In the last few days a piece of research has been published which could potentially change our approach to studying evolutionary patterns in the fossil record. So far I have only managed to read the press release and the abstract, so much of what I say could be a complete misunderstanding pulled from my backside. Since the 1970s there has been a debate in evolutionary palaeobiology with regards to the ways in which a lineage evolves. At times this debate has seemed like it has reached its peak, but then something changes the game. On my old blog I did a poorly formatted post explaining punctuated equilibrium, which may be some decent background reading, but I intend to do an update sometime soon anyway. Here is an attempt at a brief explanation of what happened in the debate:
Evolutionary biologists tended to assume that a species evolved with most change taking place within the lineage (often labelled phyletic gradualism).
In the 1970s, Eldredge and Gould came along and pointed out that the fossil record shows that a species appears geologically abruptly and changes little during their duration. Most morphological evolution takes place at speciation. This is called punctuated equilibria.
A comparison of the two concepts.
The introduction of punctuated equilibria caused rich debate, resulting in a lot of study into the patterns of evolution in the fossil record (and some additional concepts which will not be discussed here).
Examples of phyletic gradualism were found in the fossil record, as was another pattern, punctuated anagenesis, however, punctuated equilibria appeared to be the most common pattern.
One of the issues has always been the techniques used to study these patterns, not to mention, there is a degree of subjectivity when trying to determine which best fits the data (it is often not as unambiguous as the conclusions would have you think). The earliest studies, including those by Eldredge and Gould, tend not to be discussed, as techniques have been refined and many old examples are thrown out or surpassed. The new study claims to have used a technique which was previously unavailable and has some results which may have us scrambling back to the rocks for more samples, or reassessing old studies to see if our conclusions were wrong.
Old studies on evolutionary mode appear to have largely focussed on a single morphological trait, whereas this study looks at a suite of traits of a single lineage, and does so using several different species. They found widespread evidence for mosaic evolution, where characters change within a species at different rates. With this taken into account, analysing a single trait cannot give us enough information as to what is going on with the species; one particular trait might show a pattern which looks punctuated, another may show gradualism, yet neither show what is going on in the bigger picture. And, as is mentioned in the abstract, a single trait may show one particular mode of evolution, whilst the rest of the characters may show another, so the overall change does not fit with the first character.
I’d need to read the paper before I could say much more, but if what it claims is accurate, then this debate may be reignited. This could get interesting…
Earlier today I attended a talk by David Penney, a world expert on fossils in amber, particularly spiders. The talk was held at Doncaster Museum and Art Galleries, and will hopefully mean more palaeontological talks will take place there in the future. Penney is a researcher at the University of Manchester and also has his own publishing company, Siri Scientific Press, through which he has also written many of his own books, including the recent Fossils in Amber: Remarkable snapshots of prehistoric forest life, co-authored with David I. Green.
Fossils in amber are amongst the most stunning fossils you could possibly hope to see, so the talk was both informative and visually appealing. I find parasitism in the fossil record fascinating, so I am pleased that Dr Penney did not skip over some of the excellent examples which have been preserved in amber. Around this time last year the news broke that a spider had been preserved in amber, along with a mite who had come along for the ride and gotten preserved on its host (see here). It is an excellent example of the use of technology in studying fossils in amber. In the picture below you can see the spider in amber, as seen through a light microscope.
Palaeontologists studying fossils in amber use a variety of photographic techniques in order to get such beautiful imagery. There was an excellent article on these, authored by Penney and Green, in Issue 27 of Deposits magazine(see also Issue 26 for a great article on biodiversity in amber). They also use CT scanning in order to produce some incredible images which allow these fossils to be studied in detail. Below is the same spider, sporting its mite parasite, as seen through CT scanning (minus the legs).
Amber is an excellent source for studying behaviour in ancient life. Flies can be seen mating, parasites escaping their hosts, spiders on webs hunting prey, and more. Palaeocast recently did a podcast on parasitism in amber.
I’d love to say more about the talk, but I don’t think I could do it justice (especially as right now I just seem to be sticking the same adjectives in every sentence). I do recommend reading any articles and books by Penney, even if just for the beautiful images, you will almost certainly marvel at what has been found.
I managed to briefly get my hands (not pictured) on this cast of the holotype of _Charnia masoni_ last week. _Charnia_ will naturally be the focus of a post very soon, as it is one of the most important fossils from the Ediacaran.
I’ve decided to start my blogging with a “What is/are…” series as one must never skip the basics and it is always useful to be able to supply a handy link when someone enquires. We can’t all launch head first into the complex side of a subject and even the most erudite amongst us were at some point laymen. I’ve claimed to be a palaeontologist (of sorts) and sometimes people I meet haven’t a clue about what one does, or they harbour serious misconceptions, so here it is, an explanation in my own words.
I felt like including an image of myself. I’m not vain, honest…
What is Palaeontology?
Palaeontology, or paleontology to Americans, is essentially the study of ancient life (anything older than 10,000 years) through the traces they left behind (it is also the name of a journal, a copy of which just came through my letterbox). The most well known traces are body fossils, including those bits of bone which get the headlines, but most body fossils are shells of invertebrates and microscopic organisms (every time you look at a chalk cliff you are seeing billions of microscopic fossils called coccoliths). Another form of fossil is a trace fossil, which is essentially any remnant of animal behaviour which has been preserved in the rock record. These include burrows, footprints, bite marks, and even bits of poo (coprolites). The study of trace fossils is often called palaeoichnology. Ancient life can also be studied through chemical traces which they left behind, sometimes labelled chemofossils or biomarkers.
You may have come across other terms which start with “palaeo-“, such as ‘palaeoichnology’, which I just mentioned. Many of these are disciplines within palaeontology, studying something very specific. Palaeobotany is the study of fossil plants, palaeopalynology is the study of ancient pollen (and similar things), and palaeoecology is the study of ancient animal interactions (with each other and with the environment). Palaeoanthropology is the study of human evolution, a very small subset of palaeontology, yet it often gets the headlines. Palaeobiology is a term which can create confusion, as it is often used synonymously with palaeontology, though the palaeobiologist uses the findings of biology to understand the fossils; it might sound like an odd distinction to make, but some sub-disciplines in palaeontology do not require as much biology as others. I’m not done yet…
You may also come across terms such as ‘palaeozoology’ or ‘palaeobiochemistry’, but we also seem to like sticking extra words into our titles too. You’ll find vertebrate palaeontologists, invertebrate palaeontologists, micropalaeontologists (these study microfossils, they are not automatically tiny themselves), and even evolutionary palaeobiologists. And then there are those sub-disciplines which don’t even have palaeontology in the title. Taphonomy is the study of what happens when an animal dies, up until it becomes a fossil. Biostratigraphy is the use of fossils for correlating rocks, allowing us to work out how old they are. And then there are some less serious titles, such as ‘dinosaurologist’, but I have forgotten what they study. A palaeontologist is usually a trained geologist, naturally focussing on sedimentology, and is often also an evolutionary biologist. Perhaps we just love titles.
Palaeontologists engage in a whole range of research, studying life which spans nearly four billion years of Earth history. We reconstruct ancient organisms, work out how they lived, how they died, how they decayed, how they were preserved. We work out how they were related to other organisms and study how evolution has taken place through geological time. We study major diversifications and mass extinctions, not to mention smaller radiations and minor extinctions. Palaeontologists use fossils to work out the age of the rocks, the environments in which they were deposited, and even help work out where ancient continents used to be.
This research can be used in some interesting ways. Oil companies commonly employ palaeontologists (mostly biostratigraphers) to help them correlate rocks and work out the environment of deposition. Studies on extinction and evolution are useful for conservation, particularly when predicting how an ecosystem might react to change. As palaeontology is useful for studying climate change it can be used to understand what is currently going on with our planet. Studying our evolutionary heritage can also help us to work out why our bodies sometimes fail us and how we can deal with it. And, of course, some fossils just look very pretty and show us some fascinating organisms, which people like to see in museums and on TV.
Palaeontologists can be found in museums, working at universities, on oil rigs, writing books and blogs, on TV shows, and out in the field searching for new finds. If you find a palaeontologist wandering aimlessly in the street, please point him or her in the direction of the nearest museum, rock outcrop, or pub.
What a palaeontologist is not.
Not a palaeontologist.
Palaeontologists are often muddled up with archaeologists, with members of the public often saying “are you like Indiana Jones, then?”. Archaeologists study the history of man through artefacts, going back only as far as 10,000 years. They do not come close to the time-scales dealt with by a palaeontologist. Sometimes people say “like Ross from FRIENDS?”, which we hear all the time, but at least they are correct. We do not all study dinosaurs, in fact, most of us do not. Dinosaur palaeontology just happens to be very much in the public eye, so much so that many do not seem to know that things actually existed before dinosaurs (I die a little inside when people say that). Sometimes palaeontologists are depicted as bearded men, out in the desert, getting rough with the rocks. Many palaeontologists will be found in offices studying diligently, or laboratories sporting white coats, and many are women who hopefully don’t have beards.
Bob Bakker, the sort of guy who probably automatically springs to mind. Most palaeontologists are not like Bob.
What makes a person a palaeontologist?
At the start of the post I said that I was a palaeontologist “of sorts”, because defining exactly what a palaeontologist is can be tricky. Palaeontology is like astronomy, in that amateurs, even sometimes complete novices, can contribute to the field. Many amateur astronomers, with their telescopes and diligent searching, find things which were previously unknown; in palaeontology we have amateur fossil collectors, who sometimes make some incredible discoveries. There is a whole spectrum, from those who simply like to search for fossils on the beach, to palaeontologists publishing original research. Somewhere between those two ends is a point where one can label oneself a palaeontologist, and I would say that I am personally somewhere near that point. It depends how specific we want to be, so I will try a few definitions.
A palaeontologist is someone who studies prehistoric life through fossils. This broad definition would include many amateurs who simply collect fossils and endeavour to learn more about them. It would even include some fossil dealers, as having an understanding of fossils will increase understanding of their worth. It is too broad to be workable.
A palaeontologist is someone who does original research in palaeontology. This definition is broad enough to include student palaeontologists who are undertaking an original project. (I loosely fit this category as I consider myself in between studies, but am also volunteering at Doncaster Museum.) Students in palaeontology get a bit of a free pass and will fit any definition, as they can label themselves “trainee palaeontologists”.
A palaeontologist contributes their research to the palaeontological community. This definition limits palaeontology to academia, and is where I currently fall short but aim to be at some point in the future. It does, however, mean that some non-palaeontologists will fit this label, as not all whom contribute to the palaeontological literature are palaeontologists. Science, after all, is incredibly intertwined (I recently saw an image intended to depict the relationships of the sciences, yet it put palaeontology very close to geology and with seemingly no link to evolutionary biology, genetics, or embryology).
Some in academia will only label you a palaeontologist if you fit the last definition and have the necessary degrees from university, which is a bit snobby really. The raw material of palaeontology is available to anyone, as fossils can be found all over the place. Granted, the technical literature can seem a bit closed off to those lacking in university education in the geosciences, but many have contributed to the field without that background and deserve respect (I like to label them “autodidact” palaeontologists). My good friend Dean Lomax is doing just that at the moment, having written a handful of papers and published a book on Whitby fossils (he also runs Palaeocritti) with much more in the pipeline.
After all I have written so far, I feel bad for not mentioning preparators, many of whom are trained palaeontologists. Without good fossil preparation, many palaeontologists would have poorer material on which to work. It is a skill which is essential to palaeontology and requires a lot of dedication.
Anyway, to round things up, I could have simply said “palaeontology is the study of fossils” and left it at that. Or I could have shared this song:
This was very much an ‘off-the-cuff’ post, lacking the usual planning I would put into something of this length, so if I have missed something important let me know and I will amend it.
This, is my blog. Or at least I hope it will be. I used to write a blog, also called The Palaeobabbler, where I covered a wider range of topics until it fell out of use, and I have decided to have a fresh start. Whereas the old blog used to include creative writing, theology, philosophy, random musings and more, this new blog will focus completely on palaeontology and evolution. I wanted to do something more focussed and related to where my life was going, so I decided that I would start this blog when I started my MSc studies and would write about those experiences, along with my favourite palaeontological subjects (more on those later). However, life took a wrong turn, or a pause, or something annoying and slow. Getting accepted on the MSc course was no problem, but funding it was, so I had to defer my place and hope to raise money for the following year (I am so far failing miserably). This also meant a year-long delay on blogging if I stuck to the plan, but why wait? Much of what I hoped to write could be written regardless of my study situation, and it would prevent my writing from stagnating.
Here I am, babbling on already, yet nobody knows who I am (except those rare few who might have followed my old blog). Earlier this year I graduated from the BSc Palaeobiology and Evolution course at the University of Portsmouth and am attempting to pay for the Bristol MSc in palaeobiology. I also volunteer at Doncaster Museum and Art Gallery so I am getting my hands on fossils on a regular basis, until I find a job which will sadly likely take me away from the museum. I do spend a lot of my spare time researching, trying to keep up with palaeontological advances so that I don’t lose touch with the discipline (who knows where research will lead, even casual research…). I so far only have one publication, and it is not peer reviewed (a short article in Deposits which I don’t actually like that much – the article, not the magazine, the magazine is awesome!). If I do get anything published properly, ever, it will likely end up on my Academia.edu profile, which still thinks I am at Portsmouth…
So, what to expect from this blog? Well, one of my major interests has long been evolutionary biology, particularly when the fossil record is taken into account, but I like to dip into the genetics side of things (particularly developmental genetics; evo-devo is a very exciting field), so expect much about evolution, particularly macroevolution. I am known to be very critical of creationism and Intelligent Design, but I will try to keep any critiques to a minimum. I will cover some broad aspects of palaeontology, touching on subjects which I do not know as well as others, but like anyone I have some key interests. My major passion is for the Ediacaran biota, so much of this blog will be dedicated to them, whatever they are, and I intend to run a Tumblr account alongside this blog, helping to spread Ediacaran awesomeness. Naturally, a love of Ediacarans goes hand in hand with the Cambrian Explosion, and I will certainly discuss it rather a lot. I also have a soft spot for trace fossils, which ties in nicely with the Cambrian Explosion as there were some incredible changes going on at that time – the Cambrian Substrate Revolution! The subject of my undergrad dissertation was Early Cambrian trace fossils, so I at least have some first hand knowledge. I also have my volunteer work with Doncaster Museum, which tends to expose me to local fossils, particularly the Permian fossils deposited in the Zechstein Sea, and of course it will come with stories about some of the random finds in the collection.
I think that’s everything, so hopefully I will keep it up. If things get slow I can always be lazy and reblog things from my old blog, as I am sure I wrote at least one interesting post…
P.S. Check out Palaeocritti if you have never had a peek.
The Palaeobabbler 