Bernard Kettlewell
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'''Henry Bernard Davis Kettlewell''' ([[24 February]] [[1907]] - [[1979]]) was a [[United Kingdom|British]] [[geneticist]], [[lepidopterist]] and [[medical doctor]], who carried out important research into the influence of [[industrial melanism]] on natural selection in moths, showing why moths are darker in polluted areas.
==Early life==
Kettlewell was born in [[Howden]], [[Yorkshire]], was educated at [[Charterhouse School]], and from 1926 studied medicine with [[zoology]] at [[Gonville and Caius College, Cambridge]]. In 1929 he began clinical training at [[St Bartholomew's Hospital]], London, then in 1935 joined a general medical practice in [[Cranleigh]], [[Surrey]]. He also worked as an anesthetist at St. Luke's Hospital, [[Guildford]]. During [[World War II]], from 1939 to 1945, he worked for the [[Emergency medical services|Emergency Medical Service]] at [[Woking]] War Hospital.<ref name=bio>{{cite web |url=http://www.wolfson.ox.ac.uk/library/archives/kettlewell/bio/ |title=Biographical Data on Henry Bernard Davis Kettlewell - Wolfson College |accessdate=2007-09-10 |format= |work=}}</ref>
He emigrated to [[South Africa]] in 1949, and from then until 1954 was a researcher at the [[International Locust Control Centre]] at [[Cape Town University]], investigating methods of locust control and going on expeditions to the [[Kalahari]], the [[Knysna Forest]], the [[Belgian Congo]] and [[Mozambique]].<ref name=bio/>
In 1952 he was appointed to a [[Nuffield Foundation|Nuffield Research Fellowship]] in the Department of Genetics of the Department of Zoology at [[University of Oxford|Oxford University]]. Until 1954 he divided his time between South Africa and [[Oxford]], then he gained the position of Senior Research Officer in the Department of Genetics and spent the rest of his career in Oxford as a genetics researcher.<ref name=bio/> His supervisor was [[E. B. Ford]].<ref>Hooper, Judith 2002. ''Of moths and men''. Claims Kettlwell's work was fraudulent and/or incompetent.</ref>
==Peppered moth investigation and experiments==
His grant was to study [[industrial melanism]] in general, and in particular the [[peppered moth]] ''Biston betularia'' which had been studied by [[William Bateson]] in the 1890s. Kettlewell's research from three surveys between 1952 and 1972 appeared to show a static pattern with a high frequency of the dark-coloured ''carbonaria'' [[phenotype]] in industrial regions, and the light coloured ''typica'' moths becoming the most common in more rural areas. In the first of [[Kettlewell's experiment]]s moths were released into an aviary to observe how insectivorous birds reacted. He showed that the birds ate the moths, and found that where the camouflage of the moths made them difficult for him to see against a matching background, the birds too had difficulty in finding the moths.<ref name=cook>{{cite web |url=http://www.streaming.mmu.ac.uk/cook/ |title=The Peppered Moth |accessdate=2007-09-10 |author=Prof. Laurence Cook |authorlink=Laurence Cook |coauthors= |date=February 2003 |format= |work=The Melanic Peppered Moth, Seminar to Post Grad Students |publisher=Manchester Metropolitan University |pages= |language= |archiveurl= |archivedate= |quote=}}</ref> Most famously he then carried out experiments involving releasing then recapturing marked moths in polluted woodlands in [[Birmingham]], and in unpolluted rural woods at Deanend Wood, [[Dorset]], [[England]].<ref>{{ cite web|url=http://www.blackwellpublishing.com/ridley/tutorials/The_theory_of_natural_selection__part_1_15.asp|title = The theory of natural selection (part 1)|publisher = Blackwell Publishing|accessdate = 2007-07-12 }}</ref> He demonstrated experimentally the efficiency of natural selection as an evolutionary force: light-coloured moths are more conspicuous than dark-coloured ones in industrial areas, where the vegetation is darkened by pollution, and are therefore easier prey for birds, but are less conspicuous in unpolluted rural areas, where the vegetation is lighter in colour, and therefore survive predation better. His experiment led to better understanding of industrial melanism and its effects on the evolution of species.
In 1979 Kettlewell died from an accidental drug overdose.<ref name=bio/>
== References ==
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[[Category:1907 births]]
[[Category:1979 deaths]]
[[Category:People from the East Riding of Yorkshire]]
[[Category:Lepidopterists]]
[[Category:British biologists]]
[[Category:Old Carthusians]]
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