Sex, Death, and Anonymity on Quora

February 9, 2011 § 4 Comments

By: Anon User

1. The Price

The price of sex, it turns out, is death.

Four billion years ago, the earliest life forms were born immortal and capable of reproducing alone, without any mating partners. Asexual bacteria, if given infinite food and space, could theoretically continue to reproduce and live forever; they would “continue clonal expansion through [their] progeny indefinitely….we would likely never find a single dead cell in such a culture.” [1]. Asexual bacteria do not gradually get older, become creaky, or die of natural causes; they do not senesce. When these organisms had the planet to themselves, the end of life was either predation or an accident.

Two billion years later, eukaryotes evolved when one bacteria was subsumed into and subjugated by another, resulting in a more metabolically complex organism. About a billion years after that, during the Stenian period, sexual reproduction between two cells arose for the first time [2]; for these lucky eukaryotes, their offspring would be genetically different from them (and from their mating partner), allowing their species to evolve and adapt to changing environments faster than their more chaste competition could.  With sexual reproduction came the first multicellular life, organisms capable of differentiating their cells into specialized functions, allowing them to scale up in both size and capability. All plant and animal life today is descended from these sexual pioneers.
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