Page 14 - Reptiles & Dinosaurs (Britannica Illustrated Science Library)

10 DINOSAURS REPTILES AND DINOSAURS 11

The Triassic Period A New World 250 TO 203

THE TRIAS
were named in 1834 by German After the extinction of nearly 95 percent of plants to grow. There was only one continent,
called Pangea, which was surrounded by a single
all life at the end of the Permian Period, the
MILLION YEARS AGO
he biological crisis of the late Permian Period was followed by a slow paleontologist Friedrich August Earth was a dry place with hot deserts and rocky ocean, Panthalassa. This supercontinent was the The Earth had only one continental mass,
von Alberti, who in doing so
resurgence of life in the Triassic Period. The Mesozoic Era has grouped the three rock formations areas. Only the coasts had enough moisture for home of dinosaurs and other animals. called Pangea. This continent had an upper
T commonly been called the “Age of Reptiles,” and its most famous that defined this period. region called Laurasia and a lower region
called Gondwana. The two areas were partly
members are the dinosaurs. In the earliest part of the period, the first separated by the Tethys Sea, which later
representatives of today's amphibians appeared, and toward the end of GREENHOUSE EFFECT almost completely disappeared.
the period the first mammals emerged. In the middle to late Triassic A rapid, extreme global
warming event is one of
Period, the many families of ferns and conifers appeared several possible causes of
that continue to exist today, as well as other groups the great extinction of the
late Permian Period. It could
of plants that are now extinct. have created the hot, dry
climate that prevailed during
the Triassic Period.
NUMEROUS SPECIES
VEGETATION Reptiles and mammals
Giant conifers were flourished alongside the PANGEA
among the trees that
lived on Pangea. dinosaurs.

Flora FIRST COUSINS
In addition to the dinosaurs,
the pterosaurs—winged
Pangea was mostly a dry, hot desert
with palm trees, ginkgoes, and other dinosaurs—and Lagosuchus
lived during the Triassic
gymnosperms. Some small species of
horsetail rushes (genus Equisetum), Period. Together these three
ferns, and marine algae also types of animals make up the
survived there. Ornithodira group, though this
is often debated today.

EXTINCTION
Toward the end of Fauna
this period, a new
extinction event removed
several groups of species while In addition to land reptiles, such as the
opening up new horizons for those crocodile, and the most primitive
that survived—especially the dinosaurs, such as Eoraptor, the first
dinosaurs, which spread rapidly. mammals appeared during this period.