We Don't Need No Men, Man
Most denizens of the animal kingdom thinks sex is the best since sliced bread. It's an easy way to reproduce, it provides change and variation for the genome, and it's mostly low risk. However, there's one invertebrate that doesn't like sex, and, in fact, doesn't like having the other gender around at all.
Meet the bdelloid rotifers: an all female group of freshwater invertebrates that don't need males, and haven't for the past 80 million years. They are lifetime asexuals, so no Death by Snu Snu if a male should happen to enter the picture.
In sexually reproducing populations, a set of chromosomes can exchange genetic information, which can lead to advantageous and/or harmful combinations. Either way, genetic mingling helps to weed out harmful combinations and spread beneficial ones. So, how do bdelloid rotifers gain the same evolutionary advantages as sexually reproducing organisms?
To enhance their genetic fitness, bdelloid rotifers engage in "horizontal gene transfer." They recruit foreign genes from bacteria, fungi and even some plants and integrate them into their own genetic code.
Scientists believe that the rotifers habitually break down their own genome and then rebuild it using genes from surrounding rotifers and even other species. Another way they receive new genetic information is from the food they eat. They enter into a period of desiccation, a severe drying out, and go into a deep hibernation period for months or even years. During this period, their cell membranes and DNA may be severely altered or broken down. When water is found again, they rebuild their genome using strands of their own DNA, and also strands from the food they had consumed before entering hibernation. The food they eat then becomes a part of them, literally.