What is moss? - The first kind of plant to leave the water
Quatr.us answers questions

What is Moss?

Moss
Moss

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.

Moss close up
Moss close up

Because moss was just beginning to get used to being out of the water, it still needed a lot of water nearby, and it could only grow in very wet places, like right next to streams, or where it rained a lot. There wasn't much dirt yet on the land, because there were no plants to decay and turn into soil, or to break up the rocks with their roots, or to hold back the crumbled rock from falling into the ocean. So moss has very shallow roots, just enough to hold on to the bare rock it lives on. Moss gets most of its food from the water washing over it, instead of through its roots.

Like other plants, moss plants make their own food by photosynthesis. All of the cells in a moss plant can photosynthesize, thanks to their chloroplasts, so moss plants don't need a circulatory or vascular system.

To grow bigger, moss plants make new cells through mitosis. But when they want to reproduce, moss plants use meiosis to produce spores, which blow away in the wind. For more than a hundred million years, moss and mushrooms had the land to themselves, but then, about 400 million years ago, these early mosses evolved into the earliest ferns.

Learn by doing - Moss Gardens
Next kind of plant - ferns


Bibliography and further reading:

Plants
Animals
Biology
Chemistry
Math
Quatr.us


Professor Carr

Karen Eva Carr, PhD.
Assoc. Professor Emerita, History
Portland State University

Professor Carr holds a B.A. with high honors from Cornell University in classics and archaeology, and her M.A. and PhD. from the University of Michigan in Classical Art and Archaeology. She has excavated in Scotland, Cyprus, Greece, Israel, and Tunisia, and she has been teaching history to university students for a very long time.

Professor Carr's PSU page

Help support Quatr.us!

Quatr.us (formerly "History for Kids") is entirely supported by your generous donations and by our sponsors. Most donors give about $10. Can you give $10 today to keep this site running? Or give $50 to sponsor a page?

Now that the weather's nice, try some of these outdoor activities! How about bicycle polo, or archery for a Medieval Islam day? Or kite flying or making a compass for a day in Medieval China? How about making a shaduf for a day in Ancient Egypt? Holding an Ancient Greek Olympic Games or a medieval European tournament? Building a Native American wickiup?