When you think of an animal, you will most likely think of a vertebrate. Since we are animals with a backbone ourselves, it is not strange that that which is closest to us comes to mind first. But when and how did vertebrates evolve? To answer that question, Nature editor Henry Gee takes a good hard look at invertebrates, convincing the reader that they are not all equal. More than 20 years ago, Gee wrote Before the Backbone: Views on the Origin of the Vertebrates, which took a look at historical explanations for the origins of vertebrates. Which group of invertebrates is closest to us remains a topic of active research and Across the Bridge brings readers up to date with our current thinking.
Cambrian Period
Book review – Earth History and Palaeogeography
This book is an example of what happens when you go down rabbit holes. I have been reading several books on the subject of palaeontology and geology lately, and I know that the face of the earth has shifted over the hundreds of millions of years of deep history covered in these books. But where were all the continents at different times? Many will have seen the iconic maps of the supercontinent Pangaea. But I want to know more. What happened in between? And before? As Nield tells in Supercontinent: 10 Billion Years in the Life of Our Planet, Pangaea was only one of several such supercontinents in Earth’s history. But I want to know more still. Where exactly were the continents located? And how did they move? Several accessible books have provided snapshots of iconic moments, such as the formation of the Himalayas (Mike Searle’s Colliding Continents: A Geological Exploration of the Himalaya, Karakoram, & Tibet) or the disappearance of the Tethys ocean (Dorrik Stow’s Vanished Ocean: How Tethys Reshaped the World). But I want to know more! This technical reference work contains lots of fantastic palaeogeographical maps that answered all my questions.
The Inquisitive Biologist