Here we have Graham Stride’s excellent paper given to ANVIL 11th July 17
The Legacy of Charles Darwin 1809- 1882
Introduction Everyone links Charles Darwin with his five weeks in the early 1830’s in the Galapagos archipelago, 600 miles off Ecuador, whilst travelling on board HMS Beagle (for five years) as the ships naturalist.
This supposedly inspired him to write his opus The Origin of Species published in1859.
Actually Darwin visited some forty islands in his lifetime and it was the British Isles, his first and last island, that saw him do most of his groundbreaking works.
Darwin was born into an England where leeches and arsenic infusions were state of the art medicines.
The water closet was yet to become popular. Gas lighting was still a rare curiosity.
Received wisdom was that The Earth was unchanged since the Creation.
Neanderthal fossils had not yet been found in Germany.
In Shrewsbury School he only washed his feet once a month as there were not facilities to do so.
Peoples thought processes were quite different to what we accept readily today.
In his lifetime he would help create a paradigm shift in science, thought, society and literature which
would leave a legacy which is still making its mark on the world today.
In his lifetime as well as writing two earthshaking masterpieces :
The Origin of Species (1859) in which he did not use the word evolution but ‘descent with modification’ and ‘natural selection’.
The Descent of Man, and Selection in Relation to Sex. (1871)
He wrote at least six million words; nineteen published works; innumerable letters (of which 14,000
still survive) ; five hundred drawings, engravings and plates; and the first scientific publication with photographs ‘Expression of the Emotions in Man and Animals’.
Much of his scientific ideas and research were ahead of their time and pioneering the way for branches of modern sciences.
A Lost World
When Conan Doyle penned his Edwardian thriller The Lost World (1912) some fifty years after the publication of The Origin of Species, he could use an understanding of the theory of evolution as an acceptable plot for his novel.
Darwin was fascinated with carnivorous plants and had accumulated a large collection at his home, Down House, in Kent. Although the native sundew was the most readily available plant for his experiments he realised that separate lineages of carnivorous plants had developed across the world in response to the environments they lived in.
Darwin through patient experimentation, and tormenting, with the plants discovered they had developed their most un-plant like habits in response to living in nitrogen deficient soils or as epiphytes on tropical branches. Catching and digesting insects in ingenious ways enabled them to ingest the nitrogen they need to survive. He used them as an example of convergent modification in his formulation of The Origin.
Today, explorations into previously isolated and inaccessible parts of the world have revealed almost 600 species of these green tyrannosaurs from a wide variety of groups. Their botanic tactics in trapping and devouring hapless insects for their nitrogen rich bodies are varied indeed.
Whether in rain leached tropical soils, clinging to tropical forest branches, cool northern pine forests and bog-lands or Mediterranean scrub-lands these nitrogen deficient habitats have encouraged niche plants to develop.
Despite 4/5ths of the air being nitrogen, in soils it is a precious commodity. (1)
All animals eventually succumb to the vegetable world through mortality and decay – the carnivorous plants have just cut out the middle-man and take it directly!
Natures market in nitrogen turns over billions of tons of the element annually from air to soil, land to water, plants to animals and back again in a continuous cycle. Today though, man’s global trade in nitrogen has upset natures balance. Farmers pour nitrogenous chemicals onto the soil and factories generate a hundred million tons of of it from oil. Without doubt the world population would starve today without this human generated bounty for the crops.
But, this excess runs off the fields into surrounding areas and into water-courses. Acid rain from exhausts and industrial pollution released into the atmosphere is causing these sensitive, ultra-specialised plants to either abandon their unique lifestyle, developed over millennia, as nitrogen seeps into their once meagre eco-systems; or other plants move into their now ‘enriched’ soils and crowd them out into oblivion.
The wonderful 600 species is declining rapidly and in much of their former habitats they may soon be as fanciful a memory as Conan Doyles fabulous lost world.
It’s All in the Breeding
Charles Darwin married his cousin Emma Wedgewood following the Victorian fashion amongst the
moneyed classes of keeping it in the family!
Indeed, Darwin’s immediate family tree was filled with cousin to cousin matrimonial relationship.
Charles and Emma had ten children, three of whom died (two in infancy). Charles was much smitten with sickness himself, often serious, and after his wife’s last confinement he began to have serious concerns as to the wisdom of such close inter-relationship for the health of the offspring.
Being of ingenious thought and a practical nature he set about to find a method of testing his concerns.
Now sex with close relatives has had a long and time honoured history going back at least to Egyptian Pharaohs where brother-sister unions were quite the desired match for a god-like pedigree.
Studies in Victorian times investigated somewhat in-bred isolated communities within the British Isles
which showed some distinct comparisons with more outward marrying communities.
In 1907 Parliament passed legislation against sex with close relatives and criminalising incestuous
Darwin, ever green-fingered, first conducted numerous experiments with pollinating plants and discovered that many plants had natural defences against self-pollination and even receiving pollen from closely related sibling seedlings. They would only accept cross-pollination.
In his book ‘The effects of Cross and Self Fertilisation in the Vegetable Kingdom’ (1876) he published the results of his experiments showing how cross-pollination was generally beneficial and self-fertilisation injurious.
In studying a wide variety of goings on in the hedgerow and greenhouse he concluded that, to achieve the ends that plants sought for healthy progeny their antics would have shocked the shepherds of Arcady!
Darwin then wondered that surely what works for plants was surely transferable to animals and humans. He then proceeded with breeding experiments with pigeons and consulting with dog fanciers and breeders. Dogs of course having been bred into a plethora of breeds though selective matings.
Modern research with the added advantages of the knowledge of DNA, genes and chromosomes and the surveys of whole populations, has pinpointed the serious problems of genetically passed across imperfections and mutations. The male Y chromosome which replicates itself more often than female X chromosomes is particularly prone to passing down problems along the male line.
Britain is one of the least in-bred societies in the world. In Britain spouses are on average as far away genetically as sixth cousins. In Pakistani communities in the UK its British born children have probably the greatest tendency to marry a cousin – often back out in Pakistan.
North Africa, The Middle East and the Indian sub-continent, where close marriage within rural communities is still common, there is a higher incidence of inherited blood diseases – some of which are helpful in protecting against malaria!
Sickle cell in African populations is carried by almost half the population. A double copy inherited from both parents is dangerous.
In Saudi-Arabia where the perils of too close a relationship is not appreciated in villages; up to a fifth of admissions into children’s hospitals are due to hereditary diseases.
In cases where siblings inadvertently marry due to separation and adoption at birth (and later discovered) offspring are almost fifty percent likely to inherit some abnormality through inheriting a double copy of a faulty gene.
Interestingly – and Darwin would have been fascinated – modern biology has shown a surprising number of plants and animals that have discarded sex altogether and are self-fertilising hermaphrodites; reproduce by parthenogenesis or forms of a-sexual reproduction.
Many animal species can sense through scent or behaviour ill health or too close a gene pool in a potential mate and reject them as a partner.
Female laboratory mice (often inter-bred themselves) have been found to absorb their foetuses from
a previous mating if an obviously stronger and different gene pool male becomes available so they can mate with him for stronger offspring.
Where the Bee Sniffs
A Victorian gent of means when serious about winning a marriage partner might give her orchids.
Flashy and expensive, a real test of readiness to invest in a relationship. Indeed, their latin name Orchidacea means testicle after the shape of their roots.
In his book The Descent of Man and Selection in Relation to Sex, Charles Darwin was to show that in the animal kingdom the battle to find a mate was as formidable an agent of selection as was the struggle to stay alive.
Males can have far more offspring than females, if they can fight off rivals and impress the females.
Losers in the conflict go down the road to oblivion of bloodlines or species extinction.
Sexual selection, as Darwin termed it, can lead to the development of giant antlers,vivid posteriors and all manner of exotic paraphernalia. When studying barnacles (he wrote four books on them) Darwin found some barnacles and marine molluscs have a reproductive organ twice the length of their bodies to reach the females that other less fortunate males just cannot reach.
Back in the greenhouse, Darwin was using orchids to investigate the sexual behaviour of plants. He also studied banks of native orchids growing around his beloved Down House in Kent.
He discovered a botanical sexual world of dishonesty, deceit and discord with all ready and able to cheat whenever necessary!
Botanical relationships are more crowded with a third agent – be it wind, water, insect or other animal
necessary to transport male sex cells to the female. Female flowers, or parts thereof, readily receive as many male cells in the form of pollen as they can to select the most potent. Male flowers, or parts thereof, have to expend considerable energy and resources in producing pollen and attracting pollinators to carry the male cells for them.
Plants want to have sex with as least energy as possible and prospective cupid insects want to be fat, wanton and as idle as possible and yet reap the rewards – often in the form of nectar.
Both are willing to cheat each other as much as they can get away with!
Modern biologists and behavioural scientists have been able to travel the world with sophisticated technology and instruments of incredible complexity to record and measure the the evolutionary arms race employed by plants and animals to pass on their genes.
Giant antlers, super size, vivid feathers and spectacular blooms can be made only by those with the means to afford them. Stags annually produce antlers of prodigious proportions and leach their bones of minerals to do so. They may die in conflict or succumb to a hard winter after an exhausting rut.
A male nightingale loses a tenth of its body weight singing all night hoping to impress a possible mate.
Testosterone boosted into competing males suppresses the immune system making the male more vulnerable.
Darwin pondered on orchid specimens sent to him by collectors. Marvelling at their elaborate nectaries seemingly impossible for an insect tongue to reach; but modern technology has recorded the visits of incredible creatures to these orchids in their native habitats showing elaborate relationships which have redefined the structure of giver and receiver in a mutual partnership which has tied them in an evolutionary chain of dependence.
Other less scrupulous species have discovered how to short-cut the evolutionary engineering of millennia and just cheat their way to the goodies.
In human on-line dating research shows that it seems men are slightly more dishonest about their income and women about their weight. Dishonest daters are soon discovered and rejected so perhaps honesty does pay. In the dating game though, there are few disappointments that a bunch of orchids will not help put right!
The Worms Crawl In
Giant standing stones tilt and fall over millennia and metal detectorists find ancient lost objects deep beneath the soil layers -why?
Darwin got it right. The past had been entombed by the work of worms.
In his last book ‘Formation of Vegetable Mould, Through the Action of Worms’ Darwin sang the praises of worms. Long before the plough the land was regularly ploughed by worms and they will continue where they are allowed to do so. In disturbing the surface layers of the landscape they aerate, drain, turn over, fertilise and improve the quality of the soil .
Darwin’s patient observations and experiments on the effect of worms upon the landscape, vegetable mould creation and almost geological force of transformation became the foundation for sciences deal
ling with agriculture and soil. A science which is now waking up to the ravages man has inflicted on the soil and the plant and animal life within it.
Despite being essentially an animated intestine, earthworms of many different species work from just beneath the surface to sometimes many metres beneath. Their tunnelling, ingesting, excreting and searching for fellow hermaphrodite partners regularly mixes the soil and helps keep it in good condition for beneficial bacteria and fungi to do their job too.
Darwin considered them perhaps the most important creatures in the world; bringing up a calculated seven to twenty tons of earth to the surface every year in his local fields. Earth worked on by natures processors to become rich soil.
Mankind since the dawning of agriculture has used and abused the soil with ploughing and exhausted it with constant demands for crop production. Insufficient organic fertiliser put back onto the soil or time given before another harvest has given little time for the worms to enrich the soil again.
Heavier modern agricultural machinery has compressed the soil harder beneath the surface preventing good drainage and forming pans whereas the constantly ploughed upper levels dry out and blow away.
Herbicides and Pesticides as well as almost poisonous levels of artificial fertilisers have made the soils practically sterile and devoid of organic content.
The ploughing of the American prairies (which had fewer native earthworms) and general bad land management resulted in billions of tons of soil being blown away once the surface had been stripped off and the soil dried out to dust. This is still happening all over the world as more and more marginal land is put under the plough or over -grazed to provide food or cash crops to sell.
Thankfully, and hopefully not too late, the problem is being recognised and lighter machinery is now being developed and in many cases seeds are drilled into the fields which are not ploughed again after each crop. Mixed crops can also help soil properties and soil flora and fauna encouraged back.
Emigrants to the New World from Europe in the 1800s took earthenware pots of earthworms with them to release into foreign fields to help improve the soil quality.
By error New Zealand and Australian flatworms have been introduced back into our soils and these prey on our native worms and have devastated the earthworm population in parts of the country.
Darwin wished to rest with his beloved earthworms in the cemetery of Downe village and let them help him to become one with his beloved land – but unfortunately he was taken off and buried in Westminster Abbey instead.
The Shaved Ape
In 1859 The Origen’s author had to exercise a certain caution in promoting the concept that the forces which produced animal species had also produced humans.
He waited another twelve years to expand on the subject and ‘The Descent of Man (1871) attempts to explain How and Why?
Homo Sapiens shares its nature with other primates through a common ancestor Darwin believed, and he used humans as an exemplar of evolution – a product of common biological mechanism, shaped and refined through natural selection.
Even by 1971 (let alone 1871) the physical evidence was weak and the concept one of theory and speculation.
Now all has changed with the ability to examine genes, cells, tissues and organs with exquisite detail.
Darwin’s theory has not altered much since its proposal some 160 years ago, but the technology used to study it has been transformed.
The Human Genome Project completed in the first decade of the 21st Century has enabled the reading off and decoding of the human DNA sequence and gene sequencing of plants and animals using super-computers has provided a key to unlocking the secrets and history of life.
The egg that made us contains two metres of DNA and each of the billions of cells that descend from it has a copy.
The elegant double-helix in DNA strands has actually been shown to be rather a hotch-potch of expedience and patching marked with redundancy, decay and scars from ancient battles in our descent (or ascent) from our ancestors. Genes, like cells, guts and brains, work – but only just in places.
Human DNA contains long stretches of redundant or dormant genes; sections which are mirror images of each other and repetition is everywhere.
The remnants of viruses make up nearly half the total and the remainder contains the remains of ancient and once functional structures.
There are fewer genes than expected when the project was proposed – just over 20,000.
Some behave differently in different tissues and some, should they become active, would cause disease.
A chicken has slightly less DNA than a Nobel Laureate and half its genes are identical (or almost so) to our own. Evidence of a shared ancestor some three hundred million years ago.
A tiny plant, a relative of the sprout, has more genes than either.
Gene science is still relatively in its early stages; genes are so complicated that we have much yet to discover. The paths from chemical instructions to the results in cells are a labyrinth rather than a straight line with the same genes behaving differently and becoming folded, cut, spliced or fused into new mixtures in ways as much depending on conditions, as their own structure.
Natural selection depends on inherited differences leading to descent with modification. Even identical twins can have subtly differing DNA depending on situations within the womb such as bacteria or virus infiltration effecting either foetus.
The double-helix present in each cell nucleus are received from father and mother; the entire chain can have tens of millions of differences in the offspring from the chains of each parent.
Genome Projects are underway around the world searching for how many variations there might be and how the knowledge could help us.
The offspring of older parents inherit more mutations than those of younger parents as in our lifetime our DNA copies and re-copies itself in repairing the body and mistakes and omissions occur which then are copied and become part of the chain.
Our closest common ancestors have long gone with eons of change (the Miocene period was truly the planet of the apes) but our closest today, the chimpanzee, is often quoted as having 99% of our genes but in overall there is about a 4% genome difference depending on what is being compared.
Women have two large X chromosomes and men one large X and a smaller Y chromosome. The human and chimp X chromosome has diverged by just 0.5% whilst the Y has shifted three times more.
Women are therefore closer to chimps than men despite popular conceptions!
Some of our identical genes with primates have different functions in the human than in the primates.
Comparing the genome sequence in different primates is enabling us to trace some of our evolutionary journey.
Movement from forest to savannah and then from continent to continent means our skin colour has changed from pale to dark and in some instances back to pale again and is just one example of how our evolutionary journey has effected us and left its marks.
Charles Darwin has indeed left us a rich legacy which we are taking on further. Not just the fields of science that he prototyped through his insatiable curiosity about the natural world, but because of his genius in combining brilliance of intellect with painstaking investigation and recording to provide evidence to refine and prove, or evolve, his theories.