meiosis

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What happened in the Cambrian Period?

By |2018-04-21T11:56:36+00:00June 23rd, 2017|Geology|

Mossy rocks 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. Small arthropods like beetles were beginning to appear, and by 540 million years ago the first land plants [...]

What is a spore? – Plant reproduction – Biology

By |2018-04-13T23:51:51+00:00May 30th, 2017|Biology|

Fern spores on the underside of a frond When plants like moss first began to grow outside the water, about 540 million years ago, they needed a way to reproduce themselves that didn't depend on water so much. Some of these plants evolved to be able to produce spores. To make spores, plants [...]

Plant reproduction – Biology – Science

By |2018-04-13T17:52:39+00:00May 30th, 2017|Biology|

Cell division The very earliest photosynthesizing plants on Earth, about 3 billion years ago, had only one cell, and they reproduced the way most one-celled creatures do, by mitosis: splitting themselves in half. By about two billion years ago, some of these cells began to split themselves in a more sophisticated way, called [...]

What is mitosis? Sexual reproduction – Biology

By |2017-05-29T00:31:28+00:00May 29th, 2017|Biology|

Eukaryote cells generally reproduce themselves using a method called mitosis. When a eukaryote cell senses that there is plenty of food around, it splits into two new cells that together can eat more food. But it's pretty complicated for eukaryote cells to divide. They have a lot of DNA molecules, to control all the different parts [...]

What is meiosis? Cell reproduction – Biology

By |2017-11-24T17:38:10+00:00May 29th, 2017|Biology|

At first all eukaryote cells divided using a process called mitosis. But about 1.4 billion years ago, some eukaryote cells developed the ability to reproduce using meiosis instead. Meiosis (my-OH-siss) is a way for cells to get more diversity while they are reproducing. A cell that reproduces by meiosis has twice as much DNA in its [...]

Fish eggs and chicken eggs – Evolution and Biology

By |2018-04-13T14:34:41+00:00May 27th, 2017|Biology|

Fish eggs Check out different kinds of eggs and you'll see the difference between fish eggs, which are soft and have to be in the water to survive, and the eggs of land animals, which are hard so they can survive on dry land. It's pretty easy to get fish eggs: they sell [...]