For too long, we saw dinosaurs as prehistoric sideshow freaks. Dinosaurs used to be symbols of reptilian excess that deserved extinction. When scientists falsely believed that evolution followed the path of Progress–with our species sitting at the glorious apex and end of evolution–they saw dinosaurs as a weird, if charismatic, interlude in the story of life. Now we know better. Dinosaurs are not just icons of extinction and prehistoric lineages snuffed out. They are the grandest of Darwin’s “endless forms most beautiful and most wonderful,” prominent players on the evolutionary stage that instantly cause us to question our own place in nature and in the history of life on this planet.
–Brian Switek, My Beloved Brontosaurus
I discovered evolution through dinosaurs. Based on conversations with others, I’m not alone: many little kids are dinosaur-obsessed, and were led to discover evolution for themselves that way. Through reading about the various lineages and linkages between those magnificent animals over their long reign, we realized that the resemblances were not accidental, but the product of evolutionary processes.
Like many other young dinosaur fans, I went to all the exhibits I could (difficult as that was in small-town Iowa) and read everything I could get my hands on, whether it was old, new, or “age-appropriate”. That meant that I read The Dinosaur Heresies by renegade paleontologist Robert Bakker fairly soon after it came out. Unlike most of the other books I owned or checked out from the library, dinosaurs were real animals in Bakker’s book, connected intimately to living birds through evolution. While a lot of the stuff in Dinosaur Heresies turned out to be wildly speculative or wrong (sauropods standing on their hind legs, for example), other aspects have become widely accepted—and seemingly in yet other areas, Bakker wasn’t imaginative enough.
Of course, not every dinosaur fanatic, younger or older, has made the connection between their beloved beasts and evolution. However, for those people, a forthcoming book will certainly help: My Beloved Brontosaurus by Brian Switek. I have a full review of the book pending for Double X Science (and I’ll let you all know when that appears), but suffice to say that modern research into dinosaurs has rarely been covered as vividly, humorously, or informatively. At nearly every step, Brian ties his favorite prehistoric animals back to evolution, which shaped them then, and continues to shape the modern dinosaurs in our midst, the birds. (Anyone who doubts that birds are dinosaurs hasn’t spent much time around emus.)*
Paleontology—the study of ancient life—is sometimes considered a weak point in the evolutionary wall. After all, the fossil record is incomplete: we won’t ever be able to sample every plant or animal that ever lived, and within species we’re often challenged by lack of data on growth, sexual differences, and other natural variations. However, everything in paleontology supports evolution; the “gaps” in the fossil record are overshadowed by evidence of real transitions. We may not have the ancestors of every living species at their branching point from older forms, but thanks to uncle and aunt species, we have a truly excellent picture of how new groups arose from older lineages.
To wit, a new paper I learned about from Ed Yong covered the reconstruction of the ancestor of every placental mammal: the mammals including humans, whales, dogs, bats, guinea pigs, tigers…everything except the marsupials (kangaroos, opossums, etc.) and monotremes (echidnas and platypuses). It’s not a specific animal, mind you: it’s what paleontologists have learned from studying a plethora of species, living and dead. Even better: paleoartist Carl Buell painted a truly lovely picture of what the animal probably looked like, in breathtakingly accurate detail.
My Beloved Brontosaurus is about dinosaurs, of course, but evolution is evolution. Charles Darwin, born this day in 1809, didn’t write much about paleontology in Origin of Species, but in the intervening 154 years since the book came out, the fossil record has only strengthened the case for evolution (as Brian pointed out in his earlier book, Written in Stone). Let our love for dinosaurs remind us of the interconnectedness of all life on Earth: we are linked to dinosaurs in the distant past, through a common ancestor. If our histories have shaped us in vastly different ways, that’s evolution too.
* Despite my joke, it’s a mistake to think that way, as superficial resemblances don’t always reveal evolutionary connections. To wit: pterosaurs, the flying reptiles that lived at the same time as dinosaurs and similarly went extinct at the end of the Cretaceous Period weren’t dinosaurs, and therefore weren’t closely related to the lineage that evolved into birds. However, pterosaurs are popularly lumped in with dinosaurs, and I’ve even seen people use them as examples of the connection between birds and dinosaurs. That’s an evolutionary coincidence, which may or may not reveal something about how flight evolved multiple times in vertebrates. Emus are living dinosaurs, just like every other bird species, but it’s not their appearance or fractious behavior that tells us that.