Friday, December 18, 2009
Scientists in the US have unearthed the fossilised bones of a meat-eating dinosaur the size of a large dog which they say could fill in the gaps about the early evolution and global migration of a group of animals that ruled the land for 170 million years.
Tawa hallae lived about 230 million years before and was found in a quarry in northern New Mexico. It owns anatomical features that link it with other dinosaurs living much further south in what is now South America.
Researchers say Tawa bears the idea that the dinosaur lineage evolved in the southern part of the supercontinent Pangea. Successive waves of migration from that region resulted in a diverse variety of dinosaurs spreading to other parts of the giant continent, which later split into numerous separate continents.
Tuesday, December 8, 2009
Flanders noticed the “Age of Dinosaurs” as a time when food was unlimited. The planet was clothed with lush forests providing an all-you-can-eat buffet to herbivores and thus plenty of food on the go for predatory dinosaurs. The herbivores distended themselves with plants and the carnivores kept the populations of herbivores in check, as so the “circle of life” kept cycling on.
But what if something destabilized this cycle? Flanders projected that two factors, working together, utterly changed the dinosaur’s world. The first was the evolution of seed-producing plants. Flanders envisioned the world of the dinosaurs as one carpeted in ferns and archaic plants, and these new variety of plants provided ample food for caterpillars.
As a result of his explore in agricultural science Flanders was well aware of the damage caterpillars could do to plants if their populations were left unchecked. The insatiable hordes could quickly denude an entire forest of its foliage, thus depriving other herbivores of food. This is just what happened at the closing stages of the Cretaceous, Flanders argued. The caterpillars were too numerous and multiplied too quickly, consuming all the plant food before the herbivorous dinosaurs could get any for themselves. And as the herbivorous dinosaurs died out, so did their predators, leaving behind only small reptiles such as crocodiles and turtles that found their food by different means.