Pterosaur Palaeobiology: a paradigm for palaeontological research in a postmodern world
As a child I loved science, obsessed with dinosaurs, planets and stars and the natural world. However something happened at secondary school and I gravitated towards the arts, although I spent a brief time working in a science centre. Thus the title of Dave Unwin’s research seminar on Wednesday 28 November 2007 was quite daunting at first, all those long, hard to pronounce words. However the seminar had been billed as requiring no ‘prior knowledge or technical expertise’ which was comforting, for since my flirtation with dinosaurs as a child the last time I had seriously thought about the subject was at a museum in New York over a year ago.
The seminar was an opportunity for Dave to introduce his research area to the rest of the department. Broadly speaking this is to reconstruct the history of life from millions of years ago to the present day and to find out why certain life-forms appear to dominate over others. For example why is it that we as humans are sitting in a lecture room discussing the development of life, as opposed to bacteria, dolphins or cockroaches? Immediately this impressed upon me that even though as researchers we look at completely unconnected areas in fact we are all trying to answer the same questions effectively – why is the world or phenomena under study like this and not something else? However as Dave pointed out, palaeonbiologists are perhaps even more ambitious in that they are trying to reconstruct events beginning over 3.5 million years ago! The mind boggles as to how this is possible but Dave’s talk was very good at introducing us to the basic methods which he uses, specifically in his study of pterosaurs, also known as pterodactyls, in other words flying dinosaurs.
Dave takes a holistic approach to the study of pterosaurs, seeing the organism as an integrated whole and looking broadly at the following themes:
- Taxonomy (how many species there are)
- Phylogeny (relationships between species)
- Locomotion (flying and walking)
- Reproduction and growth
- Evolutionary history
As he talked through each of these themes a wealth of detail was uncovered, some of which was quite surprising. Most of our knowledge about pterosaurs comes from the fossil record and the first pterosaur fossil was found as far back as the 1780s. However they are incredibly rare and, in Dave’s words, the entire number of pterosaur fossils in the world would fit in one corner of the lecture room. It seems to me to be like trying to recreate the entire of the Roman Empire using only a couple of pots! Pterosaurs also vary greatly in size and shape judging by the surviving fossils, with Dave bringing a real example of a fossilised pterosaur embryo to show us, amazing how it has survived being over a million years old. However he also described how pterosaurs with 10 foot wingspans would be possible; since pterosaurs came out of the egg with their wing membranes attached scientists have deduced that they could fly as soon as they were born, so unlike birds and bats there was potentially no limit to their growth. There is clearly more to these pterosaurs then the myths perpetuated by the toy dinosaur industry; I never could have thought that they would have been able to walk on their ‘arms’ and back legs in an fluid, rollicking gait had Dave not showed us the computer models. These in turn are based on the fossil record where tracks of pterosaurs walking have been found preserved, highlighting the amount of careful and patient work that must go into the smallest illustration.
Of recent political, possibly even ethical, interest are the amounts of fossils being turned up currently in China and former Soviet satellites; apparently Chinese farmers are digging up the landscape because they can make thousands selling the fossils to museums. One concern is that because in China entire eco-systems have been preserved, by happy accident frozen in time – rather like Pompeii in Italy – it is important to get in there and catalogue the findings before they are split up and sold. Dave is working on a research project with Chinese colleagues to investigate these fossilised eco-systems which will be able to tell us a lot more about life and how it interacted, which is not always possible from isolated fossils. As with all areas of human activity however it was interesting to find out that some fossils are ‘enhanced’ for cosmetic reasons before going on display in the museum – Dave showed us an example where a leg bone had been moved to make it more ‘attractive’!
This is only a very brief run through of Dave’s talk with only time to skirt over the issues very rapidly, however it reminds me that in creating a picture of our world, both now and in the past, we rely on the efforts of so many researchers and enthusiasts focusing on very specific and detailed areas and it is often inspiring to go outside your own specific area of interest and delve into another, albeit briefly.