Dinosaurs adapted by taking to the air

By Sylvain Comeau

Dinosaurs became extinct millions of years ago. Fact or fiction? If you said fact, listen to palaeontologist Phillip J. Currie, speaking at a recent Concordia lecture:

“There are at least 10,000 species of dinosaurs alive on earth today.” And scientists who disagree may become dinosaurs themselves.

Currie, curator at Alberta’s Royal Tyrrell Museum and head of its dinosaur program, is not talking about a “lost world” with Tyrannosaurs and Brontosaurs. But the descendants of dinosaurs are alive today, and are considered to be dinosaurs themselves. Here’s a hint: they have lots of feathers.

“In a sense, dinosaurs are still around: all 10,000 species of birds today are classified by biologists as dinosaurs. We know that dinosaurs were the ancestors of birds. That theory was first advanced in 1870, and today 99 per cent of palaeontologists believe that.”

Dinosaurs used to be considered the ancestors of reptiles, but that theory is now extinct as well. Currie explains that the modern classification of birds as dinosaurs is in keeping with their family tree.

“The way we classified species before was based on how they were related to each other. Today, we look at the branch of the family tree with dinosaurs, and the birds are the end of that branch. So officially, they’re classified as dinosaurs.

“This reclassification started 20 years ago, and it will probably take another 20 years before the public is aware of it. It takes that long before it gets in all the textbooks and lectures, etc.”

It is also well known today that there were dinosaurs with feathers.

“These had an advantage, a better chance to survive the cataclysm which wiped out most dinosaurs.”

That cataclysm is believed to be an asteroid or comet crashing to earth and sending up a huge cloud of dust which blocked out the sun, killing most species.

“If the asteroid had hit 10 million years earlier, when there was much greater diversity of species, it may not have wiped out the dinosaurs.”

As it is, the ones with feathers could better survive the cold, and, luckily for us tiny humans, the big scary monsters found themselves at a disadvantage.

“There were actually many small dinosaurs too; in almost any extinction event, the small animals survive and the big ones die out. The advantage of being a big animal is that you slow your life down; you have fewer kids, you eat less, enjoy life more and have a longer life. But, having fewer kids and having a slower turn over in generations is good when things are stable. When things become unstable, it’s very bad.”

The key to this phenomenon is adaptability and evolution, Darwinian survival of the fittest. “Suddenly, when things are changing fast, big animals can’t produce enough kids, or mutants or variations to adapt and change. Small animals can; so invariably in the earth’s history, big animals get snuffed out during mass extinctions, and small ones survive.”

While palaeontology has unveiled many of the mysteries of evolution and natural selection, Currie believes that his profession has only scratched the surface. Many fossilized species remain to be found “The ecosystems back then were just as rich and diverse as they are today. The fact that we know about so few dinosaurs, and we have so few fossils, is related to our own ignorance, and the fact that we haven’t explored enough. It does not mean that there were fewer species then today. There was probably just as much diversity as today, and we only know a fraction of that.”