Charles Robert Darwin’s scientific achievement can be equaled
by very few -- either for breadth or depth. Biology came of age
as a science when Darwin published “On the Origin of Species”.
Darwin’s writing is remarkably clear and persuasive. His style
of writing has a charm seldom encountered in scientific works. As
Nicolaus Copernicus showed that the Earth has no privileged position
in the universe, Darwin convincingly proved that human’s ancestry
is no different from the other animals. Darwin was ridiculed for
his theory. Even Darwin himself towards the later part of his life
was not very convinced of his theory. But today his theory is regarded
as the cornerstone of modern biology. And as Julian Huxley said
that Darwin’s idea “is the most powerful and most comprehensive
idea that has ever arisen on earth. It helps us understand our origins…We
are part of a total process, made of the same matter and operating
by the same energy as the rest of the cosmos, maintaining and reproducing
by the same type of mechanism on the rest of life.
Charles Darwin was born on February 12, 1809 at
Shrewsbury, Shropshire, England. He was the fifth child of Dr. Robert
Waring Darwin, (the son of physician scientist Erasmus Darwin) and
his wife Susannah, the daughter of the pottery magnate Josiah Wedgwood.
Darwin’s mother died in July 1817 when he was eight years
of age and he was brought up by his sister, Caroline.
Darwin was enrolled in Dr. Butler’s Shrewsbury
School in 1818 at the age of nine. Darwin did not enjoy learning
at school. For him, studies at his Shrewsbury School were a complete
bore. Commenting on his school education Darwin wrote : “The
school as a means of education to me was simply a blank. I learned
absolutely nothing except by amusing myself reading and experimenting
with chemistry”. However, he had an intense curiosity about
natural world. Since his childhood he developed a thirst for discovery
and adventure. He liked to collect unusual objects both living and
non-living. Luckily for Darwin his home was surrounded by woods
and wildlife. The River Severn flowed right by The Mount, his family
home. There were always things to discover, places to explore. He
took interest in the birds, fish and frogs found in the surrounding
areas. He had a great fascination for collecting beetles, the rarer
the species the better. At the age of 13, he had even described,
in a scientific journal, a new species he had captured in the neighborhood.
In his autobiography he describes a particular beetle hunt in detail
: “I will give a proof of my zeal : one day on tearing off
some old bark, I saw two rare beetles and seized one in each hand
; then I saw a third and new kind, which I could not bear to lose,
so that I popped the one which I held in my right hand into my mouth.
Alas it ejected some intensely acrid fluid, which burnt my tongue
so that I was forced to spit the beetle out, which was lost, as
well as the third one.”
Darwin’s father once said to him “you
care for nothing but shooting dogs, and rat-catching, and you will
be a disgrace to yourself and all of your family.’ But Darwin
commented, “…my father, who was the kindest man I ever
knew and whose memory I love with all my heart, must have been angry
and somewhat unjust when he used such words”.
Darwin was influenced by his grandfather Erasmus
Darwin (1731-1802), who was professionally a physician but he also
established himself as a philosopher, naturalist and poet. Erasmus’
books Zoonomia : or the Laws of Organic Life and The Botanic Garden
or Lovers of the Plants were famous. Erasmus had even offered a
theory of evolution. He helped found the Lunar Society. Its members
called “Lunatics”, met only during full moons, so that
they find their way home in their horse-drawn carriages by bright
moonlight. Among its members were inventor James Watt (1736-1819),
the industrialist Matthew Boulton (1728-1809), the chemist Joseph
Priestly (1733-1804) and potter Josiah Wedgwood (1730-95). Among
Darwin’s other heroes were Georges Cuvier (1769-1832), the
great zoologist, Karl von Linne or Carolus Linnaeus (1707-78), who
classified thousands of plants and animals and Alexander von Humboldt
(1769-1859), the explorer who traveled over much of the world making
In his early years Darwin developed interest in
geology, zoology, botany and to a lesser extent in astronomy. Darwin’s
interest in natural science did not mean much to his father because
there were hardly any jobs in natural science. After seeing that
his son was not doing good at school Dr. Robert Darwin sent Charles
to the University of Edinburgh to be trained as a physician. While
studying medicine Darwin continued to pursue his old hobbies –
beetle collection, bird watching and so on. He made friends with
a few other scholars older than himself but having interest in natural
history. Robert Edmond Grant (1793-1874), a Professor of Zoology,
took him on field trips. John Edmonston, a talented taxidermist,
taught him how to mount birds and mammals specimen for collection.
Darwin could not complete his studies in medicine,
and it had to be abruptly terminated. As Darwin did not have the
courage to face his father he took refuge with his maternal uncle
Joshia Wedgwood II at the Wedgwood home called Maer Hall, at Staffordshire
about 30 km from Shrewsbury. His maternal uncle who was very fond
of him took him on tours of Scotland, Ireland, London and Paris
much to the dislike of Darwin’s father.
After seeing Darwin’s failure at becoming
a physician, his father sent him to the Christ’s College,
Cambridge in 1827 to study theology with a view to be ordained as
a clergyman. But here again Darwin could not concentrate in his
studies. Here he became attached with two scholars -- the Reverend
Adam Sedgwick, a geology professor and the Reverend John Henslow,
a botanist. The latter played a major role in shaping Darwin’s
career. Of his Cambridge years, Darwin says, “…my time
was wasted, as far as the academic studies were concerned as completely
as at Edinburg and at school.” According to Darwin the only
things he enjoyed in his studies at Cambridge were geometry, and
the works of William Paley (1743-1805), a distinguished eighteenth
century theologian. Darwin admired his beautiful logic and clear
Darwin returned home from Cambridge in 1831 without
having completed his studies. With Professor Henslow’s encouragement
Darwin had turned to be a promising naturalist and he had developed
a specific interest in learning geology but he had no formal educational
degree. At this stage something unexpected and dramatic appeared
that was to change Darwin’s life and also the course of scientific
discovery forever. It was a letter from Darwin’s favourite
professor Henslow. Henslow was requested to help Robert FitzRoy,
the captain of HMS Beagle to find a naturalist. Henslow himself
wanted to join the expedition but after realizing the fact that
he could not be away from his home, he offered the job to his brother-in-law,
the Reverend Leonard Jenyns, a qualified naturalist. However, he
also could not accept it as he was tied with Church responsibilities.
After this Henslow wrote to Darwin urging him to take up the assignment.
In a letter dated 24 August 1831 Henslow while explaining that the
captain was seeking a young man to serve as ship’s naturalist
not a `mere collector’ but also to be intelligent companion
for the captain. He further wrote : “I consider you to be
the best qualified person I know of who is likely to undertake such
a situation… I state this not in the supposition of your being
a finished naturalist, but as amply qualified for collection, observing
and noting, anything worthy to be noted in Natural History.. Don’t
put on any modest doubts or fears about your qualifications, for
I assure you I think you are the very man they are in search of.”
It may be noted here that though FitzRoy is mostly
remembered as “Darwin’s Captain’, he made his
mark as seaman, explorer, surveyor, mapmaker and meteorologist.
He also became governor of New Zealand. His family name is from
the French fils roy meaning “son of the king”. Robert
FitzRoy graduated from the Royal Naval College at Portsmouth. He
served on several vessels. In 1828, he was given the command HMS
Beagle which had been sent to map the southern coasts of South America,
including Patagonia and Tierra del Fuego. During his first command
of Beagle (1828-1830) FitzRoy became interested in the Indian tribes
of Tierra del Fuego and he brought four young members of the tribe
including a nine-year old girl to England. His idea was to teach
them English, and the plainer truths of Christianity, reading, gardening
and “the use of common tools” and subsequently return
them to their homeland. FitzRoy named the girl Fuegia Basket and
the other three boys were called : York Minster, Boat Memory and
Jemmy Button. One of the tribal youths, called Boat Memory died
soon after reaching England. Among the other three Jemmy Button
and Fuegia Basket made good progress in their learning and attracted
the attention of the Press. After a few months of their stay in
England FitzRoy wanted to take back these tribal youths to their
homeland. The British Admiralty, however, did not show any interest
in financing the project. But FitzRoy was determined to keep his
word. Accordingly he took a year’s leave and arranged the
money for hiring a ship. At this juncture one of his uncles came
in his rescue by persuading the Admiralty to sponsor another surveying
voyage for the Beagle. The British Admiralty commissioned Beagle
for a five-year voyage with the purpose of mapping the coasts of
Patagonia, Tierra del Fuego, Chile and Peru and then continue on
around the globe to survey longitudes. Besides other normal crew
FitzRoy wanted a naturalist preferably a young one to accompany
him. It was a common practice to take a naturalist on a voyage of
this kind. The main purpose of engaging a naturalist was to provide
intelligent and gentlemanly company for the ship’s captain
as British captains were expected to remain aloof from their hired
crews. The post of naturalist was an upaid one.
Darwin was very much interested in taking up the
job but his father was not in its favour. He said that no man of
common sense would approve such a foolish idea. His father thought
that his son was trying to escape the responsibility of preparing
a sensible career. He advised his son to forget about it and return
to Cambridge to complete his studies to be qualified as clergyman.
So young Darwin had no option other than to inform Henslow his inability
to accept the offer. However, Darwin did not give up the hope of
convincing his father. His only hope was that his father had said,
“If you can find any man of common sense who advise you to
go, I will give my consent”. Dawin went to his maternal uncle
Josiah Wedgwood II (or uncle Josh as Darwin called him) to persuade
him to convince Darwin’s father. Josiah Wedgwood II after
listening Darwin carefully explained the risks involved in such
a journey. And after seeing that Darwin was not only aware of the
risks but he was perfectly willing to accept them, Josiah Wedgwood
II decided to take up the matter with Darwin’s father. Darwin
provided him a list of objections raised by his father. Josiah Wedgwood
II wrote a letter answering every objection. In answer to the very
first objection that the voyage would be “disreputable to
(Darwin’s) character as a clergyman” Wedgwood replied,
“The pursuit of Natural History, though certainly not professional,
is very suitable to a clergyman”. Answering Dr. Robert Darwin’s
objection that “it would be a useless undertaking” Wedgwood
replied, “Looking upon Charles as a man of enlarged curiosity
it (the voyage) affords him such an opportunity of seeing men and
things as happens to few”. Darwin attached a separate note
stating that he would accept his father’s decision on the
subject as final and “he would never mention the subject again”.
Instead of waiting for a reply Darwin and Josiah Wedgwood II went
to Shrewsbury to meet Dr. Robert Darwin. Finally Dr. Robert Darwin
consented and agreed to pay all Darwin’s expenses.
The Beagle set sail on December 27, 1831. Darwin
was only twenty two years old. There was no proper accommodation
for Darwin. He had to share a cabin with the captain and there was
virtually no room for keeping his instrument. Darwin wrote in his
Journal: “The absolute want of room is an evil that nothing
can surmount”. Darwin was plagued with sickness throughout
Darwin took four books with him for the journey
– the Bible, a copy of Milton’s work, Alexander von
Humboldt’s account of his exploration of Venezuela and the
Orinoco basin and Volume One of Lyell’s Principle of Geology.
The other two volumes of Lyell’s book was sent to him during
the journey by Henslow. Darwin sent frequent reports on his observations
to Henslow. Many of these reports were read by Henslow at meetings
of the Philosophical Society of Cambridge.
The Beagle visited many lands in the southern
Pacific seas before returning to England in October 1836 via the
Southern Cape of Africa in an effective circumnavigation of the
globe. The ship visited amongst other places the Cape Varde Islands,
Brazil, Argentina and Chile.
After coming back from the voyage Darwin started
working on his “Journal of Researches”, a work based
upon this journal which he had kept during the voyage of the Beagle.
This was published in 1839 and become an immediate’ success.
The success of his first “literary child” always pleased
Darwin more than that of any of his other books.
Following the continued deterioration of his health
Darwin moved to a country residence at Downe, Kent. Darwin lived
a life of a country gentleman of independent means among his gardens,
conservatories, pigeons and fowls. However, he conducted extensive
experiments especially in variation and interbreeding. It was at
Downe that most of his life’s work was done. Because of his
continual health problem Darwin’s activities were mainly confined
to writing books. The books written by Darwin are given at the end
of the article. The first of his major geological works., The structure
and Distribution of Coral Reefs”, was published in 1842. In
this book Darwin presented a theory of the structure and mode of
formation of coral reefs. Darwin’s theory was very different
from the one existed them. However, his keen observation and accurate
thinking made his theory acceptable to most of the geologists. In
fact his theory is even now generally accepted among geologists.
Darwin based on his observation of various facts
of paleontology and biogeography, saw the possibility that species
might not be immutable. But then he had no theory to work upon.
However, he decided to apply the method adopted by Lyell in solving
geological problems. Lyell had attacked geological problems by accumulating
all applicable data in the absence of a working theory, in the hope
that the sheer weight of facts might throw some light upon his problems.
Darwin decided to adopt the same method to the species problem.
Accordingly he started in July 1837 his work on variation in plants
and animals, both under domestication and in nature. Darwin did
not want to overlook any possible source of information. Thus he
looked into personal observations and experiments, published papers
of other biologists, conversations with breeders and gardeners,
correspondence with biologists at home and abroad and so. Based
on the analysis of accumulated facts from various sources Darwin
realized that man’s success in producing useful varieties
of plants and animals depended upon selections of desired variation
for breeding stock. However, Darwin had no clue on how selection
could be applicable to nature.
But then he stumbled upon a theory to work upon.
In October 1838, Darwin happened to read for sheer amusement “Malthus
on Population”. The book written by Thomas Robert Matlhus
(1766-1834) was first published anonymously in 1789. It was titled
An Essay on the Principle of Population. The book was not about
biology. In his book Malthus proposed that human population increase
geometrically (e.g., 2,4,8,16…), while means to support them
increase only arithmetically (e.g.1,2,3,4,5…). Accordingly
natural selective forces such as overcrowding, disease, war, poverty
and vice take over to remove those who are not fit and thus only
the fittest survive. Darwin extended Malthus’s ideas and developed
the idea of natural selection in species, a concept that is often
referred to as “survival of the fittest”. The phrase
“survival of the fittest” is often used synonymously
with natural selection. The phrase is both incomplete and misleading.
The word survival is only one component of selection and perhaps
one of the less important ones in many populations. Aso, the word
`fit’ is often confused with physically fit. Fitness, in an
evolutionary sense, is the average reproductive output of a class
of genetic variation in a gene pool . `Fit’ does not necessarily
mean biggest, fastest or strongest.
The theory of natural selection answers the question
of who made the selection of what is to be evolved. The species
that do survive in the competition for existence will go on to produce
the next generation. The environment an organism lives in helps
to determine which organisms survive and produce young, and which
Commenting on Malthus’s work, Darwin wrote
: “In October 1938, that is fifteen months after I had began
my systematic enquiry, I happened to read for amusement Malthus
on Population, and being well prepared to appreciate the struggle
for existence which 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…”
However, Darwin took four years to write the first
outline of his theory. This is because he had to collect a great
deal of more data. In 1842 Darwin produced a pencil draft of thirty-five
pages. By 1844 Darwin enlarged this draft to 230 pages. Early in
1856 following the advice given by Lyell, Darwin began his work
on a much larger scale with a view to prepare a full account of
his ideas on the origin of species. But while Darwin was half on
its way in completing his work a certain development took place
which forced Darwin for early publication of his work. Alfred Russell
Wallace (1823-1913) sent Darwin a short essay on the “Tendency
of Varieties to Depart Indefinitely from the Original Type”
with a request that if Darwin think it worthy he should forward
it to Lyell for his comments. Darwin liked it very much because
he recognized his own theory in it. Darwin sent Wallace’s
paper to Lyell along with a covering letter. Darwin wrote: “Your
words have come true with a vengeance – that I should be forestalled;
if Wallace had my MS. Sketch written out in 1842, he could not have
made a better short abstract”. At one point Darwin decided
to withhold his own publication in favour of Wallace. However, Lyell
and Joseph Hooker (1817-1911) had for years been familier with Darwin’s
work on the transmutation of species. Lyell had read Darwin’s
outline of 1842. Lyell and Hooker therefore suggested that Darwin
write a short abstract of his theory and that it be published jointly
with Wallace’s paper in the Journal of the Linnean Society.
These papers appeared in that Journal in 1859 together with portion
of a letter which Darwin had written to Asa Gray (1810-88), the
great American botanist, in September 1857, in which Darwin set
forth his views on natural selection and the origin of species.
In his autobiography, Darwin wrote : “Early
in 1856 Lyell advised me to write out my views pretty fully, and
I began at once to do so on a scale three or four times as extensive
as that which afterwards followed by my Origin of Species : yet
it was only a abstract of the materials which I had collected, and
I had got through about half the work on this scale. But my plans
were overthrown far early in the summer of 1858. Mr. Wallace, who
was in the Malaya Archipelago, sent me an eassy “On the tendency
of varieties to depart indefinitely from the original type”
and this eassay (arrived June 18th) contained exactly the same theory
as mine. Mr. Wallace expressed the wish that if I thought well of
this essay, I should send it to Lyell for perusal. The circumstances
under which I consented at the request of Lyell and Hooker to allow
an extract from my own M.S., together with a letter to Asa Gray,
dated September 5, 1857 to be published at the same time with Wallace’s
assay, are given in the Journal of the Linnean Society 1858 p. 45.
I was at first very unwilling to consent, as I thought that Mr.
Wallace might consider my doing so unjustifiable, for I did not
then know how generous and noble was his disposition.”
Following this Lyell and Hooker persuaded Darwin
to prepare for early publication of a book on transmutation of species.
Accordingly, he condensed the manuscript he had begun in 1856 to
about one-third or even one-fourth its original size. The “Origin
of Species” thus produced, was finally published in November
The original title of the manuscript was “An
Abstract of an Essay on the Origin of Species and Varieties through
Natural Selection”. However, his publisher, John Murrey, persuaded
Darwin to reduce this to On the Origin of Species, but Darwin insisted
on keeping the words by means of Natural Selection as a kind of
subtitle. Darwin also included on the title page the words Or the
Preservation of Favoured Races in the Struggle for Life. Every copy
of the original 1, 250-copies printed was sold on the VERY first
day. Commenting on the success of Origin Darwin wrote :
“The success of the `Origin’ may, I
think, be attributed in large part to my having long before written
two condensed sketches, and to my having finally abstracted a much
larger manuscript, which was itself an abstract. By this means I
was enabled to select the more striking facts and conclusions. I
had, also, during many years followed a golden rule, namely that
whenever a published fact, a new observation or thought came across
me, which was opposed to my general results, to make a memorandum
of it without fail at once; for I had found by experience that such
facts and thoughts were far more apt to escape from the memory than
favorable ones, owig to this habit, very few objections were raised
against my views which I had not at least noticed and attempted
Darwin always referred to his Origin of Species
as abstract. He wrote in its introduction: “This Abstract,
which I now publish, most necessarily be imperfect. I cannot have
given reference and authorities for my several statements, and I
must trust to the reader reposing some confidence in my accuracy.
No doubt errors will have crept in though I hope I have always been
cautious in trusting to good authorities alone. I can have given
only the general conclusions at which I have arrived, with a few
facts in illustration, but which, I hope in most cases will suffice.
No one can feel more sensible than I do of the necessity of hereafter
publishing in detail all the facts, with references, on which my
conclusions have been grounded ; and I hope in a future work to
do this. For I am well aware that scarcely a single point is discussed
in this volume on which facts cannot be adduced, after apparently
leading to conclusions directly opposite to those at which I have
arrived. A fair result can be obtained only by fully stating and
balancing the facts and arguments on both sides of each question;
and this cannot possibly be here done.”
Darwin is mostly known for his hypothesizing the
pattern of common descent and proposing a mechanism for evolution
-- natural selection. Darwin’s theory of evolution is no longer
just a theory -- an overwhelming amount of evidence has accumulated
since Darwin. This it may be said that Darwin discovered a law as
Copernicus, Galileo and Newton discovered laws -- natural laws.
According to Darwin’s law life has come into being and exists
and is depended on the process of natural selection. In Darwin’s
theory of natural selection, new variants arrives continually with
in population. Some of the variation may be neutral, but others
help or hinder the organism in its struggle for survival. What Darwin
did not know was the mode of inheritance.
Today we know that the true mode of inheritance
was discovered by Gregor Mendel through his experiments on hybrid
peas. In fact Mendel mailed his paper to Darwin, but Darwin never
The idea of evolution was not new to Darwin. Francis
Bacon (1561-1626) in his book Novum organum (1620) noted the way
in which species vary naturally from one generation to the next.
Bacon observed that such natural variation could be used by the
breeders of plants and animals to produce “many rare and unusual
results:” Gottfried Wilhelm Leibniz (1646-1716), the German
mathematician, speculated that species had changed because of difference
in environmental conditions. Leibniz’s observation was based
on his studies of fossils and the possible relationship between
the extinct ammonites and living species such as the nautilus. The
term evolution was first used in its modern biological context in
1826 by Robert Jameson. In the eighteenth century Georges Louis
Lecrec, Comte de Buffon (1707-88) suggested that the North American
bison might be descended from an ancestral variety of ox that had
migrated there. Darwin’s grandfather Erasmus Darwin was convinced
about the importance of evolution. However, Erasmus mistakenly though,
that individual members of a species developed different characteristics
during their, lifetime. And once acquired these advanced characteristics
are passed on to their offsprings.
Jean-Baptiste Lamarck (1744-1829) proposed a theory
of evolution in 1809. He believed that species arose continually
from nonliving sources. These species were initially very primitive,
but increased in complexity over time due to some inherent tendency.
Such type of evolution is called orthogenesis. Further Lamarck proposed
that an organism’s acclimation to environment could be passed
on to its offspring. For example Lamarck thought proto-giraffes
stretched their necks to reach higher twigs and which caused their
offspring to be born with longer necks. This is known as the inheritance
of acquired characteristics. Lamarck also believed that species
never went extinct, although they may change into newer forms. Lamarck’s
ideas have been proved to be wrong. The observations made by a number
of scientists implicitly included the concept of evolution and also
the notion that species have evolved to fit their environments --
adaptation. Darwin offered an explanation of how evolution works
– that is natural selection.
Darwin’s theory of evolution made him many
enemies among orthodox scientists and churchmen since beliefs in
the Creation and divine guidance were threatened by Darwin’s
revelations. Apelike cartoons of Darwin appeared in newspapers.
Essays and sermons proliferated everywhere. Among the scientific
opponents were Richard Owens, a renowned geologist at Oxford, Louis
Agassiz at Harvard University in the USA and Adam Sedgwick, an old-school
geologist from Cambridge. Darwin was not in a position to combat
the furor, raised against his theory because of his continued illness.
Moreover, he never recovered from the untimely death of his daughter
The task of defending his theory was left to Thomas
Henry Huxley (1825-95), a brilliant zoologist who became famous
as “Darwin’s bulldog”. Huxley did his job quite
well notably at the famous Oxford debate on June 30, 1860, where
Huxley confronted Samuel Wilberforce, the powerful Bishop of Oxford.
Besides Huxley and Wilberforce those present on the platform included
: Darwin’s old teacher and anti evolutionist J.S. Huxley’s
friends Joseph Hooker and John Lubbock, John Draper of New York
University and Sir Benjamine Brodie, the Queen’s physician
and President of the Royal Society. Seven hundred people were crowded
into the University Museum where the debate was organized. In this
debate Huxley instead of being ridiculed had won a wider interest
and fair hearing for the new theories.
Besides Huxley, Darwin’s prominent supporters
were Charles Lyell and James Hooker. Lyell though convinced that
Darwin was correct but he refused to come out squarely in favour
of evolution in his public statements and writings before 1868 when
he embraced the theory at the age of 71.
Though the debate following the publication of
the Origin of Species led to wide acceptance of Darwin’s theory
among the scientists but it was far from being established during
Darwin’s lifetime. The main reason for this was that Darwin
could not explain how characteristics passed on from one generation
to another and why there are variations from one individual to another.
Variation is found among individuals who share the same parents.
It is important to note that in the successive revisions to the
Origin of Species Darwin himself backed away from natural selection.
In the first edition of his Descent of Man Darwin wrote : “In
the earlier editions of my “Origin of Species” I probably
attributed too much to the action of natural selection or the survival
of the fittest”. The first reason for Darwin’s retreat
was the failure to explain the cause of variation, a key component
in Darwin’s theory of natural selection. The second important
reason was the enormous timescale required for evolution. In the
second half of the nineteenth century the scientists believed that
the Sun could not have been hot for more than a few millions years
as there was no process known to scientists which could supply energy
to keep the Sun shining for hundreds of millions of years required
for the variety of forms of life on Earth to have evolved through
small steps. Scientists of the twentieth century have established
that the long time-scale required for evolution by natural selection
is not a problem as the Sun has essentially remained unchanged for
about 4.5 billion years, a more than sufficient time for evolution
to happen. Today we know that the energy is supplied by nuclear
processes. In the twentieth century biologists developed an understanding
of genetics and how characteristics are inherited by offspring from
their parents. As mentioned earlier it was Mendel who had first
initiated work in this direction.
By the 1940s Darwin’s theory of natural selection
as spelt out in the first edition of the Origin of Species had become
firmly established. So today, Darwin’s theory of evolution
and common descent are considered facts by the scientific community.
Though debates continue how various aspects of evolution work. For
examples, all the details of pattern of relationship are not fully
Evolution is regarded as the cornerstone of biology.
While it is possible to do research in biology with little or no
knowledge of evolution but then without evolution biology becomes
a disperate sets of fields. Evolutionary explanations pervade all
fields of biology and brings them together under one theoretical
The process of evolution can be summerised in three
sentences: Genes (hereditary units) mutate. Individuals are selected.
Population evolve. Evolution requires genetic variation. In order
to continue evolution there must be mechanism to increase or create
genetic variation and mechanism to decrease it . Mutation is a change
in a gene. These changes are the source of new genetic variation.
Natural selection operates on this variation. Natural selection
favours traits or behaviours that increase a genotype’s inclusive
fitness. The opportunity or natural selection to operate does not
induce genetic variation to appear. Selection only distinguishes
between existing variants. Selection merely favours beneficial genetic
changes when they occur by chance — it does not contribute
to their appearance. The potential for selection to act may long
precede the appearance of selectable genetic variations. Natural
selection does not have any foresight. It only allows organisms
for adapt to their current environment. Structures or behaviours
do not evolve for future utility. An organism adapts to its environment
at each stage of its evolution. As the environment changes, new
traits may be selected for.
Darwin died on April 19, 1882 after prolong illness.
Following a suggestion from of a group of members of British Parliament,
he was accorded the honour of being buried in Westminster Abbey.
(A burial place for English monarchs, outstanding statesmen etc).
We would like to end this article by quoting Julian
Huxley on Darwin. “Darwin’s work…put the world
of life into the domain of natural law. It was no longer necessary
or possible to imagine that every kind of animal or plant had been
specially created, not that the beautiful and ingenious devices
by which they get their food or escapes their enemies have been
thought out by some supernatural power, or that there is any conscious
purpose behind the evolutionary process. If the idea of natural
selection holds good, then animals and plants and man himself have
become what they are by natural causes, as blind and automatic as
those which go to mould the shape of a mountain, or make the earth
and the other planets more in ellipses round the sun. The blind
struggle for existence, the blind process of heredity, automatically
result in the selection of the best adopted types, and a steady
evolution of the stock in the direction of progress…
Darwin’s work has enabled us to see the position
of man and of our present civilization in a truer light. Man is
not a finished product incapable of further progress. He has a long
history behind him, and it is a history not of a fall, but of an
ascent. And he has the possibility of further progressive evolution
before him. Further, in the light of evolution we learn to be patient.
The few thousand years of recorded history are nothing compared
to the million years during which man have been on earth, and the
thousand million years of life’s progress. And we can afford
to be patient when the astronomers assure us of at least another
thousand million years ahead of us in which to carry evolution to
Books written by Charles Darwin
1. Voyage of the Beagle or Journal of Researches. London. 1839
2. Structure and Distribution of Coral Reefs. London. 1842
3. Geological observations on Volcanic Island. London. 1844
4. Geological observation on South America. London. 1846
5. On the Origin of Species by Means of Natural Selection. London.
6. The Various Contrivances by which orchids are Fartilised by Insects
and on the Good Effects of Intercrossing. London. 1862.
7. The Variations of Plants and Animals under Domestication. London.
8. Descent of Man and Selection in Relation to Sex. London. 1871
9. The Expression of the Emotion in Men and Animals. London. 1872
10. Insectivorous Plants. London. 1875
11. Climbing Plants. London. 1875
12. The Effects of Cross- and Self-Fertilisation in Vegetable Kingdom.
13. Different Forms of Flowers on Plants of the Same Species. London.
14. The Power of Movements in Plants. London. 1880
15. The Formation of Vegetable Mould through the Action of Worms
with Observations on Their Habits. London. 1881
16. Autobiography of Charles Darwin (Nora Barlow.ed). New York.
Books on Darwin and His Theory
1. Allan, Mea, Darwin and His Flowers . New York, Taplinger, 1977
2. Brent, Peter, Charles Darwin : A Man of Enlarged Curiosity. New
York : Harper & Row
3. Clark, Ronald. The Survival of Charles Darwin. New York : Random
4. Colp, Ralph. To Be an Invalid : The Illness of Charles Darwin.
Chicago : University of Chicago 1977.
5. Gould, Stephen Jay, Ever Since Darwin. New York : Norton , 1979.
6. Hyman, Stanley. The Tangled Bank : Darwin, Marx, Frazer and Freud
as Imaginative Writers. New York: Atheneum. 1962.
7. Irivine, William Apes, Angles and Victorians; The Story of Darwin,
Huxley and Evolution. London : Wedden field & Nicholson, 1956.
8. Moore, James and Adrian Desmond, Darwin. New York : Warner Books,
9. Bowler, Peter J. Evolution : The History of an Idea, Berkeley
: University of California Press. 1984.
10. Futuyma, Dauglas. Science on Trial : The Case for Evolution.
New York : Patheon. 1982..
11. Moorchead, Alan. Darwin and the Beagle. New York ; harper and
12. Darwin, Fancis (Ed.) Life and Letters of Charles Darwin. New
York : Appleton, 1966.