The 10 Essential Facts to Know About Animals

Animals are familiar creatures to most of us. We are, after all, animals ourselves. Beyond that, we share the planet with a remarkable diversity of other animals, we rely on animals, we learn from animals, and we even befriend animals. But do you know the finer points of what makes one organism an animal and another organism something else, such as a plant or a bacterium or a fungus? Below, you'll find out more about animals and why they are unlike the other lifeforms that populate our planet. The First Animals Appeared About 600 Million Years Ago

The oldest evidence of life dates back some 3.8 billion years. The earliest fossils are of ancient organisms called stromatolites. Stromatolites were not animals—animals would not appear for another 3.2 billion years. It was during the late Precambrian that the first animals appear in the fossil record. Among the earliest animals are those of the Ediacara biota, an assortment of tubular and frond-shaped creatures that lived between 635 and 543 million years ago. The Ediacara biota appears to have vanished by the end of the Precambrian.