CHARLES DARWIN

THE ORIGIN OF SPECIES BY MEANS OF NATURAL SELECTION Compiled by Lorraine Kuun

In a corner inside Westminster abbey there is a flagstone with the following inscription:

CHARLES ROBERT DARWIN.

Born 12 February, 1809.

Died 19 April, 1882.

Thousands of tourists walk over this stone; close by there are also stones commemorating Faraday, Herschel and Maxwell, as well as a statue of Sir Isaac Newton. However, in the small bookshop there is not a single copy of The Origin of Species …

Where did it all start?

Darwin was born as the grandson of two famous people: his grandfather Erasmus Darwin was a well known medical doctor, poet and scientist He was also the author of a book, Zoonomia , that referred to evolution, amongst other things.

Darwin grew up in a privileged, intellectual environment

His other grandfather, Josiah Wedgwood, was the man who created the famous Wedgwood pottery. Both his grandfathers were rich, intelligent and interested in scientific matters.

Darwin’s mother, Susannah, died when he

was just eight years old. He was the fifth child, and pampered by his older sisters. He got on well with his older brother, Eras.

Always a loner …

• • • Darwin had a lonely childhood. His mother’s death affected him profoundly; his deeply depressed father forbid any mention of her name.

His older sister tutored him at home until he started school at 8. He did not like the classical education as he was more interested in being out in nature.

Went for long solitary walks and started collecting objects of nature.

The little boy was a keen naturalist at an early age …

• At the age of 11 he was painted with a pot plant in his arms – a sign of his interest in Nature?

• He and his older brother, Eras, had their own home laboratory where they performed experiments (and caused one or two explosions!). • He also was a keen collector of beetles – the Victorians almost had an obsession with “beetling”.

Charles the student …

• • • • • His father wanted him to become a doctor; he did study in Edinburgh, but did not like the work and never qualified.

His biggest interests were hunting and shooting. Got on well with fellow-students.

Joined Plinian Society whose members read papers on Natural History to each other.

His father, Robert, then decided Charles should study to enter Church. Spent more time collecting beetles than studying. Only said yes to church because it would give him the opportunity to continue his studies of nature.

The student gets some direction and the table is set.

• • • Met John Henslow, professor of Botany. Opened Darwin’s (21) eyes to wonders of Botany.

Graduated from Cambridge in 1831.

Received invitation to accompany Fitzroy on Beagle via Henslow.

Role of Wedgwoods in his life

• • • • Had to convince father of wisdom/ benefit of trip to South America.

Uncle Josiah helped him to answer all of father’s objections.

Cousins were friends and one of them, Emma, would later become his wife.

The letters of cousins sustained him during long trip, at times a very lonely adventure.

The captain and the ship…

• • • • Captain Robert Fitzroy in command of ship Beagle since 1831.

HMS Order from admiralty to chart coastline of South America and islands, specifically Patagonia and around Cape Need naturalist to make observations and collect material, as well as to act as gentleman companion. Henslow proposed young Charles Darwin.

• • •

The voyage that started everything…

Darwin and Fitzroy “clicked” immediately; Darwin had to share captain’s living quarters as “gentleman” – the class-conscious Victorian society ruled even here. Left on 27 December 1831 – Darwin immediately seasick.

First port of call the Canaries, then Bahia (now Salvador), moved down coast towards southern point. Darwin collected specimens and studied natural environment.

Darwin began reading …

• • • • Darwin received Lyell’s book on geology as gift from Fitzroy ( Principles of Geology ). (Lyell later became a lifelong friend.) Darwin made notes of everything he saw, made drawings and collected specimens.

He and Fitzroy talked and argued for hours on matters related to the environment, geology and True to tradition the names of officers, royals etc. given to mountains, rivers and sea passages.

DARWIN’S PASSAGE MNT FITZROY

Darwin slowly started to think …

• • • Earthquake on west coast of South America made Darwin realise how natural geological processes can gradually change the appearance of the earth.

He also collected fossils from the area.

At last they were on their way to the Galapagos Islands.

GALAPAGOS A WORLD ON ITS OWN

• • • The Galapagos Islands were named after the giant tortoises found there by the earliest seafarers.

It is a group of volcanic islands on the equator on the west coast of South America.

The islands are still changing and today serve as a living laboratory to study evolution and changes on earth.

GALAPAGOS where everything began

• • • However dramatic it may sound, Darwin did not immediately thought of evolution and natural selection.

He did realise that the earth was much older than previously thought, and that changes took place slowly over long periods of time.

Fossils in mountainous areas therefore not a result of the Biblical flood, but because of geological events.

• He also realised that the environment played a role in speciation.

The voyage is almost over

• • • The voyage of The Beagle would last 5 years in the end, and included Australia, New Zealand and Cape Town, South Africa.

Darwin’s observations and preserved specimens were sent to Cambridge from time to time. Darwin wrote long letters to Henslow with detailed descriptions and observations.

• • • •

DARWIN’s reputation made well in advance

Henslow read Darwin’s notes and letters to interested friends at the Royal Society . He also organized exhibitions of Darwin’s preserved specimens, and made sure that they were classified and restored where necessary.

Darwin’s name as scientists was made by Henslow by the time he returned to England.

He was received as a hero by the intellectuals and gentlefolk of the Victorian society.

• • Landed at Falmouth on 2 October 1836, almost 5 years after their departure.

Met Richard Owen, prominent biologist, who would prepare and classify his enormous collection.

LIFE AFTER THE BEAGLE

• • • Darwin’s health problems started almost immediately after his return.

They would plague him for the rest of his life, sometimes even stopping him from work.

It was originally thought that he picked up some “bug” on his travels, but he himself and later medical experts think it might have been a problem with his immune system.

• • • Darwin always blamed himself for marrying a close cousin (although he loved her very much) – some of his children also suffered from immune diseases.

Darwin was an extremely dedicated scientist, and with his reputation as well as his father’s financial support, he could pursue a career as a naturalist.

He moved to London although he missed the countryside.

His wife Emma was his lifelong support and devoted partner.

• He thought of marriage and made a list of the pros and cons. The list still exists.

• • The marriage was very happy; they were blessed with 6 sons and 4 daughters.

They also moved to the village of Downe, living in Down House.

• He married his cousin and childhood friend, Emma Wedgwood.

DARWIN’S WORK:

• Darwin worked extremely hard at organizing his notes on the Beagle voyage.

• Eventually the book was published in two parts; Darwin’s being the best-seller and Fitzroy being jealous.

• He and Fitzroy initially planned to co-write a book, but the break between the two men occurred soon after the end of the voyage. It was mostly caused by different thoughts on what they saw on their trip, as well as Fitzroy’s sometimes irrational behaviour.

• Darwin started to make sense from all that he has seen and learnt, and started on his great work, The Origin . He kept it secret,

though …

The Origin …

• • Darwin was “brought up as a Christian, studied to be a cleric, and died an atheist”.

Contrary to popular belief, his theory of evolution did not make him doubt God; he went on the voyage as not totally a believer.

• • • His concern for his wife, Emma and her strong faith, kept him from making his ideas on evolution known immediately.

He also worried about public opinion.

It eventually took him 20 years before he published his ideas.

In the meanwhile he was not idle

• • Darwin published a book on the geology of South America.

After a chance remark about scientific credibility he studied and reclassified the Barnacles – a study that took 8 years and established him as a renowned scientist.

• • He also intermittently suffered from a variety of symptoms, all pointing to a weak immune system, disabling him from time to time.

One of his favorite children, 10-year Annie, died of organ failure, a tragedy from which he never quite recovered. This, more than most things, removed him from God.

THE “ORIGIN” IS STILL WAITING TO HAPPEN

• • Darwin continued his work on evolution and natural selection, constantly thinking and rethinking his ideas.

He also made contact with Lyell ( Principles of Geology and attended meetings of the Geological Society and the ), met Hooker, Royal Society .

At this stage he was still careful not to say too much about his work; his notes and drawings show his progress.

At one stage he wrote to Hooker …

I am convinced (quite contrary to the opinion I started with) that species are not (it is like confessing to a murder) immutable.

The time is ripe …

• • • • Darwin’s words to Hooker illustrates his own initial doubts.

Lyell and Hooker not totally convinced either.

After two years of his own studies, thoughts and observations Hooker becomes one of Darwin’s staunchest supporters.

The first edition is started in 1844 as a brief review of 231 pages.

Time is running out …

• • Darwin met Huxley, also am ardent supporter. He corresponds with Wallace and to his utter shock and amazement, found that Wallace had the same ideas on evolution!

ALFRED WALLACE • • • Lyell and Hooker forced Darwin to publish his work.

The submitted Darwin’s review, with Wallace’s letter, to the Society Linnaean on 1 July 1858.

Wallace received recognition for his work and Darwin is recognized as the first author of the “evolution theory”.

A NEW BEST-SELLING AUTHOR

• • • The Origin of Species by Means of Natural Selection was published in the winter of 1859.

The first run of 1 250 copies was immediately sold out.

It met with an uproar, from both sides – Darwin took to his beloved sand walk to think … and worry.

Exactly what did “Origin” say?

• • • • • Remember, Darwin was NOT the first to talk about evolution!

It was an acceptable concept in Aristotelian times and after.

St Augustine and Thomas of Aquinas also accepted the concept.

The 15 th against it.

century church in Spain started a campaign Lamarck and Lyell both published ideas and “evidence” in the 19 th century… • • • It was widely discussed in the mid-nineteenth century. Darwin (and Wallace) provided an explanation of how evolution occurs.

The novelty of Darwin’s work is that it was in language that people without scientific background could easily understand.

EVOLUTION IN A NUTSHELL

• 1.

According to Darwin evolution worked like this: It keeps an existing species tailored to its existing ecological niche, as long as that niche still exists.

2.

New species can be created from the varieties among existing species.

This may happen when groups or individuals become separated from one another and take up slightly different life styles – through change or necessity.

“Adaptive radiation”

• Darwin’s Galapagos finches are an excellent example of speciation: • The finches of Galapagos lived in different habitats on the islands. Slowly new adaptations enabled them to exploit different food sources. Slowly they developed into new species; one with a beak to crack seeds, another to get worms from wood etc.

Adaptiewe radiasie by vinke

The “Origin” causes an uproar …

• The problem was not evolution as such, but the fact that Darwin included man by implication (even though “The descent of man ..” would only be published later.

• “The Origin” , according to critics, said that man and the apes developed from a common ancestor, by implication man came from an ape (although Darwin never said exactly that).

• Debate followed debate, cartoons were published – for and against Darwin, his book and his theory. • “Origin” remains a bestseller.

What was/is the problem people have with evolution?

• It does not allow for so-called Intelligent Design – Darwin (and those after him) relied on “coincidences”.

• Man is treated as any other animal – he is not more special than any other organism.

• The Creationists believe that Earth was created in seven 24-hour days: the Bible’s story of Creation should be taken literally.

Why do we not agree with the previous viewpoints?

• • • The randomness of change does not mean that there is no God. God did create heaven and earth, but used (and still uses) natural processes such as natural selection.

Man, although in the (spiritual) image of God, is another biological organism who shares 98% of his DNA with chimpanzees! There is overwhelming evidence that life on earth is very old, actually 3,5 billion years!

More about evolution …

• Adaptations between organisms of the same species, and between different species are driven by “the struggle for life”.

• This struggle for existence does not only influence the everyday life of an organism, but also its ability to reproduce.

• The secret to adaptations lies in natural selection.

• “Natural selection is daily and hourly scrutinizing, throughout the world, every variation, even the slightest; rejecting that which is bad, preserving and adding up all that is good …”

Darwin says …

• • • The earth is much older than originally thought.

Natural processes e.g. earthquakes contribute to changes of the earth over long periods of time.

Organisms adapt to changing conditions.

• • Adaptations of organisms occur “by chance” through natural selection.

“Survival of the fittest” means survival of those most suited to survive in a changing environment.

Darwin vs Lamarck

• Lamarck said that conditions forced organisms to adapt, and that new adaptations can be transferred to the next generation. These

changes can transfer from one generation

to the next.

• Darwin said that changes were coincidental (by chance) and that these changes occur over a long period of time. Some can be to the benefit of the organism and will ensure survival.

Patterns of van evolution

• Evolution is not a direct sequence of organisms with changes. • Evolution causes groups to be less and less related to each other, the longer the time span, and vice versa.

What Darwin did not know …

• Today we know that many catastrophic events caused mass extinctions.

• These extinctions gave rise to “explosions” of new species.

• Some areas are richer in species than others – centres of biodiversity.

Another problem that Darwin had ...

• • • Darwin knew that natural selection “chooses suitable characteristics”, but how this happened and how even regular features were transferred, he did not know.

The irony was that a contemporary of Darwin, the Austrian monk Gregor Mendel , developed the science of Genetics . Mendel studied the inheritance of traits, but because of geographical isolation, language and long distances, the two never new one another.

Darwin did work on much more than just evolution

• • Darwin was a dedicated scientist and published books, most of them best-sellers on topics such as orchids, insects, farming, vegetable growing etc.

He was also a landowner with tenant farmers, invested money and took part in local politics.

• • • One of his children, Francis, worked with him in his later years and was responsible for the preservation of Darwin’s diaries and notes. Down house can be visited today; Darwin’s study is a special place of interest.

The famous sand walk still exists and can be followed.

THE END

• • • Charles Robert Darwin died on 19 April 1882.

He never received the honour he deserved from his country of birth, but was buried in Westminster as were many other important men of science.

His funeral service was attended by every prominent scientist of the time as well as hundreds of other people.