Abstinence-only animals avoid extinction by blowing around

Scientists discover how small invertebrates named rotifers have avoided extinction -- despite not having sex for 30 million years.

By

Bryan Nelson

Thu, Jan 28 2010 at 8:31 PM

Related Topics:

Ecology, Viruses & Diseases, Science

ROTIFERS: Could these be the only animals in the world capable of cheating natural selection? (Photo: Damián H. Zanette/Wiki Commons)

Small, freshwater invertebrates called bdelloid rotifers have long puzzled and fascinated evolutionary scientists. These unusual, asexual organisms have managed to survive and avoid disease for at least 30 million years without sexual reproduction. Now according to the Cornell Chronicle, researchers are unlocking their secrets for the first time.

One of the advantages of sexual reproduction is that it mixes up the genes for each new generation, allowing populations of organisms to adapt quickly to changes in their environment and to fend off relentlessly evolving parasites and pathogens. But since rotifers have forsaken sex, they should have been driven to extinction by disease long ago. Instead, they have defied natural selection by proliferating into more than 450 species.

Their secret? Rotifers, it turns out, are the ultimate biological Houdinis. They are capable of cheating death and escaping disease — essentially surviving without sex — by shriveling up and blowing away. Since harmful parasites and fungi can't survive dehydration like the rotifers can, the dried-up tricksters make a clean getaway.

"These animals are essentially playing an evolutionary game of hide and seek," said Paul Sherman, Cornell professor of neurobiology and behavior. "They can drift on the wind to colonize parasite-free habitat patches where they reproduce rapidly and depart again before their enemies catch up. This effectively enables them to evade biotic enemies without sex, using mechanisms that no other known animals can duplicate."

The study was performed by infecting populations of rotifers with deadly fungi, allowing them to dry out, then placing them in a wind chamber. To the surprise of scientists, the rotifers were able to disperse without the fungi and establish parasite-free populations.

In fact, it took only seven days on the wind for the rotifers to establish the same number of fungus-free populations that took three weeks to establish without wind, demonstrating that the key to their survival without sex is likely that rotifers blow around.

"It also helps answer one of the deepest puzzles in evolutionary biology — why sex is nearly ubiquitous," said Chris Wilson, lead author of the study.

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Comments: 2

Gear shift Feb 06 2010 at 11:57 AM

Here we have another America first and the most astounding lack of common sense in the vast field of political whoredom. Out of fifty United States here in Chatham County, Geogia we have the most pecular situation that baffles one's mind in taking a look at political whordom and it inside network of well-heeled lawyers. This is the only place on earth that would tolerate placing a dog pound directly in front of an individual family home one hundred feet property line. Hold own there is another twist.

.... More

Directly in the back of this home was placed another dog pound. Neither one of these business went through the process of law, in fact The Metro Politan Planning Commission was told to jump into the river. The local Building Inspections Department completely ignored the whole situation. The conclusion is that money talks Can one imagine wrecking one's home and family life because two business have operated for years through political whoredom in rezoning two plots of adjacent land zoned for family dwelling. Evey to official was met with but no results. For years at listening to loose running dogs have brought on heart condition with husband and total disability with wife, one 83 the other 74, This is a master crime against anyone. Such individuals connected with this dreadful situation be imprisoned. For years dog feces and urine has run out into the street while neighborhood traffic splashed through it. And the worst of it is that no attorney in the state or out would take the case, all were afraid to fight the system. The state's attorney general was consulted with charts, graphs, etc;, we were to get a lawyer. When a child of about 10 years of age I over heard two politicians talking while they were drunk. One made the remark that this area of Georgia was the rectum of civilization when it came to lawful activities. Incidentally, my taxes jumped $500 one year for complaining about outside perpetual barking and fighting dogs. Our ages qualified relief of taxes through a Steven's day law in giving elderly folks a break. I complained: get a lawyer was the answer. There is little doubt in my mind that lawyers are the original agents of Satan.