The last page in a comic book is often a cliffhanger, so you’ll be more inclined to buy the next issue. It happens so regularly that as I read through the comic (yes, I still read a comic or two), I find myself trying to anticipate what kind of twist will be on the last page. The best twists are the ones you could have seen coming, but didn’t. The story in this book also has a chemical twist here, near the end. This twist is innovative, expensive, and predictable from chemistry. For this twist, the periodic table plays spoiler. Before the Cambrian explosion, hidden in the nets of signaling proteins within cells and signaling molecules outside cells, the cells held a secret chemical potential that could send a much faster signal, built from four elements involved in two of the balances set up in Chapter 5. This form of signaling would be incredibly expensive, but also incredibly fast. It would be electric in its nature and in its effects, the basis of both muscles and brains. Like water flowing randomly down a rocky slope, this fast signaling built from fast chemistry spread out in many different ways in life. At certain points, evolution came together and converged, repeatedly finding that a particular shape or signal was the best solution to a particular problem. Because the liquid flow of life was increased, it could diverge and converge more quickly, while predictably fitting into the shape of its landscape and efficiently moving downhill. The fast chemistry that forms the basis of fast muscles and faster neurons developed with the Cambrian explosion, along with oxygen and calcium use. The explosion of life provided predators that ate and prey that was eaten. Oxygen’s energy (resulting from its place on the periodic table) allowed more complex food chains, with more predators and more prey. For example, some calculate that more oxygen in the late Cambrian made more predators evolve. In response to this oxygen, certain species moved onto dry land, where they had more contact with that element.
Decoupled evolution of soft and hard substrate communities during the Cambrian Explosion and Great Ordovician Biodiversification Event
