Distorted Darwin: common misconceptions about evolution and natural selection

A few months' ago, I discussed how disagreements with religious texts can lead the devout to disagree with key scientific theories; presumably this is a case of fundamentalists denying the fundamentals? Of all the areas of scientific research that cause issues today, it is evolutionary biology that generates the most opposition. This is interesting in so many ways, not least because the primary texts of the Abrahamic religions have little to say on the topic beyond the almost universal elements seen in creation myths, namely that one or more superior beings created all life on Earth and that He/They placed humanity at the zenith.

Thanks to opposition to the modern evolutionary synthesis, there is a plethora of misinformation, from material taken out of context to complete falsehoods, that is used to promote Creationist ideas rather than scientifically-gleaned knowledge. Even those with well-meaning intentions often make mistakes when condensing the complexity of the origin and history of life into easy-to-digest material. I've previously written about the concepts of evolutionary bushes rather than ladders, concurrent rather than consecutive radiation of sister species and speciation via punctuated equilibrium (i.e., the uneven pace of evolution) so here are a few other examples where the origin, implications and illustrations of natural selection has been distorted or overly simplified to the point of inaccuracy.

I've previously mentioned that Charles Darwin was the earliest discoverer - but only a decade or two ahead of Alfred Russel Wallace - of natural selection, and not as is often written, evolution per se. However, this is not completely accurate. Darwin's hypothesis was more complete than Wallace's, in the sense of being entirely scientific and therefore testable. Wallace on the other hand maintained there must have been divine intervention in the creation of our species, making us different from all other life forms.

In addition, there were several precursors who partially formulated ideas regarding natural selection, but who were unable to promote a consistent, evidence-based hypothesis to anywhere near the extent that Darwin achieved. For example, as early as 1831 the Scottish agriculturalist Patrick Matthew published some notes on what he termed 'new diverging ramifications of life' as he thought must occur after mass extinctions. Nevertheless, he failed to expand and fully explain his ideas, seemingly unaware of where they could lead. In this sense, he is a minor figure compared to the thorough research Darwin undertook to back up his hypothesis. 

Darwin appears to have been unaware of Matthew's ideas, although the same could not be said for Robert Chambers' (anonymous) 1844 publication Vestiges of the Natural History of Creation, which although highly speculative contained some kernels of truth about the mechanisms behind biological evolution. Just as Thomas Malthus' 1798 An Essay on the Principle of Population inspired Darwin, so the mid-nineteenth century contained other combinations of ideas and real-world inspiration that provided,an ideal background for the formulation of natural selection. In other words, the conditions were ready for those with the correct mindset to uncover the mechanism behind evolution. What Darwin did was to combine the inspiration with an immense amount of rigour, including examples taken from selective breeding.

Another frequently quoted fallacy is that evolution always maintains a single direction from earlier, simpler organisms to later, more complex ones. I've covered this before in discussions of the evolution of our own species, as many popular biology accounts seek parallels between technological progress and a central branch of animal evolution leading ever upwards until it produced us. 

Modern techniques such as genetic analysis and sophisticated examination of fossils - including scanning their internal cavities – has negated this appealing but incorrect idea. For example, mammals evolved around the same time as the dinosaurs (and over one hundred million years before flowering plants) while parasitic species often have a far more rudimentary structure than their ancestors. 

Despite this, we still see countless illustrations showing a clear-cut path from primordial organisms 'up' to Homo sapiens. No-one who has seen the cranial endocast of a dinosaur would consider it to be superior to even the least intelligent of mammals, although the later medium-sized carnivorous species were on the way to developing a bird-like brain-to-body mass ratio. Yet throughout the Jurassic and Cretaceous periods, dinosaurs filled most ecological niches at the expense of the mammals; you would be hard-pressed to state that the latter were the dominant type of land organism during the Mesozoic!

Research published last year shows that New Zealand's unique tuatara, the sole remaining member of the Rhynchocephalia, is a reptile that shares some genetic similarities to the Monotremata, the egg-laying mammalian species known as platypus and echidna. In addition, a report from the beginning of this year states that the ancestors of today's five monotreme species diverged from all other mammals 187 million years ago; therefore, they have spent approximately three times as long on their own evolutionary journey as they did when part of all the other mammalian lineages. As a result of retaining many ancestral features, the platypus genome is in some ways more like that of birds and reptiles rather than placental and marsupial mammals. But we still include them amongst the mammals rather than as a hybrid or separate class; both platypus and echidna have fur, are warm-blooded and produce milk (although with a unique delivery system!) This allows their inclusion in Mammalia; does this mean we arbitrarily allow certain traits and discard others?

Would it be fair to say that the boundaries we make between organisms are more for our convenience than the underlying reality? Are you happy to label birds as 'avian dinosaurs' and if not, why not? If they had feathers, nests and even underground burrows, some dinosaurs were clearly part of the way there; physiologically, it was teeth, bony tail, and a crocodilian-type brain that provided the differentiation from birds. Scans of fossils show that dinosaur hearts may have been more like birds than other reptiles, which along with the possible discovery of bird-like air sacs, means that they could have had something of the former's more active lifestyle. 

This doesn't confirm that they were warm-blooded: today there are eight species, including leatherback turtles, that are mesothermic and therefore lie between warm- and cold-blooded metabolisms. Eggshell analysis suggests that some of the theropod (carnivorous) dinosaurs could have been warm-blooded, but as dinosaurs existed for around 165 million years it may be that some evolved to be mesothermic and others to be endothermic (i.e., fully warm-blooded). In this respect then, some meat-eating dinosaurs especially may have had more in common with us mammals than they did with other reptiles such as lizards and snakes.

All this only goes to show that there is far more to life's rich pageant than the just-so stories still used to illustrate the history of life. Science communication to the public is fundamental to our society but it needs to present the awkward complexities of evolution via all the tortured pathways of natural selection if it is not to fall victim to those who prefer myths of the last few thousand years to the history of countless millennia, as revealed in the genes and rocks waiting for us to explore.

Science, society & stereotypes: examining the lives of trailblazing women in STEM

I was recently flicking through a glossily illustrated Australian book on the history of STEM when I found the name of a pioneer I didn't recognise: Marjory Warren, a British surgeon who is best known today as the 'mother of modern geriatric medicine'. Looking in the index I could find only two other women scientists - compared to over one hundred and twenty men - in a book five hundred pages long! The other two examples were Marie Curie (of course) and American astronomer Vera Rubin. Considering that the book was published in 2008, I was astounded by how skewed this seemed to be. Granted that prior to the twentieth century, few women had the option of becoming involved in science and mathematics; but for any history of STEM, wouldn't the last century contain the largest proportion of subject material?

I therefore thought it would be interesting to choose case studies from the twentieth century to see what sort of obstacles - unique or otherwise - that women scientists faced until recently. If you ask most people to name a female scientist then Marie Curie would probably top the list, although a few countries might have national favourites: perhaps Rosalind Franklin in the UK or Rachel Carson in the USA, for example. Rather than choose the more obvious candidates such as these I have selected four women I knew only a little about, ordered by their date of birth.

Barbara McClintock (1902-1992) was an American cytogeneticist who was ahead of her time in terms of both research and social attitudes. Although her mother didn't want her to train as a scientist, she was lucky to have a father who thought differently to the accepted wisdom - which was that female scientists would be unable to find a husband! McClintock's abilities showed early in her training, leading to post-graduate fellowships which in turn generated cutting-edge research.

At the age of forty-two, Barbara McClintock was only the third woman to be elected to the US National Academy of Sciences. However, her rapid rise within the scientific establishment didn't necessarily assist her: such was the conservative nature of universities that women were not allowed to attend faculty meetings. 

After publishing her research to broad acceptance, McClintock's work then moved into what today would broadly come under the term of epigenetics. Several decades' ahead of its time, it was seen as too radical by most of her peers and so after facing intense opposition she temporarily stopped publishing her results. It is unlikely that being a woman was entirely responsible for the hostility to her work; similar resistance has frequently been experienced throughout the STEM avant-garde. It seems that only when other researchers found similar results to McClintock did the more hidebound sections of the discipline re-examine their negative attitude towards her work.

There has been a fair amount of discussion as to whether it was because McClintock was female, or because of her secretive personality (both at home as well as at work, for she never married) - or a combination of both - that delayed her receipt of the Nobel Prize in Physiology or Medicine. Even by the slow standards of that particular awards committee, 1983 was rather late in the day. However, by then she had already been the recipient of numerous other awards and prizes.

Regardless of the recognition it gave her, Barbara McClintock relished scientific research for the sake of uncovering nature's secrets. In that regard, she said: "I just have been so interested in what I was doing and it's been such a pleasure, such a deep pleasure, that I never thought of stopping...I've had a very, very, satisfying and interesting life."

Tikvah Alper (1909-1995) was a South African radiobiologist who worked on prions - otherwise known as 'misfolded' or 'rogue' proteins - and their relationship to certain diseases. Her outstanding abilities were recognised early, allowing her to study physics at the University of Cape Town. She then undertook post-graduate work in Berlin with the nuclear fission pioneer Lise Meitner, only to be forced to leave before completing her doctorate due to the rise in anti-Semitism in Germany.

Having had her research curtailed by her ethnicity, Alper was initially also stymied on her return to South Africa thanks to her private life: due to the misogynist rules of that nation's universities, married women were not allowed to remain on the faculty. Therefore, along with her husband the veterinary medicine researcher Max Sterne, she continued her work from home. However, eventually her talents were acknowledged and she was made head of the Biophysics section at the South African National Physics Laboratory in 1948. Then only three years later, Alper's personal life intervened once again; this time, she and her husband were forced to leave South Africa due to their opposition to apartheid.

After a period of unpaid research in London, Alper turned to studying the effects of radiation on different types of cells, rising to become head of the Medical Research Council Radiopathology Unit at Hammersmith Hospital. Alper's theories regarding prions were eventually accepted into the mainstream and even after retirement she continued working, writing a renowned text book, Cellular Radiobiology, in 1979. 

Alper's life suggests she was very much a problem solver, tackling anything that she felt needed progressing. As a result of this ethos she worked on a wide range of issues from the standing of women in science and society, to the injustice of apartheid, even to learning and teaching sign language after one of her son's was born profoundly deaf. Despite being forced to leave several nations for different reasons - not because she was a woman - Alper was someone who refused to concede defeat. In that respect she deserves much wider recognition today.

Dorothy Crowfoot Hodgkin (1910-1994) was interested in chemistry, in particular crystals, from a young age. Although women of her generation were encouraged in this area as a hobby, it was highly unusual for them to seek paid employment in the field. Luckily, her mother encouraged her interest and gave Hodgkin a book on x-ray crystallography for her sixteenth birthday, a gift which determined her career path. 

After gaining a first-class honours chemistry degree at Oxford, she moved to Cambridge for doctoral work under the x-ray crystallography pioneer J.D. Bernal. Not only did Hodgkin then manage to find a research post in her chosen field, working at both Cambridge and Oxford, she was able to pursue cutting edge work labelled as too difficult by her contemporaries, Hodgkin and her colleagues achieved ground-breaking results in critical areas, resolving the structure of penicillin, vitamin B12 and insulin. 

Hodgkin's gained international renown, appearing to have faced few of the difficulties experienced by her female contemporaries. In addition to having a well-equipped laboratory at Oxford, she was elected to the Royal Society in 1947 and became its Wolfson Research Professor in 1960. She was also awarded the Nobel Prize in Chemistry in 1964 - the only British woman to have been a recipient to date. Other prestigious awards followed, including the Royal Society's Copley Medal in 1976; again, no other woman has yet received that award.

Presumably in response to the loss of four maternal uncles in the First World War, Hodgkin was an active promoter of international peace. During the 1950s her views were deemed too left wing by the American government and she had to attain special permission to enter the United States to attend science conferences. Ironically, the Soviet Union honoured her on several occasions, admitting her as a foreign member of the Academy of Sciences and later awarding her the Lenin Peace Prize. She also communicated with her Chinese counterparts and became committed to nuclear disarmament, both through CND and Operation Pugwash.

Her work on insulin, itself of enormous importance, is just one facet of her life. Ironically, as someone associated with left-wing politics, she is often remembered today as being one of Margaret Thatcher's lecturers; despite their different socio-political leanings, they maintained a friendship into later life. All this was despite the increasing disability Hodgkin suffered from her mid-twenties due to chronic rheumatoid arthritis, which left her with seemingly minimal dexterity. Clearly, Dorothy Hodgkin was a dauntless fighter in her professional and personal life.

Marie Tharp (1920-2006) was an American geologist best known for her oceanographic cartography work regarding the floor of the Atlantic Ocean. Despite followed the advice of her father (a surveyor) and taking an undergraduate degree in humanities and music, Tharp also took a geology class; perhaps helping her father as a child boosted her interest in this subject. It enabled her to complete a master's degree in geology, thanks to the dearth of male students during the Second World War. Certainly, it was an unusual avenue for women to be interested in; at the time less than four percent of all earth sciences doctorates in the USA were awarded to women.

From a modern perspective, geology during the first half of the twentieth century appears to have been exceedingly hidebound and conservative. Tharp found she could not undertake field trips to uncover fossil fuel deposits, as women were only allowed to do office-based geological work - one explanation for this sexism being that having women on board ship brought bad luck! In fact, it wasn't until 1968 that Tharp eventually joined an expedition. 

However, thanks to painstaking study of her colleague Bruce Heezen's data, Tharp was able to delineate geophysical features such as the mid-Atlantic ridge and consider the processes that generated them. Her map of the Atlantic Ocean floor was far more sophisticated than anything that had previously been created, giving her insights denied to both her contemporaries as well as her predecessors. As such, Tharp suspected that the long-denigrated continental drift hypothesis, as envisaged by Alfred Wegener three decades previously, was correct. It was here that she initially came unstuck, with Heezen labelling her enthusiasm for continental drift as 'girl talk'. Let's hope that phrase wouldn't be used today!

In time though, yet more data (including the mirrored magnetic striping either side of the mid-Atlantic ridge) proved Tharp correct. Heezen's incredulity was replaced by acceptance, as continental drift was reformulated via seafloor spreading to become the theory of plate tectonics. Mainstream geology finally approved what Wegener had proposed, and Marie Tharp was a fundamental part of that paradigm shift. 

What is interesting is that despite receiving many awards in her later years, including the National Geographic Society's Hubbard Medal in 1978, her name is mentioned far less often than other pioneers of plate tectonics such as Harry Hess, Frederick Vine, Drummond Matthews, even Heezen. It's unclear if Tharp's comparative lack of recognition is due to her being female or because she was only one of many researchers working along similar lines. Her own comment from the era suggests that just being a women scientist was reason enough to dismiss her work: she noted that other professional's viewed her ideas with attitudes ranging "from amazement to skepticism to scorn."

There are countless other examples that would serve as case studies, including women from non-Western nations, but these four show the variety of experiences women scientists underwent during the twentieth century, ranging from a level of misogyny that would be unthinkable today to an early acceptance of the value of their work and a treatment not seemingly different from their male colleagues. I was surprised to find such a range of circumstances and attitudes, proving that few things are as straightforward as they are frequently portrayed. However, these examples do show that whatever culture they grow up in, the majority of the population consider its values to be perfectly normal; a little bit of thought - or hindsight - shows that just because something is the norm, doesn't necessarily mean it's any good. When it comes to the attitudes today, you only have to read the news to realise there's still some way to go before women in STEM are treated the same as their male counterparts.