Download Charles Darwin Biography

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BIOGRAPHY- Charles Darwin: gentleman naturalist
Standard: 7a, 7d
Objective:


Give students a better understanding of who Charles Darwin was and emphasize the
important his contributions to biology and science in general.
Establish a foundation of teaching evolution by introducing students to Darwin’s life
achievements
Procedure:
Read Darwin’s biography and answer questions (short answer).
Discuss how Charles Darwin’s contributions have changed the way scientists do their work.
A biographical sketch by John van Wyhe
CHARLES Robert Darwin (1809-1882) was born the fifth
of six children into a wealthy Shropshire gentry family in
the small market town of Shrewsbury. His father, the
hugely portly Robert Waring Darwin (1766-1848), was a
successful physician and financier and son of the famous
poet, Erasmus Darwin. Charles Darwin's mother,
Susannah Wedgwood (1765-1817), died when he was
eight years old. Darwin watched over by his elder sisters
and maidservants grew up amidst wealth, comfort and
country sports. He attended the nearby Shrewsbury
School as a boarder from 1818-1825. In October 1825
Darwin went to
Edinburgh
University with his
brother Erasmus to
study medicine with a view to becoming a physician.
While in Edinburgh, Darwin investigated marine
invertebrates with the guidance of Robert Grant. Darwin's
name first appeared in print in one of Grant's articles.
Darwin did not like the study of medicine and could not
bear the sight of blood or suffering and so his father
proposed the church as a respectable alternative. The
advantage to becoming a country parson, as Darwin saw
it, would be the freedom to pursue his growing interest in
natural history. He read several books on Christianity
while making up his mind. Some of these survive here. To
become ordained in the Church of England he must first obtain a B. A. degree from an English
university.
On 15 October 1827 he was admitted a member of Christ's College, Cambridge. However, as he
had forgotten most of the Greek he had learned at school, and advanced Greek was required in
the daily college lectures, Darwin could not come up in October. He studied under a private
tutor at home until he was able to translate Greek with some ease. Therefore he did not come
into residence in Cambridge until 26 January 1828. As all of the College rooms were full, Darwin
first lived in lodgings for Christ's students above W. Bacon, the tobacconist, on Sidney Street
just down the street. (The original building was destroyed in the 1930s but two plaques on the
site of a branch of Boots the chemist mark the location today.) He matriculated, that is signed
the role as a member of the University, at the Senate House on 26 February 1828 (not in
January as maintained by some biographies). Darwin's student bills were recently discovered at
Christ's College and shed new light on his time in Cambridge.
Darwin was never a model student, but he did become a passionate amateur naturalist. He
began avidly collecting beetles along with fellow undergraduates. His name appeared in print
when some of his records of insect captures were published by Stephens in his British
Entomology in 1829. Darwin's first published word was "Cambridge". Darwin became the
devoted follower of Professor of botany John Stevens Henslow (1796-1861). Through their
close friendship Darwin learned a great deal about the practice of natural science. Darwin
passed his B.A. examination in January 1831. As he had not fulfilled the residence requirement
to take a degree, it was not awarded until 26 April 1831. Shortly thereafter he was taught the
rudiments of field geology by Professor Adam Sedgwick during a tour of north Wales.
Henslow was able to pass on to Darwin the offer of Commander Robert FitzRoy of travelling on
a survey ship, HMS Beagle, as a "scientific person" or
naturalist. The round-the-world journey lasted five
years. Darwin spent most of these years investigating
the geology and zoology of the lands he visited,
especially South America, the Galapagos islands, and
Pacific oceanic islands. He recorded many of his
specimens and observations immediately in field
notebooks. His telegraphic pocket notes were later
used in writing up more formal notes, such as his
animal notes. Later he recorded his experiences in a
diary which became the basis of his famous book
Journal of researches (1839) now known as Voyage of
the Beagle. (This latter title was first used on the title page of a 1905 edition.)
Darwin was particularly influenced by the works of men of science like astronomer Sir John
Herschel, traveller Alexander von Humboldt and geologist Charles Lyell. Lyell's new book,
Principles of Geology (1830-3), profoundly influenced Darwin. Lyell offered not just a new
geology but a new way of understanding nature. Lyell showed how tiny, slow, gradual and
cumulative change over immense periods of time could produce large changes. Natural, visible,
non-miraculous causes should be sought to explain natural phenomenon. Darwin had the
opportunity to witness all of these forces, such as erosion, earthquakes and volcanoes, during
the Beagle voyage and he became convinced that Lyell's views were correct. Darwin made
several very important discoveries about the geology of South America, volcanic islands and the
origins of coral reefs by building on Lyell's ideas. Darwin later wrote in the 2nd edition of his
Journal of researches:
“Where on the face of the earth can we find a spot, on which close investigation
will not discover signs of that endless cycle of change, to which this earth has been, is,
and will be subjected?”
Darwin also collected organisms of all sorts which he recorded in his specimen lists and zoology
notes. These formed the basis of the five volume series he edited and superintended after
returning home The zoology of the voyage of H.M.S. Beagle (1838-43).
Geological sections from Darwin's Geological observations on South America.
Darwin also unearthed many fossil creatures in South America. He wondered why the fossils
resembled the present inhabitants of that continent more than any other species. Where had
the new species come from? In fact, why was the world covered with so many different kinds of
living things? Why were some very similar to one another and others vastly different? If species
were somehow created to fit their environments, as was then believed, why were jungle
species different in Asia, Africa and South America despite the similarity of
climate?
Darwin did not conceive of a solution during the Beagle voyage, but rather a
few years later in London, while writing books on his travels and studying the
specimens he had collected. Experts in London, such as the ornithologist
John Gould, were able to tell him how many of the specimens of plants and
animals he had collected in the Galapagos Islands unique species, found
nowhere else were. Clearly they resembled species from South America 600 miles away. It
seemed to Darwin as if stray migrants from South America had come to the Galapagos, after
the islands rose from the sea as volcanoes, and then changed over time in isolation on the
islands.
Darwin began to speculate on how new species could arise by natural observable causes. His
idiosyncratic eclecticism led him to investigate some unconventional
evidence. He made countless inquiries of animal breeders, both farmers
and hobbyists like pigeon fanciers, trying to understand how they made
distinct breeds of plants and animals. Gradually Darwin concluded that
organisms were infinitely variable, and that the supposed limits or
barriers to species were a belief without foundation. In modern terms
we would say that Darwin came to accept that life evolves. One
conventional view of the time was that species had been created where
they are now found, in accordance with the environment. Few men of
science then held to the view that there had been only a single species
creation event. The fossil evidence seemed to show very many creations
had occurred in different geological eras.
Darwin then sought to explain how living forms changed over time. He was familiar with the
evolutionary speculations proposed earlier by his grandfather Erasmus Darwin and by the great
French zoologist Jean-Baptiste Lamarck. But already Darwin's theorizing had extended in novel
directions. He was thinking of the history of life not as a number of independent lineages
somehow impelled to progress upwards from monads to monkeys. Instead Darwin saw all life
as a single genealogical tree, branching and re-branching. Thus similarities between different
kinds of living things would be expected from their joint ancestry or common descent. Darwin's
speculations and early theorizing were recorded in a series of notebooks similar to those he
kept during the Beagle voyage.
In September 1838 Darwin read Thomas Malthus's Essay on the Principle of Population (1798).
As Janet Browne has written, Darwin was 'clearly following up lines of inquiry relating to
individual variation, averages, and chance, as well as seeking information on human population
statistics.' (Browne 1995, p. 385) Malthus argued that human
population growth, unless somehow checked, would necessarily
outstrip food production. Population growth was geometrical. For
example, two parents might have four children, each of whom
could have four children, whose children could also have four
children. Thus in four generations there would be an increase
from 2 to 4 to 24 to 96 and so forth.
The focus of this argument inspired Darwin. He realized that an
enormous proportion of living things are always destroyed before
they can reproduce. This must be true because every species
would otherwise breed enough to fill the earth in a few hundred
generations. Instead populations remain roughly stable year after
year. The only way this can be so is that most offspring (from
pollen, to seeds and eggs) do not survive long enough to
reproduce.
Darwin, already concentrating on how new varieties of life might
be formed, suddenly realized that the key was whatever made a
difference between those that survive to reproduce and those that do not. He came to call this
open-ended collection of causes 'natural selection' because it was analogous to breeders
choosing which individuals to breed from and thus changing a breed markedly over time.
As Darwin wrote in his Autobiography in 1876:
'In October 1838, that is, fifteen months after I had begun my systematic enquiry, I
happened to read for amusement Malthus on Population, and being well prepared to appreciate
the struggle for existence which everywhere goes on from long-continued observation of the
habits of animals and plants, it at once struck me that under these circumstances favourable
variations would tend to be preserved, and unfavourable ones to be destroyed. The result of this
would be the formation of new species. Here, then, I had at last got a theory by which to work'.
Below is the famous passage from Darwin's notebook where these ideas were first
recorded:
[Sept] 28th.[1838] Even the energetic language of <Malthus> «Decandoelle» does not convey
the warring of the species as inference from Malthus.— «increase of brutes, must be prevented
soley by positive checks, excepting that famine may stop desire.—» in Nature production does
not increase, whilst no checks prevail, but the positive check of famine & consequently death..
...—The final cause of all this wedging, must be to sort out proper structure, and adapt it to
change.—to do that for form, which Malthus shows is the final effect by means however of
volition of this populousness on the energy of man. One may say there is a force like a hundred
thousand wedges trying [to] force every kind of adapted structure into the gaps in the economy
of nature, or rather forming gaps by thrusting out weaker ones. [Notebook D 134e-135e]
Or, as Darwin later put it in the Origin of Species (1859):
As many more individuals of each species are born than can possibly survive; and as,
consequently, there is a frequently recurring struggle for existence, it follows that any being, if it
vary however slightly in any manner profitable to itself, under the complex and sometimes
varying conditions of life, will have a better chance of surviving, and thus be naturally selected.
From the strong principle of inheritance, any selected variety will tend to propagate its new and
modified form.
Therefore only the survivors would pass on their form and abilities. Their characteristics would
persist and multiply whilst characteristics of those that did not live long enough to reproduce
would decrease. Darwin did not know precisely how inheritance worked—genes and DNA were
totally unknown. Nevertheless he appreciated the crucial fact of inheritance. Offspring resemble
their parents. Darwin thought in terms of populations of diverse heritable things with no
essence—not representatives of ideal types as many earlier thinkers had done. From his
observations and experiments with domesticated and wild plants and animals he could find no
limits to the extent organic forms could vary and change through generations. Thus the existing
species in the world were related not along a 'chain of being' or separated into artificially
separate species categories but were all related on a genealogical family tree through 'descent
with modification'.
As Darwin wrote in the Origin of Species (1859):
“Why should the species which are supposed to have been created in the Galapagos
Archipelago, and nowhere else, bear so plain a stamp of affinity to those created in America?
There is nothing in the conditions of life, in the geological nature of the islands, in their height or
climate, or in the proportions in which the several classes are associated together, which
resembles closely the conditions of the South American coast: in fact there is a considerable
dissimilarity in all these respects. On the other hand, there is a considerable degree of
resemblance in the volcanic nature of the soil, in climate, height, and size of the islands,
between the Galapagos and Cape de Verde Archipelagos: but what an entire and absolute
difference in their inhabitants! The inhabitants of the Cape de Verde Islands are related to those
of Africa, like those of the Galapagos to America. I believe this grand fact can receive no sort of
explanation on the ordinary view of independent creation; whereas on the view here
maintained, it is obvious that the Galapagos Islands would be likely to receive colonists, whether
by occasional means of transport or by formerly continuous land, from America; and the Cape
de Verde Islands from Africa; and that such colonists would be liable to modification;—the
principle of inheritance still betraying their original birthplace.”
Darwin also identified another means by which some individuals would
have descendants and others would not. He later called this sexual
selection. This theory explained why the male sexes in many species
produce colorful displays or specialized body parts to attract females or to
compete against other males. Those males who defeat other males, or are
selected for breeding by females leave more offspring and so subsequent
generations resemble them more than those who succeed less often. As
Darwin pointed out, "A hornless stag or spurless cock would have a poor
chance of leaving offspring." (Origin p. 88)
Darwin, deeply studied in the sciences of his time, yet living somewhat
independently from his colleagues, was able to think in new ways and to
conceive of worlds quite unimaginable to his more orthodox friends. However, the legend of
Darwin as a lone genius discovering evolution on the Galapagos Islands is now known by
historians to be a groundless myth.
It is now clear that Darwin did not keep his ideas about species changing secret; he discussed
them with many friends, family and colleagues during succeeding years. But his full-time
occupation before and long after he became an evolutionist was the publication of his
recollections and scientific work resulting from the Beagle voyage.
Darwin in 1840. Watercolour by George Richmond. Reproduced courtesy of the Darwin
Heirlooms Trust.
He married his cousin Emma Wedgwood (1808-1896) in 1839. Darwin's many acute and
innovative books and articles forged a great reputation as a geologist, zoologist and scientific
traveller. His eight years grueling work on barnacles, published 1851-4 enhanced his reputation
as an authority on taxonomy as well as geology and the distribution of flora and fauna as in his
earlier works. Nevertheless there is no reason to allege, as is so often done, that Darwin needed
to supplement his reputation or skills before he could publish his species theory. Marine
invertebrates had been of central interest for Darwin since his student days in Edinburgh.
During the Beagle voyage a large percentage of his notes were devoted to them, and he did not
give this class of organisms to another expert to identify but kept them for himself.
Darwin conducted breeding experiments with animals and plants and
corresponded and read widely for many years to refine and
substantiate his theory of evolution. In 1842 he prepared an essay
outlining his theory. This was greatly expanded in another essay
written in 1844. After completing his work on barnacles Darwin
immediately turned to his theory to explain species. He was more than
half way through a great work on the subject when he was interrupted
in 1858 by a letter from an English naturalist and collector, Alfred
Russel Wallace (1823-1913) ( see picture left). Wallace was then
collecting in South East Asia. In an essay enclosed Wallace described his
ideas 'On the Tendency of Varieties to Depart Indefinitely From the
Original Type'. Darwin was struck by the similarity to his concept of
Natural Selection. He sent the letter on to Lyell and it was decided, together with Darwin's
friend J. D. Hooker, to avoid competition for priority, to publicize abstracts by both men as soon
as possible. The papers were read, in the absence of Darwin and Wallace, at a meeting of the
Linnaean Society of London on 1 July 1858 and later published in their Proceedings. Darwin was
urged by friends to publish an 'abstract' or overview of his work-in-progress on natural
selection. This abstract became one of the most famous books ever written: On the Origin of
Species (1859).
Although Darwin convinced most of the scientific community within 15-20 years that descent
with modification, or evolution, was true, many rejected natural selection as the primary
mechanism. Darwin was not the first to propose that species can change. A glance at his 'An
historical sketch of the progress of opinion on the origin of species' shows that Darwin made no
pretense to have originated or discovered evolution. However, Darwin's understanding of
branching descent was more accurate, refined and convincing than his predecessors who
considered, for example, that the members of one genus might be commonly derived. We
know that a wide popular literature such as George Combe's Constitution of Man (1828) and
the anonymous Vestiges of the Natural History of Creation (1844) had already shocked and
converted vast popular audiences to belief in the power of natural laws to control the
development of nature and society. Historians of science now believe that Darwin's effect was,
as James Secord put it, a 'palace coup' amongst elite men of science rather than a revolution.
Indeed recent research suggests that the reaction to Darwin's Origin was less of a furore than
once believed. (Fleming & Goodall 2002) Nevertheless to the end of his life Darwin was
regarded as a great scientific revolutionary who had overturned the ideas of his generation.
Darwin, as an unquestionably respectable authority in elite science, publicly threw his weight
on the side of evolution, and soon young allies like Hooker, T. H. Huxley, and John Tyndall
publicly threw their own weight towards the same position. Darwin's name is so linked with
evolution because his works convinced the international scientific community that evolution
was true. In the two decades after the publication of Origin the great majority of the scientific
community came to accept that Darwin was right about the evolution of life. But natural
selection was often not accepted. In fact, a generation of biologists regarded Darwin as correct
in uncovering the evolution of life but mistaken in stressing natural selection. Natural
selection's canonisation had to wait until the modern synthesis of Darwinism with Mendelian
genetics in the 1930s.
Like Combe, Charles Babbage, Robert Chambers, Herbert Spencer and countless other authors
before him, Darwin represented his doctrine as furthering the domain of natural laws. We see
this in the following epigraph Darwin used for the Origin of Species:
" But with regard to the material world, we can at least go so
far as this-we can perceive that events are brought about not by
insulated interpositions of Divine power, exerted in each particular case, but by the
establishment of general laws."
Darwin even saw the power of his law of natural
selection extending beyond life to what we would
call psychology, linguistics and to society and
history (see for example Descent of Man, 1871,
chapter 3).
The Origin of Species
In the Origin of Species Darwin first tried to
convince his readers that organisms are
malleable and not fixed natural kinds. He
demonstrated that domesticated plants and
animals were known to be highly variable and to
have changed so much as to be classified as
different species if they were not already
familiar.
He then showed that the existence and
abundance of organisms was dependent on many
factors, which tended to hold their numbers in
check such as climate, food, predation, available space etc.
Only then did Darwin set about showing the effects of differential death and survival on
reproduction and the persistence and diversification of forms—natural selection. In other
words Darwin's theory of evolution has three main elements or requirements: variation,
selection and heredity. If all individual life forms are unique, which no one denied, and these
differences could make a difference to which organisms lived to reproduce and which did not,
then, if these differences could be inherited by offspring, subsequent generations would be
descended from those which were lucky enough to survive.
An illustrative example is seen in the recent work of biologists in the Galapagos Islands. During
a drought season when no new seeds were produced for an island's finches to eat, the birds
were forced to hunt for remaining seeds on the ground. Soon all the visible seeds had been
devoured. It so happened that those with slightly thicker beaks than average could turn over
stones a little bit better than the rest to find the remaining seeds and so the birds which
survived the famine tended to be thicker beaked. When the drought ended and the birds again
had young, this new generation had slightly thicker beaks. This is an example of Darwinian
evolution observed and measured in the field. (See Weiner. 1994. Beak of the Finch.)
Darwin's theory of genealogical evolution (as opposed to earlier theories by Lamarck or
Vestiges which entailed independent lineages unfolding sequentially because of an innate
tendency towards progress) made sense of a host of diverse kinds of evidence such as the
succession of fossil forms in the geological record, geographical distribution of life
(biogeography), recapitulative appearances in embryology, homologies like the hand of a man
and the wing of a bat, vestigial organs, nesting taxonomic relationships observed throughout
the world and so forth.
The famous last paragraph of the Origin of Species is a concise and eloquent précis of Darwin's
vision:
“It is interesting to contemplate an entangled bank, clothed with many plants of many kinds,
with birds singing on the bushes, with various insects flitting about, and with worms crawling
through the damp earth, and to reflect that these elaborately constructed forms, so different
from each other, and dependent on each other in so complex a manner, have all been produced
by laws acting around us. These laws, taken in the largest sense, being Growth with
Reproduction; Inheritance which is almost implied by reproduction; Variability from the indirect
and direct action of the external conditions of life, and from use and disuse; a Ratio of Increase
so high as to lead to a Struggle for Life, and as a consequence to Natural Selection, entailing
Divergence of Character and the Extinction of less-improved forms. Thus, from the war of
nature, from famine and death, the most exalted object which we are capable of conceiving,
namely, the production of the higher animals, directly follows. There is grandeur in this view of
life, with its several powers, having been originally breathed into a few forms or into one; and
that, whilst this planet has gone cycling on according to the fixed law of gravity, from so simple
a beginning endless forms most beautiful and most wonderful have been, and are being,
evolved.”
Modern readers often misunderstand the meaning of the title of Darwin's book. They take the
origin of species to mean the origin of life. Then it is pointed out that Darwin 'failed' to throw
light on the origin of life. Others seem to think that his book is called The origin of THE species
i.e. aimed at human beings. But this was not Darwin's aim. Darwin argued that species—that is
the different kinds of organisms in the world —come not from multiple unique creation events
on each island or particular place—but instead that species are the modified descendants of
earlier forms. Darwin demonstrated that the origination of species could be entirely explained
by descent with modification and that a host of facts were inconsistent with the belief in
spontaneous creations according to environmental circumstances or divine interventions.
The reactions to Darwin's evolutionary theories were varied and pronounced. In zoology,
taxonomy, botany, paleontology, philosophy, anthropology, psychology, literature and religion
Darwin's work engendered profound reactions—many of which are still ongoing. Most
disturbing of all, however, were the implications for the cherished uniqueness of man. Although
Darwin refrained from discussing the derivation of any particular species, including man, in the
Origin except for his famous sentence: 'Much light will be thrown on the origin of man and his
history' many people who read the book could think only about what this genealogical view of
life meant for human beings. This is a subject Darwin later took up in The Descent of Man
(1871) and The Expression of the Emotions in Man and Animals (1872). In these brilliantly
original and seminal works Darwin showed that there is no difference of kind between man and
other animals, but only of degree. Rather than an unbridgeable gulf, Darwin showed there is a
gradation of change not only between man and other animals, but between all organic forms
which is a consequence of the gradual change continuously and cumulatively operating over
time.
Darwin's extraordinary achievements are not restricted to his early scientific works and his
evolutionary works. His keen observation, imagination, curiosity and determination allowed
him to make strikingly prescient contributions to ecology, botany and a dozen of what would
later be distinct disciplines. Darwin was very impressed by the inter-relatedness of different
species, climate and environment. He stressed that the life in any area was the outcome of an
amazing history of struggle or 'great battle for life'. He proposed new solutions to how
organisms spread across the globe. His numerous discoveries and theories are too numerous to
list here. Only by reading his works themselves can one gain an
accurate sense of Darwin's achievements.
His final book, The formation of vegetable mould through the action of
worms (1881), was published the year before his death. In it Darwin
made another important contribution, and, characteristically,
revealed the amazing complexity and importance of a natural
process of gradual accumulation, which no one seemed to have grasped before, and that
had all along been under our feet.
A myth about Darwin still circulates today—that he repented of evolutionism or converted
to Christianity on his deathbed. These stories are usually told by those who would like
them to be true, but they are not. There are no mysteries surrounding Darwin's death; his
relatives present at the time wrote detailed accounts of his last hours. The history of the
legend, however, is revealed in James Moore, The Darwin legend (1994). For most of his life
Darwin was not an atheist, but a deist; that is he believed that a creator had designed the
universe and set up natural laws according to which all of nature was unwaveringly
governed. It was the pursuit of a man of science to discover the laws by which nature
operated. He discussed his religious views in his autobiography (these appear, however,
only in the 1958 edition by Nora Barlow with original omissions restored.)
Darwin's new study at Down House, engraved shortly after his death by Axel Haig.
Charles Darwin was a kind, good-humored, pleasant man, unassuming and profoundly
modest. He suffered from ill health much of his adult life. We will probably never know the
causes for his illness. He nevertheless remained driven to understand nature and to remain
part of the elite scientific world he respected and admired. Darwin died in April 1882 and is
buried in Westminster Abbey.
After his death Darwin's private papers were mostly preserved and many of these were
later deposited in Cambridge University Library
In 1909 over 400 scientists and dignitaries from 167 different countries gathered at
Cambridge to celebrate the centenary of Darwin's birth and the fiftieth anniversary of the
publication of On the Origin of Species. The event was an unprecedented success - never
before had such a celebration been held, not for an institution or a nation - but for an
individual scientist. In the year 2000, we witnessed another unprecedented celebration of
an extraordinary man.
Questions to answer
1. Describe Darwin’s family life and his schooling experience with school. Was he a model student?
Where did he attend college? What did he study? What was his reaction to medical school?
2. What professor made biggest impact on Darwin while at Cambridge? How did his influence affect
Darwin after graduating from Cambridge?
3. Darwin was influenced by several scientists, but especially by Charles Lyell. How did Lyell’s work
change the way Darwin viewed the world?
4. What does Darwin think about fossils?
5. What influenced did breeders have on Darwin’s understanding of how traits are passed on? What
conclusion did he come to?
6. Explain the key idea that Darwin gains by reading Thomas Malthus. How does this lead to his
formation of the process of natural selection?
7. Summarize Darwin’s concept of sexual selection. How are the roles of males different from females?
8. How did Alfred Wallace’s work affect Darwin’s writing of book?
9. What effect did the publishing of The Origin of Species by Means of Natural Selection have on the
scientific community?
10. Darwin did not set out on his voyage on the Beagle with solving the mystery of evolution. What
observations did he make along the way lead to the formation of the process of natural selection?
11. Previous to Darwin, how was the origin of life explained? After the publication of Origin, how was
the origin of life explained?