The Formation of Vegetable Mould Through the Action of Worms, with Observations on their Habits (sometimes shortened to Worms) is an 1881 book by Charles Darwin on earthworms.[1] It was his last scientific book, and was published shortly before his death (see Darwin from Insectivorous Plants to Worms). Exploring earthworm behaviour and ecology, it continued the theme common throughout his work that gradual changes over long periods of time can lead to large and sometimes surprising consequences. It was the first significant work on soil bioturbation, although that term was not used by Darwin (it first appeared in the soil and geomorphic literature one hundred years later).
After returning from the Beagle survey expedition in October 1836, Darwin was intensively occupied with further establishing his reputation as an innovative geologist, as well as finding suitable experts to describe his natural history collections and arranging for publication of their work as the multi-volume Zoology of the Voyage of H.M.S. Beagle. Near the outset of the voyage he had planned a book on geology, and during it extracts from his letters on geology had been privately published by his tutor John Stevens Henslow. Darwin now published papers on "proofs of recent elevation on the coast of Chili", "deposits containing extinct Mammalia" and "coral formations". He also rewrote his journal to incorporate observations from his notebooks as the book now called The Voyage of the Beagle, and began brain-storming in his notebooks about transmutation of species.[2]
Darwin's health suffered from the pressure of work, and on 20 September 1837 having been urged by his doctors "knock off all work" he visited his home in Shrewsbury then went on to stay with his relatives at Maer Hall, Staffordshire, home of his uncle Josiah Wedgwood. Uncle Jos pointed out an area of ground where lime and cinders spread years previously had vanished into the soil, forming layers under a top layer of loam. Jos suggested that this might have been the work of earthworms, but apparently thought that this would be of little interest to his nephew, who was working on continental scale geological problems.[3] Actually, Charles did find it interesting and throughout his life he sustained an interest in this "unsung creature which, in its untold millions, transformed the land as the coral polyps did the tropical sea".
Piles of worm castings atop existing soil in a garden
He returned to London on October 21, and prepared a paper on worms forming mould.[4] The paper on the role of earthworms in soil formation was read out by Darwin at the Geological Society of London on 1 November 1837.[5] This was an uncommonly mundane subject for the society, and his peers may have hoped to hear of something more grandiose, even seeing this paper as highlighting Darwin's growing idiosyncrasies.[3] The leading geologist William Buckland subsequently recommended Darwin's paper for publication, praising it as "a new & important theory to explain Phenomena of universal occurrence on the surface of the Earth—in fact a new Geological Power", while rightly rejecting Darwin's suggestion that chalkland could have been formed in a similar way.[6]
The paper appeared in the Proceedings of the Geological Society of London in 1838,[5] and was published with a woodcut illustration in the Transactions of the Geological Society in 1840.[7]
Renewed work on earthworms
From his brain-storming about transmutation towards the end of 1838, Darwin conceived of his theory of natural selection "by which to work", as his "prime hobby". His main work on the Beagle collections continued, and in 1842 he published the first of three volumes on geology, The Structure and Distribution of Coral Reefs. He then allowed himself to write out the first "pencil sketch" of his theory. Subsequently, in September 1842, the family moved to rural Down House where he had space for experimental plant and animal breeding, and surroundings to observe nature.[2] In December of that year he had a quantity of broken chalk spread over a part of a long established pasture field near the house, "for the sake of observing at some future period to what depth it would become buried."[8]
In 1872 he was having disagreements with St George Mivart about The Descent of Man.[citation needed] Darwin cut communication with Mivart [citation needed] and went the less controversial direction of the lowly worm. His network of correspondents and fans responded to his interest and "earthworm anecdotes began surfacing in his mountain of mail". He had been interested in earthworms "since his first fishing days at The Mount and flirting days at Maer". Still, other work constrained him. Broken off from Descent, he had to finish his next work The Expression of the Emotions in Man and Animals.[9]
His research included a railway trip to Stonehenge
By 1876, with his first grandson on the way, he felt his writing life was nearly over, with so much unfinished. He wanted to write on earthworms "before joining them", but also had two more plant books in mind, and a revision of Fertilisation of Orchids to work on. He also began an autobiographical work intended for his family's eyes only.[10] After turning away a request to support a controversial book on contraception (Fruits of Philosophy) – Darwin was opposed to it – he got back to work on flowers and worms. As with much of his geological and evolutionary work, worms were a case of gradual, barely noticeable changes accumulating over time into large effects. He even went on a two-hour excursion to Stonehenge to see how its monoliths had been buried by earthworm castings.[11]
A photograph of Darwin around the time the book was published.
He was occupied by worms at Downe in 1880, his work coming first. He had help from the family, even receiving soil samples from Abinger's Roman ruins.[12] He told Vladimir Kovalevsky (his Russian translator) of slow progress with his new book.[13]
Darwin calculated that there were 53,767 earthworms recycling away per acre. He carried out experiments indoors, where they worked the earth inside pots in a worm-littered room. He experimented with stimuli at night: strong light would send them into their burrows ("like a rabbit" said Darwin's grandson Bernard), but heat and sound had no effect. Their food preferences were also tested, raw carrots being their favourite.[14]
Earthworms mate in daylight, but are generally nocturnal above ground.
Darwin was fascinated by their behaviour, from enjoying "the pleasure of eating" (based on their eagerness for certain foods) to their sexual passions, "strong enough to overcome... their dread of light", even to their social feelings ("crawling over each other's bodies").[15] Their foraging was especially intriguing: they dragged leaves into their burrows, pulling them in the most efficient way, by their pointed end. On these semi-intelligent creatures Darwin wrote that they obtained a "notion, however rude, of the shape of an object", perhaps by feeling it out. Worms, "five or six feet" below the ground ploughed farmers fields. Darwin felt we "ought to be grateful" to these little recyclers, which he compared to "a man... born blind and deaf". He was wondering how long it would be until he would be consumed by worms himself[citation needed]. It would surely be his last major work; he told German translator Victor Carus "I have little strength & feel very old".[14]
By 1881 he was unable to summon the strength for revisions and handed Worms on to Frank. His health gave him troubles; he complained to his long-time friend Hooker that he looked forward to "Down graveyard as the sweetest place on earth."[16] Concerned about the book he had been anticipating for decades, he hurried his publisher John Murray to hasten publication of Worms even at the risk of not making a profit.[17]
At a dinner with Edward Aveling (soon the son-in-law of Karl Marx) and other atheists, he was asked how he had turned to such an "insignificant" subject as worms, to which he replied "I have been studying their habits for forty years." As with his religious views, the old naturalist did not see things the same way as Aveling. In Darwin's view, the "insignificant" was the foundation of much greater phenomena.[18]
Summary
A casting from the Nilgiri Mountains in South India
Worms are found in many places, from the forest floor to mountains, and in many locations around the world. Though they are considered terrestrial animals, they are really semi-aquatic, like other annelids; they die quickly in air but survive for months in water. Though inactive during the day, they sometimes come out of their burrows at night. They are eaten by thrushes and other birds in large numbers because they lie close to the surface. They have well-developed muscular, nervous, circulatory and digestive systems, the latter being quite unique. Though eyeless, they respond to the intensity and duration of light. They also slowly respond to temperature. They have no hearing, but are sensitive to vibrations. Their sense of smell is feeble, but they are able to find their preferred foods. Omnivorous animals, they swallow much earth and extract food from it. Worms live chiefly on half decayed leaves, partially digested by a pancreatic solution before ingestion. This extra-stomachal digestion is not unlike that which Darwin had previously described as occurring in Insectivorous Plants. The structure and physiology of the calciferous glands of earthworms are described. Many hypotheses had been advanced for their function; Darwin believed them to be primarily for excretion and secondarily a digestion aid.
Thin leaves are seized with the mouth, while thick ones are dragged by creating a vacuum. Leaves and stones are used to plug up the burrow. This may deter predators, keep out water and/or keep out chilled air (the latter is Darwin's preferred function). Leaves are dragged in mostly by the tips, which is the easiest way of doing it, but when the base is narrower the worms change behaviour. They drag pine needle clusters in by the base. Petioles are used to plug up burrows, and for food. Worms drag experimental triangles of paper by the apex most of the time, and do not rely on trial and error. Worms excavate burrows by consuming material or, preferably, pushing it away. They mainly consume soil for nutrients. They are found down to six or more feet, especially in extreme conditions. Burrows are lined, which serve several functions, and terminate in a chamber lined with stones or seeds. Worms are found all over the planet, some on isolated islands; how they got there is a mystery. Darwin draws on correspondence with people from around the world such as Fritz Müller in Brazil.
Figure from the book showing a sunken stone from Stonehenge
The amount of earth brought to the surface by worms can be estimated by the rate at which objects on the surface are buried and by weighing the earth brought up in a given time. Information from farmers on marl, cinders etc. sinking into the ground allowed Darwin to make calculations. He conducted a 29-year experiment on chalk at a field near his house. Objects of all sorts "work themselves downards" as farmers say. Large stones sink because worms fill up any hollows with castings, then eject them beyond the perimeter and the ground around them starts to rise. He visited Stonehenge and found some outer stones partly buried, the turf sloping up to meet them (see figure 7). Darwin weighed castings and had friends do so in other countries. He also weighed castings per unit area per year, then worked out how thick a layer castings would make, compared with rates of sinking. Additionally, he worked out casting weight per worm per year.
Darwin's experiments included measuring the speed with which stones slowly settle into the earth.
Worms have preserved many ancient objects under the ground. Darwin describes an ancient Roman villa in Abinger, Surrey. Worms have penetrated the concrete walls and even mortar. Similar subsidence occurred at Beaulieu Abbey, Hampshire, with worms penetrating gaps between the tiles. His sons Francis and Horace visited Chedworth Roman Villa in Gloucestershire, while William reported on Brading Roman Villa, Isle of Wight. Darwin goes into some detail on the well preserved ruins of Silchester Roman Town, Hampshire, with the help of the Rev. J. G. Joyce. Finally he discusses the case of the Viroconium Roman town ruins at Wroxeter, Shropshire, with the help of Dr. H. Johnson, who made observations including depth of vegetable mould. He concludes that both worms and other causes, such as dust deposition and washing down of soil, have buried such ruins.
Denudation (removal of matter to a lower level) is caused mainly by air and water movement. Humic acids generated by worms disintegrate rock; their burrowing behaviour speeds this up. But as the soil layer thickens, this process is slowed down. Worms swallow hard objects (e.g. stones) to aid digestion, which causes attrition to such objects. This has geological significance, especially for the smaller particles which otherwise are eroded very slowly.
Rain causes castings to move down an incline; Darwin worked out the weight moving a certain distance in a given time. Some also roll down, and collect in drains etc., or get blown. There is a greater effect on casting movement in the tropics, because of increased rain. The finest earth is washed away. Ledges on hillsides, formerly believed to be caused by grazing mammals, are partly due to casting accumulations. High winds, especially gales, are almost as effective as the slope/rain in moving castings. Crowns and furrows of formerly ploughed lands slowly vanish when under pasture, due to worms, but more slowly when there is no incline. Fine earth is washed down from slopes, making a shallow layer. Dissolving of chalk supplies new earth.
Darwin writes in the conclusion that worms "have played a more important part in the history of the world than most persons would at first suppose."[19] They are important for many reasons, including their role in decomposition of rocks, gradual denudation of the land, preservation of archaeological remains, and improving soil conditions for plant growth. Despite their rudimentary sense organs, they show complex, flexible behaviour.
Reception
"Man is but a worm" caricature published in Punch at the end of 1881
Worms became available in October 1881 and sold thousands of copies in its first few weeks, despite Darwin's comment to Carus that it was "a small book of little moment".[15] Darwin received a "laughable" number of letters containing questions, observations and ideas, even "idiotic" ones. A week's holiday with Emma in Cambridge was to follow. Darwin died the next year on 19 April 1882.[20]
On the Origin of Species is a work of scientific literature by Charles Darwin that is considered to be the foundation of evolutionary biology. It was published on 24 November 1859. Darwin's book introduced the scientific theory that populations evolve over the course of generations through a process of natural selection although Lamarckism was also included as a mechanism of lesser importance. The book presented a body of evidence that the diversity of life arose by common descent through a branching pattern of evolution. Darwin included evidence that he had collected on the Beagle expedition in the 1830s and his subsequent findings from research, correspondence, and experimentation.
The Voyage of the Beagle is the title most commonly given to the book written by Charles Darwin and published in 1839 as his Journal and Remarks, bringing him considerable fame and respect. This was the third volume of The Narrative of the Voyages of H.M. Ships Adventure and Beagle, the other volumes of which were written or edited by the commanders of the ships. Journal and Remarks covers Darwin's part in the second survey expedition of the ship HMS Beagle. Due to the popularity of Darwin's account, the publisher reissued it later in 1839 as Darwin's Journal of Researches, and the revised second edition published in 1845 used this title. A republication of the book in 1905 introduced the title The Voyage of the "Beagle", by which it is now best known.
Charles Darwin's views on religion have been the subject of much interest and dispute. His pivotal work in the development of modern biology and evolution theory played a prominent part in debates about religion and science at the time. In the early 20th century, his contributions became a focus of the creation–evolution controversy in the United States.
Following the inception of Charles Darwin's theory of natural selection in 1838, the development of Darwin's theory to explain the "mystery of mysteries" of how new species originated was his "prime hobby" in the background to his main occupation of publishing the scientific results of the Beagle voyage. He was settling into married life, but suffered from bouts of illness and after his first child was born the family moved to rural Down House as a family home away from the pressures of London.
The publication of Darwin's theory brought into the open Charles Darwin's theory of evolution through natural selection, the culmination of more than twenty years of work.
The inception of Darwin's theory occurred during an intensively busy period which began when Charles Darwin returned from the survey voyage of the Beagle, with his reputation as a fossil collector and geologist already established. He was given an allowance from his father to become a gentleman naturalist rather than a clergyman, and his first tasks were to find suitable experts to describe his collections, write out his Journal and Remarks, and present papers on his findings to the Geological Society of London.
Charles Darwin's education gave him a foundation in the doctrine of Creation prevalent throughout the Western world at the time, as well as knowledge of medicine and theology. More significantly, it led to his interest in natural history, which culminated in his taking part in the second voyage of HMS Beagle and the eventual inception of his theory of natural selection. Although Darwin changed his field of interest several times in these formative years, many of his later discoveries and beliefs were foreshadowed by the influences he had as a youth.
Nathaniel Southgate Shaler was an American paleontologist and geologist who wrote extensively on the theological and scientific implications of the theory of evolution, whose work is now considered scientific racism.
Biogeomorphology and ecogeomorphology are the study of interactions between organisms and the development of landforms, and are thus fields of study within geomorphology and ichnology. Organisms affect geomorphic processes in a variety of ways. For example, trees can reduce landslide potential where their roots penetrate to underlying rock, plants and their litter inhibit soil erosion, biochemicals produced by plants accelerate the chemical weathering of bedrock and regolith, and marine animals cause the bioerosion of coral. The study of the interactions between marine biota and coastal landform processes is called coastal biogeomorphology.
The second voyage of HMS Beagle, from 27 December 1831 to 2 October 1836, was the second survey expedition of HMS Beagle, made under her newest commander, Robert FitzRoy. FitzRoy had thought of the advantages of having someone onboard who could investigate geology, and sought a naturalist to accompany them as a supernumerary. At the age of 22, the graduate Charles Darwin hoped to see the tropics before becoming a parson, and accepted the opportunity. He was greatly influenced by reading Charles Lyell's Principles of Geology during the voyage. By the end of the expedition, Darwin had made his name as a geologist and fossil collector, and the publication of his journal gave him wide renown as a writer.
The early concepts of soil were based on ideas developed by a German chemist, Justus von Liebig (1803–1873), and modified and refined by agricultural scientists who worked on samples of soil in laboratories, greenhouses, and on small field plots. The soils were rarely examined below the depth of normal tillage. These chemists held the "balance-sheet" theory of plant nutrition. Soil was considered a more or less static storage bin for plant nutrients—the soils could be used and replaced. This concept still has value when applied within the framework of modern soil science, although a useful understanding of soils goes beyond the removal of nutrients from soil by harvested crops and their return in manure, lime, and fertilizer.
Charles Robert Darwin was an English naturalist, geologist, and biologist, widely known for his contributions to evolutionary biology. His proposition that all species of life have descended from a common ancestor is now generally accepted and considered a fundamental scientific concept. In a joint publication with Alfred Russel Wallace, he introduced his scientific theory that this branching pattern of evolution resulted from a process he called natural selection, in which the struggle for existence has a similar effect to the artificial selection involved in selective breeding. Darwin has been described as one of the most influential figures in human history and was honoured by burial in Westminster Abbey.
This is a list of the writings of Charles Darwin.
William Whitaker was a British geologist.
An earthworm is a soil-dwelling terrestrial invertebrate that belongs to the phylum Annelida. The term is the common name for the largest members of the class Oligochaeta. In classical systems, they were in the order of Opisthopora since the male pores opened posterior to the female pores, although the internal male segments are anterior to the female. Theoretical cladistic studies have placed them in the suborder Lumbricina of the order Haplotaxida, but this may change. Other slang names for earthworms include "dew-worm", "rainworm", "nightcrawler", and "angleworm". Larger terrestrial earthworms are also called megadriles as opposed to the microdriles in the semiaquatic families Tubificidae, Lumbricidae and Enchytraeidae. The megadriles are characterized by a distinct clitellum and a vascular system with true capillaries.
The Structure and Distribution of Coral Reefs, Being the first part of the geology of the voyage of the Beagle, under the command of Capt. Fitzroy, R.N. during the years 1832 to 1836, was published in 1842 as Charles Darwin's first monograph, and set out his theory of the formation of coral reefs and atolls. He conceived of the idea during the voyage of the Beagle while still in South America, before he had seen a coral island, and wrote it out as HMS Beagle crossed the Pacific Ocean, completing his draft by November 1835. At the time there was great scientific interest in the way that coral reefs formed, and Captain Robert FitzRoy's orders from the Admiralty included the investigation of an atoll as an important scientific aim of the voyage. FitzRoy chose to survey the Keeling Islands in the Indian Ocean. The results supported Darwin's theory that the various types of coral reefs and atolls could be explained by uplift and subsidence of vast areas of the Earth's crust under the oceans.
The soil biomantle can be described and defined in several ways. Most simply, the soil biomantle is the organic-rich bioturbated upper part of the soil, including the topsoil where most biota live, reproduce, die, and become assimilated. The biomantle is thus the upper zone of soil that is predominantly a product of organic activity and the area where bioturbation is a dominant process.
A stonelayer, or soil stonelayer, or stone line, is a three-dimensional subsurface layer, or soil horizon, dominated by coarse particles (>2mm), that generally follows (mimics) the surface topography. A stonelayer occupies the basal horizon of two-layered soil biomantles. A stonelayer may be one stone thick, and thus appear in a trench or pit as a "stone line," or it may be several stones thick and appear as a "stone zone". The gravel components of stonelayers may be compositionally variable, and while many are lithic clasts, often of quartzose composition, others may be metallic nodules and concretions of iron and manganese oxides, human artifacts, snail and clam shells, precious and semi-precious stones, or some combination thereof.
Geological Observations on South America is a book written by the English naturalist Charles Darwin. The book was published in 1846, and is based on his travels during the second voyage of HMS Beagle, commanded by captain Robert FitzRoy. HMS Beagle arrived in South America to map out the coastlines and islands of the region for the British Navy. On the journey, Darwin collected fossils and plants, and recorded the continent's geological features.
Before Charles Darwin and his groundbreaking theory of evolution, primates were mainly used as caricatures of human nature. Although comparisons between man and animal are rather old, it was not until the findings of science that mankind recognised itself as a part of the animal kingdom. Caricatures of Darwin and his evolutionary theory reveal how closely science was intertwined with both the arts and the public during the Victorian era. They display the general perception of Darwin, his "monkey theory" and apes in 19th-century England.
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