Transcript Triassic - Digging-Up-The-Past

Triassic
Plants
Seed ferns like Glossopteris, ferns
and early species of gymnosperms
(seed plants, such as the
evergreens, in which the seeds are
not enclosed) dominate the Triassic
terrain. Cycads , with tufts of tough,
palm-like leaves and a woody trunk,
appeared in the late Carboniferous
and were abundant in the Triassic.
Laurasia was dominated by
conifers, other seed plants and
ferns; Gondwanaland was
dominated by
Jurassic
Animals
It lived about 22 to 215 million years ago in the Late
Triassic period. Its name means 'Flat lizard'.
Plateosaurus belonged to a group of dinosaurs known
as prosauropods which was related to the sauropods of
the Jurassic and Cretaceous periods.
Plateosaurus was a 9 metre long herbivore weighing
about 4 tonnes. It was about 4 metres tall. It evolved in
the Late Triassic period and lived up till the Early
Jurassic period.
It was the first of the giant dinosaurs to feed only on
plants and the first to be able to feed on vegetation in
trees by evolving a long neck. It had long back legs and
a long tail. Its mouth was like a beak but had teeth. It
walked on four legs but probably stood on its back legs
and grabbed branches with the claws on its front legs as
it fed on leaves. Palaeontologists believe that they may
have lived in herds.
Jurassic animals
The dominant land animals were the huge dinosaurs, the
largest land animals ever. They were the gigantic herbivore
(plant-eaters) sauropods such as Diplodocus and
Brachiosaurus. Other herbivores included Stegosaursaurus.
Carnivorous (meat-eating) dinosaurs included Allosaurus and
Dilophosaurus.
The dinosaurs of the Jurassic were much more different from
each other than in other periods: there was a greater variety.
Because of the different climate, the forests grew, and the
herbivores became huge in order to feed on the tall trees.
The carnivores then had to become larger and more fierce to
deal with such huge prey.
The first birds appeared, such as Archaeopteryx. The seas
were full of marine reptiles such as the plesiosaurs,
crocodiles, ichthyosaurs, sharks and rays.
Cretaceous
Plants
Imagine the time before the evolution of flowering plants, the time of the
dinosaurs, 200 million years ago. The air is damp and smells of moist
earth. The raucous cries of strange creatures reverberate through the
jungle, and all around you are strange plants. What kind of
plants? Jurassic plants -- Cycads.
Cycads, (pronounced si'kads), formed an extensive portion of the flora of
that time, and no doubt the herbivorous dinosaurs grazed contentedly on
the abundance. However, the dinosaurs disappeared, and so did most of
the cycads -- except for a few incredibly resilient species that still cling
tenaciously to existence today. Now they are referred to as living fossils,
for they have remained virtually unchanged, and give us a glimpse into a
long-distant past.
Cycads are commonly mistaken for ferns, palms or bamboo but they are
actually conifers, bearing conspicuous naked cones. Comprising only 11
genera (Bowenia, Ceratozamia, Chigua, Cycas, Dioon, Encephalartos,
Lepidozamia, Macrozamia, Microcycas, Stangeria and Zamia)
and approximately 300 species, they are the rarest plants on Earth.
Cycads display a remarkable diversity. Leaf size ranges from 8 inches in
the diminutive Zamia pygmaea, to 23 feet in the gigantic Encephalartos
laurentianus. Leaflet colour varies from yellow-green, lime green, dark
green, purple-green, to silver and even blue. There
are cycads with arborescent (tree-like) trunks, and cycads with
subterranean trunks. Longevity and growth rate also varies by species;
Zamias can mature and reach coning age in only three to five years, while
other, larger species such as the Dioons can take decades to cone and
may live to be 1,000 years old.
Animals
. The
Cretaceous period marks the end of The Age of the
Dinosaurs.
Big and small dinosaurs lived in great forests of cycads,
conifers and ferns. There were great marine reptiles in the
seas and great flying reptiles in the skies.
Some things happened in the Cretaceous period that were
important to life on earth. One of these was the development
of flowering plants. By the end of the period, there were many
that we would recognise today, such as magnolias and
waterlilies.