Grassy biomes, including grasslands, savannahs and crops, cover over 40% of all land on Earth. They play a significant role in carbon and silica cycles and have a large impact upon the climate. Grasslands (grass-dominated ecosystems) have shaped the evolution of numerous groups of organisms, most obviously grazing mammals, and can support a huge amount of biodiversity. Humans evolved in the savannas and through domestication of grasses formed agriculture, leading to a modern diet dominated by grasses such as oats, rice, wheat and corn.

As anthropogenic climate change threatens large scale uncertainty, it’s vital that we understand the controls that govern the success of this fundamentally important group. It is only by studying the evolutionary history of grasses that we might be able to predict how they will fare in future.

Joining us in this episode to speak about the challenges of piecing together the evolutionary history of grasses from a relatively poor fossil record is Prof. Caroline Stromberg of the University of Washington.

Determining the origin of teeth in vertebrates is an incredibly significant but notoriously difficult problem within palaeontology. Teeth didn’t evolve in the mouths of our ancestors, but are first seen as part of the external skeletons of jawless fish as structures called ‘odontodes’. These would later migrate into the mouth with the evolution of jaws, becoming the teeth we have today, but odontodes still remain present in the skin of modern cartilaginous fish, giving them their rough texture.

The oldest known odontodes are from the late Cambrian Period and represent the very first evidence for vertebrates in the fossil record. Unfortunately, they are only ever found as part of fragmentary pieces of exoskeleton, however, given that their specific construction is only known in vertebrates, there is little else they could possibly be…

Joining us for this episode is Dr Yara Haridy, University of Chicago, who set out to use modern new scanning techniques to better understand the nature of these first teeth and what they tell us about the evolution of vertebrates. What she discovered was unexpected, but also led to better understanding of the purpose of odontodes in the dermal exoskeletons of our ancestors.

Determining the origin of teeth in vertebrates is an incredibly significant but notoriously difficult problem within palaeontology. Teeth didn't evolve in the mouths of our ancestors, but are first seen as part of the external skeletons of jawless fish as structures called 'odontodes'. These would later migrate into the mouth with the evolution of jaws, becoming the teeth we have today, but odontodes still remain present in the skin of modern cartilaginous fish, giving them their rough texture.

The oldest known odontodes are from the late Cambrian Period and represent the very first evidence for vertebrates in the fossil record. Unfortunately, they are only ever found as part of fragmentary pieces of exoskeleton, however, given that their specific construction is only known in vertebrates, there is little else they could possibly be...

Joining us for this episode is Dr Yara Haridy, University of Chicago, who set out to use modern new scanning techniques to better understand the nature of these first teeth and what they tell us about the evolution of vertebrates. What she discovered was unexpected, but also led to better understanding of the purpose of odontodes in the dermal exoskeletons of our ancestors. Her research was recently published in Nature and is free to access.

Ants are a hugely successful family of eusocial insects with over 14,000 modern species described. They are known from every continent except Antarctica and show a wide range of ecologies. Whilst many of us are familiar with their highly organised social structures and castes, there still remain a lot of public misconceptions about how their societies function.

The evolutionary history of ants is equally as impressive, with roughly as many fossil ant species known as there are of dinosaurs! Since their appearance in the Cretaceous, several early lineages of ants (stem ants) have gone extinct. In this episode, we’re joined by Dr Christine Sosiak of the Okinawa Institute of Science and Technology as we explore what some of these stem ants were like and ask how the different groups of ants fared over geological time.

Ants are a hugely successful family of eusocial insects with over 14,000 modern species described. They are known from every continent except Antarctica and show a wide range of ecologies. Whilst many of us are familiar with their highly organised social structures and castes, there still remain a lot of public misconceptions about how their societies function.

The evolutionary history of ants is equally as impressive, with roughly as many fossil ant species known as there are of dinosaurs! Since their appearance in the Cretaceous, several early lineages of ants (stem ants) have gone extinct. In this episode, we’re joined by Dr Christine Sosiak of the Okinawa Institute of Science and Technology as we explore what some of these stem ants were like and ask how the different groups of ants fared over geological time.

An ecosystem can be described as all the interactions that occur between organisms and their physical environment. The processes acting within an ecosystem operate on a wide range of spatial and temporal scales and include both biotic and abiotic factors.

Ecosystem engineers are those species that have a significant impact on the availability of resources to other species and can be responsible for the creation, maintenance, modification or destruction of an ecosystem. The introduction, or even removal, of such a species can have profound effects on both physical and biological elements of an ecosystem.

Whilst we can recognise the impact of ecosystem engineers in modern systems (e.g. the introduction of an invasive species), we don’t fully understand what happens when an entirely new ecosystem engineering behaviour evolves. This has undoubtedly happened numerous times throughout geological time with the Great Oxygenation Event and the Cambrian Substrate Revolution being notable examples.

Joining us for this episode is Dr Tom Smith, University of Oxford, who has been using a computational approach to try to model what happens when an ecosystem engineer is introduced into an environment. The open access study is available to read here.

Found in the fossil record between the Jurassic and the middle Miocene, Notosuchia was a highly diverse and strange group of crocodylomorphs, most notable for their terrestrial lifestyle.

Joining us for today’s episode is Dr Yohan Pochat-Cottilloux from the Laboratoire de Géologie de Lyon, who specialises in the study of crocodylomorphs. Together, we will explore the wide range of scientific methodologies that have so far been used to study the lives of these strange reptiles and discuss how they may have looked and behaved.

The field of evolutionary biology has been greatly influenced by the development of modern genetic methodology. The understanding of genes, genomes and the molecular mechanisms key to life on Earth are all goals of evolutionary biology in the 21st century, yet its potential applications seem to be near limitless. Palaeontology and evolutionary biology continue to be closely related and both, with their deeply rooted origins, have been essential to our understanding of macroevolution (major evolutionary change over long periods of time) ever since the major development of the theory in the 19th century.

In this episode, Prof. Erica Bree Rosenblum introduces us to this diverse and constantly evolving field. We cover fundamental questions such as: what are genes and genomes and why does understanding them matter; which evolutionary roles do environmental and genetic mechanisms play; and what ultimately causes the rise and fall of species. In order to better understand life on Earth, we show how evolutionary biology brings together the fields of genetics, biochemistry, ecology, palaeontology and more.

In 12 years of podcasting, we have never actually taken the time to address the fundamentals of our field. Such questions could include: what is palaeontology, what is a fossil, how does one become a palaeontologist, and why is palaeontology important?

For what should have been our very first episode, we've invited Prof. Roy Plotnick, University of Illinois Chicago, to help us outline everything you need to know about the field of palaeontology. Roy has had a long and varied palaeontological career, he maintains a blog all about the field, and he is author of the book Explorers of Deep Time.