Transcript Mesozoic - Digging-Up-The-Past

Mesozoic
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Triassic
• Animals
• Pleseosaurus or flat lizard: Plateosaurus was an herbivore
(it ate only plants). This long-necked dinosaur ate leaves high in the trees (like those
of conifers and cycads) with sharp, leaf-shaped teeth. Plateosaurus was about 27.5 feet
(8 m) long and weighed about 1,500 pounds (700 kg). It had a long neck, a very long tail, a small
head with a long snout, and large, five-fingered hands with a large thumb claw (and smaller claws
on the other fingers). Plateosaurus may have been able to use its hand for grasping in addition to
walking. Its back legs were larger than its front legs.
Jurassic
• Allosaurs
•
•
Diet: Allosaurus was a carnivore (meat-eater) who may have hunted in packs. In these groups,
Allosaurus could have ambushed even the very large sauropods (like Diplodocus and
Camarasaurs.
Size This bipedal predator was up to 38 feet (12 m) long and weighed roughly 1 to 5 tons. It had
solid, heavy bones, long claws on its 3-fingered hands, and large, powerful jaws
.
Cretaceous
• Cretaceous
Centrosaurus was an herbivore (a plant eater) that ate low-lying plants
This ceratopsian dinosaur had a large, forward-pointing snout horn 18 inches (46 cm) long. The skull
was over 3 ft (1 m) long. Its scalloped frill had two hooked spikes near the centre. Centrosaurus
was about 20 feet (6 m) long, 6 feet (1.8 m) tall, and weighed up to 3 tons.
Plants in Triassic
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Leptocycas was a cycad, a primitive seed plant from the late Triassic period. It was a palm-like
tree with a long, woody trunk and tough leaves. It lived in warm climates. This tree was about 4
.8 ft (1.5 m) tall.
The dinosaurs evolved early in the Mesozoic Era, during the Triassic period (about 228 million
years ago). At the start of the Mesozoic Era, the continents of the Earth were jammed together
into the supercontinent of Pangaea; this land mass had a hot, dry interior with many deserts. The
polar regions were moist and temperate.
Plants in Jurassic
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Conifers (like Araucarioxylon) were the dominant land plant during the Jurassic
period. Other land plants included Ginkgophytes (like Ginkgos), club mosses,
horsetails, ferns, seed ferns, Sphenopsids (like Neocalamites), Filincophyta (like
Matonidium), Cycadeodia (like Otozamites, Ptilophyllum, and Cycadeoidea), and
cycadophytes.
Plants in Cretaceous
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Williamsonia sewardiana was a cycadeoidphyte (a bennettitalean). It had a woody
stem and simple leaves. It lived from the Jurassic period through the late Cretaceous
period. Williamsonia was a bennettitalean (a primitive gymnosperm that resembled
cycads but was not a cycad). Williamsonia had a long, thin, branching, woody trunk
covered with spirals of broken-off leaf scars
Environment in Cretaceous
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It was a warm tropical place in which many angiosperms (flowering plants) developed and
became dominant. Because of this, many new herbivores appeared and others went extinct.
During the Cretaceous the climate was warmer than today. In the seas, marine
invertebrates flourished, and bony fishes evolved. On land, flowering plants arose,
and insects, bees in particular, began their thriving partnership with them. Mammals
and birds remained inconspicuous throughout the Cretaceous, while the reptiles
continued their dominance. The dinosaurs reached the peak of their evolution during
this period but rather suddenly became extinct at its end.
Environment in Jurassic
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The Jurassic landscape was much greener and more lush than in the Triassic. There was a wider
variety of vegetation. The tall tree ferns made up the second understory of trees, and the smaller
ferns and horsetails were the most common low growing foliage. There were successive
accumulations of marine sandstones, limestones, and shales.
•
Barley is a cereal grain related to wheat, oats, and rice. Barley seeds (the part of the plant that is
highest in nutrition) grow in spikes at the tips of the stems - it resembles wheat. This important
crop is grown in temperate areas and is used as animal feed, for malt (used in making beer,
malted milk, and food flavoring), and for human consumption (used as a flour, a thickener, a
cereal, in soups, etc.). Barley was cultivated thousands of years ago; it was grown by the
Egyptians from 5,000 to 7,000 years ago. The countries that produce the most barley are Russia,
Canada, and Germany. Classification: family Poaceae (Gramineae) (grasses), genus Hordeum,
species H. vulgare.
Environment in Triassic
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The Triassic Period was born 250 million years ago (mya) from the violent close of the
Permian Period. It was here that thousands of doomed species witnessed the collision of
the world’s continents, and the subsequent formation of the super continent, Pangea. The
land trembled and buckled as great mountains thrust their way into the sky, volcanoes
erupted and other lands sank beneath the waves. During the geologically brief existence of
Pangea, the rest of the earth was covered by one vast ocean, Panthalassa.
Although the primary cause is not known, during the turbulent birth of Pangea great
stresses so plagued the global environment that 95% of all species disappeared from the
face of the earth.
When history’s greatest known extinction ended, the environment was ripe for the rise of
thousands of new species, including early dinosaurs and small mammals. Most species
living today would not exist were it not for the mysterious global disaster that marked the
birth of the Triassic.
The Triassic Period came to its own violent end about 200 mya as great convective forces
deep within the earth split apart the northwestern region of Pangea, and set North America
adrift from what would become the African continent. With the death of Pangea and the
Triassic, the Jurassic was born. This would be the time of the dinosaurs, great and small,
and they would rule the earth for the next 135 million years.