September+MEB

9/22/14

When you hear the word shark what do you think of? Great white,hammerhead, or tiger. Well have you ever thought of the //helicoprion.// The //helicoprion// had saws for jaws. That's all there was to the 270 million year old ratffish's dental cutlery. No upper teeth or anything else to slice against just an overgrowing whorl of spiky teeth anchored to the lower jaw. Paleontologist and artist had offen supposed that //helicoprion// had upper teeth to pierce slippery cephalopods and squirming fish,but the fossils colleagues examined showed that //helicoprion// only had a buzz saw embedded in the lower. How did the long-lived and prolific genus of Permian fish eat with a saw for a jaw. The process went something like this. Teeth at the front snagged the prey,and as the jaws closed,moved the flesh backward. Here the middle teeth speared the food, securing it in the mouth,before the back teeth bit in and sent the prey down the hatch.

nationalgeographic.com http://www.prehistoric-wildlife.com

9/28/14

Have you ever heard of birds are what todays dinosaurs are. Well I really never knew what to say about that so I decided to research about it. When i looked it up i found lots of good information but to much to write so i found the best and decided to use it for this week so here it is. Today, we can safely declare that birds evolved from a group of dinosaurs known as maniraptoran theropods-generally small meat-eating dinosaurs that include Velociraptor of Jurassic Park. Evidence that birds evolved from the carnivorous predators that ruled the Mesozoic ecosystems is plentiful and it comes from disparate lines of evidence. Traditionally, the prime source of evidence in support of this scientific view was the similar shape of the bones of birds and a variety of maniraptorans but spectacular new discoveries have added other lines of evidence to the table. One of these lines of evidence involves the handful of snapshots that tell us about the behavior of the maniraptoran theropods. Fossils of animals in brooding poses or in resting postures also show a startling similarity with the behaviors we see among living birds. Yet, perhaps the most compelling new line of evidence comes from the discovery of soft tissues associated with the skeletons of these predatory dinosaurs, many fossils of these creatures are now known to have been covered by plumage. All this evidence has highlighted the fact that many features that were previously thought to be exclusively avian-from feathers to a wishbone-have now been discovered in the immediate dinosaur predecessor of birds. Even flight is likely to have been an attribute inherited by birds from their dinosaurian ancestors!

http//evolution.berkeley. edu /evolibrary/article/evograms//