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Asexual reproduction in single-celled organisms
Single-celled organisms which use asexual reproduction can do so very rapidly simply by dividing into two equal halves. This is called binary fission.
In yeasts the cell does not divide equally in two halves; instead, there is a large mother cell and a smaller daughter cell. This is called budding.
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Some of the simple algae, such as Spirogyra shown above, grow in long threads called filaments. They grow longer each time a cell in the filament divides. If, however, the filament is broken into pieces, each part can grow into a new plant. |
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Binary fission and budding are very rapid ways of reproducing. For example, if conditions are good, the cell of a Paramecium can divide, grow, and divide again in the space of 8 hours.
One of the best places to look for Paramecia is in a flower vase which has had the same water in it for a few days. The clean water becomes cloudy because of the millions of micro-organisms swimming in it, all of them produced by asexual reproduction within a few days.
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©
Paul Billiet and Shirley Burchill 2008 |