標題: Photo Gallery: Permian Period [打印本頁] 作者:
路人甲 時間: 2008-4-24 08:05 PM 標題: Photo Gallery: Permian Period
A sail-backed dimetrodon forages amid a Permian landscape in this artist's depiction. These primitive predators, though dinosaur-like in appearance, are actually considered the forerunners of mammals. Scientists think their large back fins were used to regulate body temperature.
The Permian period saw the creation of the supercontinent Pangaea, where shallow seas in and around the huge landmass offered a home to an abundance of life. This diorama at the University of Michigan's Museum of Natural History shows some of the flora and fauna that thrived in Permian seas, including trilobites, gastropods, clams, nautiluses, and corals.
Nautiluses, like this one swimming in the waters off Palau, Micronesia, have changed little in their 270-million-year history. The first nautiluses appeared during the Permian period and were among only a handful of organisms to survive the widespread extinctions that wiped out nearly 95 percent of life on Earth about 250 million years ago.
Paleontologists (from left) Stuart Sumida, David Berman, and Thomas Martens examine the fossilized remains of a young Orobates pabsti, an ancient herbivorous reptile that lived some 290 million years ago at the beginning of the Permian. The remains were found in 2006 at Germany's Bromacker Quarry, one of the world's most productive sites for Permian-era fossil finds.
An artist's depiction shows lystrosaurs foraging near a stream. Flat-faced with a beak and two teeth that resembled tusks, lystrosaurs were synapsids, animals that arose in the Permian and eventually gave rise to mammals.
A quarter of a billion years ago, long before dinosaurs or mammals evolved, the 10-foot (0.3-meter) predator Dinogorgon, whose skull is shown here, hunted floodplains in the heart of today's South Africa. In less than a million years Dinogorgon vanished in the greatest mass extinction ever, along with about nine of every ten plant and animal species on the planet.
From : Nationalgeographic作者:
Franco仔 時間: 2008-4-24 10:06 PM
