Category Archives: Charles Darwin

When is a yucca not a Yucca?

Notice the difference?  The italicisation and capital initial of the second Yucca.  That’s how the genus name of a species should be formally presented in a scientific paper, or in a newspaper article, or wherever.  Like Homo – the genus in which our own species (Homo sapiens) sits.

It might seem like a narrow and pedantic point, but it’s important.  Accurate and descriptive naming of species, genera, families and other taxonomic ranks is crucial to those of us who study biodiversity and is at the core of our science: without names for species, for example, we cannot make informed conservation judgements or comparisons between habitats in relation to which species are present or absent.  Names matter.

But it’s not just the names themselves, it’s also how they are presented which is important:  when I see the words yucca and Yucca in print, they signify two different things to me.  The word “yucca” is an informal name for a group of plants that is widely applied by gardeners and has no formal scientific status.  Yucca on the other hand refers to a very specific group of plants and has a clear meaning to a biologist.

To give you an example of this I’ll first have to introduce you to the Northamptonshire Natural History Society (NNHS) which was founded in 1876 and must be one of the oldest surviving local natural history societies in the country.  Some important 19th Century scientists were honorary members, including Charles Darwin, Thomas Huxley and Joseph Hooker.  This perhaps reflects Northampton’s proximity to London though there may be other factors: one could compile quite a long list of scientists with links to Northamptonshire.

The Journal of the Northamptonshire Natural History Society was first published in 1880 and continues to the present day.  Which brings us back to yuccas.  Last year a short article by a NNHS  member summarised the local weather conditions in Northampton for each month of 2010 (J. Northants Nat. Hist. Soc. vol. 45, no. 1).  December of that year was a particularly cold month and the author notes that “the species of Yucca trees planted in Northampton, which although thriving in recent years, were killed by the cold period”.

Strictly speaking Yucca refers to plants of a particular group which are endemic (i.e. only naturally occurring) to the New World.  The genus Yucca is a member of the asparagus family (Asparagaceae), subfamily Agavoideae.  The plants which suffered so much in the cold winter of 2010 are in fact New Zealand Cabbage Trees (Cordyline australis) which, as the name suggests, are endemic to New Zealand.  The genus Cordyline is also a member of the family Asparagaceae but belongs to the subfamily Lomandroideae and is therefore only distantly related to Yucca.

The leaves and stems of Cordyline and Yucca do look very similar, hence gardeners tend to use yucca as an informal name for both.  However when these plants flower it is clear that they are very different.  Flowers of the various species of Yucca are typically quite large and are adapted to pollination by a very specialised group of moths which lay their eggs within the flowers.  The reward for these moth pollinators is a brood site for their caterpillars, which feed on a proportion of the developing seeds of the Yucca plant.  In contrast the flowers of Cordyline australis are small and produced in very large numbers in dense inflorescences.  They are also highly fragrant, to which anyone who has grown one of these plants to maturity in their garden can testify.  The fragrance attracts a range of insects which feed on the nectar produced by the flowers and so pollinate them in the process.  It is these differences in flower structure, more than characters of stems and leaves, which taxonomists use to classify such plants.

Until recently large New Zealand Cabbage Trees were a feature of many front gardens across Northampton.  Some particularly fine examples were to be found along the Kingsthorpe Road between Osborne Road and Balmoral Road.  I suspect that the largest Northampton specimens were planted in the 1970s, perhaps because people wished to recreate something of the exotic feel of package holidays to Spain and Portugal.  Following the freezing weather of December 2010, the growing tips of most of Northampton’s New Zealand Cabbage Trees were killed and the top growth gradually withered and died.  I was sad to see this happen to my own plant, a medium-sized specimen that I had rescued from a skip at the University several years ago, and which had become well established in my garden.  However later in 2011 my plant, and those in neighbouring gardens, re-sprouted from its deep tap root and started to produce multiple rosettes of leaves around the base of its dead trunk.  Give it a few years and Northampton gardens will once again be crowned by these exotic imports from the Southern Hemisphere.  I moved house in early 2012 and wasn’t able to take my rescued plant with me, but I have a feeling it will survive many more cold winters to come.

Names matter to biologists, indeed to scientists of all types.  They signify and tell us things beyond just the words themselves.  To give a very personal example, a few people have asked me why I chose the title “Professor of Biodiversity” rather than “Ecology” (my main area of training, though confused in some peoples’ minds with New Age philosophies); or “Biology” (a much broader designation than I feel comfortable with); or even “Pollination Ecology” (narrow, to the point, but too restrictive).  After a LOT of thought I chose “Biodiversity” because it very broadly reflects my interests in the whole of Earth’s life forms, the interactions between these species, and how they come together as assemblages, communities and ecosystems.   But I’m also interested in the history of our understanding of biological diversity and this title gives me scope to pursue those interests too.

It’s all in the name.



Filed under Biodiversity, Charles Darwin, Gardens, History of science, Pollination, University of Northampton

Wrestling the oiled serpent

Understanding the Earth’s biodiversity is not just about knowing where organisms are currently found, their interactions and community structure, and the threats to them and how they can be conserved.  It is also about understanding the evolutionary origins of that biological diversity.  With this in mind I was interested to read a number of news reports over the last few weeks about the relationship between science and religion, including a piece on a debate between scientists and theologians on the origin of the universe, and the removal of a young Earth creationist perspective in an exhibition about the formation of the Giant’s Causeway.

Whilst religious and scientific views of the universe are not necessarily incompatible, literal interpretations of the origin of the world and its biodiversity are clearly at odds with our understanding of the diversification of life through evolutionary processes.  Reading these reports brought back memories (not all of them positive) of an event I was involved in a few years ago.

Back in 2006, Northamptonshire Creation Group (motto: “Let true science speak” [sic]) approached our former Vice-Chancellor with the suggestion that the University of Northampton might care to put forward a speaker to debate creationist versus the evolutionary world views with a prominent Australian creationist who was undertaking a fairly high profile lecture tour of the UK that year.  I was asked if I was interested in taking part and agreed because I have a long-standing interest in creationist arguments.  One of my main research areas, the ecology and evolution of plant-pollinator interactions, is claimed by some to be one of those (supposedly) wonderful examples of how God has created precise interactions between species which could not possibly have evolved.

Richard Dawkins and others have argued that scientists should not be engaging in such debates  as this because it gives creationists publicity and a credence that they do not deserve.  However my perspective has always been that creationists are not going to go away and their influence on school curricula, for example, needs to be tackled head on.

This debate, in front of an audience of about 200 members of the public, colleagues and students, was undoubtedly the most difficult thing I’ve ever had to do professionally:  we were each given 15 minutes to present our case and that is a very short space of time in which to summarise 200 years of scientific research supporting the validity of the evolutionary world view.  But I gave it my best shot and pointed out at the end of the quarter hour that, had I more time, there was so much more evidence I could have presented, evidence which supports the evolutionary hypothesis.

Hopefully, I went on,  I’d convinced some of the audience of the validity of that way of viewing the world and the life it sustains, though I didn’t imagine that I’d changed my opponent’s worldview.  He was clearly a man of great energy and commitment to his cause to have sustained his point of view for 30 years.  But I wished for his sake that he’d not wasted that energy on a debate which was over long ago. which in fact Charles Darwin thought was finished when he died in 1882.

Rather than squabble over the source of biological diversity, I continued, I would rather that these creationists spent their time and energy on trying to save biodiversity.  Human activity has put enormous pressure on the species with which we share this planet and whole ecosystems are being dramatically altered even as we argued that night.  If creationists really care about God’s creation of life, why are they not furious at the way humanity treats it?  Why are they not directing their passion towards saving it?

I thanked the audience for their time and attention and passed the floor to my opponent.  What followed was not the evidence based “creation science” [sic] I was expecting (having researched his previous claims on the subject of the Earth’s age, etc.) but a rapid-fire delivery of theological arguments.  Over those 15 minutes I counted 50 PowerPoint slides, a Biblical smoke and mirrors approach to arguing evolution.  Interestingly, it was clear when he was loading up his presentation that he had about 8 different “Northampton lecture” that he could choose from, depending upon the tack that I took.  Had I gone for a theological approach to the debate, he would have argued “science” I am sure.

After our presentations we had an opportunity to ask one another one question before it was opened up to the audience.  The question that was addressed of me is one that to this day I don’t really understand.  To paraphrase he asked:

“Can you provide a single example of a species which has evolved into another species, without reference to the assumption that evolution has already occurred”

The second half of the question really made no sense to me and perhaps was designed to throw me off.  It worked: I asked my opponent to explain the question and received some heckling from nearby creationists who accused me of being evasive.  But he clarified his question: what he was really asking was, could I provide examples of species evolving recently.  I talked about antibiotic resistance in bacteria, insects which are now immune to pesticides, and also mentioned peppered moth evolution.  Then the debate was opened up to questions from the floor and the first thing I was asked (by a smirking creationist) was what the peppered moths had changed into: other moths or something different?  I explained the difference, in timescales and outcome, of microevolution and macroevolution.  But that was lost on him.

There was also a question about why peacocks and other species were so beautiful, if not for human enjoyment?  I spoke about sexual selection but my opponent countered that sweet peas in his garden were never visited by bees because they self fertilise, so why are they still attractive?  I suggested he grow some different Lathyrus species, ones which had not been selectively bred by people.

So it went on, trading example for example, neither side giving any ground, until we ran out of time .

The woman who asked me the question about beauty happened to be of Afro-Caribbean descent, and came up to me afterwards when the formal debate had ended.  She forcefully asked how I could support a theory which, according to her, stated that “black people are closer to apes and therefore lower on the evolutionary ladder than white people”.  I firmly explained that evolution says nothing about racism and “Darwinian” arguments about racial superiority were a later bastardisation of Darwin’s original ideas.  But to no avail:  the woman “knew” Darwin was a racist; everyone in her church knew that.

Another post-debate exchange with a creationist went something like:

Him:  Darwin states in Origin of Species that the fossil record was insufficient to support his ideas.

Me:  That was 150 years ago.

Him: Yes, but Darwin said it.

Me: But that was 150 years ago; as I showed, we have acquired an enormous amount of new fossil data since then.

Him:  But Darwin said it and he’s the father of evolution.

Me: But he was only one scientist and that was 150 years ago.

Him: But Darwin said it.

Etc. etc. etc.  Darwin seems to have an almost mythic, bogey-man status amongst creationists, as if everything he wrote HAS to be true and if it’s false then evolution is not true.  A weird interpretation of how science works.

At the end of the evening I went home exhausted and not a little depressed.  Wine was drunk and the evening dissected and I wrote up some notes about the event, including the title of this blog.  That phrase struck me as a suitably Biblical description of trying to have rational arguments with creationists: well greased serpents will always have a way of squirming out of the grip of logic and evidence, whilst throwing distracting coils around your limbs.  I don’t regret taking part in the debate but I’m not in a hurry to do another.


Filed under Biodiversity, Charles Darwin, Creationism, Evolution, University of Northampton

Lend us a Darwin?

It’s been a momentous month for science, following the announcement that the CERN group have found the first hard evidence of the existence of the predicted Higgs boson.  Finally we seem to be getting to the crux of what matter actually is, funded by sums of money that those of us involved in biodiversity, ecology and conservation research cannot conceive.  The journalists have clearly enjoyed their role of demonstrating that they understand the highly technical concepts explicit within the Higgs quest.  But why is it that some science writers seem to be able to “get” the most complex of theoretical physics yet struggle to understand what the environment is and why it is important to understand how it functions, its current state, and its preservation?

In sharp contrast to the CERN coverage was a rather silly analysis by BBC correspondent Michael Easton.  His piece concluded that the idea of the UK as a predominantly urban country is a “myth” because the UK National Ecosystem Assessment has found that “6.8% of the UK’s land area is now classified as urban” and further that “78.6% of urban areas is designated as natural rather than built”.  Therefore, in Easton’s opinion, the proportion of the UK that is built upon is 2.27%, ergo, the rest is natural and everything’s ok.  I’ve searched for both of those quotes in the document that he cites but can’t find them.  But leaving aside sloppy scholarship that would shame a first year undergraduate, to focus purely on the directly urbanised fraction of this country ignores the fact that over 40% of the country is designated as “enclosed farmland” with much of the remainder devoted to agriculture of one form or another.    That agriculture supports the urban population, of course, and so the urban “footprint” extends far beyond the physical infrastructure of our towns and cities.

Easton’s analysis assumes that because it’s green, it’s natural.  Which ignores the fact that the majority of our “green and pleasant land” supports only a limited biodiversity.  The notion of what is “natural” is a complex one and can’t simply be equated to attractive landscapes with lots of trees and green fields.  That’s no more “natural” than an aesthetically pleasing painting; both are human constructs and both reflect human interpretations of the world.

The problem with these kinds of ad hoc analyses by journalists is that people who read them assume it’s based on solid evidence and that the writer knows what they are talking about.  In this case, the statistics have been spun to suggest that that we should not worry so much about the UK’s environment because only about 2% is urbanised.  Urbanisation is not the biggest threat to biodiversity by any means and in fact urban environments can support greater levels of biodiversity than “countryside”.

It was therefore nice to see the publication of a perfectly timed study by David Tilman and colleagues showing that biodiversity loss has a greater impact on how ecosystems function, in terms of productivity, than other factors such as nitrogen deposition, drought, increased carbon dioxide, fire, etc.  This is mega-ecological research at CERN-like scales involving thousands of measurements in 11 long-term studies, some lasting over a decade.   It’s the kind of science we require if we are to understand how the loss of biological diversity might affect the environment on which we depend.

One evening last week I took up an invitation to speak to a group of students from Emory University in the States, currently staying in Oxford for a summer school.  They were an attentive lot, and the politest and best dressed group of students I’d ever encountered, though in fairness my talk followed a formal dinner at Regents Park College, their British base.  I began by asking if anyone had a £10 note.  A few held one up and were able to identify the profile of Charles Darwin and the fact that there were images of a hummingbird and flowers, plus HMS Beagle, printed on one side.  “That’s how important Charles Darwin (and pollinators) are to us” I stated “We put them on our money!” 

That’s perhaps stretching the point a little as Darwin’s interest in hummingbirds was limited – on its release the £10 note was originally criticised by Steve Jones as “there are no hummingbirds on the Galapagos Islands”.  True, but it was the whole voyage which inspired Darwin’s ideas, not just his brief visit to that archipelago, and hummingbirds are to be found across mainland South America.  Darwin certainly mentions seeing them in a couple of his Beagle notebooks, which are searchable online.  The great man also had a strong interest in flowers and pollinators, so the images are more fitting than Steve Jones believes.  In any case, a “Darwin” quickly became British slang for a tenner and “Lend us a Darwin?” is a useful shorthand when borrowing money from friends.  As a brilliant writer and explainer of complex ideas, Darwin was a science populariser long before the distinction was made.  Many of his books were best sellers in their day and all were founded on solid data and examples gleaned from his contacts around the world.  Current science writers could learn a lot from him.

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Filed under Biodiversity, Charles Darwin, Pollination

Scientists Must Write (and Speak and Listen and Review and Edit)

“Scientists Must Write” was the title of a book published back in the late 1970s by a former tutor of mine, Robert Barrass, at what was then Sunderland Polytechnic (now the University of Sunderland).  I had assumed the book was now a long gone publishing memory and no longer available.  But it turns out that Robert updated it in the early 2000s and it’s still in print.  Almost 30 years (30!) later I can clearly remember Robert impressing upon us the importance of good writing skills for scientists-in-training.  At the time I was as far from being a professional scientist as it’s possible to be and so didn’t fully grasp this, but nonetheless what he said chimed with my own notions that writing was important, even for a scientist.

Nowadays I realise that it’s not just the writing of standard, academic papers, book chapters and books which  is essential: writing of all kinds is a necessary facet of the life of a research active scientist.   This June sees the publication of two contrasting articles that illustrate this point.  The Royal Horticultural Society’s journal The Plantsman has published a piece entitled “The Importance of Native Pollinators“, whilst the historical journal Notes and Records of the Royal Society has published my paper on “John Tweedie and Charles Darwin in Buenos Aires“.  Neither of these is standard academic fare, at least for me.  The first is a popular article aimed largely at gardeners and others interested in understanding more about pollinator conservation.  The second, whilst academic and rigourously peer reviewed, is primarily historical rather than scientific.

Why am I writing popular conservation articles and historical papers?  Largely for different reasons, though they are linked by my overall fascination with biodiversity.  The Plantsman article is an example of taking ideas and findings from the LBRG‘s research and presenting it to a wider audience who might, at the least, find it interesting and hopefully useful.  One might describe it as “popular science” though I don’t really like the term: it suggests that it’s somehow different to “real” science, which is not the case: it’s really only the format of the presentation which is different.

The John Tweedie/Charles Darwin paper reflects my desire to understand where our scientific knowledge of biodiversity comes from.  As scientists and conservationists, we draw conclusions about species’ distributions, conservation threats, extinctions, and so forth, based on information from specimens that have been collected by people like Tweedie and Darwin, and curated at places such as Kew and the Natural History Museum.  By its nature it’s a historical process and historical research helps us to understand how we arrived at our current understanding.  The only reason we know that 23 species of bee have gone extinct in England since about 1800 for example, as I cite in my Plantsman article, is that over the past two centuries specimens and observations have been recorded and analysed.  This is an ongoing process, exemplified by the BWARS project mapping the spread of Bombus hypnorum   the most recent addition to the UK’s native bee list.

As well as writing we scientists gain much from listening to what others in our field have to say and a well attended, and very interesting, meeting in London last week launched the British Ecological Society’s Macroecology Special Interest Group .  The range of talks spanned community structure, interaction networks, ecosystem services, latitudinal gradients and disease biology, all at the large spatial and temporal macroecological scales covered by this subdiscipline of ecology.  Or is it really a multidisciplinary field, a merging of old fashioned biogeography with more modern ecological approaches?  Who knows, perhaps this is sterile semantics; as I mentioned to one of the organisers in the pub afterwards, “macroecology” seems to me to be more about a philosophy of approach rather than a field in itself.

Formal teaching has largely finished for the time being, so in addition to research activities and university administrative work, much of the remainder of the last couple of weeks seems to have been taken up with editorial and peer reviewing duties for journals, including PLoS ONE, for which I’m an academic editor. This can be time consuming and thankless, but is absolutely vital if the whole system of scientific publishing is not to grind to a halt.  Scientists must write, but that writing is supported by a body of individuals who act as peer reviewers, editors, proof readers, and so forth.  Collectively that eats up a lot of scientist-hours and is something we should never take for granted.


Filed under Bees, Biodiversity, Biogeography, British Ecological Society, Charles Darwin, Ecosystem services, John Tweedie, Macroecology, PLoS ONE, Pollination, Royal Horticultural Society, Royal Society, University of Northampton