Fossils are cool. Why? Two very big and complex reasons. First, fossils allow us to reconstruct species that don’t exist any more. This is usually done by studying species that do exist, and using the information we glean from living things to interpret the details of the fossil species, giving it life. Second, fossils tell us about evolutionary change, both by showing us what evolutionary events happened that we would not be able to see in living species, and by showing us change. In order to understand the evolutionary history of life on our planet, we need to look at a lot of different fossil species, to develop histories of change and adaptation.
(OK, there may be more than two reasons fossils are cool. Feel free to add your fossil are cool ideas in the comments section below. Please to not say “to grind them up to make aphrodisiacs.”)
So, what if you had to describe the history of life by focusing on a small number of fossils? And, why would you do that? Last year, Paul Taylor and Aaron O’Dea did this with 100 fossils in A History of Life in 100 Fossils. I’ve looked through that book, and it is nice. But here I’m going to review a somewhat more recent book, just out, by Don Prothero, which has at least as much information in it but by focusing on a smaller number of cases: The Story of Life in 25 Fossils: Tales of Intrepid Fossil Hunters and the Wonders of Evolution.
Several of the fossils Prothero chose to illustrate the story of life represent major events or changes in the planet’s evolutionary history and diversification. For example, the nature of the earliest life forms is represented by the stramotlite, which is really fossil scum. Others illustrate key transitions within major groups such as the origin of hard body parts, or the major divisions of animals, such as the origin of the amphibians. Others are exemplars chosen because they are spectacular and/or because they are touchstones to understanding very different times in the past, or important categories of living and extinct forms. These examples include the extremes, as well as good exemplars of the “diversity in adaptations to size, ecological niche, and habitat.” Generally, the chosen representatives are fossils with good preservation, detailed study, and in general, piles of information.
Prothero also provides rich detail about discovery, early interpretations, and the role of specific fossils (or extinct species) in the history of thought about evolution. In some ways this may be the most interesting parts of the discussion of several of the fossils. And, the book is chock full of excellent and interesting illustrations.
As a result, the chosen 25 are somewhat biased towards the more spectacular, and intentionally, towards those extinct forms that people tend to gravitate towards because they are either very interesting or very spectacular (generally, both). It would probably be difficult to develop a panoply of species that ignore the dinosaurs, but the history of life on Earth could probably have been written without humans, as long as “providing a viable existential threat to all known life forms” was not on your list of key attributes to do cover, but Prothero takes on human ancestors, and covers more than one, because most of the book’s readers are likely to be humans.
There are far more than 25 life forms in The Story of Life in 25 Fossils: Tales of Intrepid Fossil Hunters and the Wonders of Evolution, because the author makes use of a much richer body of information than just the key chapter-titling form.
Also, Prothero is a world renowned expert on certain fossil groups, found among the mammals. Well, actually, a lot of fossil groups. And, his expertise is applied richly here, with the selection of a disproportionate share of mammals.
The author writes excellent, readable prose, and vigorously makes connections between evolutionary questions and evolutionary data. It is hard to say if this book supplants or enhances his earlier major monograph for the public on evolution, Evolution: What the Fossils Say and Why It Matters. Either way, you can safely assume the more recent volume is more up to date in areas where research has been active.
I’m thinking of getting a copy of this book for the local school’s library, as a gift.
A selection of other books by Donald Prothero: