100-408: The Science of Discworld is a 1999 book by novelist Terry Pratchett and popular science writers (and University of Warwick science researchers) Ian Stewart and Jack Cohen . Three sequels, The Science of Discworld II: The Globe , The Science of Discworld III: Darwin's Watch , and The Science of Discworld IV: Judgement Day , have been written by the same authors. Following publication of
200-724: A humanist . He was a Distinguished Supporter of Humanists UK (formerly known as the British Humanist Association) and an Honorary Associate of the National Secular Society . Pratchett wrote that he read the Old Testament as a child and "was horrified", but liked the New Testament and thought that Jesus "had a lot of good things to say ... But I could never see the two testaments as one coherent narrative". He then read On
300-708: A knighthood for "services to literature" in the 2009 UK New Year Honours list. He was previously appointed Officer of the Order of the British Empire , also for "services to literature", in 1998. He formally received the accolade at Buckingham Palace on 18 February 2009. Pratchett commented in the Ansible science fiction/fan newsletter, "I suspect the 'services to literature' consisted of refraining from trying to write any", but added, "Still, I cannot help feeling mightily chuffed about it." On 31 December 2008, it
400-428: A telegraph ) are programmed to repeat the name of its creator's deceased son; the sentiment in the novel is that no one is ever forgotten as long as their name is still spoken. A June 2015 web server survey reported that approximately 84,000 websites had been configured with the header. Pratchett's humanist funeral service was held on 25 March 2015. In 2015, Pratchett's estate announced an endowment in perpetuity to
500-493: A zygote changes the surrounding membrane to not allow any more sperm to penetrate the egg, so multiple fertilizations can be prevented. Fusion of a zygote also activates the egg so it can begin undergoing cell division. Each animal species might not have specifically a sperm and an egg, but two gametes that contain half of the species' typical genetic material and the membranes of these gametes fuse to start creating an offspring. Not long after successful fertilization by sperm,
600-743: A BBC television documentary, Terry Pratchett: Choosing to Die , about assisted suicide. It won the Best Documentary award at the Scottish BAFTAs in November 2011. In September 2012, Pratchett told an interviewer: "I have to tell you that I thought I'd be a lot worse than this by now, and so did my specialist." In the same interview he said that the cognitive part of his mind was "untouched" and his symptoms were physical (normal for PCA). However, in July 2014 he cancelled his appearance at
700-449: A bank of six monitors to ease writing. When he travelled, he always took a portable computer, originally a 1992 Olivetti Quaderno , with him to write. In a 1995 interview with Microsoft co-founder Bill Gates , Pratchett expressed concern about the potential spread of misinformation online. He felt that there was a "kind of parity of esteem of information" on the internet, and gave the example of Holocaust denial being presented on
800-449: A blastocyst. Other species such as sea stars , frogs , chicks , and mice have all the same structures in this stage, yet the orientation of these features differs, plus these species have additional types of cells in this stage. After blastulation, the single-layered blastula expands and reorganizes into multiple layers, a gastrula (seen in the figure to the right). Reptiles , birds and mammals are triploblastic organisms, meaning
900-535: A book about his experiences if he thought anyone would actually believe them". The first Discworld novel, The Colour of Magic , was published in hardback by Colin Smythe Ltd in 1983. Pratchett gave up working for the CEGB to make his living through writing in 1987, after finishing the fourth Discworld novel, Mort . His sales increased quickly and many of his books occupied top places on bestseller lists; he
1000-487: A butterfly. Adulthood is the stage of when physical and intellectual maturity have been achieved and this differs between species. In humans , adulthood is thought to be around 20 or 21 years old and is the longest stage of life, but in all species it ends with death. In dogs , small breeds (e.g., Yorkshire Terrier , Chihuahua , Cocker Spaniel , etc.) physically mature faster than large breeds (e.g., Saint Bernard , Great Dane , Golden Retriever , etc.), so adulthood
1100-421: A cavity and fuse with the central canal of the neural tube. Secondary neurulation occurs in the small region starting at the spinal tail bud up to the posterior neuropore, which is the open neural folds near the tail region that don't close through primary neurulation. As canalization progresses over the next few weeks, neurons and ependymal cells (cells that create cerebral spinal fluid ) differentiate to become
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#17327805623441200-452: A cluster of nerve bodies positioned along the spinal cord at the dorsal and ventral roots of a spinal nerve, which is a pair of nerves that correspond to a vertebra of the spine. In secondary neurulation, caudal and sacral regions of the spine are formed after primary neurulation is finished. This process initiates once primary neurulation is finished and the posterior neuropore closes, so the tail bud can proliferate and condense, then create
1300-619: A few more books yet", and added that while he understood the impulse to ask "is there anything I can do?", in this case he would only entertain such offers from "very high-end experts in brain chemistry". Discussing his diagnosis at the Bath Literature Festival in early 2008, Pratchett revealed that by then he found it too difficult to write dedications when signing books. In his later years Pratchett wrote by dictating to his assistant, Rob Wilkins, or by using speech recognition software. In March 2008, Pratchett announced he
1400-427: A hollow sphere of cells, which is a blastula . These outer cells form a single epithelial layer, the blastoderm, that essentially encases the fluid-filled inside that is the blastocoel. The figure to the right shows the basic process that is modified in different species. Blastulation differs slightly in different species, but in mammals, the eight-cell stage embryo forms into a slightly different type of blastula, called
1500-403: A larval form of an animal is the caterpillar of butterflies and moths . Caterpillars keep growing and feeding in order for enough energy during the pupal stage, when necessary body parts for metamorphosis are grown. The juvenile phase is different in plants and animals, but in plants juvenility is an early phase of plant growth in which plants can't flower. In animals, the juvenile stage
1600-403: A month), blobs of life emerge, ready to begin evolving into more complex forms. The book also features a fictional crab civilization and the dinosaurs (both of which are wiped out by comets/asteroids colliding with the earth), before jumping ahead to when an advanced civilization (presumably humans) has evacuated the earth due to an impending natural disaster. The science centres on the origins of
1700-802: A number of game adaptations of his books. He favoured games that are "intelligent and have some depth", citing Half-Life 2 (2004) and fan missions for Thief as examples. The red army in Interesting Times prompted comparisons to the 1991 puzzle game Lemmings . When asked about this connection, Pratchett said: "Merely because the red army can fight, dig, march and climb and is controlled by little icons? Can't imagine how anyone thought that ... Not only did I wipe Lemmings from my hard disk, I overwrote it so I couldn't get it back." He described The Elder Scrolls IV: Oblivion (2006) as his favourite video game, saying that he used many of its non-combat-oriented fan-made mods , and contributed to
1800-490: A parallel manner but branch off to develop more specific features for the organism such as hooves, a tail, or ears. In developing vertebrate offspring, a neural tube is formed through either primary or secondary neurulation . Some species develop their spine and nervous system using both primary and secondary neurulation, while others use only primary or secondary neurulation. In human fetal development, primary neurulation occurs during weeks 3 and 4 of gestation to develop
1900-1060: A part of the Nebula Award ceremony. In 2016 the SFWA named Pratchett the recipient of Kate Wilhelm Solstice Award , given for "significant impact on the science fiction or fantasy landscape". He received the NESFA Skylark Award in 2009 and the World Fantasy Award for Life Achievement in 2010. In 2011 he won Margaret A. Edwards Award from the American Library Association , a lifetime honour for "significant and lasting contribution to young adult literature". The librarians cited nine Discworld novels published from 1983 to 2004 and observed that "Pratchett's tales of Discworld have won over generations of teen readers with intelligence, heart, and undeniable wit. Comic adventures that fondly mock
2000-752: A regional newspaper under the pseudonym Patrick Kearns. After various positions in journalism, in 1979 Pratchett became press officer for the South West Region of the Central Electricity Generating Board (CEGB) in an area that covered three nuclear power stations . He later joked that he had demonstrated "impeccable timing" by making this career change so soon after the Three Mile Island nuclear accident in Pennsylvania , US, and said he would "write
2100-504: A serious and ultimately fatal illness to choose to die peacefully with medical help, rather than suffer". Pratchett was selected to give the 2010 BBC Richard Dimbleby Lecture , Shaking Hands With Death , broadcast on 1 February 2010. Pratchett introduced his lecture on the topic of assisted death (he preferred this to the term "assisted suicide"), but the main text was read by his friend Tony Robinson because his condition made it difficult for him to read. In June 2011, Pratchett presented
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#17327805623442200-455: A slightly different journey through these stages, since some stages might be shorter or longer when compared to other species, and where the offspring develops is different for each animal type (e.g., in a hard egg shell, uterus, soft egg shell, on a plant leaf, etc.). In humans, the process of fetal development starts after sperm fertilizes an egg and they fuse together, kickstarting embryonic development . The fusion of egg and sperm into
2300-456: A small publishing company, Colin Smythe Ltd. Pratchett mentioned that he had written a manuscript, The Carpet People . Colin Smythe Ltd published the book in 1971, with illustrations by Pratchett. It received strong, although few, reviews and was followed by the science fiction novels The Dark Side of the Sun (1976) and Strata (1981). In the 1970s and 1980s, Pratchett published stories in
2400-927: A species. Another way to think of ontogeny is that it is the process of an organism going through all of the developmental stages over its lifetime. The developmental history includes all the developmental events that occur during the existence of an organism, beginning with the changes in the egg at the time of fertilization and events from the time of birth or hatching and afterward (i.e., growth, remolding of body shape, development of secondary sexual characteristics, etc.). While developmental (i.e., ontogenetic) processes can influence subsequent evolutionary (e.g., phylogenetic) processes (see evolutionary developmental biology and recapitulation theory ), individual organisms develop (ontogeny), while species evolve (phylogeny). Ontogeny, embryology and developmental biology are closely related studies and those terms are sometimes used interchangeably. Aspects of ontogeny are morphogenesis ,
2500-537: A style described as "more that of urban cowboy than city gent". Concern for the future of civilisation prompted him to install five kilowatts of photovoltaic cells (for solar energy ) at his house in 2007. Pratchett had an observatory built in his back garden and was a keen astronomer from childhood. He made a 2005 appearance on the BBC programme The Sky at Night . Pratchett started to use computers for writing as soon as they were available to him. His first computer
2600-518: A two-part documentary series about his illness, Terry Pratchett: Living With Alzheimer's . The first part was broadcast on BBC Two on 4 February 2009, drawing 2.6 million viewers and a 10.4% audience share. The second, broadcast on 11 February 2009, drew 1.72 million viewers and a 6.8% audience share. The documentary won a BAFTA award in the Factual Series category. On 26 November 2008, Pratchett met Gordon Brown , then Prime Minister of
2700-474: A writer, was born there in 1976. In 1993 the family moved to Broad Chalke , a village west of Salisbury , Wiltshire. Pratchett was the patron of the Friends of High Wycombe Library. In 2013 he gave a talk at Beaconsfield Library, which he had visited as a child, and donated the income from the event to it. He also visited his former school to speak to the students. Pratchett often wore large black hats, in
2800-593: A year. His 2011 Discworld novel Snuff became the third-fastest-selling hardback adult-readership novel since records began in the UK, selling 55,000 copies in the first three days. As of 2023, Pratchett's works have sold more than 100 million copies in 43 languages. Pratchett married Lyn Purves at the Congregational Church, Gerrards Cross , on 5 October 1968. They moved to Rowberrow , Somerset, in 1970. Their daughter Rhianna Pratchett , also
2900-481: A year. The final Discworld novel, The Shepherd's Crown , was published in August 2015, five months after his death. With more than 100 million books sold worldwide in 43 languages, Pratchett was the UK's best-selling author of the 1990s. He was appointed an Officer of the Order of the British Empire (OBE) in 1998 and was knighted for services to literature in the 2009 New Year Honours . In 2001, he won
3000-414: Is metamorphosis . For example, amphibian tadpoles have a maturation of liver enzymes, hemoglobin , and eye pigments, in addition to their nervous, digestive, and reproductive systems being remodeled. In all species, molting and juvenile hormones appear to regulate these changes. The figure to the right shows the stages of life in butterflies and their metamorphosis transforms the caterpillar into
3100-590: Is a parody of the 1768 painting " An Experiment on a Bird in the Air Pump " by Joseph Wright of Derby . The Discworld part of the book begins when a new experimental power source for the Unseen University is commissioned in the university's squash court. The new "reactor" is capable of splitting the thaum (the basic particle of magic), in homage to the Chicago Pile-1 nuclear reactor, which
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3200-477: Is as entertaining as it is accessible." The New England Science Fiction Association considered it "a fine popularization of science and of the scientific method", and "most unusual and entertaining", but observed that this makes it "something of an oddity". The book and its sequel, The Science of Discworld II: The Globe , have been reviewed by Ian C.W Hardy for Trends in Ecology & Evolution . Writing about
3300-416: Is discontinuous and can start at different points along the cranial-caudal axis necessary for it to close. After the neural crest closes, the neural crest cells and ectoderm cells separate and the ectoderm becomes the epidermis surrounding this complex. The neural crest cells differentiate to become components of most of the peripheral nervous system in animals. Next, the notochord degenerates to become only
3400-519: Is easier to bend the universe around the story." In the acceptance speech for his Carnegie Medal, he said: "Fantasy isn't just about wizards and silly wands. It's about seeing the world from new directions", pointing to the Harry Potter novels and The Lord of the Rings . In the same speech, he acknowledged benefits of these works for the genre. Ontogeny Ontogeny (also ontogenesis )
3500-523: Is most commonly found in social mammals, such as wild dogs , monkeys , apes , lions , wolves , and more. In humans, puberty marks the end of this stage and adolescence follows. Some species begin puberty and reproduction before the juvenile stage is over, such as in female non-human primates. The larval and pupal stages can be seen in the figure to the right. The process of an organism's body undergoing structural and physical changes after birth or hatching to become suitable for its adult environment
3600-424: Is reached anywhere from 12 to 24 months or 1 to 2 years. In contrast, many insect species have long larval stages and the adult stage is only for reproduction. The silkworm moths don't have mouthparts and don't feed, so they have to consume enough food during the larval stage for energy to survive and mate. Senescence is when cells stop dividing but don't die, but these cells can build up and cause problems in
3700-423: Is the origination and development of an organism (both physical and psychological, e.g., moral development ), usually from the time of fertilization of the egg to adult. The term can also be used to refer to the study of the entirety of an organism's lifespan. Ontogeny is the developmental history of an organism within its own lifetime, as distinct from phylogeny , which refers to the evolutionary history of
3800-613: Is used in anthropology as "the process through which each of us embodies the history of our own making". The word ontogeny comes from the Greek on meaning a being, individual; and existence, and from the suffix -geny from the Greek - geniea , meaning genesis, origin, and mode of production. The term ontogeny was coined by Ernst Haeckel , a German zoologist and evolutionist in the 1860s. Haeckel, born in Germany on February 16, 1834,
3900-519: The Daily Mail in which he denied that he had found God, and clarified that he believed the voice had come from a memory of his father and a sense of personal elation. In August 2007, Pratchett was misdiagnosed as having had a minor stroke a few years before, which doctors believed had damaged the right side of his brain. In December 2007, he announced that he had been diagnosed with early-onset Alzheimer's disease , which had been responsible for
4000-529: The Bookseller's Pocket Yearbook (2005), in 2003 Pratchett's UK sales amounted to 3.4% of the fiction market by hardback sales and 3.8% by value, putting him in second place behind J. K. Rowling (6% and 5.6%, respectively), while in the paperback sales list Pratchett came 5th with 1.2% and 1.3% by value (behind James Patterson (1.9% and 1.7%), Alexander McCall Smith , John Grisham and J. R. R. Tolkien ). He has UK sales of more than 2.5 million copies
4100-622: The University of South Australia . The Sir Terry Pratchett Memorial Scholarship supports a Masters scholarship at the university's Hawke Research Institute. In 2023, several stories published in a regional newspaper in the 1970s and 1980s under the pen name Patrick Kearns were discovered to have been authored by Pratchett. They were published as A Stroke of the Pen: The Lost Stories in October 2023. Pratchett received
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4200-501: The University of Warwick in 1999, the University of Portsmouth in 2001, the University of Bath in 2003, the University of Bristol in 2004, Buckinghamshire New University in 2008, the University of Dublin in 2008, Bradford University in 2009, University of Winchester in 2009, The Open University in 2013 for his contribution to Public Service and his last, from the University of South Australia , in May 2014. Pratchett
4300-560: The ectoderm is the outer layer of cells that become the epidermis and hair while being the precursor to the mammary glands, central nervous system , and the peripheral nervous systems . The figure above shows how the development of a pig , cow , rabbit , and human offspring are similar when compared to one another. This figure shows how the germ layers can become different organs and tissues in evolutionarily higher life-forms and how these species essentially develop very similarly. Additionally, it shows how multiple species develop in
4400-402: The nucleus pulposus of the intervertebral discs and the mesoderm cells differentiate to become the somites and skeletal muscle later on. Also during this stage, the neural crest cells become the spinal ganglions, which function as the brain in organisms like earthworms and arthropods . In more advanced organisms like amphibians , birds and mammals ; the spinal ganglions consists of
4500-469: The right to die public debate and his Humanist values. Pratchett's Discworld novels have led to dedicated conventions, the first in Manchester in 1996, then worldwide, often with the author as guest of honour. Publication of a new novel was sometimes accompanied by an international book signing tour; queues were known to stretch outside the bookshop as the author continued to sign books well after
4600-716: The "Top 200". Pratchett's highest-ranking novel was Mort , number 65, but he and Charles Dickens were the only authors with five in the Top 100 (four of his were from the Discworld series). He also led all authors with fifteen novels in the Top 200. An asteroid ( 127005 Pratchett ) is named after Pratchett. In 2013, Pratchett was named Humanist of the Year by the British Humanist Association for his campaign to fund research into Alzheimers, his contribution to
4700-432: The "stroke". He had a rare form of posterior cortical atrophy (PCA), a disease in which areas at the back of the brain begin to shrink and shrivel. Describing the diagnosis as an "embuggerance" in a radio interview, Pratchett appealed to people to "keep things cheerful" and proclaimed that "we are taking it fairly philosophically down here and possibly with a mild optimism". He stated he felt he had time for "at least
4800-506: The 2001 Carnegie Medal from the British librarians , which recognised The Amazing Maurice and His Educated Rodents as the year's best children's book published in the UK. Night Watch won the 2003 Prometheus Award for best libertarian novel. Four of the five Discworld novels that centre on the trainee witch Tiffany Aching won the annual Locus Award for Best Young Adult Book in 2004, 2005, 2007 and 2016. In 2005, Going Postal
4900-590: The Discworld Conventions have adopted Orangutan Foundation as their nominated charity, which has been acknowledged by the foundation. One of Pratchett's most popular fictional characters, the Librarian , is a wizard who was transformed into an orangutan in a magical accident and decides to remain in that condition as it is so convenient for his work. Pratchett, who was brought up in a Church of England family, described himself as an atheist and
5000-490: The Egregious Professor of Cruel and Unusual Geography, and send him down (against his will) to investigate this strange world. The wizards create a series of balls of matter in space, and give one of them a Moon (accidentally). This stabilizes the ball enough that, over a score of millennia (the wizards can skip over vast periods of Roundworld time, allowing them to view the history of the universe in less than
5100-678: The High Wycombe Technical School's magazine in 1962. It is the tale of a man named Crucible who finds the Devil in his flat in a cloud of sulphurous smoke. "The Hades Business" was published in the school magazine when he was 13, and published commercially when he was 15. Pratchett earned five O-levels and started A-level courses in Art, English and History. His initial career choice was journalism and he left school at 17, in 1965, to start an apprenticeship with Arthur Church,
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#17327805623445200-526: The Origin of Species , which "all made perfect sense ... Evolution was far more thrilling to me than the biblical account." He said that he had never disliked religion and thought it had a purpose in human evolution . In an interview Pratchett cites a quotation from the protagonist in his novel Nation , "It is better to build a seismograph than to worship the volcano", a statement Pratchett said he agreed with. Pratchett told The Times in 2008: "I believe in
5300-493: The UK, and asked for an increase in dementia research funding. Pratchett tested a prototype device to address his condition. The ability of the device to alter the course of the illness has been met with skepticism from Alzheimer's researchers. In an article published in 2009 Pratchett stated that he wished to die by assisted suicide (a term he disliked) before his disease progressed to a critical point. He later said that he felt "it should be possible for someone stricken with
5400-547: The annual Carnegie Medal for The Amazing Maurice and His Educated Rodents , the first Discworld book marketed for children. He received the World Fantasy Award for Life Achievement in 2010. In December 2007 Pratchett announced that he had been diagnosed with early-onset Alzheimer's disease . He later made a substantial public donation to the Alzheimer's Research Trust (now Alzheimer's Research UK , ARUK), filmed three television programmes chronicling his experiences with
5500-445: The biennial International Discworld Convention , citing his condition and "other age-related ailments". Pratchett died at his home from complications of Alzheimer's disease on the morning of 12 March 2015. He was 66 years old. The Telegraph reported an unidentified source as saying that, despite his previous discussion of assisted suicide, his death had been natural. After Pratchett's death, his assistant, Rob Wilkins, wrote from
5600-494: The body. These cells can release substances that cause inflammation and can damage healthy nearby cells. Senescence can be induced by un-repaired DNA damage (e.g., from radiation, old age, etc.) or other cellular stress and also is the state of being old. Most organisms undergo allometric changes in shape as they grow and mature , while others engage in metamorphosis . Even reptiles (non-avian sauropsids, e.g., crocodilians , turtles , snakes , and lizards ), in which
5700-487: The books were inspired by a "bloody awful" book on the science of Star Trek , and noted that Pratchett was initially reluctant to write about science on the Discworld "because there isn't any science on the Discworld". Stewart discussed his views on the book series in his paper "Mathematics, the media, and the public". Terry Pratchett Sir Terence David John Pratchett OBE (28 April 1948 – 12 March 2015)
5800-400: The brain and spinal cord. Then during weeks 5 and 6 of gestation, secondary neurulation forms the lower sacral and coccygeal cord. The diagram to the right illustrates primary neurulation, which is the process of cells surrounding the neural plate interacting with neural plate cells to proliferate, converge, and pinch off to form a hollow tube above the notochord and mesoderm. This process
5900-414: The change of behavioral machinery during development was distinct from the change in behavior during development. We can conclude that the thrush itself, i.e. its behavioral machinery, has changed only if the behavior change occurred while the environment was held constant...When we turn from description to causal analysis, and ask in what way the observed change in behavior machinery has been brought about,
6000-573: The condition for the BBC , and became a patron of ARUK. Pratchett died on 12 March 2015, at the age of 66. Pratchett was born on 28 April 1948 in Beaconsfield in Buckinghamshire , England, the only child of David (1921–2006), a mechanic, and Eileen Pratchett (1922–2010), a secretary, of Hay-on-Wye . His maternal grandparents came from Ireland. Pratchett attended Holtspur School, where he
6100-407: The developing organism have been established. He proposed that individual development followed developmental stages of previous generations and that the future generations would add something new to this process, and that there was a causal parallelism between an animal's ontogeny and phylogeny. In addition, Haeckel suggested a biogenetic law that ontogeny recapitulates phylogeny, based on the idea that
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#17327805623446200-451: The development of at least one popular fan-made mod. Pratchett had a fascination with natural history that he referred to many times, and he owned a greenhouse full of carnivorous plants . He described them in the biographical notes on the dust jackets of some of his books, and elsewhere, as "not as interesting as people think". By Carpe Jugulum the account had become that "he used to grow carnivorous plants, but now they've taken over
6300-458: The development of form and shape of an organism; tissue growth; and cellular differentiation . The term ontogeny has also been used in cell biology to describe the development of various cell types within an organism. Ontogeny is a useful field of study in many disciplines, including developmental biology , cell biology , genetics , developmental psychology , developmental cognitive neuroscience , and developmental psychobiology . Ontogeny
6400-447: The digestive system and the lungs. The mesoderm gives rise to other tissues not formed by the ectoderm, such as the heart, muscles, bones, blood, dermis of the skin, bone marrow, and the urogenital system. This germ layer is more specific for species, as it is the distinguishing layer of the three that can identify evolutionarily higher life-forms (e.g., bilateral organisms like humans) from lower-life forms (with radial symmetry). Lastly,
6500-803: The editor of the Bucks Free Press . In this position he wrote, among other things, more than 80 stories for the Children's Circle section under the name Uncle Jim. Two of the stories contain characters found in his novel The Carpet People (1971). While on day release from his apprenticeship, Pratchett finished his A-Level in English and took the National Council for the Training of Journalists proficiency course. In 1968 Pratchett interviewed Peter Bander van Duren , co-director of
6600-406: The fantasy genre, the Discworld novels expose the hypocrisies of contemporary society in an intricate, ever-expanding universe. With satisfyingly multilayered plots, Pratchett's humor honors the intelligence of the reader. Teens eagerly lose themselves in a universe with no maps." In 2003, BBC conducted The Big Read to identify the "Nation's Best-loved Novel" and finally published a ranked list of
6700-433: The figure below, human germ cells are able to differentiate into the specific organs and tissues they become later on in life. Germ cells are able to migrate to their final locations to rearrange themselves and some organs are made of two germ layers; one for the outside, the other for the inside. The endoderm cells become the internal linings of organisms, such as the stomach, colon, small intestine, liver, and pancreas of
6800-476: The first book in 1999 Terry Pratchett made both Jack Cohen and Professor Ian Stewart "Honorary Wizards of the Unseen University" at the same ceremony at which the University of Warwick gave Terry Pratchett an honorary degree. The book alternates between a typically absurd Discworld story and serious scientific exposition after each chapter. The cover of the book, designed by Paul Kidby ,
6900-420: The first book, he noted that it "deals with the ontogeny of our universe and recapitulates phylogeny ", or, in simpler words, the authors "give us their take on chimpanzees and human origins, brains, pattern recognition, self-awareness, self-referentiality, cultural evolution and space exploration". He concluded that the books are a "fun" and "engaging" example of popular science writing. Cohen reports that it
7000-406: The following topics: The concept of narrativium, introduced in the book (a fictional element responsible for the creation of narrative , a parody of phlogiston ), has been used by Pratchett and his co-authors to explore the role of narratives in real-world literature and science. Publishers Weekly , reviewing the 2014 edition, described it as "unique and outrageously funny", with "writing [that]
7100-502: The gastrula comprises three germ layers ; the endoderm (inner layer), mesoderm (middle layer), and ectoderm (outer layer). As seen in the figure below, each germ layer will become multi-potent stem cells that can become a specific tissue depending on the germ layer and is what happens in humans. This differentiation of germ layers differs slightly, because not all of the organs and tissues below are in all organisms, but corresponding body systems can be substituted in place of these. In
7200-541: The greenhouse and he avoids going in". In 1995, a fossil of a sea-turtle from the Eocene epoch of New Zealand was named Psephophorus terrypratchetti in his honour by the palaeontologist Richard Köhler. In 2016, Pratchett fans unsuccessfully petitioned the International Union of Pure and Applied Chemistry (IUPAC) to name chemical element 117, temporarily called ununseptium , as octarine with
7300-443: The hereditary modification of embryonic development. Marine biologist Walter Garstang reversed Haeckel's relationship between ontogeny and phylogeny, stating that ontogeny creates phylogeny, not recapitulates it. A seminal 1963 paper by Nikolaas Tinbergen named ontogeny as one of the four primary questions of biology, along with Julian Huxley's three others: causation, survival value and evolution. Tinbergen emphasized that
7400-533: The intended finishing time. His fans were not restricted by age or gender, and he received a large amount of fan mail from them. Pratchett enjoyed meeting fans and hearing what they think about his books, saying that since he was well paid for his novels, his fans were "everything" to him. In March 2017, Beaconsfield Town Council commissioned a commemorative plaque dedicated to Pratchett for Beaconsfield Library. Pratchett said that to write, you must read extensively, both inside and outside your chosen genre and to
7500-438: The lumbar and tail vertebrae of frogs and chicks and in both instances, this process is like a continuation of gastrulation. In most species, the young organism that is just born or hatched is not sexually mature yet and in most animals, this young organism looks quite different than the adult form. This young organism is the larva and is the intermediate form before metamorphosing into an adult. A well known example of
7600-554: The natural first step is to try and distinguish between environmental influences and those within the animal...In ontogeny the conclusion that a certain change is internally controlled (is 'innate') is reached by elimination . Tinbergen was concerned that the elimination of environmental factors is difficult to establish, and the use of the word innate is often misleading. Development of an organism happens through fertilization, cleavage, blastulation, gastrulation, organogenesis, and metamorphosis into an adult. Each species of animal has
7700-484: The necessary mathematical skills. He developed an interest in science fiction and attended science fiction conventions from about 1963–1964, but stopped a few years later when he got his first job as a trainee journalist at the local paper. His early reading included the works of H. G. Wells , Arthur Conan Doyle , and "every book you really ought to read", which he later regarded as "getting an education". Pratchett published his first short story, "Business Rivals", in
7800-525: The official Terry Pratchett Twitter account: A T LAST, S IR T ERRY, WE MUST WALK TOGETHER. Terry took Death's arm and followed him through the doors and on to the black desert under the endless night. The End. Public figures who paid tribute included the British prime minister David Cameron , the comedian Ricky Gervais , and the authors Ursula K. Le Guin , Terry Brooks , Margaret Atwood , George R. R. Martin , and Neil Gaiman . Pratchett
7900-437: The point of "overflow". He advised that writing is hard work, and that writers must "make grammar, punctuation and spelling a part of your life". However, Pratchett enjoyed writing, regarding its monetary rewards as "an unavoidable consequence" rather than the reason for writing. Although during his early career he wrote for the science fiction and horror genres, Pratchett later focused almost entirely on fantasy, and said: "It
8000-513: The proposed symbol Oc (pronounced "ook"). The final name chosen for element 117 was tennessine with the symbol Ts. Pratchett was a trustee for the Orangutan Foundation but was pessimistic about the future of orangutans . His activities included visiting Borneo with a Channel 4 film crew to make an episode of Jungle Quest in 1995, seeing orangutans in their natural habitat. Following Pratchett's lead, fan events such as
8100-540: The same God that Einstein did ... And it is just possible that once you have got past all the gods that we have created with big beards and many human traits, just beyond all that on the other side of physics, there just may be the ordered structure from which everything flows." In an interview on Front Row he described an experience of hearing his dead father's voice and feeling a sense of peace. Commentators took these statements to mean that Pratchett had become religious, but Pratchett responded in an article published in
8200-404: The same terms as peer-reviewed research, with no easy way to gauge reliability. Gates disagreed, saying that online authorities would index and check facts and sources in a much more sophisticated way than in print. The interview was rediscovered in 2019, and seen by Pratchett's biographer as prescient of fake news . Pratchett was an avid video game player, and collaborated in the creation of
8300-510: The space and "twiddles" them, inadvertently creating the universe . The wizards soon discover that they can move things around in the universe, using Hex. They call it the Roundworld (the Earth ), because in it, matter seems to accrete into balls in space (instead of discs on the backs of turtles). They decide to appoint Rincewind, whom they dragged out of bed in the early hours of the morning,
8400-480: The successive and progressive origin of new species was based on the same laws as the successive and progressive origin of new embryonic structures. According to Haeckel, development produced novelties, and natural selection would eliminate species that had become outdated or obsolete. Though his view of development and evolution wasn't justifiable, future embryologists tweaked and collaborated with Haeckel's proposals and showed how new morphological structures can occur by
8500-410: The tail end of the spinal cord. Next, the closed neural tube contains neuroepithelial cells that immediately divide after closure and a second type of cell forms; the neuroblast. Neuroblast cells form the mantle layer, which later becomes the gray matter , which then gives rise to a marginal layer that becomes the white matter of the spinal cord. Secondary neurulation is seen in the neural tube of
8600-555: The universe, earth and the beginnings of life, the fiction on the creation of a world (the Earth) in a jar. One of the themes is that most scientific explanations are in reality a good deal more complicated than most of us realize. It is explained that this is because their teachers use Lies-To-Children or, in Ponder Stibbons ' case, Lies-To-Wizards. The even-numbered chapters are self-contained essays that discuss, among others,
8700-449: The zygote undergoes many mitotic divisions , which are also non-sexual cell divisions. Cleavage is the process of cell division, so the starting zygote becomes a collection of identical cells which is a morula and contains cells called blastomeres. Cleavage prepares the zygote to become an embryo, which is from 2 weeks to 8 weeks after conception (fertilization) in humans. After the zygote has become an embryo, it continues dividing into
8800-533: Was a ZX81 ; the first computer he used properly for writing was an Amstrad CPC 464 , later replaced by an IBM PC compatible . Pratchett was one of the first authors to routinely use the Internet to communicate with fans, and was a contributor to the Usenet newsgroup alt.fan.pratchett from 1992. However, he did not consider the Internet a hobby, just another "thing to use". He had many computers in his house, with
8900-483: Was a key member of the debating society and wrote stories for the school magazine. Pratchett described himself as a "non-descript" student and, in his Who's Who entry, credited his education to the Beaconsfield Public Library. Pratchett's early interests included astronomy . He collected Brooke Bond tea cards about space, owned a telescope and wanted to be an astronomer, but lacked
9000-528: Was also a strong supporter of Darwinism . Haeckel suggested that ontogeny briefly and sometimes incompletely recapitulated or repeated phylogeny in his 1866 book, Generelle Morphologie der Organismen ("General Morphology of Organisms"). Even though his book was widely read, the scientific community was not very convinced or interested in his ideas, so he turned to producing more publications to get more attention. In 1866, Haeckel and others imagined development as producing new structures after earlier additions to
9100-456: Was an English author , humorist , and satirist , best known for the Discworld series of 41 comic fantasy novels published between 1983 and 2015, and for the apocalyptic comedy novel Good Omens (1990), which he co-wrote with Neil Gaiman . Pratchett's first novel, The Carpet People , was published in 1971. The first Discworld novel, The Colour of Magic , was published in 1983, after which Pratchett wrote an average of two books
9200-511: Was announced that Pratchett would be knighted (as a Knight Bachelor ) in the Queen's 2009 New Year Honours. Afterwards he said, "You can't ask a fantasy writer not to want a knighthood. You know, for two pins I'd get myself a horse and a sword." In 2010, Pratchett created his own sword from deposits of iron he had found in a field near his home as he believed a knight should have a sword. Ten honorary doctorates were conferred on Pratchett: from
9300-405: Was bullied for his speech impediments . He was bothered by the head teacher, who, he said, thought "he could tell how successful you were going to be in later life by how well you could read or write at the age of six". Pratchett's family moved to Bridgwater , Somerset, briefly in 1957. He passed his eleven plus exam in 1958, earning a place at High Wycombe Technical High School , where he
9400-467: Was donating $ 1 million (about £494,000) to the Alzheimer's Research Trust (later called Alzheimer's Research UK), and that he was shocked "to find out that funding for Alzheimer's research is just 3% of that to find cancer cures". He said: "I am, along with many others, scrabbling to stay ahead long enough to be there when the cure comes along." In April 2008, Pratchett worked with the BBC to make
9500-425: Was extremely difficult to find a publisher who was willing to purchase the book, saying "I spent two-and-a-half years going around editors. I must have had 80 [meetings with editors]. And they all said 'don't be stupid'. At last Ebury took it. The editor there was made to understand that if it sold less than 10,000 copies, he'd lose his job. (...) It sold more than 200,000 copies in the first year." He also states that
9600-505: Was housed in a rackets court at the University of Chicago. However, the wizards' new reactor produces vastly more magical energy than planned and threatens to explode, destroying the University, the Discworld, and the entire universe. The university's thinking engine, Hex , decides to divert all the magic into creating a space containing nothing—no matter, no energy, no reality, and, importantly, no magic. The Dean sticks his fingers in
9700-650: Was made an adjunct Professor in the School of English at Trinity College Dublin in 2010, with a role in postgraduate education in creative writing and popular literature. Pratchett won the British Book Awards ' "Fantasy and Science Fiction Author of the Year" category in 1994, the British Science Fiction Award in 1989 for his novel Pyramids , and a Locus Award for Best Fantasy Novel in 2008 for Making Money . He won
9800-580: Was memorialised in graffiti in East London. The video game companies Frontier Developments and Valve added elements to their games named after him. Users of the social news site Reddit organised a tribute by which an HTTP header , " X-Clacks-Overhead: GNU Terry Pratchett ", was added to web sites' responses, a reference to the Discworld novel Going Postal , in which "the clacks" (a semaphore system, used as Discworld 's equivalent to
9900-569: Was shortlisted for the Hugo Award for Best Novel ; however, Pratchett recused himself, stating that stress over the award would mar his enjoyment of Worldcon . In the same year, A Hat Full of Sky won a Mythopoeic Award . In 2008, Making Money was nominated for the Nebula Award for Best Novel . I Shall Wear Midnight won the 2010 Andre Norton Award , presented by the Science Fiction and Fantasy Writers of America (SFWA) as
10000-568: Was the UK's bestselling author of the 1990s. According to The Times , Pratchett was the top-selling and highest earning UK author in 1996. Some of his books have been published by Doubleday , another Transworld imprint. In the United States, where his books are published by HarperCollins , Pratchett had poorer sales, marketing and distribution until 2005, when Thud! reached the New York Times bestseller list. According to
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