Life across space... And time.

If you're doing these sites in order, we're almost done! Before we finish, I wanted to introduce a rich field of research that incorporates fossils and their distribution. By extension, that means the distributions of extinct species in deep time. This is palaeobiogeography. It's super cool.


We'll cover:

  • Introduction and history – Section 1.
  • Principles and provinces – Section 2.
  • Barriers, mixing and evolution – Section 3.
  • Iapetus – Section 4.
  • Patterns of biodiversity – Section 5.

As we will see throughout this website, how organisms are distributed today can tell us a great deal about their evolution. But also, when we consider distributions, we have to think about invasions: what happens continents join or split? Or species are carried between areas? This is really important for conservation today – and also really interesting.

1 – Introduction and history

What is palaeobiogeography? When did we start to study the distribution of organisms? We address this in our first video!


  • Palaeobiogeography is the scientific study of the geographic distribution of fossils.
  • Biogeography (the study of the distribution of living species) has a surprisingly deep history with roots around the time of the Enlightenment.
  • Charles Darwin and Alfred Russel Wallace made key observations about the distribution of living species, and fossils were key to establishing continental drift.
  • Beware whiggism.

2 – Principles and provinces

What structures do we use to understand the distribution of life? Let's cover some basics.


  • Biogeography can describe distributions, and also try and explain these (interpretative biogeography) – the latter form can be historical or ecological.
  • Endemic is a term applied to a species or other taxonomic group that is restricted to a particular geographic region. A province is the association of multiple endemic species.
  • Cosmopolitan species are widespread, i.e. not endemic.
  • Provinces were present in the past, and can be seen in fossil assemblages back to the late Ediacaran.

Hey, it's time for a quiz. You know the score.

3 – Barriers, mixing and evolution

What defines provinces? What happens when provinces collide? What effect does this have on biodiversity? All this, and more... In video #3.


  • Biogeographic provinces are partitioned by barriers: these are often porous, and a barrier for one group of organisms may be a corridor for another.
  • When a barrier is removed, a biotic immigration event (BIME) can result.
  • Modelling suggests that repeated BIMEs can lead to increased biodiversity.
  • Vicariance is the process by which a barrier appears across a species range resulting in new species sharing a common ancestor.

4 – Iapetus

Let's dig into a real example and look at the picture fossils (and other approaches) provide of the birth, growth and then death, of an ocean over 300 million years ago.


  • The Iapetus ocean:
    • Developed in the Cambrian.
    • A series of continental collisions are recorded by the fossil fauna across North America, the UK, and Scandinavia.
    • The ocean shrank into the Devonian, before finally closing with the assembly of a large continent Laurussia.
  • Not all fossils are equally good for palaeobiogeographic analysis: knowledge of the precise age and lifestyles of organisms are really useful for palaeogeographic analyses.

5 – Patterns of biodiversity

Let's finish this week's learning by looking at some big scale patterns. Big in terms of space, and also big in terms of time.


  • Biodiversity reflects a balance between the rates of speciation and extinction, which are in turn impacted by a great many other factors.
  • This makes untangling the causes of large scale patterns quite challenging.
  • For example, on Earth today there is a patter called the latitudinal biodiversity gradient, with greater biodiversity at the equator than the poles.
  • But this has not always been the case – and we don't know the ultimate underlying cause.

Bonus stuff!

Very well done. You've made it to the end of this session. Why not spend a little time learning more about palaeobiogeography?

Like computers?

If you're interested in the kind of cutting edge analyses that researchers are using to understand the distribution of fossils, and how this interacts with a group's phylogeny, then search no further. This is a conference talk by my colleague Graeme Lloyd from a few years ago looking at the palaeobiogeography of dinosaurs:

It has dinosaurs! Trees! Computers! Biodiversity! It's super cool, and well worth your time, especially if your interests lie in the computational and palaeontological.


You can find an interesting and approachable overview of Whig History in the article linked below, on the Guardian website.

Why whiggish won't do.