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Dinosaur discoveries continually being unearthed |
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Written by Caroline Zentner LETHBRIDGE HERALD
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Wednesday, November 04 2009, 8:50 PM |
New fossil discoveries, improved scientific methods and a different classification system have helped increase the body of knowledge about dinosaurs and produced conclusions that wouldn’t have occurred to scientists before.
“Now people are going to places like South America, Antarctica and China where they never went before,” said Donald Henderson, curator of dinosaurs at the Royal Tyrrell Museum at Drumheller. “There’s constantly new things being discovered all over the world.”
In Lethbridge Wednesday, he was the featured speaker at the Galt Museum’s The Curator Presents... and tour guide for the museum’s recently opened exhibit Dinosaurs & Company.
“There’s a whole group of animals from the southern continents, India, South America and Africa, that have little stubby arms like tyrannosaurs but they’re not related at all,” Henderson said in an interview with The Herald prior to his evening presentation. “That’s an example of convergent evolution where two separate groups of animals ended up looking like each other; they fill the same niche. It seems that tyrannosaurs and this group seemed to focus their growth into their legs and head.”
Their long legs allowed them to cover a lot of distance and their large jaws were perfect for tackling big prey. But studying dinosaurs isn’t just about digging up bones. Henderson uses math and physics to study their biomechanics — how their muscles and limbs worked as levers, for example. Such techniques have led to the conclusion that tyrannosaurs weren’t runners. The bones of running animals need to withstand three to four times the normal body weight and tyrannosaur bones would have snapped. Their big legs let them walk quickly and efficiently to patrol a large area.
Scientists these days also look more closely at living animals when studying dinosaurs and many bring a background in zoology or biology. That has brought new ideas to the field, including the one that the horns on triceratops, for example, were more likely for display than for attack or defence, as was thought before. Living horned animals typically only fight as a last resort.
Organisms used to be classified according to kingdom, phylum, class, order, family, genus and species. Phylogenetic systematics is now used to describe the evolutionary relationships among the kinds of life on earth, both living and dead.
“When you look at what we have in common at the cellular level, the simplest explanation is that all life had a single common origin,” he said. “The genetic program in our cells and in bacteria is basically the same thing. Ours is just a little more fancy.”
The system and new discoveries in China have allowed scientists to conclude that tyrannosaurs at some stage in their life had feathers.
“Feathers evolved first for insulation and only later were they adapted for flight,” Henderson said. “I also stress that birds are dinosaurs. They’re not just descended, they are living dinosaurs.”
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