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Home » Emma Schachner: Think You Know Why Dinosaurs Dominated? Think Again (Transcript)

Emma Schachner: Think You Know Why Dinosaurs Dominated? Think Again (Transcript)

Emma Schachner on dinosaurs @ TEDxLSU

Full text of paleontologist Emma Schachner’s talk: Think You Know Why Dinosaurs Dominated? Think Again at TEDxLSU conference.

TRANSCRIPT:

We’ve all heard about how the dinosaurs died.

The story I’m going to tell you happened over 200 million years before the dinosaurs went extinct. This story starts at the very beginning, when dinosaurs were just getting their start.

One of the biggest mysteries in evolutionary biology is why dinosaurs were so successful.

WHAT LED TO THEIR GLOBAL DOMINANCE FOR SO MANY YEARS?

When people think about why dinosaurs were so amazing, they usually think about the biggest or the smallest dinosaur, or who was the fastest, or who had the most feathers, the most ridiculous armor, spikes or teeth.

But perhaps the answer had to do with their internal anatomy — a secret weapon, so to speak. My colleagues and I, we think it was their lungs.

I am both a paleontologist and a comparative anatomist, and I am interested in understanding how the specialized dinosaur lung helped them take over the planet.

So we are going to jump back over 200 million years to the Triassic period. The environment was extremely harsh, there were no flowering plants, so this means that there was no grass. So imagine a landscape filled with all pine trees and ferns.

At the same time, there were small lizards, mammals, insects, and there were also carnivorous and herbivorous reptiles — all competing for the same resources.

Critical to this story is that oxygen levels have been estimated to have been as low as 15%, compared to today’s 21%. So it would have been crucial for dinosaurs to be able to breathe in this low-oxygen environment, not only to survive but to thrive and to diversify.

So, how do we know what dinosaur lungs were even like, since all that remains of a dinosaur generally is its fossilized skeleton? The method that we use is called “extant phylogenetic bracketing.” This is a fancy way of saying that we study the anatomy — specifically in this case, the lungs and skeleton — of the living descendants of dinosaurs on the evolutionary tree.

So we would look at the anatomy of birds, who are the direct descendants of dinosaurs, and we’d look at the anatomy of crocodilians, who are their closest living relatives.