Cambrian

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What happened in the Cambrian Period?

By |2019-02-26T21:09:50-07:00June 23rd, 2017|Geology|

Mossy rocks The Cambrian gets started At the beginning of the Cambrian Period, about 542 million years ago, there were sea creatures like hydras, jellyfish, sponges and seaweed living in the oceans, but only one-celled algae on land yet. Proterozoic Era More geological eras All our geology articles First plants and animals on [...]

What is moss? Plant Biology and Evolution

By |2017-05-29T22:55:45-07:00May 29th, 2017|Biology|

A moss-covered rock During the Cambrian period, about 540 million years ago, some early plants evolved from earlier algae that could live on land, outside of the water. These plants were like modern moss. All of the animals were still living in the water, so on land there was only moss and mushrooms. [...]

Evolution of bones – Skeletons and Biology

By |2017-05-28T00:44:16-07:00May 28th, 2017|Biology|

A fish skeleton One-celled animals don't have any support system that holds them in a certain shape. Plants do have a support system, but it's the cellulose in the cell wall of each cell, rather than bones. Early multi-celled animals like jellyfish and sponges and worms also didn't have skeletons, but beginning with [...]

What are segmented worms? Annelids, evolution, and biology

By |2019-01-27T20:52:49-07:00May 27th, 2017|Biology|

An annelid, or segmented worm When did annelids evolve? Roundworms probably evolved into segmented worms, or annelids, about 545 million years ago. What's a roundworm? More about the Proterozoic All our biology articles What were annelids like? The earliest annelids all lived in the ocean, as most kinds of annelid still do today. Some [...]

What are mollusks? What’s a cephalopod? Biology and Evolution

By |2018-04-16T08:32:28-07:00May 26th, 2017|Biology|

Evolution of mollusks: Slugs are a kind of mollusk. When did the first mollusks appear? Mollusks are animals like mussels, clams, snails and slugs. Their name means "soft", because mollusks don't have any skeletons. The first mollusks probably evolved from early segmented worms around 500 million years ago.  That was in the Cambrian period. At [...]

What does a stomach do? – Digestion and Evolution

By |2017-05-26T19:21:38-07:00May 26th, 2017|Biology|

Fish Stomach The first multi-cellular animals like hydras had no stomachs, or you could say they were all stomach, because they were shaped like a bag. Roundworms, a little later, were shaped like a tube, and the cells along that tube made mucus to protect the tube from the bacteria that digested food [...]

History of Fish – Biology

By |2019-06-09T19:14:03-07:00May 26th, 2017|Biology|

History of fish: it looks like a severed tentacle but it's a lamprey. When did fish evolve? About 510 million years ago, in the Cambrian period, some of the worms on Earth evolved into the earliest fish. Segmented worms The Cambrian Period All our biology articles How were fish different from worms? Fish [...]