81-416: Architectibranchia is a clade of marine snails , gastropod molluscs . It was originally established containing the superfamilies Acteonoidea , Ringiculoidea , and Diaphanoidea . Architectibranchia was not used in the taxonomy by Bouchet & Rocroi (2005) and this taxon name has been listed as an available name . Clade Architectibranchia was reinstated by Malaquias et al. in 2009; they limited
162-442: A common ancestor is now generally accepted and considered a fundamental scientific concept. In a joint publication with Alfred Russel Wallace , he introduced his scientific theory that this branching pattern of evolution resulted from a process he called natural selection , in which the struggle for existence has a similar effect to the artificial selection involved in selective breeding . Darwin has been described as one of
243-451: A genealogical branching of a single evolutionary tree , in which "It is absurd to talk of one animal being higher than another", thereby discarding Lamarck's idea of independent lineages progressing to higher forms. While developing this intensive study of transmutation, Darwin became mired in more work. Still rewriting his Journal , he took on editing and publishing the expert reports on his collections, and with Henslow's help obtained
324-581: A monophyletic group or natural group , is a grouping of organisms that are monophyletic – that is, composed of a common ancestor and all its lineal descendants – on a phylogenetic tree . In the taxonomical literature, sometimes the Latin form cladus (plural cladi ) is used rather than the English form. Clades are the fundamental unit of cladistics , a modern approach to taxonomy adopted by most biological fields. The common ancestor may be an individual,
405-588: A population , or a species ( extinct or extant ). Clades are nested, one in another, as each branch in turn splits into smaller branches. These splits reflect evolutionary history as populations diverged and evolved independently. Clades are termed monophyletic (Greek: "one clan") groups. Over the last few decades, the cladistic approach has revolutionized biological classification and revealed surprising evolutionary relationships among organisms. Increasingly, taxonomists try to avoid naming taxa that are not clades; that is, taxa that are not monophyletic . Some of
486-479: A "ladder", with supposedly more "advanced" organisms at the top. Taxonomists have increasingly worked to make the taxonomic system reflect evolution. When it comes to naming , this principle is not always compatible with the traditional rank-based nomenclature (in which only taxa associated with a rank can be named) because not enough ranks exist to name a long series of nested clades. For these and other reasons, phylogenetic nomenclature has been developed; it
567-555: A 230-page "Essay", to be expanded with his research results if he died prematurely. In November, the anonymously published sensational best-seller Vestiges of the Natural History of Creation brought wide interest in transmutation. Darwin scorned its amateurish geology and zoology, but carefully reviewed his own arguments. Controversy erupted, and it continued to sell well despite contemptuous dismissal by scientists. Darwin completed his third geological book in 1846. He now renewed
648-827: A Bachelor of Arts degree as the first step towards becoming an Anglican country parson . Darwin was unqualified for Cambridge's Tripos exams and was required instead to join the ordinary degree course. He preferred riding and shooting to studying. During the first few months of Darwin's enrolment at Christ's College, his second cousin William Darwin Fox was still studying there. Fox impressed him with his butterfly collection, introducing Darwin to entomology and influencing him to pursue beetle collecting. He did this zealously and had some of his finds published in James Francis Stephens ' Illustrations of British entomology (1829–1932). Through Fox, Darwin became
729-660: A Treasury grant of £1,000 to sponsor this multi-volume Zoology of the Voyage of H.M.S. Beagle , a sum equivalent to about £115,000 in 2021. He stretched the funding to include his planned books on geology, and agreed to unrealistic dates with the publisher. As the Victorian era began, Darwin pressed on with writing his Journal , and in August 1837 began correcting printer's proofs . As Darwin worked under pressure, his health suffered. On 20 September, he had "an uncomfortable palpitation of
810-579: A beginning to each crop of species". Darwin's book The Structure and Distribution of Coral Reefs on his theory of atoll formation was published in May 1842 after more than three years of work, and he then wrote his first "pencil sketch" of his theory of natural selection. To escape the pressures of London, the family moved to rural Down House in Kent in September. On 11 January 1844, Darwin mentioned his theorising to
891-542: A book on geology. When they reached Brazil, Darwin was delighted by the tropical forest , but detested the sight of slavery there , and disputed this issue with FitzRoy. The survey continued to the south in Patagonia . They stopped at Bahía Blanca , and in cliffs near Punta Alta Darwin made a major find of fossil bones of huge extinct mammals beside modern seashells, indicating recent extinction with no signs of change in climate or catastrophe. He found bony plates like
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#1733084937125972-446: A branch of mammals that split off after the end of the period when the clade Dinosauria stopped being the dominant terrestrial vertebrates 66 million years ago. The original population and all its descendants are a clade. The rodent clade corresponds to the order Rodentia, and insects to the class Insecta. These clades include smaller clades, such as chipmunk or ant , each of which consists of even smaller clades. The clade "rodent"
1053-709: A break and went "geologising" in Scotland. He visited Glen Roy in glorious weather to see the parallel "roads" cut into the hillsides at three heights. He later published his view that these were marine-raised beaches, but then had to accept that they were shorelines of a proglacial lake . Fully recuperated, he returned to Shrewsbury in July 1838. Used to jotting down daily notes on animal breeding, he scrawled rambling thoughts about marriage, career and prospects on two scraps of paper, one with columns headed "Marry" and "Not Marry" . Advantages under "Marry" included "constant companion and
1134-465: A calm spell. On their first stop ashore at St Jago in Cape Verde, Darwin found that a white band high in the volcanic rock cliffs included seashells. FitzRoy had given him the first volume of Charles Lyell 's Principles of Geology , which set out uniformitarian concepts of land slowly rising or falling over immense periods, and Darwin saw things Lyell's way, theorising and thinking of writing
1215-623: A clade can be described based on two different reference points, crown age and stem age. The crown age of a clade refers to the age of the most recent common ancestor of all of the species in the clade. The stem age of a clade refers to the time that the ancestral lineage of the clade diverged from its sister clade. A clade's stem age is either the same as or older than its crown age. Ages of clades cannot be directly observed. They are inferred, either from stratigraphy of fossils , or from molecular clock estimates. Viruses , and particularly RNA viruses form clades. These are useful in tracking
1296-557: A close friend and follower of botany professor John Stevens Henslow . He met other leading parson-naturalists who saw scientific work as religious natural theology , becoming known to these dons as "the man who walks with Henslow". When his own exams drew near, Darwin applied himself to his studies and was delighted by the language and logic of William Paley 's Evidences of Christianity (1795). In his final examination in January 1831, Darwin did well, coming tenth out of 178 candidates for
1377-412: A copy of his journal for his family. He had some expertise in geology, beetle collecting and dissecting marine invertebrates, but in all other areas, was a novice and ably collected specimens for expert appraisal. Despite suffering badly from seasickness, Darwin wrote copious notes while on board the ship. Most of his zoology notes are about marine invertebrates, starting with plankton collected during
1458-596: A fascination and expertise in marine invertebrates, dating back to his student days with Grant, by dissecting and classifying the barnacles he had collected on the voyage, enjoying observing beautiful structures and thinking about comparisons with allied structures. In 1847, Hooker read the "Essay" and sent notes that provided Darwin with the calm critical feedback that he needed, but would not commit himself and questioned Darwin's opposition to continuing acts of creation . In an attempt to improve his chronic ill health, Darwin went in 1849 to Dr. James Gully 's Malvern spa and
1539-518: A fortnight mapping strata in Wales. After leaving Sedgwick in Wales, Darwin spent a few days with student friends at Barmouth . He returned home on 29 August to find a letter from Henslow proposing him as a suitable (if unfinished) naturalist for a self-funded supernumerary place on HMS Beagle with captain Robert FitzRoy , a position for a gentleman rather than "a mere collector". The ship
1620-518: A freed black slave who had accompanied Charles Waterton in the South American rainforest . In Darwin's second year at the university, he joined the Plinian Society , a student natural-history group featuring lively debates in which radical democratic students with materialistic views challenged orthodox religious concepts of science. He assisted Robert Edmond Grant 's investigations of
1701-469: A friend in old age ... better than a dog anyhow", against points such as "less money for books" and "terrible loss of time". Having decided in favour of marriage, he discussed it with his father, then went to visit his cousin Emma on 29 July. At this time he did not get around to proposing, but against his father's advice, he mentioned his ideas on transmutation. He married Emma on 29 January 1839 and they were
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#17330849371251782-518: A giant capybara . The armour fragments were actually from Glyptodon , a huge armadillo-like creature, as Darwin had initially thought. These extinct creatures were related to living species in South America. In mid-December, Darwin took lodgings in Cambridge to arrange expert classification of his collections, and prepare his own research for publication. Questions of how to combine his diary into
1863-556: A giant version of the armour on local armadillos . From a jaw and tooth he identified the gigantic Megatherium , then from Cuvier's description thought the armour was from this animal. The finds were shipped to England, and scientists found the fossils of great interest. In Patagonia, Darwin came to wrongly believe the territory was devoid of reptiles. On rides with gauchos into the interior to explore geology and collect more fossils, Darwin gained social, political and anthropological insights into both native and colonial people at
1944-500: A great name among the Naturalists of Europe". On 2 October 1836, Beagle anchored at Falmouth , Cornwall. Darwin promptly made the long coach journey to Shrewsbury to visit his home and see relatives. He then hurried to Cambridge to see Henslow, who advised him on finding available naturalists to catalogue Darwin's animal collections and to take on the botanical specimens. Darwin's father organised investments, enabling his son to be
2025-509: A minor role to natural selection, and it was not until the emergence of the modern evolutionary synthesis from the 1930s to the 1950s that a broad consensus developed in which natural selection was the basic mechanism of evolution. Darwin's scientific discovery is the unifying theory of the life sciences , explaining the diversity of life . Darwin was born in Shrewsbury , Shropshire, on 12 February 1809, at his family's home, The Mount . He
2106-532: A programmer of laws. Darwin stayed with his freethinking brother Erasmus, part of this Whig circle and a close friend of the writer Harriet Martineau , who promoted the Malthusianism that underpinned the controversial Whig Poor Law reforms to stop welfare from causing overpopulation and more poverty. As a Unitarian, she welcomed the radical implications of transmutation of species , promoted by Grant and younger surgeons influenced by Geoffroy . Transmutation
2187-422: A revised taxonomy based on a concept strongly resembling clades, although the term clade itself would not be coined until 1957 by his grandson, Julian Huxley . German biologist Emil Hans Willi Hennig (1913–1976) is considered to be the founder of cladistics . He proposed a classification system that represented repeated branchings of the family tree, as opposed to the previous systems, which put organisms on
2268-587: A sand beach. He theorised that as the land rose, oceanic islands sank, and coral reefs round them grew to form atolls . On the geologically new Galápagos Islands , Darwin looked for evidence attaching wildlife to an older "centre of creation", and found mockingbirds allied to those in Chile but differing from island to island. He heard that slight variations in the shape of tortoise shells showed which island they came from, but failed to collect them, even after eating tortoises taken on board as food. In Australia,
2349-506: A self-funded gentleman scientist , and an excited Darwin went around the London institutions being fêted and seeking experts to describe the collections. British zoologists at the time had a huge backlog of work, due to natural history collecting being encouraged throughout the British Empire, and there was a danger of specimens just being left in storage. Charles Lyell eagerly met Darwin for
2430-570: A series of books, and in his final book, The Formation of Vegetable Mould, through the Actions of Worms (1881), he examined earthworms and their effect on soil. Darwin published his theory of evolution with compelling evidence in his 1859 book On the Origin of Species . By the 1870s, the scientific community and a majority of the educated public had accepted evolution as a fact . However, many initially favoured competing explanations that gave only
2511-719: A similarity between farmers picking the best stock in selective breeding, and a Malthusian Nature selecting from chance variants so that "every part of newly acquired structure is fully practical and perfected", thinking this comparison "a beautiful part of my theory". He later called his theory natural selection , an analogy with what he termed the "artificial selection" of selective breeding. On 11 November, he returned to Maer and proposed to Emma, once more telling her his ideas. She accepted, then in exchanges of loving letters she showed how she valued his openness in sharing their differences, while expressing her strong Unitarian beliefs and concerns that his honest doubts might separate them in
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2592-429: A suffix added should be e.g. "dracohortian". A clade is by definition monophyletic , meaning that it contains one ancestor which can be an organism, a population, or a species and all its descendants. The ancestor can be known or unknown; any and all members of a clade can be extant or extinct. The science that tries to reconstruct phylogenetic trees and thus discover clades is called phylogenetics or cladistics ,
2673-468: A time of revolution, and learnt that two types of rhea had separate but overlapping territories. Further south, he saw stepped plains of shingle and seashells as raised beaches at a series of elevations. He read Lyell's second volume and accepted its view of "centres of creation" of species, but his discoveries and theorising challenged Lyell's ideas of smooth continuity and of extinction of species. Three Fuegians on board, who had been seized during
2754-471: Is in turn included in the mammal, vertebrate and animal clades. The idea of a clade did not exist in pre- Darwinian Linnaean taxonomy , which was based by necessity only on internal or external morphological similarities between organisms. Many of the better known animal groups in Linnaeus's original Systema Naturae (mostly vertebrate groups) do represent clades. The phenomenon of convergent evolution
2835-471: Is known as a Malthusian catastrophe . Darwin was well-prepared to compare this to Augustin de Candolle 's "warring of the species" of plants and the struggle for existence among wildlife, explaining how numbers of a species kept roughly stable. As species always breed beyond available resources, favourable variations would make organisms better at surviving and passing the variations on to their offspring, while unfavourable variations would be lost. He wrote that
2916-515: Is responsible for many cases of misleading similarities in the morphology of groups that evolved from different lineages. With the increasing realization in the first half of the 19th century that species had changed and split through the ages, classification increasingly came to be seen as branches on the evolutionary tree of life . The publication of Darwin's theory of evolution in 1859 gave this view increasing weight. In 1876 Thomas Henry Huxley , an early advocate of evolutionary theory, proposed
2997-489: Is still controversial. As an example, see the full current classification of Anas platyrhynchos (the mallard duck) with 40 clades from Eukaryota down by following this Wikispecies link and clicking on "Expand". The name of a clade is conventionally a plural, where the singular refers to each member individually. A unique exception is the reptile clade Dracohors , which was made by haplology from Latin "draco" and "cohors", i.e. "the dragon cohort "; its form with
3078-660: The Linnean Society of London . Darwin's work established evolutionary descent with modification as the dominant scientific explanation of natural diversification. In 1871, he examined human evolution and sexual selection in The Descent of Man, and Selection in Relation to Sex , followed by The Expression of the Emotions in Man and Animals (1872). His research on plants was published in
3159-541: The Narrative were resolved at the end of the month when FitzRoy accepted Broderip's advice to make it a separate volume, and Darwin began work on his Journal and Remarks . Darwin's first paper showed that the South American landmass was slowly rising, and with Lyell's enthusiastic backing he read it to the Geological Society of London on 4 January 1837. On the same day, he presented his mammal and bird specimens to
3240-590: The Royal Society 's Royal Medal, and it made his reputation as a biologist . Upon the conclusion of his research, Darwin declared "I hate a barnacle as no man ever did before." In 1854, he became a Fellow of the Linnean Society of London , gaining postal access to its library. He began a major reassessment of his theory of species, and in November realised that divergence in the character of descendants could be explained by them becoming adapted to "diversified places in
3321-912: The Zoological Society . The ornithologist John Gould soon announced that the Galápagos birds that Darwin had thought a mixture of blackbirds , " gros-beaks " and finches , were, in fact, twelve separate species of finches . On 17 February, Darwin was elected to the Council of the Geological Society, and Lyell's presidential address presented Owen's findings on Darwin's fossils, stressing geographical continuity of species as supporting his uniformitarian ideas. Early in March, Darwin moved to London to be near this work, joining Lyell's social circle of scientists and experts such as Charles Babbage , who described God as
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3402-516: The first Beagle voyage then given Christian education in England, were returning with a missionary. Darwin found them friendly and civilised, yet at Tierra del Fuego he met "miserable, degraded savages", as different as wild from domesticated animals. He remained convinced that, despite this diversity, all humans were interrelated with a shared origin and potential for improvement towards civilisation. Unlike his scientist friends, he now thought there
3483-509: The marsupial rat-kangaroo and the platypus seemed so unusual that Darwin thought it was almost as though two distinct Creators had been at work. He found the Aborigines "good-humoured & pleasant", their numbers depleted by European settlement. FitzRoy investigated how the atolls of the Cocos (Keeling) Islands had formed, and the survey supported Darwin's theorising. FitzRoy began writing
3564-585: The ordinary degree. Darwin had to stay at Cambridge until June 1831. He studied Paley's Natural Theology or Evidences of the Existence and Attributes of the Deity (first published in 1802), which made an argument for divine design in nature , explaining adaptation as God acting through laws of nature . He read John Herschel 's new book, Preliminary Discourse on the Study of Natural Philosophy (1831), which described
3645-596: The "final cause of all this wedging, must be to sort out proper structure, & adapt it to changes", so that "One may say there is a force like a hundred thousand wedges trying force into every kind of adapted structure into the gaps of in the economy of nature, or rather forming gaps by thrusting out weaker ones." This would result in the formation of new species. As he later wrote in his Autobiography : In October 1838, that is, fifteen months after I had begun my systematic enquiry, I happened to read for amusement Malthus on Population, and being well prepared to appreciate
3726-605: The Wedgwoods were adopting Anglicanism . Robert Darwin, a freethinker , had baby Charles baptised in November 1809 in the Anglican St Chad's Church, Shrewsbury , but Charles and his siblings attended the local Unitarian Church with their mother. The eight-year-old Charles already had a taste for natural history and collecting when he joined the day school run by its preacher in 1817. That July, his mother died. From September 1818, he joined his older brother Erasmus in attending
3807-453: The afterlife. While he was house-hunting in London, bouts of illness continued and Emma wrote urging him to get some rest, almost prophetically remarking "So don't be ill any more my dear Charley till I can be with you to nurse you." He found what they called "Macaw Cottage" (because of its gaudy interiors) in Gower Street , then moved his "museum" in over Christmas. On 24 January 1839, Darwin
3888-497: The anatomy and life cycle of marine invertebrates in the Firth of Forth , and on 27 March 1827 presented at the Plinian his own discovery that black spores found in oyster shells were the eggs of a skate leech . One day, Grant praised Lamarck 's evolutionary ideas . Darwin was astonished by Grant's audacity, but had recently read similar ideas in his grandfather Erasmus' journals. Darwin
3969-437: The botanist Joseph Dalton Hooker , writing with melodramatic humour "it is like confessing a murder". Hooker replied, "There may, in my opinion, have been a series of productions on different spots, & also a gradual change of species. I shall be delighted to hear how you think that this change may have taken place, as no presently conceived opinions satisfy me on the subject." By July, Darwin had expanded his "sketch" into
4050-538: The duties of Secretary of the Geological Society. After initially declining the work, he accepted the post in March 1838. Despite the grind of writing and editing the Beagle reports, Darwin made remarkable progress on transmutation, taking every opportunity to question expert naturalists and, unconventionally, people with practical experience in selective breeding such as farmers and pigeon fanciers . Over time, his research drew on information from his relatives and children,
4131-713: The family butler, neighbours, colonists and former shipmates. He included mankind in his speculations from the outset, and on seeing an orangutan in the zoo on 28 March 1838 noted its childlike behaviour. The strain took a toll, and by June he was being laid up for days on end with stomach problems, headaches and heart symptoms. For the rest of his life, he was repeatedly incapacitated with episodes of stomach pains, vomiting, severe boils , palpitations, trembling and other symptoms, particularly during times of stress, such as attending meetings or making social visits. The cause of Darwin's illness remained unknown, and attempts at treatment had only ephemeral success. On 23 June, he took
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#17330849371254212-582: The first time on 29 October and soon introduced him to the up-and-coming anatomist Richard Owen , who had the facilities of the Royal College of Surgeons to work on the fossil bones collected by Darwin. Owen's surprising results included other gigantic extinct ground sloths as well as the Megatherium Darwin had identified, a near complete skeleton of the unknown Scelidotherium and a hippopotamus -sized rodent -like skull named Toxodon resembling
4293-575: The heart", so his doctors urged him to "knock off all work" and live in the country for a few weeks. After visiting Shrewsbury, he joined his Wedgwood relatives at Maer Hall , Staffordshire, but found them too eager for tales of his travels to give him much rest. His charming, intelligent, and cultured cousin Emma Wedgwood , nine months older than Darwin, was nursing his invalid aunt. His uncle Josiah pointed out an area of ground where cinders had disappeared under loam and suggested that this might have been
4374-472: The highest aim of natural philosophy as understanding such laws through inductive reasoning based on observation, and Alexander von Humboldt 's Personal Narrative of scientific travels in 1799–1804. Inspired with "a burning zeal" to contribute, Darwin planned to visit Tenerife with some classmates after graduation to study natural history in the tropics. In preparation, he joined Adam Sedgwick 's geology course, then on 4 August travelled with him to spend
4455-518: The latter term coined by Ernst Mayr (1965), derived from "clade". The results of phylogenetic/cladistic analyses are tree-shaped diagrams called cladograms ; they, and all their branches, are phylogenetic hypotheses. Three methods of defining clades are featured in phylogenetic nomenclature : node-, stem-, and apomorphy-based (see Phylogenetic nomenclature§Phylogenetic definitions of clade names for detailed definitions). The relationship between clades can be described in several ways: The age of
4536-524: The most influential figures in human history and was honoured by burial in Westminster Abbey . Darwin's early interest in nature led him to neglect his medical education at the University of Edinburgh ; instead, he helped to investigate marine invertebrates . His studies at the University of Cambridge 's Christ's College from 1828 to 1831 encouraged his passion for natural science . However, it
4617-498: The nearby Anglican Shrewsbury School as a boarder . Darwin spent the summer of 1825 as an apprentice doctor, helping his father treat the poor of Shropshire, before going to the well-regarded University of Edinburgh Medical School with his brother Erasmus in October 1825. Darwin found lectures dull and surgery distressing, so he neglected his studies. He learned taxidermy in around 40 daily hour-long sessions from John Edmonstone ,
4698-433: The official Narrative of the Beagle voyages, and after reading Darwin's diary, he proposed incorporating it into the account. Darwin's Journal was eventually rewritten as a separate third volume, on geology and natural history. In Cape Town , South Africa, Darwin and FitzRoy met John Herschel, who had recently written to Lyell praising his uniformitarianism as opening bold speculation on "that mystery of mysteries,
4779-483: The origin of species". Without telling Darwin, extracts from his letters to Henslow had been read to scientific societies, printed as a pamphlet for private distribution among members of the Cambridge Philosophical Society , and reported in magazines, including The Athenaeum . Darwin first heard of this at Cape Town, and at Ascension Island read of Sedgwick's prediction that Darwin "will have
4860-517: The parents of ten children, seven of whom survived to adulthood. Continuing his research in London, Darwin's wide reading now included the sixth edition of Malthus 's An Essay on the Principle of Population . On 28 September 1838, he noted its assertion that human "population, when unchecked, goes on doubling itself every twenty-five years, or increases in a geometrical ratio", a geometric progression so that population soon exceeds food supply in what
4941-568: The possibility that "one species does change into another" to explain the geographical distribution of living species such as the rheas, and extinct ones such as the strange extinct mammal Macrauchenia , which resembled a giant guanaco , a llama relative. Around mid-July, he recorded in his "B" notebook his thoughts on lifespan and variation across generations – explaining the variations he had observed in Galápagos tortoises , mockingbirds, and rheas. He sketched branching descent, and then
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#17330849371255022-482: The relationships between organisms that the molecular biology arm of cladistics has revealed include that fungi are closer relatives to animals than they are to plants, archaea are now considered different from bacteria , and multicellular organisms may have evolved from archaea. The term "clade" is also used with a similar meaning in other fields besides biology, such as historical linguistics ; see Cladistics § In disciplines other than biology . The term "clade"
5103-512: The replacement of extinct species by others" as "a natural in contradistinction to a miraculous process". When organising his notes as the ship sailed home, Darwin wrote that, if his growing suspicions about the mockingbirds, the tortoises and the Falkland Islands fox were correct, "such facts undermine the stability of Species", then cautiously added "would" before "undermine". He later wrote that such facts "seemed to me to throw some light on
5184-735: The spread of viral infections . HIV , for example, has clades called subtypes, which vary in geographical prevalence. HIV subtype (clade) B, for example is predominant in Europe, the Americas and Japan, whereas subtype A is more common in east Africa. Charles Darwin Charles Robert Darwin ( / ˈ d ɑːr w ɪ n / DAR -win ; 12 February 1809 – 19 April 1882) was an English naturalist , geologist , and biologist , widely known for his contributions to evolutionary biology . His proposition that all species of life have descended from
5265-408: The struggle for existence which everywhere goes on from long-continued observation of the habits of animals and plants, it at once struck me that under these circumstances favourable variations would tend to be preserved, and unfavourable ones to be destroyed. The result of this would be the formation of new species. Here, then, I had at last got a theory by which to work... By mid-December, Darwin saw
5346-409: The systematics of the taxa. He wrote his first examination of the species in 1846, but did not formally describe it until 1854. FitzRoy's long delayed Narrative was published in May 1839. Darwin's Journal and Remarks got good reviews as the third volume, and on 15 August it was published on its own. Early in 1842, Darwin wrote about his ideas to Charles Lyell, who noted that his ally "denies seeing
5427-445: The taxon to Acteonoidea and Ringiculoidea. There are five families within the clade Architectibranchia: Taxon Architectibranchia is not explicitly mentioned in the molecular analysis by Jörger et al. (2010). However, some of its members were included: Acteonoidea was moved to Lower Heterobranchia . Clade In biological phylogenetics , a clade (from Ancient Greek κλάδος (kládos) 'branch'), also known as
5508-420: The voyage began on 27 December 1831; it lasted almost five years. As FitzRoy had intended, Darwin spent most of that time on land investigating geology and making natural history collections, while HMS Beagle surveyed and charted coasts. He kept careful notes of his observations and theoretical speculations, and at intervals during the voyage his specimens were sent to Cambridge together with letters including
5589-421: The voyage, Darwin began detailed investigations and, in 1838, devised his theory of natural selection. Although he discussed his ideas with several naturalists, he needed time for extensive research, and his geological work had priority. He was writing up his theory in 1858 when Alfred Russel Wallace sent him an essay that described the same idea, prompting the immediate joint submission of both their theories to
5670-403: The work of earthworms , inspiring "a new & important theory" on their role in soil formation , which Darwin presented at the Geological Society on 1 November 1837. His Journal was printed and ready for publication by the end of February 1838, as was the first volume of the Narrative , but FitzRoy was still working hard to finish his own volume. William Whewell pushed Darwin to take on
5751-694: Was elected a Fellow of the Royal Society (FRS). On 29 January, Darwin and Emma Wedgwood were married at Maer in an Anglican ceremony arranged to suit the Unitarians, then immediately caught the train to London and their new home. Darwin now had the framework of his theory of natural selection "by which to work", as his "prime hobby". His research included extensive experimental selective breeding of plants and animals, finding evidence that species were not fixed and investigating many detailed ideas to refine and substantiate his theory. For fifteen years this work
5832-418: Was a " wren " was in the finch group . Darwin had not labelled the finches by island, but from the notes of others on the ship, including FitzRoy, he allocated species to islands. The two rheas were distinct species, and on 14 March Darwin announced how their distribution changed going southwards. By mid-March 1837, barely six months after his return to England, Darwin was speculating in his Red Notebook on
5913-465: Was anathema to Anglicans defending social order, but reputable scientists openly discussed the subject, and there was wide interest in John Herschel's letter praising Lyell's approach as a way to find a natural cause of the origin of new species. Gould met Darwin and told him that the Galápagos mockingbirds from different islands were separate species, not just varieties, and what Darwin had thought
5994-423: Was coined in 1957 by the biologist Julian Huxley to refer to the result of cladogenesis , the evolutionary splitting of a parent species into two distinct species, a concept Huxley borrowed from Bernhard Rensch . Many commonly named groups – rodents and insects , for example – are clades because, in each case, the group consists of a common ancestor with all its descendant branches. Rodents, for example, are
6075-418: Was his five-year voyage on HMS Beagle from 1831 to 1836 that truly established Darwin as an eminent geologist. The observations and theories he developed during his voyage supported Charles Lyell 's concept of gradual geological change . Publication of his journal of the voyage made Darwin famous as a popular author. Puzzled by the geographical distribution of wildlife and fossils he collected on
6156-425: Was in the background to his main occupation of writing on geology and publishing expert reports on the Beagle collections, in particular, the barnacles . The impetus of Darwin's barnacle research came from a collection of a barnacle colony from Chile in 1835, which he dubbed Mr. Arthrobalanus . His confusion over the relationship of this species ( Cryptophialus minutus ) to other barnacles caused him to fixate on
6237-500: Was no unbridgeable gap between humans and animals. A year on, the mission had been abandoned. The Fuegian they had named Jemmy Button lived like the other natives, had a wife, and had no wish to return to England. Darwin experienced an earthquake in Chile in 1835 and saw signs that the land had just been raised, including mussel -beds stranded above high tide. High in the Andes he saw seashells, and several fossil trees that had grown on
6318-516: Was rather bored by Robert Jameson 's natural-history course, which covered geology – including the debate between neptunism and plutonism . He learned the classification of plants and assisted with work on the collections of the University Museum , one of the largest museums in Europe at the time. Darwin's neglect of medical studies annoyed his father, who sent him to Christ's College, Cambridge , in January 1828, to study for
6399-574: Was surprised to find some benefit from hydrotherapy . Then, in 1851, his treasured daughter Annie fell ill, reawakening his fears that his illness might be hereditary. She died the same year after a long series of crises. In eight years of work on barnacles, Darwin's theory helped him to find " homologies " showing that slightly changed body parts served different functions to meet new conditions, and in some genera he found minute males parasitic on hermaphrodites , showing an intermediate stage in evolution of distinct sexes . In 1853, it earned him
6480-482: Was the fifth of six children of wealthy society doctor and financier Robert Darwin and Susannah Darwin (née Wedgwood). His grandfathers Erasmus Darwin and Josiah Wedgwood were both prominent abolitionists . Erasmus Darwin had praised general concepts of evolution and common descent in his Zoonomia (1794), a poetic fantasy of gradual creation including undeveloped ideas anticipating concepts his grandson expanded. Both families were largely Unitarian , though
6561-446: Was to leave in four weeks on an expedition to chart the coastline of South America. Robert Darwin objected to his son's planned two-year voyage, regarding it as a waste of time, but was persuaded by his brother-in-law, Josiah Wedgwood II , to agree to (and fund) his son's participation. Darwin took care to remain in a private capacity to retain control over his collection, intending it for a major scientific institution. After delays,
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