Patterns in Palaeontology

Patterns in Palaeontology: How do we measure biodiversity in the past?

Patterns in Palaeontology: How do we measure biodiversity in the past?

Patterns in Palaeontology
by Emma Dunne*1 Introduction: Life on Earth is incredibly diverse. More than 1.7 million species have already been described and estimates suggest that there could be as many as 9 million in total. But exactly how this rich biodiversity has developed over the last 542 million years since the Cambrian remains the subject of debate amongst palaeontologists. Did biodiversity increase steadily from one geological period to the next, or did it wax and wane without any overall direction? These questions are crucial in a modern context: today, we are flooded with urgent reports on the state of biodiversity worldwide, with many scientists stating that we are in the middle of a biodiversity crisis driven by human impact, leading to what is being called the sixth mass extinction. To understand and
Patterns in Palaeontology — The earliest skeletons

Patterns in Palaeontology — The earliest skeletons

Patterns in Palaeontology
by Amelia Penny*1 Introduction and background The ability to build and maintain a skeleton is one of the major innovations in the history of life. During the Cambrian explosion, which began around 540 million years ago, diverse animal (metazoan) skeletons appeared suddenly in the fossil record. This is also when we first see evidence for predation, the ability to move around and most of the animal body plans we would recognize today. The ability to grow a resistant skeleton was a major factor in the evolutionary arms races of the Phanerozoic eon — the time since the Cambrian explosion — and it made possible the dizzying variety of shells, bones and teeth scattered throughout the Phanerozoic fossil record. But the origin of skeletons has a much deeper root, in the Proterozoic eon (2,500 m
Patterns in Palaeontology: The development of trilobites

Patterns in Palaeontology: The development of trilobites

Patterns in Palaeontology
by Lukáš Laibl*1 Introduction: Trilobites are an iconic group of ancient animals, with a fossil record that dates back more than 500 million years and consists of some 17,000 species. These extinct arthropods are characterized by a hard, mineralized exoskeleton, which greatly enhances their chances of being preserved as fossils. The exoskeleton is thought to have been mineralised soon after they hatched from eggs, and so we can find various growth stages of trilobites in the fossil record, including individuals less than half a millimetre long. That makes it possible to study the entire post-embryonic development (that is, the development after they hatch from the egg) of numerous species. This is important because work on the development of ancient organisms provides data crucial for ou
Patterns in Palaeontology: Environments of the Cambrian explosion

Patterns in Palaeontology: Environments of the Cambrian explosion

Patterns in Palaeontology
by Thomas W. Hearing*1 Introduction: Shimmering curtains of sunlight stream down through the waters of a shallow sea that has been advancing landwards for several million years. This transgression has formed wide areas of shallow continental shelf seas. The sea bed teems with life — some of it familiar, some much less so. The oddities begin on the floor of this tropical sea: a reef built not of corals, but by carbonate-producing microbes and the strange archaeocyathan sponges, alongside creatures that look more conventionally sponge-like but probably aren’t. Streams of seaweed drift on the currents; closer examination reveals small, snail-like shelled molluscs on some of the tendrils. A trilobite scuttles for cover, startled by the flickering shadow passing overhead, and narrowly avoids
Patterns in Palaeontology: Palaeoproteomics

Patterns in Palaeontology: Palaeoproteomics

Patterns in Palaeontology
by Caitlin Colleary*1 Introduction: The fossil record is our only direct window to the history of life on Earth. The ability to find and study the remains of animals, plants and other organisms that lived millions of years ago is extraordinary, and as technology has improved over the past few decades, scientists have realized that fossils contain more information about the stories of extinct life forms than even Charles Darwin could have imagined. Biomolecules (such as DNA, proteins and lipids) that make up modern animals contain information about how their bodies work (physiology — that is, physical and chemical functions), relationships to other animals and their evolutionary histories. With the advances in analytical tools such as high-resolution mass spectroscopy, the study of biomol
Patterns in Palaeontology: From giants to dwarfs – Estimating the body mass of extinct species

Patterns in Palaeontology: From giants to dwarfs – Estimating the body mass of extinct species

Patterns in Palaeontology
by Charlotte Brassey1 Introduction Body mass is so fundamental to an organism that it is often overlooked, yet it has considerable importance in animal biology. It is, quite literally, the amount of matter making up an individual. On a day-to-day basis, we encounter values for body mass as we step onto our bathroom scales and are encouraged to maintain a healthy weight (not too heavy or too light). Veterinarians are interested in body mass for much the same reason: the weight of an animal can provide an indication of its health and is commonly used to plan medical treatments. Body mass is also tied to an animal’s physiology (including speed of metabolism and length of pregnancy), ecology (diet, home-range size) and behaviour (social status, aggression). For these reasons, zoologists are
Patterns in Palaeontology: A story of vision

Patterns in Palaeontology: A story of vision

Patterns in Palaeontology
by James Fleming*1 Introduction: Photoreception, the ability to perceive light, is a sense shared by many living organisms on Earth. However, only some can take the step beyond merely detecting light levels, and generate an image. Humans are among the animals that have image-forming vision, and are able to see in colour in the day (polychromatic diurnal vision) and in black and white at night (monochromatic nocturnal vision) — the shades of colour that we pick up on an evening out trigger our diurnal receptors at very low levels. However, this is not the only way in which animals can see the world around them. Some species, such as whales and dolphins, can see only monochromatically no matter the time of day, while others see in colour no matter how dark it gets! The elephant hawk-mot
Patterns in Palaeontology: How and why did the arthropod shed its skin? Moulting in living and fossil arthropods

Patterns in Palaeontology: How and why did the arthropod shed its skin? Moulting in living and fossil arthropods

Patterns in Palaeontology
by Harriet B. Drage*1 Introduction: 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...

Patterns in Palaeontology: Palaeogenomics

Patterns in Palaeontology
by Jeffrey R. Thompson*1 Introduction: 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

Patterns in Palaeontology: Palaeoart – fossil fantasies or recreating lost reality?

Patterns in Palaeontology
by Mark P. Witton*1 Introduction: 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