Thursday, December 8, 2016

From Giant Dinosaur to Tiny Hummingbird

So, the theory is that Tyrannosaurus Rex gave birth to today’s birds, right?

Well, not exactly. T Rex was one of the of the theropod dinosaurs. It reached 40 ft in length, stood 12 ft tall at the hips, and weighed around 10 tons. However, other members of the theropod family were of various sizes, all the way down to 1 foot in length and 110 grams (3.9 oz) in weight. And throughout the ages following the T Rex, members of the theropod family grew smaller and smaller, and their skeletons changed four times faster than the skeletons of other dinosaur families. However, the theropods had hollow bones, like birds.

From what I’ve been reading, it isn’t terribly likely that birds evolved directly from T Rex, but they are both considered members of the theropod family. The largest modern theropod is the ostrich, 9 ft tall and up to 320 pounds. The smallest avian is the bee hummingbird, just over 2 inches long and weighing less than 2 grams. Although the theropods have shrunk since the days of T Rex, they continue with a wide range of sizes.

Ever wonder where birds got their feathers? The flying reptiles that nature started with didn’t have any. But the last decade or so, scientists have discovered non-flying dinosaurs that had feathers. How did that happen?

If I understood what I read, the transition began when some scales elongated into a filament. Over time, the filament developed ‘branches’, which eventually became numerous enough to form feathers. Scales and feathers are both made of keratin, and scientists have found that embryonic alligators contain some feather keratin, but that this type of keratin is suppressed in later stages of development in favor of scale keratin. Oh, and by the way, T Rex is more closely related to birds than to alligators.

Actually, lots of dinosaurs had feathers. Perhaps they didn’t grow feathers in order to fly, they grew them as insulation against the cold. And to look pretty to the opposite gender. Only later did the feathers help some glide from tree to tree and feathers started to become part of flying.

Are you up for a story about a T Rex covered in peacock and ostrich feathers?

No comments:

Post a Comment