Asexual Reproduction 1

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Asexual Reproduction 1

By | April 2012
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Asexual Reproduction

What is fertility?
* Natural capacity to give life
* Ability to produce offspring of the same species (reproduce)

Asexual reproduction:

* Refers to production of offspring by single organism w/o formation and fusion of gametes. while Sexual reproduction refers to the fusion of gametes to produce an offspring that is not identical to the parents. * Only one parent is required, thus resulting in offspring that are usually genetically identical to the parents. Clones. * Common in plants, less common in animals.

Advantages:
* Requires less energy expenditure
* Useful for organisms which may not easily find a mate due to external environment * Useful for organisms to propagate despite catastrophe or other circumstances. * Environments that are stable and experience very little change are best places for organisms that reproduce asexually. * However, asexual reproduction results in the formation of genetically identical organisms, making the population vulnerable to the same disease or harmful conditions. There is no variation in the population, and thus natural selection nor evolution takes place.

Mitosis:

Asexual reproduction
* Used by unicellular eukaryotes, e.g. amoeba, the cellular division leads to reproduction, which then results in the formation of a new individual. Cells of the parent divide by mitosis to produce cells which will form the offspring.

Growth and cell replacement
* When a multicellular organism is formed from a single cell, each cell must have all the genes present in the original cell. * Some proteins are produced by all cells, and so the genes that code for them must be present in all cells. * As an organism develops, some of its cells differentiate into different types such as skin cells or nerve cells. * These different cells still produce many of the same proteins as each other. They switch on different genes to make their own special proteins...
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