Is Sexual Selection Really Necessary for Speciation? The Rotifer Says No.
The next time you start to complain about your lackluster love life, stop yourself and count your blessings. While you may be going through a dry spell, the bdelloid rotifer hasn't had sex in over forty million years! Let's just say that its frustrations are a little more serious than whatever problems you're currently experiencing. The bdelloid rotifer has it so bad that until recently, most scientists would have considered such a lack of sexual activity to be more than just a source of angst for the rotifer on weekend nights, as sexual selection has long been considered essential for the formation of new species through natural selection.
Recent studies of the bdelloid rotifer conducted at Imperial College in London, however, have proved that this idea is not supported by empirical evidence. While previously it was thought that asexual species should eventually become extinct because they cannot perform natural selection fast enough to adapt to environmental changes, the bdelloid rotifer has existed for millions of years, and recent DNA testing has also revealed that there are several distinct species of bdelloid rotifer that have formed without sexual selection.
The researchers reporting these findings call them "groundbreaking" in that findings such as this suggest that there is still much to learn about the basic mechanisms of evolution. Studies such as this call into question some of the central tenets of evolutionary theory. If sex isn't really essential to evolutionary divergence as once thought, then what else about Darwinian theory that we currently accept as undeniably true in theory might someday be proved wrong by experimental evidence?
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