by Harriet B. Drage*1
Arthropods are one of the most successful groups of animals, in the present day and the fossil record. There are more than 1 million described arthropod species, and it has been estimated that there are at least 5 million more undescribed alive today (Fig. 1).
This makes up more than 80% of all known animal species! Arthropods also have an extremely diverse fossil record, extending back to the Cambrian Explosion 541 million years ago. For much of the Palaeozoic era (541 million to 252 million years ago), arthropods dominated marine ecosystems, and they have been significant components of all environments since then. The phylum Arthropoda encompasses insects (Hexapoda), crustaceans (such as shrimps and lobsters) and arachnids (such as spiders), a...
by Jeffrey R. Thompson*1
Palaeontology is truly a science of the twenty-first century. Palaeontologists are no longer concerned only with fossils, but also with topics such as genetics, developmental biology and chemistry — although most of us can’t resist digging around in the dirt from time to time! You are almost as likely to find a palaeontology graduate student in a class on molecular biology as in one on stratigraphy. This is because, in recent years, the integration of fossil, developmental and genetic data has fast become one of the most promising ways to study the patterns and processes of evolution.
At this point, it may be helpful to introduce some of the sources of information that palaeontologists use to address large-scale evolutionary questions. Molecular
by Mark P. Witton*1
Illustrations, sculptures and animations of fossil organisms and the world around them are mainstays of palaeontology. Such restorations, known as palaeoart, are more important than they may at first seem: they help to communicate palaeontological ideas across age and language barriers; have inspired generations of scientists; and have provided the foundation of an international industry of palaeontology-themed merchandise and media worth hundreds of millions of pounds. Due to its increasing prominence and popularity, palaeoart is routinely scrutinized by scientists and the public alike. How can we infer so much about the postures, soft tissues, colours and behaviour of extinct animals when fossil skeletons — be they shells, bones or carapaces — are all
by Philip D. Mannion*1
Today, most living species are found in the tropics, the region of the Earth that surrounds the Equator. Species numbers, a measure of biodiversity, decline towards both the North and South poles (Fig. 1). This is known as the latitudinal biodiversity gradient (LBG), and it is the dominant ecological pattern on Earth today. Although there are exceptions to the rule, including high-latitude peaks in diversity of many marine or coastal vertebrates (including seals and albatrosses), the LBG describes the distribution of species diversity for the vast majority of animals and plants, both on land and in the sea, and in the Northern and Southern hemispheres. Understanding the causes and evolution of the LBG helps researchers to explain present-day geograp...
by Mark A. Bell*1
The body size of an animal is often considered the most important part of its biology. Large body size brings many advantages, which can include better ability to capture prey, success in evading predators, intelligence, longevity and reproductive success; it also makes a greater range of resources available. A larger animal has a lower surface area to volume ratio than a smaller animal, which results in less heat loss to the surroundings, allowing it to remain warmer for longer in a cold environment. However, one major disadvantage is that larger organisms are, in general, more specialized, and can require more food for example. This can put species at higher risk of extinction caused by rapid environmental change.
Since the work of nineteenth-century ...
By Peter D. Heintzman*1
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...
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
by Victoria McCoy*1
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
By Jo Wolfe*1
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
by Simon Darroch*1
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