Dinosaurs and Other Extinct Living Things

A place to know what animals or trees lived in the past

What is a fossil? September 20, 2007

Filed under: Knowledge — Edvan @ 4:23 am

Fossils are often the only clues to animals and plants that lived millions of years ago. But how were they made?

 Fossils are the remains of prints of animals and plants that have been preserved in rocks. Quite often, only the hard parts of an animal, such as the teeth or bones, are left. The rest has rotted away. But even when nothing remains of an animal, it may have left a hollow, the exact shape of its body, in the rock. Sometimes an animal left a footprint when it walked in soft sand or mud. A single footprint may be all that remains of an animals that was as big as four cars. Fossils can take millions of years to form.

How a dinosaur became a fossil

  1. When a dinosaur died, its body may have fallen, or washed, into a river.
  2. The dead body lay on the bottom of the river and the flesh rotted away.
  3. The skeleton was gradually buried under mud, and minerals from the water seeped into the bones and preserved them. Over millions of years, the mud turned into layers of rock and the dinosaur skeleton become a fossil.
  4. Millions of years alter, the sea level dropped. The wind and rain wear away the rock revealing the fossil: proof that dinosaurs once lived.

The Fossil Detectives

The scientists who do all the detective work on fossils are called paleontologists (pay-lee-on-toll-o-jists). They have found fossils all over the world. Their job can be very difficult because the fossil bones are often scattered in pieces. Only very rarely is a whole skeleton preserved in the rocks. Paleontologists identify the fossil bones, remove them from the ground, put them together, like a jigsaw, and decide how old they are. You can see the results of their works in natural history museums where dinosaur fossils are mounted and put on display.

Dinosaur Droppings

Fossil bones and teeth are not the only clues that these giants of the past left behind them.  Dinosaur footprints and the imprint of scaly skin, made in soft mud millions of years ago have also been found. Some of the most remarkable fossils found are dinosaurs droppings. Scientists grind up dinosaur droppings or coprolites into fine dust to find out what dinosaurs ate.

coprolite.jpg

 

How to Spot A Dinosaur September 10, 2007

Filed under: Knowledge — Edvan @ 4:15 am

Million of years ago, long before humans walked on this planet, one of the most extraordinary animals ever ruled the Earth – the dinosaur.

Dinosaurs are among the most successful animals that have ever lived. Some dinosaurs were harmless and ate plants. Others were ruthless hunters with vicious teeth who caught their prey then slashed into their bodies with razor-sharp teeth before eating their flesh.

Special Reptiles

All dinosaurs were reptiles. They lived on land, and most laid eggs with hard shells. They had tough scaly skin and claws of some sort. Reptiles cannot make their own body heat, they have to rely on the air around them to make them warm or to cool them down. Some scientists now think that some dinosaurs were ‘warm-blooded’ – that they could make their own heat inside their bodies, just as mammals do.

So what made dinosaurs different from other reptiles? Their legs were tucked straight under their bodies, not sticking out, to the side like the legs of other reptiles. They could walk and move about much more easily than other reptiles who had to drag their bodies along the ground as they walked, which made movement more difficult. Dinosaurs walked in a more upright way, either on two or on four legs and although some moved quite slowly, other dinosaurs could run very fast indeed.

Giants and Midgets

Some dinosaurs were gigantic. If they were alive today, they would be able to see over the top of a building four storeys high. There were even dinosaurs that were as long as four buses. Others scuttled around nearer to the ground. They were the size of chickens. Some were small enough to sit on a human hand.

Not A Dinosaur …

Pterosaurus, the flying reptiles were not dinosaurs. Dinosaurs do not fly.

The giant swimming reptiles, the plesiosaurs, were not dinosaurs either. They lived in the sea. Dinosaurs lived on land.

 

Life before Dinosaurs

Filed under: Knowledge — Edvan @ 1:26 am

Dinosaurs were not the first living things. Life began billions of years before them with the simplest living thing – the single cell. Gradually animals with many cells, such as reptiles and mammals, evolved.

First Life:  3,000 MYA (Million Years Ago)

The first living things on Earth were very simple, single-celled forms of life. There were bacteria and a type of algae called blue-greens. Fossils of blue-greens and bacteria have been found in rocks 3,000 million years old. The hot springs in Yellowstone Park, North America contain bacteria and simple algae. Perhaps this scene is similar to 3,000 million years ago when life began.

Life In The Sea: 600 – 530 MYA

Before fish, the seas were home to other creatures. Many of them were like sea animals that live today. There were jellyfish, shellfish called brachiopods and many sorts of sea worms. One type of animals that hasn’t survived is the trilobite. Trilobites were sea creatures with hard bodies like armour, which were jointed so that they could move. They had legs like those of shrimps. To protect themselves some would curl up into a ball, rather like a woodlouse.

Leafless Plants & Insects: 410 – 380 MYA

The first plants were leafless and flowerless and no more than 4 or 5 cm tall. They lived in boggy ground. Through this miniature jungle, scorpions hunted milipedes that fed on the plants.

Fish Teem In The Sea: 390 MYA

The first animals with backbones were fish. It is thought that sometime during this period Eusthenopteron, a fish that used its front fins to help it ‘walk’, crawled out of the water to live on land. It was the ancestor of land animals.

Amphibians Rule: 370 – 280 MYA

Amphibians live on land and in water, where they lay their eggs. Amphibians evolved from fish. At this time in history amphibians were very successful. Some amphibians were quite big. Icthyostega was about 1 m long. It looked a bit like a fish and had scales and a fin, but it had legs and could walk on land, although it spent most of its time in water.

fig7.jpg

Reptiles Rule: 310 MYA

There were more reptiles on land than amphibians. Scientists think that one group of reptiles were the ancestors of mammals. Dimetrodon belonged to this group.

Dimetrodon

Flying Insects, Towering Forests: 300 MYA

Through huge forests flew the first flying insects such as dragonflies. Some of these had vast wingspans up to 70 cm across. They were the largest flying insects ever to exist.

Dragonfly

Dinosaur Ancestor: 245 MYA

Archosaur reptiles, some of which were rather like modern crocodiles, were among the animals on Earth. Some, such as Euparkeria, may have been the ancestors of the dinosaurs.

The Age of Dinosaurs Begins: 220 MYA

dinosaurs2.jpg

 

When did dinosaurs live? September 7, 2007

Filed under: Knowledge — Edvan @ 4:35 am

The Earth is very old. It was formed about 4,500 million years ago. The first dinosaurs appeared 220 million years ago. But how long ago is that?

Dinosaur Timeline

It is hard to imagine such huge amounts of time. It seems as if the dinosaurs lived at the very beginning of time, but, in fact, the Earth existed for billions of years before the Age of the Dinosaurs.

How long did the Dinosaurs rule the Earth?

Dinosaurs lived on Earth for about 160 million years. That is an extremely long time. Humans have only existed for 3 million years, so we have a long way to go before we are as successful as dinosaurs.

The Changing Earth

Since the Earth was formed it has changed a great deal. The land masses, seas and clomate changed, so did the animals and plants. Even the dinosaurs changed (evolved). many different kinds of dinosaurs evolved during the time that they lived on Earth.

The Secrets of Dinosaur Success

Dinosaurs were a great success of the animal kingdom, they lasted for about 160 million years because:

  • They adapted to the world around them.
  • They had scaly, waterproof skin. The overlapping scales kept the dinosaur dry and protected it.
  • They laid hard-shelled eggs which helped many young to survive.
  • Dinosaurs could walk on land more easily than many of the other animals of the time, so they could find food and escape from enemies quickly.
  • Some dinosaurs ate plants and some ate meat. This meant that there was usually enough food to go round.
 

Dicraeosaurus June 22, 2007

Filed under: Dinosaur — Edvan @ 2:33 am

Dicraeosaurus was a peaceful plant-eater as big as a medium-sized truck.

Deep in the thick forest of tree-ferns, conifers (trees that have cones) and palms. Dicraeosaurus wandered about eating plants and seeds. This tall dinosaur had a long thin neck, a thin, whippy tail and long, pencil-like teeth at the front of its jaws.

Image Hosted by ImageShack.us

SMALL HEAD
Dicraeosaurus had a small head for its size. Its eyes and nostrils were also small. As a plant-eater, it must have been attacked by the large meat-eating dinosaurs. It had no armour or sharp claws to defend itself, but it may have used its tail as a whip lash. Scientists think Dicraeosaurus may also have been able to move fast enough to run away from its enemies when threatened by them.

DISCOVERING DISRAEOSAURUS
A huge discovery of dinosaur bones was made in 1907 in Tanzania, East Africa. It seems that many dinosaurs died near the mouth of a river and their bodies were washed on to mud banks. Some of the bones that were dug up belonged to dinosaurs that had not been discovered before. Among them was Dicraeosaurus although it was not called this until 1935.

Image Hosted by ImageShack.us

FACTS:
Name: Dicraeosaurus (die-cray-oh-saw-rus), called ‘forked lizard’ because of the forked spines in each of its backbones
Size: Up to 6m tall and 13-20m long
Food: Plants
Lived: about 195 – 141 million years ago, in the Jurassic Period, in East Africa

 

Avaceratops

Filed under: Dinosaur — Edvan @ 1:41 am

Avaceratops was about as long as a mini car and sturdily built, like a miniature tank.

Image Hosted by ImageShack.us

This dinosaur had a bony frill like a collar, around its neck and a short horn on its nose. The horn was probably used to protect it from much larger meat-eating dinosaurs.

BEAK LIKE A PARROT
Avaceratops was a plant-eater. It chopped off the stems with its special mouth, which was rather like a parrot’s beak. Avaceratops then sliced up the woody parts of the plants with rows of sharp teeth at the back of its jaws.

STRONG LEGS
It is possible that Avaceratorscould run quite fast on its four well-muscled legs. As it ran, it balanced itself with its heavy tail which it held off the ground.

JUST ONE SKELETON
So far, only part of one skeleton of Avaceratops has been discovered. It was found in 1981 in Montana, USA. It was not named until 1988.

Image Hosted by ImageShack.us

LIVING IN HERDS
Some scientists think that these animals may have lived in large herds, roaming the North American plains.

Image Hosted by ImageShack.us

FACTS:
Name: Avaceratops (a-va-serra-tops), ‘ceratops’ means ‘horned face’
Size: about 2.5m long and 1m high
Food: Low-growing plants
Lived: between 100 – 66 million years ago in the late Cretaceous Period, in North America

 

Tyrannosaurus Rex June 18, 2007

Filed under: Dinosaur — Edvan @ 2:48 pm

Tyrannosaurus Rex was the biggest meat-eating dinosaur that ever lived on Earth and was probably one of the fiercest.

T rex was about as long as four cars, as tall as the tallest giraffe, and weighed about the same as an African elephant. The head of a tall man would have come half way up to its thigh. No one knows exactly the sort of noises T rex made, but it may have roared or squeled to call its young and to keep in touch with other members of its group.

HUGE FEET

Each of its back feet would have covered four magazine pages and had three long claws at the front and one at the back. Its front legs were quite small and high up on its body. They ended in what looked like small ‘hands’ with two thin, clawed fingers. No one knows for certain what these front legs were used for, but they may have been used to grip prey. They were not even long enough to reach its mouth to push food in. Some experts, though have suggested that T rex used its front legs to heave itself up on to its back legs after it has been resting or sleeping on the ground.

BIG HEAD

It’s heavy head was about 1.2m long, held up by a short, strong neck. Tyrannosaurus also had huge jaws, big enough to swallow a human being whole. Its rows of sharp teeth were slightly curved to get a better grip on its prey. Like a shark, once Tyrannosaurus had bitten into its prey, the victim had no chance of sliding out of its mouth and getting away. If any teeth were broken off in a fight, they may have grown again.

Image Hosted by ImageShack.us

WALKING TALL

Walking upright on its powerful back legs, Tyrannosaurus balanced its huge body with its long, thick tail. With its enormous legs, it could run very fast, but it was probably too big and heavy to move quickly for a long time, like hunting dogs do today. Instead, T rex may have relied on ambushing its prey in the thick trees and ferns. Some experts think that Tyrannosaurus may have hunted in packs, surrounding other dinosaurs, such as a herd of plant-eating Triceratops or Edmontosaurus, so that they could not escape. Scientists think that it may alsoe have eaten carrion (dead dinosaurs), and perhaps any dying or helpless young dinosaurs that it came across.

Image Hosted by ImageShack.us

POWERFUL FIGHTERS

Many dinosaurs were very large, but they had trouble defending themselves against Tyrannosaurus. They did not have the teeth or claws to put up a real fight, but some were protected by tough, armour-plated skins, thick bony plates around their heads or long, sharp horns on their heads. Others were small and light, and could run fast enough to escape.

Image Hosted by ImageShack.us

FACT

In 1902, part of a huge skeleton was uncovered in Montana, USA. Later, another was found in Wyoming, also in the USA. From these bones the American paleontologist Henry Fairfield Osborn drew up the first picture of this giant creature. He named it Tyrannosaurus rex (meaning ‘king of the tyrant reptiles’) because it ws the biggest meat-eating dinosaur then known to have lived on Earth.

Name: Tyrannosaurus rex (ty-ran-oh-saw-rus-reks) means ‘king of the tyrant reptiles’

Size: 14m long and 5.6m high

Food: meat, especially other dinosaurs

Lived: about 67 million years ago, in the Crestaceous Period in North America, China and possibly South America and India.