Biology help?

Question

For millions of years, until around 65 million years ago, reptiles were the doninant terrestrial vertebrates. Why?

Answer 1

During the late Triassic, all the continents were together in a single super-continent called Pangaea. There were few mountain ranges over this enormous stretch of land, the interior of which was arid and dry, with widespread deserts. Coastal climates were much the same all over the world-quite warm, with a dry arid season followed by a very wet monsoon season. By the end of the Triassic, 213 million years ago, dinosaurs had become common, replacing the thecodonts and surviving amphibians.

There are at least three reasons why dinosaurs were so successful:

1. Leg Mechanics. Positioning the legs directly under the body gave dinosaurs a key advantage over their reptile ancestors, the thecodonts---it allowed them to be more agile, faster runners.

2. Drought Resistance. Pangaea (when all the continents were joined together) had an arid continental interior in the late Triassic, conditions to which dinosaurs are superbly adapted. The mammals of the late Triassic, by contrast, were not "water-tight" enough for such climates.
3. Luck. At the end of the Triassic a large meteor impacted in northeastern Canada (today the site is still visible, the Manicuoagan Crater) and appears to have been responsible for a great loss of diversity at the end of the Triassic. Thecodonts and many other species became extinct, leaving the "large animal" niche vacant for dinosaurs to fill.

sea levels began to fall and the climate to cool. Many kinds of dinosaurs become less common-and then, suddenly, 65 million years ago, all dinosaurs disappear from the fossil record. What cause the sudden extinction of the dinosaurs, after 150 million years of success? Most biologists now agree that the most likely cause was the impact of a gigantic meteor (it appears to have been 5-10 miles across!) off the coast of Yucatan. The thin line of sediment that marks the end of the Cretaceous in rocks today is rich in iridium (a mineral rare in the earth's crust but common in meteors), in tiny spheres of cooled molten rock, and in bits of quartz shocked by high-velocity impact . The impact created a huge crater 185 miles in diameter, throwing massive amounts of material into the atmosphere that would have blocked out all sunlight for a considerable period of time, creating a world-wide period of low temperature. Insulated with feathers or fur, the endothermic birds and mammals (those whose body temperature is determined by the heat generated by the animal's metabolism) survived, and the ectothermic reptiles and amphibians (those whose body temperature is determined by the temperature of the environment) did too-ectothermic animals simply lower their activity levels.

i hope this does answer your question. i have loads of material about their existence and extinction.. i gathered the above from varies books.

Answer 2

The reptiles appeared about 150 millions years before the mammals. This early apparition is perhaps due to the fact that the reptiles have cold blood.
The first mammals appeared only in at the Jurassic and they were hindered in their evolution since reptiles occupied great part of the earth until the extinction of dinosaurs.
After the extinction of dinosaurs and other reptiles except snakes ,lizards , crocodiles the mammals could evolve

Answer 3

because they are strong and tough and put the hurt on everyone else