to enhance th ...
. In 1911, he was invited to give a series of four lectures at
Columbia University Columbia University (also known as Columbia, and officially as Columbia University in the City of New York) is a private research university in New York City. Established in 1754 as King's College on the grounds of Trinity Church in Manhatt ...
. Johannsen was a corresponding member of the
Academy of Natural Sciences of Philadelphia The Academy of Natural Sciences of Drexel University, formerly the Academy of Natural Sciences of Philadelphia, is the oldest natural science research institution and museum in the Americas. It was founded in 1812, by many of the leading natura ...
(elected 1915).


References


Sources

*Anker, Jean (1932) Wilhelm Johannsen, pp. 177–180 in: Meisen, V. Prominent Danish Scientists through the Ages. University Library of Copenhagen 450th Anniversary. Levin & Munksgaard, Copenhagen. * Roll-Hansen, Nils (1983) The Death of Spontaneous Generation and the Birth of the Gene: Two Case Studies of Relativism. Social Studies of Science 13 (4): 481–519. *Kim, Kyung-Man (1991) On the Reception of Johannsen's Pure Line Theory: Toward a Sociology of Scientific Validity. Social Studies of Science 21 (4): 649–679.


External links


Wilhelm Johannsen Centre for Functional Genome ResearchImage gallery6 min silent movie showing Johannsen in action as teacher and scientist
{{DEFAULTSORT:Johannsen, Wilhelm 1857 births 1927 deaths 20th-century Danish botanists Agriculture educators Danish science writers University of Copenhagen alumni University of Copenhagen faculty People from Helsingør Carlsberg Laboratory staff Plant physiologists Danish geneticists Rectors of the University of Copenhagen 19th-century Danish botanists Members of the Royal Society of Sciences in Uppsala