How Life Began

Earth first formed about 4.6 billion years ago. When the planet was very young, life would have been impossible—the ground was blisteringly hot and there was no water in sight. So how did life begin? EARLY EARTH A sea of molten rock covered the newly formed Earth. In time, this cooled to solid rock, but volcanoes continued to spew… Read More »


Fossils of prehistoric animals show us that life on Earth is always changing. Over time, old species disappear and new ones develop from them, like new relatives appearing in a family tree. These new species appear thanks to a process of gradual change we call evolution. NATURAL SELECTION Evolution is driven by a process called… Read More »

Timeline of Life

Earth’s history stretches back 4.6 billion years to our planet’s birth. Scientists divide this vast span of time into different periods, such as the Jurassic Period, when many of the dinosaurs lived. Here you can see all the periods on a timeline showing the history of life. THE LINES TELL TALES The past leaves clues… Read More »

All About Fossils

Almost everything we know about prehistoric animals comes from fossils. A fossil is the preserved remains or trace of an ancient animal or plant. The word “fossil” comes from the Latin word fossilis. That means “dug up,” and that’s how some fossils are discovered, although most are exposed by erosion. Most fossilized animals have lain… Read More »

Changing Planet

Planet Earth is always changing. Areas of land (continents) move slowly around on Earth’s surface, changing the map of the world. The climate swings from warm to cold, and the plants and animals change from one era to the next, sometimes dramatically. Scientists divide the age of the dinosaurs into three periods, all of which… Read More »

Dinosaur National Monument

In the United States, Dinosaur National Monument, on the border between Utah and Colorado, has been the site of huge numbers of fossilized dinosaur finds.  

Fossil Hunting

You may have seen a fossil hunt on television, or you may have visited a fossil site. Perhaps you have been lucky enough to find your own fossil. What happens on an organized fossil dig? IT WAS FOUND THERE! Every dinosaur dig is different. Some fossils are found embedded in solid rock that needs to… Read More »

A Look at Dinosaur Sizes

From dinosaurs the size of chickens to lumbering sauropods, the animals that have walked and swum on Earth have varied enormously in size and shape and length. Let’s take a look at a few examples: * The sizes shown in the gallery are the maximum these animals are known to have reached. The artwork is… Read More »

What Are Invertebrates?

From insects to mollusks, and from worms to jellyfish, invertebrates dominate our planet in terms of their numbers: they make up around 97 percent of the animal kingdom. What features do these animals share in common? Very few! However, they are animals that possess neither a backbone, nor a bony internal skeleton. Invertebrates are divided… Read More »

The First Animals

Fossils tell us that animal life began about 600 million years ago. The first animals lived in darkness, rooted to the seabed, and had simple, soft bodies shaped like disks or leaves, with which they gathered nutritious chemicals or particles in the water. These strange beings seem to have had no legs, no heads, no… Read More »