December 31, 1514, O.S. (a Sunday)

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 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 Fabrica, dated August 1, 1542, Vesalius wrote:

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.

December 30, 1835 (a Wednesday)

On this date, Charles Darwin on board HMS Beagle sailed from New Zealand for Sydney, Australia.

December 28, 1894 (a Friday)

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.

December 27, 1831 (a Tuesday)

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.

December 25, 1801 (a Friday)

On this date, the first complete skeleton of a mastodon found in the United States, mounted in the “Mammoth Room” of Peale’s Museum in Philadelphia, Pennsylvania, was opened for exhibition to the public. It was the museum’s centerpiece and became an overnight success. The massive bones had been discovered in the Hudson River Valley of New York state in the spring of that year, described only as Incognitum (“unknown”). They were acquired by Charles Willson Peale who traveled there to supervise their excavation. The site was depicted in a well-known painting by Peale, whose career included working as a portrait artist. Peale’s 1801 excavation on the Hudson Valley farm drew international attention.  Convinced that “the movements of nature are in never ending circles,” Thomas Jefferson expected Lewis and Clark to find mastodons and other extinct animals still living in the American west.  Periodically, from then until now, additional complete skeletons of mastodons have been unearthed in the state of New York.

References:

• Charles Coleman Sellers, Mr. Peale’s Museum (W.W. Norton & Co., 1980)

December 23, 1924 (a Tuesday)

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”).

December 23, 1810 (a Sunday)

On this date, the English zoologist and chemist Edward Blyth was born in London. Although he was considered one of the leading zoologists in India, and a prominent figure overall in his field, he is best known for his early (1835) recognition of some of the principles of natural selection. Blyth, however, did not see the ramifications of the principle (nor did anyone else), and did little to develop his thoughts any further. Later he became one of the first to embrace Darwinism, and was a vocal supporter for the remainder of his years.

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…

December 22, 1857 (a Tuesday)

On this date, Charles Darwin replied to a letter that Alfred Russel Wallace had sent him on 27 September. He praised Wallace for his dedication to natural science, and for his work on the distribution of species. Darwin also told Wallace he will not discuss the topic of man’s origins, even though it would be of highest interest to naturalists. Darwin pointed out that he had been working on the problem of species origins for twenty years, but would not publish for a few years yet.

December 22, 1938 (a Thursday)

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.

December 21, 1889 (a Saturday)

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.”

December 21, 1835 (a Monday)

On this date, HMS Beagle arrived at New Zealand with Charles Darwin on board. He was not too impressed with the natives, whom he viewed with suspicion (they practiced cannibalism before the missions arrived).

December 19, 1835 (a Saturday)

On this date, HMS Beagle with Charles Darwin on board approached New Zealand.

December 19, 1944 (a Tuesday)

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.

December 18, 1832 (a Tuesday)

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.

December 18, 1912 (a Wednesday)

Working at Piltdown.

 

 

On this date, the discovery of the skull known as Piltdown man, the first important fossil human skull ever to be unearthed in England, was announced at a meeting of the Geological Society of Great Britain. Charles Dawson, steward of Barkham Manor, an attorney, and secretary to the Sussex Archaeological Society, and Arthur Smith Woodward, keeper of geology at the British Museum, announced their remarkable find had been made at Piltdown Common. The specimen, known as Piltdown man, occupied an honored place in the catalogues of fossil hominids for the next 40 years. But in 1953, thanks to some rigorous scholarly detective work, Piltdown man was revealed to be nothing more than a forgery, manufactured from modern human and animal remains.

December 16, 1859 (a Friday)

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:

• Douglas Houghton Campbell, “Relations of the temperate floras of North and South America,” Proceedings of the California Academy of Sciences 25, 4th ser. (1944): 139-146.

December 15, 1869 (a Wednesday)

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:

• Joseph Barrell, “Rhythms and the measurements of geologic time,” Geol. Soc. America Bull. 28 (1917): 745-904.
• Patrick Wyse Jackson, The Chronologers’ Quest: The Search for the Age of the Earth (Cambridge, UK: Cambridge University Press, 2006) 195-6.

December 14, 1914 (a Monday)

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:

• D.L. Kacian, D.R. Mills, F.R. Kramer, and S. Spiegelman, “A replicating RNA molecule suitable for a detailed analysis of extracellular evolution and replication,” Proceedings of the National Academy of Sciences U.S.A. 69(10): 3038–3042 (Oct. 1972).
• D.R. Mills, R.L. Peterson, and S. Spiegelman, “An extracellular Darwinian experiment with a self-duplicating nucleic acid molecule,” Proceedings of the National Academy of Sciences U.S.A. 58(1): 217-224 (July 1967).

December 13, 1640

On this date, Robert Plot, British vicar and professor of chemistry at Oxford University, was born. Although totally unaware of dinosaurs, Plot published in his book, The Natural History of Oxford-shire, being an essay towards the Natural History of England (1677), the first known description of fossil material that was later identified as dinosaurian (now known to be from the dinosaur Megalosaurus):

Come we next to such [stones] as concern the … Members of the Body: Amongst which, I have one dug out of a quarry in the Parish of Cornwell, and given me by the ingenious Sir Thomas Pennyston, that has exactly the Figure of the lowermost part of the Thigh-Bone of a Man or at least of some other Animal, with capita Femoris inferiora, between which are the anterior … and the large posterior Sinus … : and a little above the Sinus, where it seems to have been broken off, shewing the marrow within of a shining Spar-like Substance of its true Colour and Figure, in the hollow of the Bone … In Compass near the capita Femoris, just two Foot, and at the top above the Sinus … about 15 inches: in weight, though representing so short a part of the Thigh-Bone, almost 20 pounds. [Plot, 1677, p. 132]

He initially thought that the specimen he had described was part of a leg bone of one of the war elephants that the Roman general, Plautius, supposedly brought with him when his legions invaded Britain in 72 C.E., but Plot soon realized this could not be the case. He finally settled on what, to us, is an even more bizarre suggestion:

There happily came to Oxford while I was writing of this, a living Elephant to be shown publickly at the ACT, An. 1676, with whose Bones … I compared ours; and found those of the Elephant not only of a different Shape, but also incomparably different to ours, though the Beast were very young and not half grown. If then they are neither the Bones of Horses, Oxen, nor Elephants, as I am strongly persuaded they are not … It remains, that (notwithstanding their extravagant Magnitude) they must have been the bones of Men or Women: Nor doth any thing hinder but they may have been so, provided it be clearly made out, that there have been Men and Women of proportionable Stature in all Ages of the World, down even to our own Days. [Plot, 1677, p. 137]

Although Plot’s view may seem unsophisticated in light of what we now know about dinosaurs, Plot was doing good science in interpreting his observations on an unknown object by invoking information about similar objects which had been described or discussed in the literature of the time. His specimen was clearly part of a femur, or upper leg bone, of a terrestrial vertebrate. In suggesting that the bone came from a Roman war elephant, and later a human being, Plot made a rational interpretation based on knowledge available to him.

Although similarities between fossils and living organisms could clearly be perceived, it did not, to Plot, necessarily follow that the one had come from the other. According to the neoplatonic school of thought, the whole cosmos is a web of hidden affinities, made visible in the resemblances between Man and his external world, between the heavens and the Earth, and between living and non-living entities. Neoplatonists could therefore attribute organic resemblances to the action of a pervasive moulding force or “plastic virtue” that governed the growth of living organisms, but also operated within the Earth. For Plot, this “plastic virtue” was crystallization, which he felt capable of remarkable feats:

That Salts are the principal Ingredients of Stones, I think has so sufficiently been noted already, that to endeavour any further Evidence of the thing, would be actum agere in me, and loss of time to the Reader: And if of Stones in general, much rather sure of Formed Stones, it being the undoubted Prerogative of the Saline Principle to give Bodies their Figure, as well as Solidity and Duration: No other Principle that we yet know of naturally shooting into Figures, each peculiar to their own kind, but Salts; thus Nitre always shoots into Pyramids, Salt Marine into Cubes, Alum into Octo, and Sal Armoniac into Hexaedrums,and other mixt Salts into as mixt Figures. [Plot, 1677, p. 123]

December 13, 1836 (a Tuesday)

On this date, Charles Darwin left London for Cambridge and stayed at Reverend Henslow’s house. While there, he gave a talk to the Cambridge Philosophical Society about the formation of glassy tubes that were formed when lightening struck the sandy beaches near Maldonado, South America.