Editing Peppered moth evolution (section)

== Origin and evolution ==

[[File:Lichte en zwarte versie berkenspanner.jpg|thumb|360px|''Typica'' and ''carbonaria'' morphs on the same tree. The light-coloured ''typica'' (below the bark's scar) is nearly invisible on this pollution-free tree, [[camouflage|camouflaging]] it from predators.]]

{{Further|Industrial melanism}}

Before the [[Industrial Revolution]], the black form of the peppered moth was rare. The first black specimen (of unknown origin) was collected before 1811, and kept in the [[University of Oxford]].<ref>{{cite journal |last1=Berry |first1=R. J. |title=Industrial melanism and peppered moths (Biston betularia (L.)) |journal=Biological Journal of the Linnean Society |year=1990 |volume=39 |issue=4 |pages=301–322 |doi=10.1111/j.1095-8312.1990.tb00518.x}}</ref><ref>{{cite journal |last1=Saccheri |first1=I. J. |last2=Rousset |first2=F. |last3=Watts |first3=P. C. |last4=Brakefield |first4=P. M. |last5=Cook |first5=L. M. |title=Selection and gene flow on a diminishing cline of melanic peppered moths |journal=[[PNAS]] |year=2008 |volume=105 |issue=42 |pages=16212–16217 |bibcode=2008PNAS..10516212S |pmid=18854412 |doi=10.1073/pnas.0803785105 |doi-access=free |pmc=2571026}}</ref><ref>{{cite book |last=Neal |first=Dick |title=Introduction to Population Biology |year=2004 |publisher=Cambridge University Press |location=Cambridge |isbn=9780521532235 |page=171 |edition=Reprint |ref=neal2004 |url=https://books.google.com/books?id=XV76J3TuEz0C}}</ref> The first live specimen was caught by R. S. Edleston in [[Manchester]], [[England]] in 1848, but he reported this only 16 years later in 1864, in ''[[The Entomologist: An illustrated journal of British Entomology|The Entomologist]]''.<ref>{{cite journal |last1=Edleston |first1=R. S. |title=[No title] |journal=Entomologist |year=1864 |volume=2 |page=150 |url=https://www.scopus.com/record/display.url?eid=2-s2.0-84890135076&origin=inward&txGid=CF9355AA40D5AC0DC3C6FDF79E2BB418.N5T5nM1aaTEF8rE6yKCR3A%3a2}}</ref> Edleston notes that by 1864 it was the more common type of moth in his garden in Manchester. The light-bodied moths were able to blend in with the light-coloured [[lichen]]s and tree bark, and the less common black moths were more likely to be eaten by birds. As a result of the common light-coloured lichens and English trees, therefore, the light-coloured moths were much more effective at hiding from predators, and the frequency of the dark allele was very low, at about 0.01%.<ref name="Hart">{{cite journal |last1=Hart |first1=Adam G. |last2=Stafford |first2=Richard |last3=Smith |first3=Angela L. |last4=Goodenough |first4=Anne E. |title=Evidence for contemporary evolution during Darwin's lifetime |journal=[[Current Biology]] |year=2010 |volume=20 |issue=3 |pages=R95 |pmid=20144776 |doi=10.1016/j.cub.2009.12.010 |s2cid=31093691 |url=https://eprints.glos.ac.uk/3333/3/Evidence%20for%20contemporary%20evolution%20during%20Darwin's%20lifetime.pdf}}</ref>

During the early decades of the Industrial Revolution in England, the countryside between London and Manchester became blanketed with [[soot]] from the new coal-burning factories. Many of the light-bodied lichens died from [[sulfur dioxide|sulphur dioxide]] emissions, and the trees became darkened. This led to an increase in bird predation for light-coloured moths, as they no longer blended in as well in their [[air pollution|polluted]] [[ecosystem]]: indeed, their bodies now dramatically contrasted with the colour of the bark. Dark-coloured moths, on the other hand, were [[camouflage]]d very well by the blackened trees.<ref name="miller">Miller, Ken (1999). ''[http://www.millerandlevine.com/km/evol/Moths/moths.html The Peppered Moth: An Update]''</ref> The population of dark-coloured moth rapidly increased. By the mid-19th century, the number of dark-coloured moths had risen noticeably, and by 1895, the percentage of dark-coloured moths in Manchester was reported at 98%, a dramatic change (of almost 100%) from the original frequency.<ref name="miller"/> This effect of industrialization in body colour led to the coining of the term "[[industrial melanism]]".<ref name=majerus2008/>

The implication that industrial melanism could be evidence supporting [[Charles Darwin]]'s theory of [[natural selection]] was noticed during his lifetime. Albert Brydges Farn (1841–1921), a British entomologist, wrote to Darwin on 18 November 1878 to discuss his observation of colour variations in the Annulet moth (then ''Gnophos obscurata'', now ''[[Charissa obscurata]]''). He noted the existence of dark moths in peat in the [[New Forest]], brown moths on clay and red soil in [[Herefordshire]], and white moths on chalk cliffs in [[Lewes]], and suggested that this variation was an example of "survival of the fittest". He told Darwin that he had found dark moths on a chalk slope where the foliage had been blackened by smoke from [[lime kiln]]s, and he had also heard that white moths had become less common at Lewes after lime kilns had been in operation for a few years.<ref name="Farn">{{cite web |last=Farn |first=A. B. |title=Farn, A.B. to Darwin C.R., Darwin Correspondence Project Letter 11747 |date=18 November 1878 |work=The Darwin Papers |location=Manuscripts Room, Cambridge University Library, West Road, Cambridge, England |id=DAR 164:26 |url=https://www.darwinproject.ac.uk/letter/DCP-LETT-11747.xml}}</ref> Darwin does not seem to have responded to this information, possibly because he thought natural selection would be a much slower process.<ref name="Science Focus 2018">{{cite web |title=How an extraordinary letter to Darwin spotted industrial melanism in moths |website=Science Focus |date=27 February 2018 |url=https://www.sciencefocus.com/nature/how-an-extraordinary-letter-to-darwin-spotted-industrial-melanism-in-moths |access-date=16 June 2018}}</ref> A scientific explanation of moth coloration was only published in 1896, 14 years after Darwin's death, when [[J. W. Tutt]] explicitly linked peppered moth melanism to natural selection.<ref name=Hart/>

=== Rise and fall of phenotype frequency ===

[[Melanism]] has been observed in both European and North American peppered moth populations. Information about the rise in frequency is scarce. Much more is known about the subsequent fall in [[phenotype]] frequency, as it has been measured by [[lepidopterist]]s using [[insect trap|moth traps]].

Steward compiled data for the first recordings of the peppered moth by locality, and deduced that the ''carbonaria'' morph was the result of a single [[mutation]] that subsequently spread. By 1895, it had reached a reported frequency of 98% in Manchester.<ref name="steward">{{cite journal |last=Steward |first=R. C. |year=1977 |title=Industrial and non-industrial melanism in the peppered moth ''Biston betularia'' (L.) |journal=Ecological Entomology |volume=2 |issue=3 |pages=231–243 |doi=10.1111/j.1365-2311.1977.tb00886.x |s2cid=85624115}}</ref>

From around 1962 to the present, the phenotype frequency of ''carbonaria'' has steadily fallen in line with cleaner air around industrial cities. Its decline has been measured more accurately than its rise, through more rigorous scientific studies. Notably, Kettlewell conducted a national survey in 1956, [[Bruce Grant (biologist)|Bruce Grant]] conducted a similar one in early 1996,<ref>{{cite web |last=Grant |first=Bruce |author-link=Bruce Grant (biologist) |title=Distribution of melanism in Britain |website=Talk Origins |url=https://www.talkorigins.org/faqs/wells/images/grantfile.jpg |access-date=2 June 2022}}</ref> and L.M. Cook in 2003.<ref name=cook2003>{{cite journal |last=Cook |first=L. M. |title=The rise and fall of the Carbonaria form of the peppered moth |journal=The Quarterly Review of Biology |year=2003 |volume=78 |issue=4 |pages=399–417 |pmid=14737825 |doi=10.1086/378925 |s2cid=26831926}}</ref>

Similar results were found in North America. Melanic forms have not been found in Japan. It is believed that this is because peppered moths in Japan do not inhabit industrialised regions.<ref name=cook2003/>