Monthly Archives: August 2016

Brittle Stars

Look at any part of the seabed and you are likely to find star-shaped creatures with long, slender arms wriggling across the bottom. These are not fish, but invertebrates called brittle stars, and they are relatives of starfish and sea urchins. They are also known as snake stars because of the way they move their… Read More »


For more than 250 million years, the ancient seas teemed with trilobites prehistoric animals related to today’s insects, woodlice, and crabs. There were more than 17,000 different types of trilobite, ranging from the flea-sized to monsters twice the size of this book. Most crawled along the ocean floor in search of food, but a few… Read More »

Cambrian Explosion

About 530 million years ago, a huge range of new animals appeared in the seas, including the first creatures with clear legs, heads, sense organs, skeletons, and shells. All the main categories of invertebrates (animals without backbones) known today seem to have evolved almost at once, as well as some weird creatures quite unlike anything… Read More »