The WordPress.com stats helper monkeys prepared a 2011 annual report for this blog.
Here’s an excerpt:
The Louvre Museum has 8.5 million visitors per year. This blog was viewed about 70,000 times in 2011. If it were an exhibit at the Louvre Museum, it would take about 3 days for that many people to see it.
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Andreas Vesalius
On this date at 5:45 AM, the physician and anatomist Andreas Vesalius was born in Brussels, Belgium (at that time part of the Holy Roman Empire). Vesalius sought to understand the mechanisms of the natural world through careful observation, no longer relying on texts by ancient authorities. He is often referred to as the founder of modern human anatomy.
Vesalius studied in Louvain and Paris before earning a doctorate in medicine at the University of Padua in 1537. Appointed there as a lecturer in surgery at the age of twenty-three, he quickly consolidated his reputation as both a teacher and an anatomist.
Perhaps his most famous accomplishment was the publication in 1543 of De humani corporis fabrica libri septem (Seven Books on the Construction of the Human Body), or simply the Fabrica, a text that contained the first accurate illustrations of internal human anatomy. His book overthrew many of the previously uncontested doctrines of the second-century anatomist Galen, and caused a storm of criticism from other anatomists. It was revolutionary, as he was among the first to perform thorough cadaver dissections himself. He showed that Galen’s anatomy was merely an attempt to apply animal structure to the human body, and was not based on any direct knowledge of human anatomy. In the preface of the Fabrica, dated August 1, 1542, Vesalius wrote:
Title page of the Fabrica.
To this man they have all so entrusted their faith that no doctor has been found who believes he has ever discovered even the slightest error in all the anatomical volumes of Galen, much less that such a discovery is possible: even though (notwithstanding that Galen often corrects himself, that more than once after learning better he points out in some books a careless error he has made in others, and that he often contradicts himself) – even though it is just now known to us from the reborn art of dissection, from the careful reading of Galen’s books, and from the welcome restoration of many portions thereof, that he himself never dissected a human body, but in fact was deceived by his monkeys (granted a couple of dried-up human cadavers came his way) and often wrongly disputed ancient doctors who had trained themselves in human dissections. In fact, you will find many things in Galen which he misunderstood even in monkeys, not to mention the most astonishing fact that among the many and infinite differences between the organs of the human body and the monkey Galen noticed only those in the fingers and the flexion of the knee; he would no doubt have missed these as well, had they not been obvious to him without dissecting a human.
Vesalius’s discovery of the important differences between species also helped usher in the science of comparative anatomy, in which researchers studied animals to find their similarities and differences. In the process, they gradually began to recognize humans as being one species among many, with a few unique traits but many others shared in common with other animals. Some 300 years after Vesalius first shook off the blind obedience to Galen, Darwin used that vast stock of anatomical knowledge to build his theory of evolution.
Posted in Evolution, History, Scientific Method
Tagged Charles Darwin, Evolution, History, Scientific Method
Scales of Justice
On this date, Samuel Latham Mitchill appeared in the packed chambers of the Mayor’s Court in New York City Hall as the star witness in the case of James Maurice v. Samuel Judd, a dispute arising under a New York State statute that obliged purveyors of “fish oils” to ensure that their casks had been inspected.
The facts of the case today seem boring. On March 31, 1818, the New York State Legislature passed a law to ensure the quality of fish oils, which were widely used in the tanning and preservation of leather at the time. The law called for a corps of inspectors to “seek out any parcels of fish oil” and to certify the amount of water, sediment, and pure oil each cask contained. Three months later, a Mr. Samuel Judd, owner of the New-York Spermaceti Oil & Candle Factory at 52 Broadway, bought three casks of “fish oil” that had not been “gauged, inspected, and branded, according to law.” Judd claimed he didn’t have to pay a required fee on fish oil because he had purchased spermaceti, or whale oil, so James Maurice, a city inspector of fish oil, sued to collect the fees.
Judd’s view reflected an intellectual quandary of his time: If a whale is a fish, then why is its tail horizontal rather than vertical? Why do whales not have scales? Why do whales breathe air (that whales could drown was a proven fact by then), and give birth (and nurse their young with milk) rather than lay eggs? Why were whales so much smarter than lesser fish? (Apart from the challenge of their size was the challenge of their brains — whaling is hunting, not mere fishing.) And, perhaps most importantly, why did the insides of whales — which were known in the most minute detail as a simple commercial matter — resemble not the lesser fishes but rather cows and pigs?
A New York whaleman's drawing of a sperm whale, ca. 1810.
However, to many zoologists of the time (but not all), the inside of a whale would have been totally irrelevant. [Interestingly, Linnaeus himself had said whales were fish in the 9th edition of the Systema Naturae, but formally separated them in the 10th edition, published only two years later in 1758.] In terms of what today is known as taxonomy, shape and environment were the categorical bases for grouping animals, not internal anatomy. Whales looked like fish (tails and blowholes notwithstanding) and lived where fish lived. The 1817 edition of a leading English dictionary defined fish simply as “an animal that lived exclusively in water”. Even Genesis clearly delineated creation by environment: “fish of the sea” (so, as a matter of elementary Judeo-Christian theology, oysters and crabs are “fish”), “fowl of the air” (bats?), and “every creeping thing that creepeth upon the earth.” Again, whales don’t creepeth upon the earth, so the notion that they are “animals” was fundamentally un-Christian and even bordered on blasphemy. Therefore, whales are fish.
Nevertheless, by 1818 zoologists had generally conceded that their field was far from complete and that debate and dissent about proper taxonomic classification was not only permissible but inevitable — especially as new species of just about everything kept being discovered. Moreover, the leading naturalists — particularly Samuel Latham Mitchill, a retired politician who also happened to be the preeminent authority on the fishes of New York and the founder of what would become the New York Academy of Sciences — aimed to convert taxonomy to a science of dissection: that species should be grouped together by how they looked on the inside rather than on the outside. Mitchill presented the Linnaean argument from anatomy: whales breathe air and have lungs, not gills; they have four-chambered hearts, like horses but unlike fish; their fins contain bones that are exact analogs of the hands and arms of apes and people; they even have eyelids that move. He famously remarked that “a whale is no more a fish than a man.”
Yet William Sampson, the lead prosecutor, challenged Mitchill at every turn, using arguments that have echoes in recent debates about Darwinian evolution. Was it not true, Sampson asked, that there was wide disagreement among scholars as to exactly how various animals should be classified? And what were common folk to make of the unlikely associations Linnaean taxonomy called upon them to make? Quoting Sampson:
Now, is not man strangely mated or matched when the whale and the porpoise are his second cousins, and the monkey and the bat his germans [close relations]? Other gentlemen may choose their company, [but] I am determined to cut the connection.
So what happened? After some wrangling about whether statutory interpretation should even be a question left to the lay jurors of a municipal trial court (a debate we sometimes have to this day), the judge charged the jury — which, after only 15 minutes of deliberation, announced a verdict for the plaintiff. [However, within a month, the New York State Legislature essentially overturned the verdict by exempting whale oil from inspection — in the eyes of the law, the whale would no longer count as a fish.]
More than a century before Scopes, science was put on trial, and was convicted.
References:
Charles Darwin by G Richmond.
Alfred Sherwood Romer
On this date, the American vertebrate paleontologist and comparative anatomist Alfred Sherwood Romer was born. The Society of Vertebrate Paleontology, which Romer helped establish, says that he “was the leading contributor to the discipline of vertebrate paleontology throughout the twentieth century. . . Romer’s major contributions were in the areas of the ancestry of vertebrates, Paleozoic tetrapods, and the antecedents of mammals.” Perhaps Romer’s most notable gift to scientific posterity were his three seminal works: Osteology of the Reptiles (1956), Vertebrate Paleontology (1966), and The Vertebrate Body (1977) – immortal tomes which still adorn the shelves of any self-respecting student of vertebrate paleontology and evolution.
Charles Darwin by G Richmond.
On this date, HMS Beagle with Charles Darwin on board set sail from Plymouth, England, beginning its epic voyage with a crew of 73 men under clear skies and a good wind. Darwin became sea-sick almost immediately. Later, he wrote in his diary:
A beautiful day, accompanied by the long wished for E wind.—Weighed anchor at 11 o’clock & with difficulty tacked out.—The Commissioner Capt Ross sailed with us in his Yatch.—The Capt, Sullivan & myself took a farewell luncheon on mutton chops & champagne, which may I hope excuse the total absence of sentiment which I experienced on leaving England.—We joined the Beagle about 2 o’clock outside the Breakwater,—& immediately with every sail filled by a light breeze we scudded away at the rate of 7 or 8 knots an hour.—I was not sick that evening but went to bed early.
Louis Pasteur
On this date, the chemist and microbiologist Louis Pasteur was born in Dole in the Jura region of France.
From the time of the ancient Romans, through the Middle Ages, and until the late nineteenth century, it was generally accepted that some life forms arose spontaneously from nonliving matter. Such “spontaneous generation” appeared to occur primarily in decaying matter. For example, a seventeenth century recipe for the spontaneous production of mice required placing sweaty underwear and husks of wheat in an open-mouthed jar, then waiting for about 21 days, during which time it was alleged that the sweat from the underwear would penetrate the husks of wheat, changing them into mice. Likewise, the spontaneous generation hypothesis was proposed by scientists to explain the origin of the “animalcules” observed by Antoni van Leeuwenhoek in his magnifying lenses and had received wide acceptance all over Europe. Although such a concept may seem laughable today, it was consistent with the other widely held cultural and religious beliefs of the time.
It wasn’t until Louis Pasteur that this fallacy was finally disproved. In 1859, the French Academy of Science offered the Alhumbert Prize of 2500 francs to whoever could shed “new light on the question of so-called spontaneous generation”. Young Pasteur’s award winning experiment was a clever variation of earlier experiments performed by John Needham (1713-1781) and Lazzaro Spallanzani (1729-1799). Pasteur filled a long necked flask with meat broth. He then heated the glass neck and bent it into an “S” shape. Air could reach the broth, but gravity acted to trap airborne microorganisms in the curve of the neck. He then boiled the broth. After a time, no microorganisms had formed in the broth. When the flask was tipped so that the broth reached the microorganisms trapped in the neck, the broth quickly became cloudy with microscopic life.
Pasteur filled a flask with medium, heated it to kill all life, and then drew out the neck of the flask into a long S. This prevented microorganisms in the air from entering the flask, yet allowed air to flow freely. If the swan neck was broken, microbes could enter the flask and grow.
Thus, Pasteur disproved spontaneous generation. Furthermore, Pasteur proved that some microorganisms are airborne. “There is no known circumstance in which it can be confirmed that microscopic beings came into the world without germs, without parents similar to themselves,” he concluded in 1864. His experiment also supported germ theory. Germ theory states that specific microscopic organisms are the cause of specific diseases. While Pasteur was not the first to propose germ theory (Girolamo Fracastoro, Agostino Bassi, Friedrich Henle and others had suggested it earlier), he developed it and conducted other experiments that clearly indicated its correctness, thereby managing to convince most of Europe it was true.
Despite what creationists and proponents of “intelligent design” may insist, Pasteur’s research on spontaneous generation did not demonstrate the impossibility of life arising in simple form from nonliving matter under conditions vastly different from those today and by means of a long and propitious series of chemical steps/selections. In particular, he did not show that life cannot arise once, and then evolve. Neither Pasteur, nor any other post-Darwin researcher in this field, denied the age of Earth or the fact of evolution. What Louis Pasteur and the others who denied spontaneous generation did demonstrate is that life does not currently spontaneously (i.e., within a matter of weeks) arise in complex form from nonlife in nature.
Memorable Quote:
One does not ask of one who suffers: What is your country and what is your religion? One merely says: You suffer, this is enough for me: you belong to me and I shall help you.
– quoted in Louis Pasteur, Free Lance of Science (1950) by René Jules Dubos, p. 85
Posted in Creationism, History, Medicine, Scientific Method
Tagged Creationism, History, Medicine, Scientific Method, Spontaneous Generation
Peale's painting of 1801 excavation of mastodon.
References:
First fossil skull of Australopithecus.
On this date, Raymond Dart completed his work removing the first fossil skull of Australopithecus from its matrix of rock. Being one of the “missing links” in man’s evolution, Dart had taken exquisite care during 73 days to separate skull and stone, at work in his laboratory in Johannesburg, South Africa.
Dart with his students made the find in the Taung limestone works in the Harts Valley of Bechuanaland. When an endocranial cast was found, at first it seemed to be just another primate skull. Then, Dart noticed how amazingly close to human it looked. Dart had discovered the Taung child, who was only three years old at the time of death. He named it Australopithecus africanus. (Australis means “south” and pithecus means “ape”).
Posted in Evolution, History, Human Evolution
Tagged Evolution, History, Human Evolution
Edward Blyth
Interestingly, Blyth’s writings had a major influence on Charles Darwin. There can be no doubt of Darwin’s regard for Edward Blyth – in the first chapter of The Origin of Species he wrote:
…Mr Blyth, whose opinion, from his large and varied stores of knowledge, I should value more than that of almost any one…
Charles Darwin (1855)
Tagged Alfred Russel Wallace, Charles Darwin, Evolution, History
The coelacanth.
On this date, a coelacanth (Latimeria chalumnae) was caught at the mouth of the Chalumna River on the east coast of South Africa. The fish was caught in a shark gill net by Captain Goosen and his crew, who had no idea of the significance of their find. They thought the fish was bizarre enough to alert the local museum in the small South African town of East London.
The director of the East London Museum at the time was Miss Marjorie Courtney-Latimer. She alerted the prominent south African ichthyologist Dr J.L.B. Smith to this amazing discovery. This modern coelacanth was eventually named in honor of Miss Courtney-Latimer.
This coelacanth specimen led to the discovery of the first documented population, off the Comoros Islands, between Africa and Madagascar. For sixty years this was presumed to be the only coelacanth population in existence. However, on July 30, 1998, a coelacanth was caught in a deep-water shark net by local fishers off the volcanic island of Manado Tua in northern Sulawesi, Indonesia, about 10,000 km east of the Western Indian Ocean coelacanth population. In 1999 the Sulawesi coelacanth was described as a new species, Latimeria menadoensis, by Pouyaud, Wirjoatmodjo, Rachmatika, Tjakrawidjaja, Hadiaty and Hadie.
Coelacanths are known from the fossil record dating back over 360 million years, with a peak in abundance about 240 million years ago. Before 1938, they were thought to have become extinct approximately 80 million years ago, when they disappeared from the fossil record, so the discovery of a living coelacanth was very significant. But why are there no coelacanth fossils since the days of the dinosaurs? The explanation seems to be that the coelacanths from the fossil record lived in environments favoring fossilization, whereas modern coelacanths, both in the Comoros and Sulawesi, are found in environments that do not favor fossil formation. They inhabit caves and overhangs in nearly vertical marine reefs, at about 200 m depth, off newly formed volcanic islands.
One of the most interesting features of the coelacanth is that it has paired lobed fins that move like our arms and legs do. At the time of its discovery in 1938, the coelacanths were thought to be the ancestors of the tetrapods (terrestrial animals with four limbs). Although it is now thought that the lungfishes are the closest living relative of tetrapods, the coelacanth may still provide answers to some very interesting evolutionary questions.
Colo the gorilla (24 Aug 2009)
“She almost didn’t make it,” says Jeffrey Lyttle, author of Gorillas In Our Midst, a book about the Columbus Zoo gorillas.
“At the time, the zookeepers knew that Colo’s [mother] was pregnant, but nobody knew the gestation period of a gorilla,” Lyttle recalls. “They thought it was nine months, like humans, but it turns out it is closer to eight and a half months. So they weren’t expecting the birth. A vet named Warren Thomas was making his morning rounds when he discovered Colo, in her amniotic sack, lying on the concrete floor of her mother’s cage. He reached in, tore open the sack, and began giving Colo mouth-to-mouth resuscitation.”
Luckily, the little gorilla lived. “It was huge national news,” says Lyttle. But zookeepers believed that Colo’s mother wasn’t up to the task of raising her baby. They were probably right, since many captive gorillas never had a chance to learn parenting skills from their own parents in the wild. “So Columbus built a special nursery for her,” Lyttle explains. “Zoo visitation went through the roof. They would dress Colo up for the holidays — put her in an Easter bonnet and fancy dresses. Some people say she still likes to wear her food dish as a hat because she spent so much of her infancy wearing hats.”
Colo is also the oldest living gorilla in captivity, following the death of 55 year old Jenny in September 2008.
Sewell Green Wright
On this date, the American mathematician and biologist Sewell Green Wright was born. He was one of the founders, along with R. A. Fisher and J. B. S. Haldane, of modern theoretical population genetics. He researched the effects of inbreeding and crossbreeding with guinea pigs and, later on, the effects of gene action on inherited characteristics. The synthetic theory of evolution as described by Sewell Wright attempts to explain evolution in terms of changes in gene frequencies.
The classic example which supports this theory is that of the peppered moth in England. The moth can be either dark or light colored. Scientists have determined that body color in the peppered moth is controlled by a single gene with two alleles: the allele for dark body color is dominant and the allele for light body color is recessive. Prior to the industrialization of central England, the light-colored allele was most prevalent. The light-colored moths would hide on the white-barked trees and avoid bird predation. But the pollution generated by the new industries stained the light-colored trees dark. Gradually the light-colored moth was attacked and that allele became much less prevalent. In its place, the dark-colored allele became the most predominant allele because moths that carried that allele could camouflage themselves on the stained trees and avoid being eaten by their bird predators. Clearly the population had evolved to a higher adaptive condition.
Wright is perhaps best known for his concept of genetic drift, formerly known as the “Sewell Wright effect.” Genetic drift results when small populations of a species are isolated and due to pure chance, the few individuals who carry certain relatively rare genes may fail to transmit them. The genes may therefore disappear and their loss may lead to the emergence of new species, although natural selection has played no part in the process. Genetic drift can be summarized as “bad luck, not bad genes.”
Posted in Evolution, Genetics and Development, History
Tagged Evolution, Genetics and Development, History
Charles Darwin by G Richmond.
William Paley
On this date, William Paley was ordained as an Anglican priest. He was a prolific author, but his most influential contribution to biological thought was his book Natural Theology: or, Evidences of the Existence and Attributes of the Deity, Collected from the Appearances of Nature, first published in 1802. He introduced one of the most famous metaphors in the philosophy of science, the image of the watchmaker:
. . . when we come to inspect the watch, we perceive. . . that its several parts are framed and put together for a purpose, e.g. that they are so formed and adjusted as to produce motion, and that motion so regulated as to point out the hour of the day; that if the different parts had been differently shaped from what they are, or placed after any other manner or in any other order than that in which they are placed, either no motion at all would have been carried on in the machine, or none which would have answered the use that is now served by it. . . . the inference we think is inevitable, that the watch must have had a maker – that there must have existed, at some time and at some place or other, an artificer or artificers who formed it for the purpose which we find it actually to answer, who comprehended its construction and designed its use.
Natural theology had dominated English thinking for nearly two centuries, Paley’s arguments going back to authors such as John Ray, and have had a long intellectual history, surviving to the present day in many a piece of creationist rhetoric. Although totally discredited in modern science, natural theology was important scientifically because it guided researchers to the fundamental question of how life works. Even today, when scientists discover a new kind of organ or protein, they try to figure out its function.
Church/State sign.
On this date, Kitzmiller et al. v. Dover Area School Districtwas decided.
First, some background information. In October 2004, the Dover [PA] Area School District Board of Directors had decided that “Students will be made aware of gaps/problems in Darwin’s theory and of other theories of evolution including, but not limited to, intelligent design.” In November 2004, they had announced that Dover High School’s ninth-grade biology teachers would read a statement informing students that “Darwin’s Theory . . . is not a fact” and that “intelligent design is an explanation of the origin of life that differs from Darwin’s view.” The statement referred students to the creationist textbook Of Pandas and People to learn “what intelligent design actually involves.” On December 14, 2004, eleven parents had filed suit in the Middle District of Pennsylvania against the District’s Board of Directors. [Interestingly, in January 2005, science teachers refused to read the ID statement; administrators read it themselves.] The trial had begun on September 26, 2005.
Judge John Jones
The presiding judge, John E. Jones III, was not fooled by the defendants’ denials that they are creationists: “[Intelligent Design] cannot uncouple itself from its creationist, and thus religious, antecedents.” He was especially displeased that board members Buckingham and Bonsell had lied under oath during their depositions:
[T]he inescapable truth is that both Bonsell and Buckingham lied at their January 3, 2005 depositions about their knowledge of the source of the donation for Pandas. . . . This mendacity was a clear and deliberate attempt to hide the source of the donations . . . to further ensure that Dover students received a creationist alternative to Darwin’s theory of evolution [emphasis added].
Presented with the truth about the board’s policy and the ID creationism it promoted, Jones ruled accordingly:
A declaratory judgment is hereby issued in favor of Plaintiffs . . . such that Defendants’ ID Policy violates the Establishment Clause of the First Amendment of the Constitution of the United States and . . . the Constitution of the Commonwealth of Pennsylvania.
The victory was not just legal; the pro-ID school board was replaced by the voters on November 8, 2005.
Posted in Creationism, Education, History, Law, Religion
Tagged Creationism, Education, History, Law, Religion
Charles Darwin by G Richmond.
Richard E. Leakey
On this date, the Kenyan physical anthropologist and paleontologist Richard E. Leakey was born. Leakey, second of three sons of noted anthropologists Louis Leakey and Mary Leakey, decided at an early age that he wanted nothing to do with paleoanthropology and started a expedition business. In 1964, he led an expedition to a fossil site which sparked his interest in paleontology. Since then he has been responsible for extensive fossil finds of human ancestral forms in East Africa, including a Homo habilis skull found in 1972, and a Homo erectus skull found in 1975. His discoveries showed that man’s ancestors used tools, which shows intelligence, and lived in eastern Africa at least 3 million years ago – almost doubling the previously accepted age of human origins.
Posted in Evolution, History, Human Evolution
Tagged Evolution, History, Homo erectus, Human Evolution
HMS Beagle
HMS Beagle off Tierra del Fuego
(from an original by Raymond A Massey)
On this date, after passing through the straight of Le Maire at Tierra del Fuego, HMS Beagle anchored at Good Success Bay. Here Charles Darwin had his first encounter with savages. He was shocked by the primitive way of life they led but was also fascinated by them. A group of four male Fuegians met the landing party. After an attempt to communicate with the Feugians the party presented them with some bright red cloth and the Feugians immediately became friendly with them. The natives initiated a dialog by patting the crewmen on their chests. Apparently they had the most amazing ability to mimic the crew’s gestures and even the words they spoke, often repeating whole English sentences back to them. Darwin was bewildered by all this.
Working at Piltdown.
Posted in Evolution, History, Human Evolution, Scientific Method
Tagged Evolution, History, Human Evolution, Scientific Method
Bryophytes on brook.
On this date, the American botanist Douglas Houghton Campbell was born. He was an expert on the anatomical structure and life cycles of mosses, ferns and liverworts. Throughout his entire life, Campbell was interested in the evolution of vascular plants, which he thought occurred on land from primitive mosses. He also studied the modern geographic distribution of plants.
At a time before it was generally accepted, Campbell thought Wegener’s theory of continental drift (proposed in 1912) was plausible. Campbell recognized that a primordial supercontinent, Gondwana, splitting into smaller land masses that drifted apart would resolve many of the puzzling facts in geographical distribution, both of animals and plants:
Acceptance of the recent hypothesis of Du Toit, that there were two primordial continents, Laurasia in the Northern Hemisphere and Gondwana in the South, and from these primary continents, the existing continents were separated and shifted to their present positions, would, if true, remove most of the difficulties in explaining the present distribution of many existing plant families.
References:
On this date, the American geologist Joseph Barrell was born. Barrell was professor of structural geology at Yale University from 1908 until his death in 1919. He proposed that sedimentary rocks were produced not only by marine sedimentation but also by the action of rivers, winds, and ice (continental sedimentation). He also proposed (1916) that the bright red color of many Devonian rocks meant that the rocks had been baked dry, like bricks, in arid conditions. [Barrell had been only half right; red rocks do sometimes form in droughts, but they form in moist tropical soils as well.] He, and subsequently the great American paleontologist Alfred Sherwood Romer, speculated that droughts had caused lungfish to evolve into air-breathing land vertebrates, including tetrapods. According to this hypothesis, as the ponds dried, the fish had to adapt to life on land and so evolved features that enabled them to hop from pond to pond. [However, evidence discovered more recently suggests that the fish-to-tetrapod transition likely happened not in creatures that were adapting to land but in creatures living in water. In fact, everything special about tetrapods – limbs, digits, ribs, neck, and so on – might well have evolved in water, not on land.]
At a meeting of the Geological Society of America held in Albany, New York, in 1916 Barrell presented a paper on “Rhythms and the measurement of geologic time” that was later published in full in the Society’s Bulletin in 1917. The article became an instant classic in geology. Barrell argued that geological processes vary in intensity in a cyclical rather than a uniform fashion. Thus, current rates of geological change could not, as uniformitarians claim, be a reliable guide to the past. He suggested that the new radiometric dates should be used to interpret the sedimentological record. Thus, he accepted an age for the Earth of a few billion years at a time when many geologists still preferred an age of 100 million years.
References:
Sol Spiegelman
On this date, the American molecular biologist Sol Spiegelman was born. He developed the technique of nucleic acid hybridization, which helped to lay the foundation for advances in recombinant DNA technology. He is also given credit for an experiment that produced a self-reproducing RNA chain of only 218 nucleotides, which was nick-named Spiegelman’s Monster.
References:
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Understanding Human Anatomy through Evolution, 2nd ed. (pbk)
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