Heidelberg is a university town in Baden-Württemberg situated on the river Neckar in south-west Germany. In the 2016 census, its population was 159,914, with a quarter of its population being students. Located about 78 km south of Frankfurt, Heidelberg is the fifth-largest city in the German state of Baden-Württemberg. Heidelberg is part of the densely populated Rhine-Neckar Metropolitan Region. Founded in 1386, Heidelberg University is Germany's oldest and one of Europe's most reputable universities. A scientific hub in Germany, the city of Heidelberg is home to several internationally renowned research facilities adjacent to its university, including four Max Planck Institutes. A former residence of the Electorate of the Palatinate, Heidelberg is a popular tourist destination due to its romantic cityscape, including Heidelberg Castle, the Philosophers' Walk, the baroque style Old Town. Heidelberg is in the Rhine Rift Valley, on the left bank of the lower part of the Neckar in a steep valley in the Odenwald.
It is bordered by the Gaisberg mountains. The Neckar here flows in an east-west direction. On the right bank of the river, the Heiligenberg mountain rises to a height of 445 meters; the Neckar flows into the Rhine 22 kilometres north-west in Mannheim. Villages incorporated during the 20th century stretch from the Neckar Valley along the Bergstraße, a road running along the Odenwald hills. Heidelberg is on European walking route E1. Since Heidelberg is among the warmest regions of Germany, plants atypical of the central-European climate flourish there, including almond and fig trees. Alongside the Philosophenweg on the opposite side of the Old Town, winegrowing was restarted in 2000. There is a wild population of African rose-ringed parakeets, a wild population of Siberian swan geese, which can be seen on the islands in the Neckar near the district of Bergheim. Heidelberg is a unitary authority within the Regierungsbezirk Karlsruhe; the Rhein-Neckar-Kreis rural district surrounds it and has its seat in the town, although the town is not a part of the district.
Heidelberg is a part of the Rhine-Neckar Metropolitan Region referred to as the Rhein-Neckar Triangle. This region consists of the southern part of the State of Hessen, the southern part of the State of Rhineland-Palatinate, the administrative districts of Mannheim and Heidelberg, the southern municipalities of the Rhein-Neckar-Kreis; the Rhein-Neckar Triangle became a European metropolitan area in 2005. Heidelberg consists of 15 districts distributed in six sectors of the town. In the central area are Altstadt and Weststadt; the new district will have 5,000–6,000 residents and employment for 7,000. Further new residential space for 10,000-15,000 residents was made available in Patrick Henry Village following the departure of the US Armed Forces; the following towns and communes border the city of Heidelberg, beginning in the west and in a clockwise direction: Edingen-Neckarhausen, Schriesheim, Schönau, Neckargemünd, Gaiberg, Sandhausen, Plankstadt and Mannheim. Heidelberg has an oceanic climate, defined by the protected valley between the Pfälzerwald and the Odenwald.
Year-round, the mild temperatures are determined by maritime air masses coming from the west. In contrast to the nearby Upper Rhine Plain, Heidelberg's position in the valley leads to more frequent easterly winds than average; the hillsides of the Odenwald favour precipitation. The warmest month is July, the coldest is January. Temperatures rise beyond 30 °C in midsummer. According to the German Meteorological Service, Heidelberg was the warmest place in Germany in 2009. Between 600,000 and 200,000 years ago, "Heidelberg Man" died at nearby Mauer, his jaw bone was discovered in 1907. Scientific dating determined his remains as the earliest evidence of human life in Europe. In the 5th century BC, a Celtic fortress of refuge and place of worship were built on the Heiligenberg, or "Mountain of Saints". Both places can still be identified. In 40 AD, a fort occupied by the 24th Roman cohort and the 2nd Cyrenaican cohort; the early Byzantine/late Roman Emperor Valentinian I, in 369 AD, built new and maintained older castra and a signal tower on the bank of the Neckar.
They built a wooden bridge based on stone pillars across it. The camp protected the first civilian settlements; the Romans remained until 260 AD. The local administrative center in Roman times was the nearby city of Lopodunum. Modern Heidelberg can trace its beginnings to the fifth century; the village Bergheim is first mentioned for that period in documents dated to 769 AD. Bergheim now lies in the middle of modern Heidelberg; the people converted to Christianity. In 863 AD, the monastery of St. Michael was founded on the Heiligenberg inside the double rampart of the Celtic fortress. Around 1130, the Neuburg Monastery was founded in the Neckar valley. At the same time, the bishopric of Worms extended its influence into the valley, founding Schönau Abbey in 1142. Modern He
Lordiphosa is a genus of fly in the family Drosophilidae. L. acongruens L. acuminata L. alticola Hu, Watabe & Toda, 1999 L. andalusiaca L. antillaria L. archoroides L. baechlii Zhang, 2008 L. basdeni L. biconvexa L. chaoi Hu & Toda, 1999 L. chaolipinga L. clarofinis L. coei L. collinella L. cultrata Zhang, 1993 L. denticeps L. deqenensis Zhang, 1993 L. eminens Quan & Zhang, 2003 L. falsiramula Zhang, 1993 L. fenestrarum L. gruicollara Quan & Zhang, 2003 L. harpophallata Hu, Watabe & Toda, 1999 L. hexasticha L. himalayana L. hirsuta L. incidens Quan & Zhang, 2003 L. kurokawai L. ludianensis Quan & Zhang, 2001 L. macai Zhang, 2008 L. megalopectinata L. miki L. mommai (Takada & L. neokurokawai L. nigricolor L. nigrifemur Quan & Zhang, 2001 L. nigrocolor L. nigrostyla L. paradenticeps L. paraflabella Gupta & De, 1996 L. parantillaria L. penicilla L. penicula L. peniglobosa L. piliferous Quan & Zhang, 2003 L. porrecta L. protrusa L. ramipara L. ramosissima L. ramula Zhang, 1993 L. ripa L. serriflabella L. shennongjiana Hu & Toda, 1999 L. shii Quan & Zhang, 2001 L. spinopenicula L. stackelbergi L. subantillaria L. tripartita L. tsacasi Zhang, 2008 L. variopicta L. vittata Zhang & Liang, 1994 L. zonaria
Birmingham is a city located in the north central region of the U. S. state of Alabama. With an estimated 2017 population of 210,710, it is the most populous city in Alabama. Birmingham is the seat of Alabama's most populous and fifth largest county; as of 2017, the Birmingham-Hoover Metropolitan Statistical Area had a population of 1,149,807, making it the most populous in Alabama and 49th-most populous in the United States. Birmingham serves as an important regional hub and is associated with the Deep South and Appalachian regions of the nation. Birmingham was founded in 1871, during the post-Civil War Reconstruction era, through the merger of three pre-existing farm towns, most notably Elyton; the new city was named for Birmingham, the UK's second largest city and, at the time, a major industrial city. The Alabama city annexed smaller neighbors and developed as an industrial center, based on mining, the new iron and steel industry, rail transport. Most of the original settlers who founded Birmingham were of English ancestry.
The city was developed as a place where cheap, non-unionized immigrant labor, along with African-American labor from rural Alabama, could be employed in the city's steel mills and blast furnaces, giving it a competitive advantage over unionized industrial cities in the Midwest and Northeast. From its founding through the end of the 1960s, Birmingham was a primary industrial center of the southern United States, its growth from 1881 through 1920 earned it nicknames such as "The Magic City" and "The Pittsburgh of the South". Its major industries were steel production. Major components of the railroad industry and railroad cars, were manufactured in Birmingham. Since the 1860s, the two primary hubs of railroading in the "Deep South" have been Birmingham and Atlanta; the economy diversified in the latter half of the 20th century. Banking, telecommunications, electrical power transmission, medical care, college education, insurance have become major economic activities. Birmingham ranks as one of the largest banking centers in the U.
S. Also, it is among the most important business centers in the Southeast. In higher education, Birmingham has been the location of the University of Alabama School of Medicine and the University of Alabama School of Dentistry since 1947. In 1969 it gained the University of Alabama at Birmingham, one of three main campuses of the University of Alabama System, it is home to three private institutions: Samford University, Birmingham-Southern College, Miles College. The Birmingham area has major colleges of medicine, optometry, physical therapy, law and nursing; the city has three of the state's five law schools: Cumberland School of Law, Birmingham School of Law, Miles Law School. Birmingham is the headquarters of the Southwestern Athletic Conference and the Southeastern Conference, one of the major U. S. collegiate athletic conferences. Birmingham was founded on June 1, 1871, by the Elyton Land Company, whose investors included cotton planters and railroad entrepreneurs, it sold lots near the planned crossing of the Alabama & Chattanooga and South & North Alabama railroads, including land, a part of the Benjamin P. Worthington plantation.
The first business at that crossroads was the trading post and country store operated by Marre and Allen. The site of the railroad crossing was notable for its proximity to nearby deposits of iron ore and limestone – the three main raw materials used in making steel. Birmingham is the only place where significant amounts of all three minerals can be found in close proximity. From the start the new city was planned as a center of industry; the city's founders, organized as the Elyton Land Company, named it in honor of Birmingham, one of the world's premier industrial cities, to emphasize that point. The growth of the planned city was impeded by an outbreak of cholera and a Wall Street crash in 1873. Soon afterward, however, it began to develop at an explosive rate; the Tennessee Coal and Iron Company became the leading steel producer in the South by 1892. In 1907 U. S. Steel became the most important political and economic force in Birmingham, it resisted new industry, however. In 1911, the town of Elyton and several other surrounding towns were absorbed into Birmingham.
From the early 20th century, the city grew so it earned the sobriquet "The Magic City". The downtown was redeveloped from a low-rise commercial and residential district into a busy grid of neoclassical mid- and high-rise buildings crisscrossed by streetcar lines. Between 1902 and 1912, four large office buildings were constructed at the intersection of 20th Street, the central north-south spine of the city, 1st Avenue North, which connected the warehouses and industrial facilities along the east-west railroad corridor; this early group of skyscrapers was nicknamed the "Heaviest Corner on Earth". Birmingham was hit by the 1916 Irondale earthquake. A few buildings in the area were damaged; the earthquake was felt as far as Atlanta and neighboring states. While excluded from the best-paying industrial jobs, African Americans joined the migration of residents from rural areas to the city, drawn by economic opportunity; the Great Depression of the 1930s struck Birmingham hard, as the sources of capital fueling the city's growth dried up at the same time farm laborers, driven off the land, made their way to the city in search of work.
Hundreds poured into many riding in empty boxcars. "Hobo jungles" were established in Boyles, the Twenty-fourth Street Viaduct, G
South Bend, Indiana
South Bend is a city in and the county seat of St. Joseph County, United States, on the St. Joseph River near its southernmost bend, from which it derives its name; as of the 2010 census, the city had a total of 101,168 residents. It is the fourth-largest city in Indiana, serving as the economic and cultural hub of Northern Indiana; the ranked University of Notre Dame is located just to the north in unincorporated Notre Dame, Indiana and is an integral contributor to the region's economy. The area was settled in the early 19th century by fur traders and was established as a city in 1865; the St. Joseph River shaped South Bend's economy through the mid-20th century. River access assisted heavy industrial development such as that of the Studebaker Corporation, the Oliver Chilled Plow Company, other large corporations; the population of South Bend declined after 1960, when it had a peak population of 132,445. This was chiefly due to migration to suburban areas as well as the demise of Studebaker and other heavy industry.
Today, the largest industries in South Bend are health care, small business, tourism. Remaining large corporations include Crowe Horwath, AM General; the city population has started to grow for the first time in nearly fifty years. The old Studebaker plant and surrounding area, now called Ignition Park, is being redeveloped as a technology center to attract new industry; the city has been featured in national news coverage for Mayor Pete Buttigieg, who has achieved recognition for his various economic development projects within the city, his position as the youngest mayor to be elected in a city of more than 100,000 residents, his essay in which he came out as the first gay executive in the state of Indiana. The city attracted further attention when Mayor Buttigieg announced he will run for the Democratic nomination for the 2020 presidential election; the St. Joseph Valley was long occupied by Native Americans. One of the earliest known groups to occupy what would become northern Indiana was the Miami tribe.
The Potawatomi moved into the region, utilizing the rich food and natural resources found along the river. The Potawatomi occupied this region of Indiana until most of them were forcibly removed in the 1840s; the South Bend area was so popular because its portage was the shortest overland route from the St. Joseph River to the Kankakee River; this route was used for centuries, first by the Native Americans by French explorers and traders. The French explorer René-Robert Cavelier, Sieur de La Salle, the first white European to set foot in what is now South Bend, used this portage between the St. Joseph River and the Kankakee River in December 1679; the first permanent white settlers of South Bend were fur traders who established trading posts in the area. In 1820, Pierre Frieschutz Navarre arrived, representing the American Fur Company of John Jacob Astor, he settled near. Alexis Coquillard, another agent of the AFC, established a trading post known as the Big St. Joseph Station. In 1827, Lathrop Minor Taylor established a post for Samuel Hanna and Company, in whose records the name St. Joseph's, Indiana was used.
By 1829, the town was growing, with Taylor emerging as leaders. They applied for a post office. Taylor was appointed postmaster, the post office was designated as Southold, Allen County, Indiana; the following year, the name was changed to South Bend to ease confusion, as several other communities were named Southold at the time. In 1831, South Bend was laid out as the county seat and as one of the four original townships of St. Joseph County with 128 residents. Soon after, design began on; the town was formally established in 1835 and grew. In 1856, attorney Andrew Anderson founded May Oberfell Lorber, the oldest business in St. Joseph County, he compiled a complete index of South Bend's real estate records. In 1841, Schuyler Colfax was appointed St. Joseph County deputy auditor. Colfax purchased the South Bend Free Press and turned it into the pro-Whig newspaper, the St. Joseph Valley Register, he was a member of the state constitutional convention of 1850 where he opposed the barring of African American migration to Indiana.
He joined the Republican party, like many Whigs of his day, was elected to Congress in 1855 and became Speaker of the House in 1863 under Abraham Lincoln. In 1868, he was elected Vice President under Ulysses S. Grant. Colfax was buried in the City Cemetery. During the late 1830s through the 1850s, much of South Bend's development centered on the industrial complex of factories located on the two races. Several dams were created, factories were built on each side of the river. On October 4, 1851, the first steam locomotive entered South Bend; this led to a general shift of businesses from the river toward the railroad. In 1852, Henry Studebaker set up Studebaker wagon shop becoming the world's largest wagon builder and the only one to succeed as an automobile manufacturer; the Singer Sewing Company and the Oliver Chilled Plow Company were among other companies that made manufacturing the driving force in the South Bend economy until the mid-20th century. Another important economic act was the dredging of the Kankakee River in 1884 to create farmland.
During this time period there was a great immigration of Europeans, such as Polish, Irish, German and Swedish people to South Bend because the rise of area factories. South Bend benefited f
Macroevolution is evolution on a scale at or above the level of species, in contrast with microevolution, which refers to smaller evolutionary changes of allele frequencies within a species or population. Macroevolution and microevolution describe fundamentally identical processes on different time scales; the process of speciation may fall within the purview of either, depending on the forces thought to drive it. Paleontology, evolutionary developmental biology, comparative genomics and genomic phylostratigraphy contribute most of the evidence for macroevolution's patterns and processes. Russian entomologist Yuri Filipchenko first coined the terms "macroevolution" and "microevolution" in 1927 in his German language work, "Variabilität und Variation". Since the inception of the two terms, their meanings have been revised several times; the term macroevolution fell into a certain disfavour when it was taken over by writers such as the paleontologist Otto Schindewolf to describe their theories of orthogenesis.
This was the vitalist belief that organisms evolve in a definite direction due to an internal "driving force". Macroevolution includes changes occurring on geological time scales, in contrast to microevolution, which occurs on any time scale. Within the modern synthesis of the early 20th century, macroevolution is thought of as the compounded effects of microevolution. Thus, the distinction between micro- and macroevolution is not a fundamental one – the only difference between them is of time and scale; as Ernst W. Mayr observes, "transspecific evolution is nothing but an extrapolation and magnification of the events that take place within populations and species...it is misleading to make a distinction between the causes of micro- and macroevolution". However, time is not a necessary distinguishing factor – macroevolution can happen without gradual compounding of small changes. Changes in the genes regulating development have been proposed as being important in producing speciation through large and sudden changes in animals' morphology.
There are many ways to view macroevolution, for example, by observing changes in the genetics, taxonomy and behavior of organisms, though these are interrelated. Sahney et al. stated the connection as "As taxonomic diversity has increased, there have been incentives for tetrapods to move into new modes of life, where resources may seem unlimited, there are few competitors and possible refuge from danger. And as ecological diversity increases, taxa diversify from their ancestors at a much greater rate among faunas with more superior, innovative or more flexible adaptations." Molecular evolution occurs through small changes in the cellular level. Over a long period of time, this can cause big effects on the genetics of organisms. Taxonomic evolution occurs through small changes between populations and species. Over a long period of time, this can cause big effects on the taxonomy of organisms, with the growth of whole new clades above the species level. Morphological evolution occurs through small changes in the morphology of an organism.
Over a long period of time, this can cause big effects on the morphology of major clades. This can be seen in the Cetacea, where throughout the group's early evolution, hindlimbs were still present; however over millions of years the hindlimbs became internal. Abrupt transformations from one biologic system to another, for example the passing of life from water into land or the transition from invertebrates to vertebrates, are rare. Few major biological types have emerged during the evolutionary history of life; when lifeforms take such giant leaps, they meet little to no competition and are able to exploit many available niches, following an adaptive radiation. This can lead to convergent evolution as the empty niches are filled by whichever lifeform encounters them. Subjects studied within macroevolution include: Adaptive radiations such as the Cambrian Explosion. Changes in biodiversity through time. Genome evolution, like horizontal gene transfer, genome fusions in endosymbioses, adaptive changes in genome size.
Mass extinctions. Estimating diversification rates, including rates of speciation and extinction; the debate between punctuated equilibrium and gradualism. The role of development in shaping evolution such topics as heterochrony and phenotypic plasticity. Darwin, a unit of evolutionary change, defined as an e-fold change in a trait over one million years List of transitional fossils Transitional fossil Speciation AAAS, American Association for the Advancement of Science. "Statement on the Teaching of Evolution". Aaas.org. Archived from the original on 21 February 2006. Retrieved 2007-01-14. IAP, Interacademy Panel. IAP Statement on the Teaching of Evolution. Interacademies.net. Archived from the original on 5 July 2006. Retrieved 2007-01-14. Myers, P. Z.. Ann Coulter: No Evidence for Evolution?. Pharyngula. ScienceBlogs. Archived from the original on 22 June 2006. Retrieved 12 September 2007. NSTA, National Science Teachers Association. "An NSTA Evolution Q&A". Archived from the original on 2 February 2008. Retrieved 2008-02-01.
Pinholster, Ginger. "AAAS Denounces Anti-Evolution Laws as Hundreds of K-12 Teachers Convene for'Front Line' Event". Aaas.org. Retrieved 2007-01-14. Introduction to macroevolution Macroevolution as the common descent of all life Macroevolution in the 21st century Macroevolution as an independent discipline. Macroevolution FAQ
Emil von Behring
Emil von Behring, born as Emil Adolf Behring, was a German physiologist who received the 1901 Nobel Prize in Physiology or Medicine, the first one awarded, for his discovery of a diphtheria antitoxin. He was known as a "saviour of children," as diphtheria used to be a major cause of child death, he was honored with Prussian nobility in 1901, henceforth being known by the surname "von Behring." Behring was born in Kreis Rosenberg, Province of Prussia. His father was a schoolmaster. Between 1874 and 1878, he studied medicine at the Kaiser-Wilhelm-Akademie in Berlin, an academy for military doctors, since his family could not afford the university; as a military doctor, he studied the action of iodoform. In 1888, he became an assistant at the institute of Robert Koch in Berlin. In 1890 he published an article with Kitasato Shibasaburō reporting that they had developed "antitoxins" against both diphtheria and tetanus, they had injected diphtheria and tetanus toxins into guinea-pigs and horses. These antitoxins could cure the diseases in non-immunized animals.
In 1892 he started the first human trials of the diphtheria antitoxin. Successful treatment started in 1894, after the production and quantification of antitoxin had been optimized. In 1895 he became Professor of Hygienics within the Faculty of Medicine at the University of Marburg, a position he would hold for the rest of his life, he and the pharmacologist Hans Horst Meyer had their laboratories in the same building, Behring stimulated Meyer's interest in the mode of action of tetanus toxin. Behring won the first Nobel Prize in Physiology or Medicine in 1901 for the development of serum therapies against diphtheria, he was elected a Foreign Honorary Member of the American Academy of Arts and Sciences in 1902. In 1904 he founded the Behringwerke in a company to produced antitoxins and vaccines. At the International Tuberculosis Congress in 1905 he announced that he had discovered "a substance proceeding from the virus of tuberculosis." This substance, which he designated "T C," plays the important part in the immunizing action of his "bovivaccine", which prevents bovine tuberculosis.
He tried unsuccessfully to obtain a therapeutic agents for humans. Behring died at Marburg, Hessen-Nassau, on 31 March 1917, his name survived in the Dade Behring organisation, in CSL Behring, a manufacturer of plasma-derived biotherapies, in Novartis Behring and in the Emil von Behring Prize of the University of Marburg, the highest endowed medicine award in Germany. His Nobel Prize medal is now kept on display at the International Red Cross and Red Crescent Museum in Geneva. Von Behring is believed to have cheated Paul Ehrlich out of recognition and financial reward in relation to collaborative research in diphtheria; the two men developed a diphtheria serum by injecting the deadly toxin into a horse. The serum was used during an epidemic in Germany. A chemical company preparing to undertake commercial production and marketing of the diphtheria serum offered a contract to both men, but von Behring maneuvered to claim all the considerable financial rewards for himself. To add insult to injury, only Behring received the first Nobel Prize in Medicine, in 1901, for his contributions.
In December, 29th, 1896, Behring married the twenty-year-old Else Spinola, a daughter of Bernhard Spinola, the director of the Charité hospital in Berlin, a Jewish-born mother - Elise Spinola, born Bendix - who had converted to Christianity upon her marriage. They had six sons, they held their honeymoon at villa "Behring" on Capri 1897. In 1909–1911, the Russian writer Maxim Gorky lived at this villa. Die Blutserumtherapie Die Geschichte der Diphtherie Bekämpfung der Infektionskrankheiten Beiträge zur experimentellen Therapie E. v. Behring's Gesammelte Abhandlungen Digital edition by the University and State Library Düsseldorf German inventors and discoverers Kornelia Grundmann. "Emil von Behring: The founder of serum therapy". The Nobel Foundation. Retrieved 2008-07-21; this article incorporates text from a publication now in the public domain: Gilman, D. C.. "article name needed". New International Encyclopedia. New York: Dodd, Mead. Ulrike Enke: Salvatore dell'Infanzia Behring and Capri Christoph Hans Gerhard: Trias deutschen Forschergeistes Emil von Behring Pflaum-Verlag / Munich Naturheilpraxis 71.
Jahrgang January, 2018 www.uni-marburg.de/behring-digital Newspaper clippings about Emil von Behring in the 20th Century Press Archives of the German National Library of Economics
Evolutionary developmental biology
Evolutionary developmental biology is a field of biological research that compares the developmental processes of different organisms to infer the ancestral relationships between them and how developmental processes evolved. The field grew from 19th-century beginnings, where embryology faced a mystery: zoologists did not know how embryonic development was controlled at the molecular level. Charles Darwin noted that having similar embryos implied common ancestry, but little progress was made until the 1970s. Recombinant DNA technology at last brought embryology together with molecular genetics. A key early discovery was of homeotic genes; the field is characterised by some key concepts. One is deep homology, the finding that dissimilar organs such as the eyes of insects and cephalopod molluscs, long thought to have evolved separately, are controlled by similar genes such as pax-6, from the evo-devo gene toolkit; these genes are ancient, being conserved among phyla. Another is that species do not differ much in their structural genes, such as those coding for enzymes.
These genes are reused, many times in different parts of the embryo and at different stages of development, forming a complex cascade of control, switching other regulatory genes as well as structural genes on and off in a precise pattern. This multiple pleiotropic reuse explains why these genes are conserved, as any change would have many adverse consequences which natural selection would oppose. New morphological features and new species are produced by variations in the toolkit, either when genes are expressed in a new pattern, or when toolkit genes acquire additional functions. Another possibility is the Neo-Lamarckian theory that epigenetic changes are consolidated at gene level, something that may have been important early in the history of multicellular life. A recapitulation theory of evolutionary development was proposed by Étienne Serres in 1824–26, echoing the 1808 ideas of Johann Friedrich Meckel, they argued that the embryos of'higher' animals went through or recapitulated a series of stages, each of which resembled an animal lower down the great chain of being.
For example, the brain of a human embryo looked first like that of a fish in turn like that of a reptile and mammal before becoming human. The embryologist Karl Ernst von Baer opposed this, arguing in 1828 that there was no linear sequence as in the great chain of being, based on a single body plan, but a process of epigenesis in which structures differentiate. Von Baer instead recognised four distinct animal body plans: radiate, like starfish. Zoologists largely abandoned recapitulation, though Ernst Haeckel revived it in 1866. From the early 19th century through most of the 20th century, embryology faced a mystery. Animals were seen to develop into adults of differing body plan through similar stages, from the egg, but zoologists knew nothing about how embryonic development was controlled at the molecular level, therefore little about how developmental processes had evolved. Charles Darwin argued; as an example of this, Darwin cited in his 1859 book On the Origin of Species the shrimp-like larva of the barnacle, whose sessile adults looked nothing like other arthropods.
Darwin noted Alexander Kowalevsky's finding that the tunicate, was not a mollusc, but in its larval stage had a notochord and pharyngeal slits which developed from the same germ layers as the equivalent structures in vertebrates, should therefore be grouped with them as chordates. 19th century zoology thus converted embryology into an evolutionary science, connecting phylogeny with homologies between the germ layers of embryos. Zoologists including Fritz Müller proposed the use of embryology to discover phylogenetic relationships between taxa. Müller demonstrated that crustaceans shared the Nauplius larva, identifying several parasitic species that had not been recognised as crustaceans. Müller recognised that natural selection must act on larvae, just as it does on adults, giving the lie to recapitulation, which would require larval forms to be shielded from natural selection. Two of Haeckel's other ideas about the evolution of development have fared better than recapitulation: he argued in the 1870s that changes in the timing and changes in the positioning within the body of aspects of embryonic development would drive evolution by changing the shape of a descendant's body compared to an ancestor's.
It took a century. In 1917, D'Arcy Thompson wrote a book on the shapes of animals, showing with simple mathematics how small changes to parameters, such as the angles of a gastropod's spiral shell, can radically alter an animal's form, though he preferred mechanical to evolutionary explanation, but for the next century, without molecular evidence, progress stalled. In the so-called modern synthesis of the early 20th century, Ronald Fisher brought together Darwin's theory of evolution, with its insistence on natural selection and variation, Gregor Mendel's laws of genetics into a coherent structure for evolutionary biology. Biologists assumed that an organism was a straightforward reflection of its component genes: the genes coded for proteins, which built