Bernard Kettlewell
Encyclopedia
Henry Bernard Davis Kettlewell (born February 24, 1907; died May 11, 1979) was a British
geneticist
, lepidopterist
and medical doctor, who carried out research into the influence of industrial melanism on natural selection in moths, showing why moths are darker in polluted areas.
, Yorkshire
, and educated at Charterhouse School
. In 1926 he studied medicine and 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 Service
at Woking
War Hospital.
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
.
In 1952 he was appointed to a Nuffield Research Fellowship
in the Department of Genetics of the Department of Zoology at 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. His supervisor was E. B. Ford.
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. 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
. 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.
United Kingdom
The United Kingdom of Great Britain and Northern IrelandIn the United Kingdom and Dependencies, other languages have been officially recognised as legitimate autochthonous languages under the European Charter for Regional or Minority Languages...
geneticist
Geneticist
A geneticist is a biologist who studies genetics, the science of genes, heredity, and variation of organisms. A geneticist can be employed as a researcher or lecturer. Some geneticists perform experiments and analyze data to interpret the inheritance of skills. A geneticist is also a Consultant or...
, lepidopterist
Lepidopterist
A lepidopterist is a person who specialises in the study of Lepidoptera, members of an order encompassing moths and the three superfamilies of butterflies, skipper butterflies, and moth-butterflies...
and medical doctor, who carried out 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 HowdenHowden
Howden is a small market town and civil parish in the East Riding of Yorkshire, England. It lies north of the M62, on the A614 road about north of Goole and south-west of York. William the Conqueror gave the town to the Bishops of Durham in 1080...
, Yorkshire
Yorkshire
Yorkshire is a historic county of northern England and the largest in the United Kingdom. Because of its great size in comparison to other English counties, functions have been increasingly undertaken over time by its subdivisions, which have also been subject to periodic reform...
, and educated at Charterhouse School
Charterhouse School
Charterhouse School, originally The Hospital of King James and Thomas Sutton in Charterhouse, or more simply Charterhouse or House, is an English collegiate independent boarding school situated at Godalming in Surrey.Founded by Thomas Sutton in London in 1611 on the site of the old Carthusian...
. In 1926 he studied medicine and zoology
Zoology
Zoology |zoölogy]]), is the branch of biology that relates to the animal kingdom, including the structure, embryology, evolution, classification, habits, and distribution of all animals, both living and extinct...
at Gonville and Caius College, Cambridge
Gonville and Caius College, Cambridge
Gonville and Caius College is a constituent college of the University of Cambridge in Cambridge, England. The college is often referred to simply as "Caius" , after its second founder, John Keys, who fashionably latinised the spelling of his name after studying in Italy.- Outline :Gonville and...
. In 1929 he began clinical training at St Bartholomew's Hospital
St Bartholomew's Hospital
St Bartholomew's Hospital, also known as Barts, is a hospital in Smithfield in the City of London, England.-Early history:It was founded in 1123 by Raherus or Rahere , a favourite courtier of King Henry I...
, London, then in 1935 joined a general medical practice in Cranleigh
Cranleigh
Cranleigh is a large village, self-proclaimed the largest in England, and is situated 8 miles south east of Godalming in Surrey. It lies to the east of the A281 which links Guildford with Horsham; neighbouring villages include: Ewhurst, Alfold and Hascombe....
, Surrey
Surrey
Surrey is a county in the South East of England and is one of the Home Counties. The county borders Greater London, Kent, East Sussex, West Sussex, Hampshire and Berkshire. The historic county town is Guildford. Surrey County Council sits at Kingston upon Thames, although this has been part of...
. He also worked as an anesthetist at St. Luke's Hospital, Guildford
Guildford
Guildford is the county town of Surrey. England, as well as the seat for the borough of Guildford and the administrative headquarters of the South East England region...
. During World War II
World War II
World War II, or the Second World War , was a global conflict lasting from 1939 to 1945, involving most of the world's nations—including all of the great powers—eventually forming two opposing military alliances: the Allies and the Axis...
, from 1939 to 1945, he worked for the Emergency Medical Service
Emergency medical services
Emergency medical services are a type of emergency service dedicated to providing out-of-hospital acute medical care and/or transport to definitive care, to patients with illnesses and injuries which the patient, or the medical practitioner, believes constitutes a medical emergency...
at Woking
Woking
Woking is a large town and civil parish that shares its name with the surrounding local government district, located in the west of Surrey, UK. It is part of the Greater London Urban Area and the London commuter belt, with frequent trains and a journey time of 24 minutes to Waterloo station....
War Hospital.
He emigrated to South Africa
South Africa
The Republic of South Africa is a country in southern Africa. Located at the southern tip of Africa, it is divided into nine provinces, with of coastline on the Atlantic and Indian oceans...
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
Belgian Congo
The Belgian Congo was the formal title of present-day Democratic Republic of the Congo between King Leopold II's formal relinquishment of his personal control over the state to Belgium on 15 November 1908, and Congolese independence on 30 June 1960.-Congo Free State, 1884–1908:Until the latter...
and Mozambique
Mozambique
Mozambique, officially the Republic of Mozambique , is a country in southeastern Africa bordered by the Indian Ocean to the east, Tanzania to the north, Malawi and Zambia to the northwest, Zimbabwe to the west and Swaziland and South Africa to the southwest...
.
In 1952 he was appointed to a Nuffield Research Fellowship
Nuffield Foundation
The Nuffield Foundation is a British charitable trust, established in 1943 by William Morris , the founder of the Morris Motor Company. Lord Nuffield wanted to contribute to improvements in society, including the expansion of education and the alleviation of disadvantage...
in the Department of Genetics of the Department of Zoology at Oxford University
University of Oxford
The University of Oxford is a university located in Oxford, United Kingdom. It is the second-oldest surviving university in the world and the oldest in the English-speaking world. Although its exact date of foundation is unclear, there is evidence of teaching as far back as 1096...
. Until 1954 he divided his time between South Africa and Oxford
Oxford
The city of Oxford is the county town of Oxfordshire, England. The city, made prominent by its medieval university, has a population of just under 165,000, with 153,900 living within the district boundary. It lies about 50 miles north-west of London. The rivers Cherwell and Thames run through...
, 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. His supervisor was E. B. Ford.
Peppered moth investigation and experiments
His grant was to study industrial melanism in general, and in particular the peppered mothPeppered moth
The peppered moth is a temperate species of night-flying moth. Peppered moth evolution is often used by educators as an example of natural selection.- Distribution :...
Biston betularia which had been studied by William Bateson
William Bateson
William Bateson was an English geneticist and a Fellow of St. John's College, Cambridge...
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
Phenotype
A phenotype is an organism's observable characteristics or traits: such as its morphology, development, biochemical or physiological properties, behavior, and products of behavior...
in industrial regions, and the light coloured typica moths becoming the most common in more rural areas. In the first of Kettlewell's experiment
Kettlewell's experiment
In Great Britain during the late 1840s through the 1850s, it was noticed that there was a reduced number of light colored European peppered moths and an increased number of the darker colored moths in the industrial areas...
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. Most famously he then carried out experiments involving releasing then recapturing marked moths in polluted woodlands in Birmingham
Birmingham
Birmingham is a city and metropolitan borough in the West Midlands of England. It is the most populous British city outside the capital London, with a population of 1,036,900 , and lies at the heart of the West Midlands conurbation, the second most populous urban area in the United Kingdom with a...
, and in unpolluted rural woods at Deanend Wood, Dorset
Dorset
Dorset , is a county in South West England on the English Channel coast. The county town is Dorchester which is situated in the south. The Hampshire towns of Bournemouth and Christchurch joined the county with the reorganisation of local government in 1974...
, England
England
England is a country that is part of the United Kingdom. It shares land borders with Scotland to the north and Wales to the west; the Irish Sea is to the north west, the Celtic Sea to the south west, with the North Sea to the east and the English Channel to the south separating it from continental...
. 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.