Patterns in Palaeontology

Patterns in palaeontology: An introduction to ancient DNA

Patterns in Palaeontology
By Peter D. Heintzman*1 Introduction: Deoxyribonucleic acid, or DNA for short, is the magical molecule that encodes instructions on how to build organisms, and has been doing so successfully for at least the past 2.5 billion years. Although its function has remained constant throughout this time, the instructions themselves have been slowly modified and upgraded to cope with the changing demands of organisms and the environments in which they live. A modification to DNA is called a mutation, and it is through mutations that we are able to track how organisms have changed, or evolved, through time. In all multicellular organisms, there are two major types of DNA: mitochondrial (mtDNA) and nuclear (nuDNA) (Fig. 1). These have different histories and can therefore tell us different thing...

Patterns in Palaeontology: Why the thunder lizard was really the deceptive lizard.

Patterns in Palaeontology
by Chloe Marquart1 When I tell the average stranger that I'm a palaeontologist, the first question that I'm inevitably asked is: "Like Ross from Friends?" The second is: "Have you named any dinosaurs?" The naming of fossils is actually a very small part of the work that palaeontologists do, but it often garners the most attention from the press and public. It can be difficult for people to understand how scientists can suddenly decide that a well-known, often iconic name has never 'existed' - in a scientific sense, at least. Many grown adults still mourn the loss of their beloved Brontosaurus (more on him later), and in the past few years, campaigns were begun to ‘Save Triceratops’ when it was declared that this dinosaur and Torosaurus might be the same animal (Fig. 2). Although

Patterns in Palaeontology: Exceptional Preservation of Fossils in Concretions

Patterns in Palaeontology
by Victoria McCoy*1 Introduction: Have you ever seen a geode — a boring-looking ball-shaped rock that, when split open, reveals a remarkable crystalline interior? For most people, the first reaction to the dazzling crystal interior is to marvel at its beauty. But for some — and perhaps you fall into this group, since you are reading this article — the second and more important reaction is to wonder how it got that way. The people who ask this question understand that the beauty of nature is far greater when we understand it deeply and see it more fully; in short, they are scientists at heart. If you are a scientist at heart, I have very good news for you. There is something out there that is like a geode, but perhaps even more interesting, at least to fossil lovers: the curious rocks

Patterns in Palaeontology: Development in the Fossil Record

Patterns in Palaeontology
By Jo Wolfe*1 Introduction: Development, the process by which a single egg cell transforms into a complex adult organism, has fascinated biologists for more than 200 years. In the mid-nineteenth century, before and during the time when Charles Darwin was uncovering the principles of natural selection, a number of biologists who wondered what caused evolutionary relationships among organisms looked to development for answers. The German zoologist Ernst Haeckel popularized the phrase “Ontogeny recapitulates phylogeny” — where ontogeny is an organism’s development and phylogeny is its evolutionary relationships. You may have seen a version of his famous diagram in biology textbooks (Fig. 1). Haeckel suggested that, during each successive stage of development, an animal would pass through a

Patterns in Palaeontology: Who’s there and who’s missing?

Patterns in Palaeontology
by Simon Darroch*1 Introduction: Sitting in the sweltering heat of southern Japan, I’m faced with a conundrum. The limestone cliff in front of me preserves the boundary between the Permian and Triassic periods, a point in time around 250 million years ago that witnessed the greatest mass extinction of the Phanerozoic eon. I’m collecting rock and fossil samples from around this boundary to study how the make-up of fossil communities changed in response to this extinction event: this is palaeoecology. The boundary itself couldn’t be easier to spot — the lower (and older) part of the cliff is composed of a pale white-yellow limestone packed full of fossils of shelled marine invertebrates including brachiopods, bivalves and gastropods, as well as microscopic sea-floor-dwelling (benthic) crea

Patterns in Palaeontology: Old shapes, new tricks — The study of fossil morphology

Patterns in Palaeontology
by Verity Bennett1 Introduction: The size and shape of an organism is the product of genetics and environment. It is the raw material on which the process of natural selection (survival of particular animals over others) acts, and so is of central interest in studies of the evolution of ancient forms of life for which DNA information is not available. Fossil morphology, or shape, is the basis of most palaeontological studies, be they describing new species or making deductions about the animal’s lifestyle. Phylogenetic studies, those that place species in groups depending on how closely they are related to each other, are based on the presence and absence of particular features. This works on the theory that the more closely related two animals are, the more features they are likely to h

Patterns in Palaeontology: The first 3 billion years of evolution

Patterns in Palaeontology
by Russell Garwood *1 Introduction: Breathe in. Breathe out. It’s a good bet that you’re currently sitting in front of a computer, reading; I’m going to go ahead and assume that you’re breathing, too. In, and out. You probably weren’t even thinking about breathing until I mentioned it, but all the same, it’s keeping you alive. Oxygen from the air is being transported into the cells of your body, which are using it to create energy. So far, so good. But what you may not realize is that the cellular machinery performing this process so integral to our existence (Fig. 1) has roots buried deep in the geological past. It’s a story that begins before the origin of organized cells, in an ancient, alien world. But if we’re going back that far, we might as well go all the way back, to the very be

Patterns in Palaeontology: The Cambrian explosion – Paradoxes and possible worlds

Patterns in Palaeontology
by Jonathan B. Antcliffe1 Introduction: The transition between the Precambrian and the Cambrian period (about 550 million to 500 million years ago) records one of the most important patterns of fossils in all the geological record. Complex animals with a suite of shells, intricate body plans and associated movement traces appeared for the first time, suddenly and unambiguously, in sequences all over the world during this interval. This ‘Cambrian explosion’ remains one of the most controversial areas of research in all of the history of life, and one of the most exciting. Palaeontological data like this is definitive in its support for evolutionary theory, the relative sequence of first appearances in the fossil record over the past several billion years ties very closely with what we wou

Patterns in Palaeontology: Parsimony and Palaeobiology

Patterns in Palaeontology
by Javier Ortega-Hernández *1 Introduction: The principle of parsimony, also known as Occam’s razor, has been widely attributed to the English Franciscan friar William of Occam (c. 1288–1348). It states Pluralitas non est ponenda sine necessitate, which translates to ‘Plurality is not to be assumed without necessity’. In other words, when one is faced with a problem or question that can have several different answers, the solution that requires the fewest assumptions is most likely to be correct, unless there is evidence that proves that it is false. Parsimony has an enduring influence in most scientific activities, as it allows researchers to make comparisons and choose between different hypotheses that aim to explain a phenomenon using the same body of evidence. The incomplete nature

Patterns in Palaeontology: The Paleocene–Eocene Thermal Maximum

Patterns in Palaeontology
by Phil Jardine*1 Introduction: The Paleocene–Eocene Thermal Maximum (PETM) is one of the most intense and abrupt intervals of global warming in the geological record. It occurred around 56 million years ago, at the boundary between the Paleocene and Eocene epochs. This warming has been linked to a similarly rapid increase in the concentration of greenhouse gases in Earth’s atmosphere, which acted to trap heat and drive up global temperatures by more than 5 °C in just a few thousand years. The fossil record gives us the means of understanding how life was affected by the PETM, and so provides an excellent opportunity to study the relationships between evolution, extinction, migration and climate change. The early Palaeogene world: At the time of the PETM, the world was already much w