Evolutionary Ancestors of Dinosaurs

Video Transcript

" Some dinosaurs had fins. For example this entity right the Dimetrodon, whose name means two front teeth, was actually in a sense a pre-dinosaur, a pelycosaur that actually predated the dino's just before that first dino period, the Triassic. It was a long creature, nine and a half feet, weighed about one to two tons and was a vicious predator. Intriguingly, it had a cousin, the Edaphosaur, that also had a fin and that was a vegetarian dino. Now the question is what purpose did this fin or tail sail serve ? Was it just decorative or did it have a more important purpose ? Well the theory is that there were tiny blood vessels running all through the fin and this entity, when it wanted to heat up would stand perpendicular to the rays of the sun. So this sort of acted like a solar sail. A modern device on an ancient creature. And when it wanted to cool off, it would stand parallel to the sun and radiate heat off. Also this could have been decorative to try to attract mates. we're not sure. it could have served multipurpose, but one of the most intriguing features on a dinosaur or a pre-dinosaur. Now, fast forward to the cretaceous period and we have the Spinosaurus, i.e. the spiny dinosaur who was basically found in north Africa. He was a vicious predator, as vicious as T-Rex, stood about twenty feet tall and actually had a vegetarian counterpart himself known as the Aronosaurs. You see once again he also has a sail on his back. The same idea that this might have helped him heat himself standing perpendicular to the rays of the sun, cool off parallel to it and also attract mates. Very attractive. Then in the intermediate Jurassic Period, we had the Stegosaurus, i.e the roofed lizard. And this was another giant about thirty feet long, five to ten tons, a vegetarian dino but well protected. And again we don't know if this was for protection, display or a number of many solar panels on his back. Originally we thought they ran parallel but the idea now is that they're staggered, one on the left one on the right, one on the left one on the right, to maximize the heat it might enjoy. So this idea of the sail actually persisted through all of the dinosaur era. He's especially interesting for a couple of reasons. First he, as a vegetarian had this vicious multi-pronged tail so he swish that at enemies. Secondly, he had a tiny little brain for his body. In fact, originally paleontologists thought because his brain was so small for this large body that he might have had a second brain located in his tail. But no study yet as revealed such a cavity for a brain. So, here we have a tiny brained creature using the modern scientific device, the solar sail. How bout that."