Angels, dinosaurs and artists’ impressions

We have long used optical telescopes to view distant objects, both living and non-living, making them easier to identify. More recently, technology has provided us with telescopes that record information transmitted over vast distances, allowing us to see distant stars, and even to look back in time as we view the expanding universe.

Similarly, optical microscopes reveal much more than we can see with the naked eye, and electron microscopes, of both scanning and transmission types, make very minute structures visible, although preparation methods require that care must be taken in interpreting what we see. Advances have also been made in the analysis of living and non-living materials that enable us to look at traces of organic chemicals from small samples and, using these approaches, we can analyse the composition of fragments and relate these to their origins. The commonplace use of an individual’s DNA in a blood stain is just one example.

Even armed with this information, we need expert analysis of what we see to make sense of it and this is aided by visual imagery, either generated by computer technologies, or by the hand of an artist. Artists’ impressions are invaluable in re-creating images of things that are no longer present and which we therefore have no chance of seeing. An example comes in the very numerous portrayals of religious scenes, where we are frequently shown images of Jesus, although we have no record of how He looked. The same goes for God, the disciples and all the other characters, as well as Heaven and Hell.

Other beings in religious paintings are given a physical presence that is unlikely or symbolic. The Holy Spirit is frequently depicted as a white dove, while angels have a characteristic appearance that we all recognise [1], with bird wings on a human body that also has arms (an example by Tiepolo is shown above). Taken as being real, these angels would not be able to fly, as the wings of birds have developed from the fore limbs of their reptile ancestors. With arms already present, the wings of angels, and the muscles to operate them, must be located quite differently on the body (I’m not suggesting here that angels do not exist, but that their physical form in paintings and sculpture means that they cannot fly using their wings). It’s an example of where artists’ impressions are very useful in creating images that subsequently have "reality".

Another world that fascinates us, and of which we have no direct knowledge, is that of dinosaurs. We’ve never seen a dinosaur (although there are some modern-day reptiles, like crocodiles, that give us some clues as to behaviour), so how do we know what they looked like and how they lived? We have evidence from which to work, unlike the images created of angels, where there is no fossil evidence. Bones, skin, muscle attachments, and feathers (where present) allow us to reconstruct dinosaurs and then put them into an imaginary landscape. We accept these images, and models based on them, because we believe what experts tell us (quite rightly?). The images are also informed by speculation. In Benton’s book on dinosaurs, with its catchy sub-title [2], we read that the discovery of pigment cells meant that “for the very first time, we knew the colour patterns of a dinosaur, and could use these insights to speculate about dinosaurian behaviour”. Can we really gain information about dinosaur behaviour from colour patterns? Perhaps we can. Later in the book, Benton describes the swimming of Stenopterygius, an ancient reptile from the Mesozoic: 

Stenopterygius swoops after a belemnite, an extinct relative of modern squid and octopus. The belemnite has a fleshy body and fins and swims backwards, just as modern cephalopods do. We know, too, that it has an ink sac, and so, like its modern relatives, likely squirts ink when alarmed, and zips off by blasting jets of water through its siphons. By the time the predator has recovered and snapped a few times at the ink cloud, the belemnite has long disappeared to safety. 

The Stenopterygius is not too fazed, as this is not an infrequent occurrence, and he lines up to chase another group of belemnites. 

Is the language a little flowery here? Admittedly, the book was written for a general audience, and books about dinosaurs sell well, but how critically do we, as members of the public, consider what is said by popularisers?

Further in Benton’s book [2], the dust cover of which shows Tupandactylus in flight (see above), we read this about head crests in bird-like dinosaurs: 

[It is] suggested that such prominent head crests and beaks sheathed in keratin as are seen in various dinosaurs and pterosaurs might have been photoluminescent.. ..[and] we can imagine the elaborate head crests of Tupandactylus flashing different colours at dusk, males and females perhaps showing different patterns, and putting on a spectacular in the crepuscular gloom. 

Please note the use of the words “suggested”, “imagine” and “perhaps” in this quote.

Moving images take artists’ impressions one step further and we are entertained not only by coloured images of landscapes, but also grunts and hisses from different dinosaurs. There is a good selection in the video linked in [3], (complete with an accompanying musical soundtrack to add tension to each scene). How much of this is supported by evidence? I accept that teeth marks on bones correspond to the dentition of certain dinosaurs, but the rest of it?

As we know, dinosaurs are not only important in palaeontology, but also in entertainment and in retailing. Go into any home with young children and you will find many dinosaur-related toys, pyjamas, t-shirts etc. and there is a popular fascination with mythological dinosaurs like the Loch Ness Monster and Sea Serpents. While there are artists’ impressions based on the sightings of the latter two, that is all we have to go on and the transformations of known dinosaur types that appear on clothing, or as toys, may be very far from the creatures that existed hundreds of millions of years ago. Steve Brusatte, reviewing Bentons’ book (see above) remarks that the images of dinosaurs it contains are real and can be used by media professionals, but is this so? Is there a point where palaeontologists can get a bit carried away with their liaison with the world of entertainment?

One important view of science is that it is based on falsifiable hypotheses and this is an approach that I have tried to follow in my research. However, falsifiable hypotheses are not possible with extinct animals (and plants) and, however ingenious our attempts, we are bound to make suppositions about the effects of time: we can design experiments that last hundreds of millions of years, but it is impossible to get the results. It means that palaeontology, including the study of dinosaur fossils, is a highly-informed guessing game, with some practitioners and artists going further into the world of imagination than others. Thus, the need for caution.

 

[1] Roger S. Wotton (in press) Birds and Christian Imagery. In Winged Worlds (eds. Olga Petri and Michael Guida). London, Routledge.

[2] Michael J. Benton (2021) Dinosaurs: New Visions of a Lost World. London, Thames & Hudson.

[3] https://www.youtube.com/watch?v=ZzXGSFVbVvU&t=847s&ab_channel=BBCEarth

Natural history and COVID-19

 

Every evening, I watch the BBC News to get the latest data on COVID-19, supplemented by images of patients in intensive care, and knowing that their numbers are increasing. It’s grim for all of us and, as I have a temperament like A. A. Milne’s Eeyore, I feel a strong need to escape from the current situation. I do this by reading and by walking. 

Taking a break from a succession of novels by Anthony Trollope, I have thoroughly enjoyed “The Consolation of Nature: Spring in the Time of Coronavirus” by Michael McCarthy, Jeremy Mynott and Peter Marren [1]. The three authors all write beautifully about their observations of Nature, set against the backdrop of the first wave of the pandemic. This coincided with the glorious weather of Spring 2020 and the book ends with the easing of lockdown and the transition into summer. 

Michael lives near Kew, Jeremy in Suffolk and Peter in Wiltshire and they all kept diaries of the local walks they made; entries being edited during joint sessions held to fit the publishing schedule. As Jeremy writes in a splendid blog post on the “Winged Geographies” website [2]: 

There was another, self-imposed intensity to the writing, since we agreed with a publisher at the outset that we would deliver a complete typescript in June if they would publish it in October, a demanding schedule that had us every day walking out from our front doors to see what we encountered, notebooks in hand, writing up our discoveries later, and then sharing our copy every evening for some rapid and ruthless joint editing. In the event, working so fast was surprisingly liberating – our experiences not so much ‘recollected in tranquillity’ but penned with an al fresco spontaneity. 

Jeremy’s post also provides an excellent taster for the book. I love the enthusiasm expressed in “The Consolation of Nature” (even forgiving the occasional lapses into anthropomorphism) and I wish I had the skill of the three authors in being able to identify all that they saw, especially the birds. As they remark, many birds are identified by their song and, unfortunately, this is something that I never learned and never will learn, as I am now rather deaf to high frequency sounds. I can recognise the commoner birds by sight, and was able to identify most of the butterflies and some of the wild flowers that I saw in the warm spring, but it was the smells of the walks that most affected me. The scent of honeysuckle always bowls me over and Michael describes the familiar aroma of elderflowers and Peter the characteristic smell of privet, the latter always taking me back to the warm days of my childhood and walking through the local park to go trainspotting. That association works every time for me. 

Some sections of “The Consolation of Nature” had a special appeal for me and these are given below in the form of a dialogue. They are just a small selection of my responses to the many delightful observations in the book. The initials of the author of each quote are given, together with my comment: 

JM – [In discussing the names of moths] …you can have a pretty good evening just reading the index of a moth fieldguide!… …it will be a spiritual tragedy if we risk losing, along with the moths, this treasury of the most extraordinary and beautiful names given to any animal group. 

RW – Agreed, but among many other groups, I think the extraordinary and beautiful names of sea anemones run those of moths very close [3]. 

PM – [Who has chalk streams in his walking “patch”] In chalk streams, most of the small life of the river clings to the underside of stones, or finds other refuges in the waterweed – our champion ranunculus, which puts forth its gorgeous yellow-centred white blossom in May (its botanical name is the stream water-crowfoot). 

RW – I also live within walking distance of chalk streams (that are very rare worldwide). In addition, I have been involved in a research project that investigated “ecological engineering” by Ranunculus. Individual stands of water crowfoot alter the pattern of flow in streams and this serves to keep the finely-divided leaves at the margins clean, while sediment builds up under the plant to provide nutrients. The leaves of each stand are also colonised by huge numbers of tiny invertebrates that transform organic matter, so each plant is a mini-ecosystem of its own. 

PM – [On a visit to a spring feeding a chalk stream]. I fish about in the gravel bed to see what is living in these gin-clear cold springs. Looking down on it, you would think the water to be near lifeless, but remove some of the stones into an enamel dish and life appears, scuttling, wriggling, crawling, or, in the case of the tiny black limpets anchored to the flints, just sitting there. There are caddis cases attached to the stones, a few young stonefly nymphs with their double-pronged tails, and numerous shrimps, named Gammarus pulex from their resemblance to Pulex, the flea. There are also skeletons of last year’s leaves, as black as Florentine lace. 

RW – As we are terrestrial animals, we are not familiar with aquatic life, whether marine of freshwater. As Peter points out, taking some stones from a stream and placing them in a dish of water shows us what is living there. The limpets move slowly over the surface using a rasping tongue to feed on algae and bacterial biofilm adhering to the rock. Stonefly nymphs are either predators or feeders on detritus, and the freshwater shrimps, often very abundant indeed. feed mainly on decaying vegetation – contributing to the lacy appearance of the leaves provided by the strengthened veins that are less favoured in the diet of the shrimps. Gammarus is found throughout the year, so what sustains the high population densities, other than the supply of vegetation in autumn? I think I know the answer, but interested readers should seek out research papers on the topic to find out more (with apologies for the sense of mystery). 

PM – [Describing his observation of “pond slime” using a binocular microscope]. I have to say that, even as pond slime goes, this isn’t prime material. This is very low-grade gunk. The delight I used to take in microscopy as a boy was in large part due to its revelation of beauty in surprising places. There are wonders in the leg of a flea, the tongue of a fly, even the guts of a worm. The disgusting sludge on your slide dissolves into a microcosm, the world of single cells, shaped like stars. bananas, violins, boats (one of the commonest algae is Navicula, the ‘little ship’). 

RW – I spent much of my research career looking at material using a binocular microscope. Not only did that provide insights into a world hidden to the naked eye, but it also enabled measurements to be made and, after various stains were used, the ability to see the location of materials on/in the bodies of organisms and in the slime to which Peter refers. Then, a compound microscope allowed observation of organisms and detritus at a yet finer scale, including bacteria and other microorganisms. When I retired, I decided to leave that world behind and I have rarely used a microscope since. What I can never forget is all that accumulated knowledge and I carry it with me on walks. It gives me a sense of understanding of what might be going on at a very fine level and adds a great deal to my enjoyment of Nature – alongside the birds, insects, wild flowers, trees and all the rest. As readers of “Walking with Gosse” will know, I was introduced to microscopy as a boy and was delighted to spend half hours in the tiny world, to quote the title of a book published at the end of the 19th Century. That century saw the development of the passion for natural history, and books by some talented authors, of whom Michael, Peter and Jeremy are the literary descendants. 

JM – [When considering the world of fungi] People sometimes recoil from fungi, because of their associations with decomposition and their other-worldly appearances, but they play a crucial role in the world’s nutrient cycles and ecology. 

RW – Much of the folklore associated with fungi comes from our observations of fruiting bodies and most of us know little about the mass of filaments that form the mycelium. Yet it is these filaments that are involved in decomposition and there are very many fungi that do not have obvious fruiting bodies. Together with the bacteria, they are the great decomposers and, as Jeremy says, they have a vital role to play in the turnover of organic matter. It is the colonisation of dead leaves by decomposers that makes them attractive as food for animals like Gammarus and many terrestrial invertebrates and they, in turn produce masses of faecal pellets. If decomposition incites recoil in people, a consideration of faeces does so even more. Yet our compost heaps contain extraordinary numbers of pellets and it is these, together with their colonising microorganisms, that provide many nutrients for growing plants. 

MM – Beauty right in front of me, beauty in the distance – it is a fitting end to the coronavirus spring, the loveliest spring that ever was. I have never looked so closely at nature before, and I think I have learned something worthwhile: the more you observe it, the more there is to observe, and you realise that the richness of it is infinite. 

RW – I agree so much with this statement in the coda of “The Consolation of Nature”. We are discovering more and more, yet that makes us realise that we know only a smaller and smaller fraction of what is out there – the infinite to which Michael refers. Towards the end of my research career, I realised that I could never get answers to the myriad of questions that I had about how ecosystems actually “worked”. It was humbling and I turned to other types of research, but I will always be a natural historian and my knowledge accompanies me on my solitary walks. There is so much to see, hear and smell throughout the year. 

Reading “The Consolation of Nature” in this second, major wave of COVID-19 makes it easy to conjure up how we felt in the first half of 2020. We have yet to have the warm and sunny days described and, indeed, the bleakness of the data on the pandemic are matched by the current bleakness of the landscape. Yet there is still much to see and I walk as regularly now as I did then. Solitary walks in nature have always appealed to me and I know of their beneficial effects [4]. However, there are occasional disappointments. The image below was taken in one of the country lanes that is part of a favourite walk of mine and, on seeing the fly-tipped refuse, I initially felt anger that then softened as I walked on. Maybe it was a case of “out of sight out of mind”, but I certainly remembered the unsightly mess and I wonder whether the people who dumped it have any appreciation of Nature at all? Our local Council is good at cleaning up this kind of mess (unfortunately, it occurs fairly often) but, even if they didn’t, plants, animals and microorganisms would get to work on it and either decompose the contents or hide their presence.

As I wait, with millions of others, for vaccination and the first signs of the Spring so well described by McCarthy, Mynott and Marren, there’s still an exhilaration in solitary walks and also in the simple pleasure of watching birds in the garden. A consolation indeed and I’m lucky to be aware of so many aspects of Nature and yet so few. It keeps “Eeyoreness” at bay.

 

[1] Michael McCarthy. Jeremy Mynott and Peter Marren (2020) The Consolation of Nature: Spring in the time of Coronavirus. London, Hodder & Stoughton.

[2] https://www.wingedgeographies.co.uk/post/the-consolation-of-nature-spring-in-the-time-of-coronavirus

[3] https://rwotton.blogspot.com/2019/09/pufflets-pimplets-and-muzzlets-gosse.html

[4] https://rwotton.blogspot.com/2014/10/solitary-walks-in-nature.html

 

Gosse, Elgar and the wonders of microscopy

Philip Henry Gosse was at the forefront of popularising the use of microscopes and in his book Evenings at the microscope; or researches among the minuter forms of animal life,¹ he writes: “Great and gorgeous as is the display of Divine power and wisdom in the things that are seen of all, it may safely be affirmed that a far more extensive prospect of these glories lay unheeded and unknown, till the optician’s art revealed it. Like the work of some mighty genie of Oriental fable, the brazen tube is the key which unlocks a world of wonder and beauty before invisible, which one who has once gazed upon it can never forget, and never cease to admire.” Even through this expression of the religious ardour that dominated Henry Gosse’s life, it is easy to feel his amazement at what he saw and he conveyed this both to his friends and, through the book, to a wider public.

Microscopy became a popular pastime of the Victorian middle classes, once quality microscopes became less expensive, and an industry then developed in supplying slides of mounted specimens, often having elaborate paper labels or covers.² While Henry Gosse, as a zoologist of note, described animals and parts of animals through 21 chapters of vivid description and with 113 of his own illustrations in Evenings at the microscope, algae were also a major fascination for Victorian microscopists, and the most important of these algae were the diatoms. These single cells (which may also form colonies or filaments) live within a coat of silicates termed a frustule, having two opposed valves that are secreted by the alga. The coats have characteristics unique to each species and provide the diagnostic features used in their classification. Victorian slides of mounted diatoms show not only an interest in individual algae, but also in the arrangement of frustules into “artistic” patterns.³ This tradition continues today in the work of the brilliant Klaus Kemp.⁴

 

Looking at diatoms provided inspiration in some unusual quarters. In his article in Gramophone of June 1957, published to mark the centenary of Edward Elgar’s birth, the author and raconteur Compton Mackenzie quotes this exchange with Elgar: “'Not that I care,' he growled quickly. 'I take no more interest in music. You'll find as you grow older that you'll take no more interest in literature. The secret of happiness for an artist when he grows old is to have a passion that can take the place of his art. I have discovered the joy that diatoms [my emphasis] can give me. This miraculous world of beauty under the ocean revealed by the microscope is beyond music,' and he went on to expatiate on the exquisite patterns formed by these fossilised algae and the spiritual comfort that observation of them brought to his mind.”⁵ The conversation from which the quote is taken took place in 1923, when Elgar was 66 years old. Although a famous and great composer, Elgar was prone to bouts of self pity and the quote is a reflection of one of those moods, but no-one can doubt his fascination for microscopy, the same fascination that Henry Gosse had done much to popularise over sixty year earlier. (By the way, for those of you who enjoy coincidences, Elgar was brought up in High Street, Worcester, the same street in which Henry Gosse was born many years before).

In the Natural World, diatom frustules are found extensively in the sediments of water bodies, from ponds to oceans. It may be thought that the coats developed to deter predators, and some of the more spiky types may do so, yet diatoms are fed upon by zooplankton and other animals, just as are algal cells without that protection. The result is not only the sedimentation of the frustules of dead algal cells but also of the frustule-loaded faecal pellets of animals which have eaten the algae. All fall through the water and accumulate over the bed. By taking cores, we can therefore know which species have been present in the surface waters through time, just as we can record the presence of plants by the types of pollen we see in cores taken from soil profiles. The deposits of diatom frustules can be so packed that they result in “diatomaceous earth” or diatomite, familiar for its many applications in industry after it is extracted by mining, or the use of quarrying techniques. These, of course, are ancient deposits and will have lost the clear stratification which occurs over short time periods of hundreds of years and where the contents of the annual layers of sediment can be recorded. We use information from these strata to date accurately the appearance of various species of diatom that we know are indicators of certain chemical conditions, or temperature regimes. In this way, diatoms give us a means of recording changes over centuries and much research has focussed on this use frustules. For example, changes in the diatom flora occurred after the Industrial revolution in Europe, when acid precipitation became a major feature and lakes changed in water quality. They are also used to show changes which have resulted from global warming.

Such practical applications do not detract from the beauty of diatom frustules, so stunning when observed under the microscope, especially under special lighting. It is easy to comprehend Gosse’s conclusion that we are witnessing “the display of Divine power and wisdom” but, for those that do not believe in the chronology of events described in the book of Genesis, there is an equal, or perhaps greater, sense of awe. One is left with the question: How and why did diatoms evolve their many varieties? The fossil record shows that they have existed for tens of millions of years in forms that are recognisable today⁶ and we can only speculate on the steps that occurred in the evolution of the siliceous frustule before that. It’s the frustule that makes diatoms so popular and useful but that is only the covering of the living algae, which are so important in trapping carbon dioxide through photosynthesis and thus playing a major role in the metabolism of energy in fresh waters, marine coasts and the oceans.

¹ Philip Henry Gosse (1859) Evenings at the microscope; or researches among the minuter forms of animal life. London, Society for Promoting Christian Knowledge.

² http://www.livescience.com/16841-victorian-microscope-slides-gallery.html

³ http://www.victorianmicroscopeslides.com/slidedia.htm

⁴ http://www.diatoms.co.uk/

⁵ http://www.gramophone.co.uk/editorial/elgar-remembered-a-centenary-tribute-by-compton-mackenzie-gramophone-june-1957

⁶ http://www.ucl.ac.uk/GeolSci/micropal/diatom.html