BY DR. JOSE PALU-AY DACUDAO
(Part 1)
WHEN was the last time you ate dinosaur?
The last time you ate chicken.
Birds are dinosaurs.
Dinosaurs are not extinct.
Specifically, birds are theropod coelurosaurian maniraptoran dinosaurs.
Huh? Dinosaurs are the most famous of all extinct organisms because of their fantastic size. Most dinosaurs weighed in at around 5 tons.
The mostly predatory theropod dinosaurs were around half a ton, but many were much larger than that. Numerous movies depict the famed theropod Tyrannosaurus rex swallowing hapless humans in a gulp or two. Imagine, a 10-ton tiger. Frightening.
The largest so far discovered is Spinosaurus, which probably was at least 50 feet long and 20 metric tons. It could swallow a tiger for snacks.
The plant-eating dinosaurs grew even larger. The herbivorous sauropods, the theme park stereotypes being the robust Brontosaurus and the slender Diplodocus, were the most massive animals ever to walk the Earth.
Even the small ones were far larger than any other terrestrial animal. The slender ones boasted lengths that may have reached at least 130 feet, making them the longest animals in geological history.
The robust ones may have weighed at least 100,000 kilos, rivalling the biggest of the baleen whales. Bruhathkayosaurus is the biggest so far discovered, and some generous estimates place it at 150,000 kilograms.
Even now, there are debates on how exactly such massive creatures supported themselves. (Not a problem in marine baleen whales since the water buoys them up. But how do you lift a hundred-ton body above the ground?)
And chickens are dinosaurs? The little sparrows we see all the time are dinosaurs? The 2-inch 2-gram hummingbird is a dinosaur? Birds (Avialae) are dinosaurs?
In the 1860s, the discovery of Archaeopteryx lithographica shocked biologists. This creature lived about 150 million years ago in the Jurassic Period, was about the size of a dove, had the skeleton of a theropod dinosaur, had reptilian teeth, and yet clearly had feathers.
The upper extremities were observed to have formed primitive wings. Without feathers it was so dinosaur-like that a specimen without fossilized feathers was misidentified as Compsognathus, definitely a theropod dinosaur. So why did most biologists believe that birds and dinosaurs belong to separate although closely related taxa? (To be continued)/PN
