How birds followed the way of the dinosaurs

The science is settled. Birds evolved from dinosaurs, according to Dr Mike Lee, who is the South Australian Museum’s Palaeontology Senior Research Scientist and is a Fellow at Flinders University.

“For about 150 years after Charles Darwin came up with the idea of evolution, the idea that dinosaurs evolved into birds didn’t have a huge amount of support either from the fossils or the scientists,” Lee says. “There was only one fossil that seemed to suggest a link between birds and dinosaurs. That was Archaeopteryx but one bird doesn’t necessarily sway scientific opinion or prove overwhelmingly any particular radical theory.

“It was only in about 1998 that the first dinosaurs with feathers, apart from Archaeopteryx, were discovered in China. Since then we’ve had about 20 different dinosaurs with feathers, which almost show a perfect gradation from dinosaurs, which are only just a little bit bird-like all the way up to dinosaurs that for all intents and purposes you can’t really separate from primitive birds.”

Artist’s depiction of a Psittacosaurus

The problem now: where to draw the line between bird and dinosaur.

“At what point does something change from a bird-like dinosaur into a primitive dinosaur-like bird? That’s tremendously exciting and this exhibition really emphasises all the new discoveries, which conclusively proves that birds are nothing more than miniature-flighted feathered dinosaurs.”

Anyone who has seen Steven Spielberg’s 1993 monster movie Jurassic Park will know that the question of birds evolving from dinosaurs was debated before the 1998 discovery. Lee says that up until 20 years ago it was a vigorous debate because the evidence for the evolutionary change wasn’t overwhelming.

“We didn’t have too many intermediate fossils. Now, we’ve not only got a whole, almost like a perfect line of intermediates stretching from birds to dinosaurs and all of them have feathers. There is really no debate now because, almost like watching a time-lapse movie in the fossil record, you can see the changes happening as you go from fossil-to-fossil.”

Artist’s depiction of a Kosmoceratops

This change from bird-like dinosaur to dinosaur-like bird occured over a period of 50 million years.

“As dinosaurs got smaller the feathers got more and more elaborate,” Lee says. “The most primitive bird, at the beginning, when dinosaurs first evolved feathers, they weren’t the feathers you see in birds today, they were just little tuffs of fuzz, which really didn’t provide any sort of flight function, they were probably more for insulation, and maybe for display. As you progress towards more bird-like dinosaurs you can see the feathers becoming more elaborate and more bird-like. Then you start getting the flight feathers on the wings. You can actually see how a radical change in body-plan can happen step by step with very small changes; it was incremental, a bit like compound interest, actually. Evolution is basically nature’s version of compound interest where you can, given time, have a massive change.”

According to Lee, this change from dinosaurs to birds epitomises evolutionary change.

“Within the space of a decade it changed from that debate [of whether dinosaurs evolved into birds] into one of the best examples of major evolutionary change. Every time somebody wants to demonstrate the realities of evolution, dinosaurs and birds are pretty much the poster child.”

Artist’s depiction of a Triceratops

Children are fascinated by dinosaurs. Why does Lee think these creatures from hundreds of millions of years ago continue to capture children’s imagination?

“I think that children are always fascinated by big, fierce scary animals. Dinosaurs tick all those boxes but what makes them much more exciting than a dragon or an orc or something like that is we know they were real. We know that they did inhabit the world and they walked the world and they dominated the world for 150 million years. So the combination of being big and scary and real living creatures really attracts the imagination and attention of children.”

And dinosaurs are a pathway for children to discover science.

“All the major concepts in biology you can teach using dinosaurs as examples: evolution, physiology and taxonomy. You can teach them using other creatures as well, bugs and birds, but if you want a particular group of creatures to teach these concepts, dinosaurs, I think, have one of the broadest appeals. For instance, taxonomy is quite a dry area of science. It’s just basically scientists as librarians naming things, when you attach it to something like a brontosaurus and attach these fairly dry, boring names to these extinct charismatic creatures, even taxonomy can appeal to kids.”

Dinosaur rEvolution
South Australian Museum
Friday, February 23 to Sunday, May 6
samuseum.sa.gov.au

The Adelaide Review is a media partner of The South Australian Museum

Header image: Artist’s depiciton of a Sinosauropteryx Caudipteryx