O8. Offspring that are the result of sexual reproduction are usually not genetically identical.

Student Outcome: O8.1

Describe how the events in meiosis and fertilisation contribute to variation in offspring.

For most of the history of life on Earth, organisms have reproduced only by asexual reproduction. Each individual was a genetic copy (or clone) of its “parent”, and the only variation was due to random genetic mutation. The development of sexual reproduction in the eukaryotes around one billion years ago led to much greater variation and diversity of life. Sexual reproduction is slower and more complex than asexual, but it has the great advantage of introducing genetic variation (due to genetic recombination in meiosis and random fertilisation). This variation allows species to adapt to their environment and so to evolve. This variation is clearly such an advantage that practically all species can reproduce sexually. Some organisms can do both, using sexual reproduction for genetic variety and asexual reproduction to survive harsh times.

Source: http://www.biologymad.com/master.html?http://www.biologymad.com/CellDivision/CellDivision.htm

Here is a video introduction of meiosis

Here are some real cells undergoing meiosis - no labels or commentary but it's real!

Although not directly related, checkout this video about an animator who used natural selection to help develop artificial intelligence: