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The complete history of the Universe -- from the Big Bang to 200 my into the future

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History of the Universe eBook. 398 pages, 300 illustrations only $2.99

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Colony of Algae 1 bya

The next big step in evolution was when algae began to live together in colonies.

By living together, algae gained in several ways:

    They were larger than any protozoan, so they could not be eaten so easily.

    Their cells could specialize to do just one job. For example some cells, the reproductive cells, specialized in making new colonies. Cells which specialized did their job better than cells which didnít, so the colony gained.

    Specialized cells in colonies could do new types of job which could not be done by single cells living alone. For example some cells specialized in swimming.

Colonies of algae probably first appeared around 1 billion years ago. The simplest ones had only a few cells forming a flat plate. More advanced ones formed solid balls.

Pediastrum image courtesy of Luis FernŠndez GarcŪa

The most advanced forms had thousands of cells and formed hollow balls.

All sorts of algae evolved in lakes and on the shores of oceans. Today seaweed and many other forms of algae are still common. Nine out of every ten cells which use sunlight are algae or blue-green bacteria.

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History of the Universe eBook. 398 pages, 300 illustrations only $2.99

eBook only $2.99
398 pages, 300 images

"I find the science fabulous...an extremely useful teaching tool."
Professor David Christian

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