Rotifers and the Pausing of Time

If you're like most people, you've never heard of rotifers (right). I'm not going to go and say these little creatures determine our way of life or anything, but a mystery about them has recently been solved. They've been examined ever since the microscope was invented, and have a couple interesting traits. For one, they have little spinning arms that propel food into their mouth – see the two furry things in the picture. For another, as reported on Science Friday, they don't have sex.

How do we know there never comes a point when two rotifers love each other very much? Well, not only has it never been observed, but also in 300 years of watching rotifers through microscopes, no one has ever even seen a male. There is additional modern genetic evidence that there are only female rotifers.

What's the big with not doing it? Well, the genetic exchange that occurs during meiosis greatly enhances variability of individuals within a species, speeding up evolution. Eliminate sex and a species basically freezes form.

Why is a static genome a problem? Everyone else is evolving, including your enemies. Say there's something in your blood that gives your species a resistance to certain parasite. Well, those parasites are having sex all the time, and eventually one might come about that happens to have a resistance to your blood. Since your species hasn't been having sex all this time, you have almost no genetic variation, and no one has any resistance, and you all die out and go extinct.

So that's why sex is good. There are even species of animals that under favorable circumstances skip the males and just have female offspring and basically clone themselves. However, once the environment turns sour, there starts being males born who then have sex with females, increasing variability, with the evolutionary "hope" that some new individuals will happen to have a greater tolerance to dry weather, or smaller size, or whatever. These species will skip sex for several generations, but eventually do it.

But bdelloid rotifers haven't done it in 35 million years. How do they get away with such genetic similarity? One possibility is that they don't have enemies. Oh, but they do. As researchers at Cornell University showed, certain species of fungus will decimate rotifer populations. As in, kill every single active rotifer.

What, you ask, is an inactive rotifer? Well, that's what the Cornell scientists figured out. Rotifers have the ability to dehydrate themselves, completely expunging any water from their body. They go into a state of suspended animation, essentially stopping time for anywhere from a few weeks to ten years. But when the rotifer comes back from its stasis field, won't the infecting fungus also reanimate?

Rotifers have extremely robust DNA that is good at reassembling itself after it gets broken when the rotifer dries out. The fungus does not have the same ability and the drying period kills it. The Cornell scientists even determined how much of the fungus was killed after 2, 3, 4, and 5 weeks, and found that a month was all the rotifer needed to purge the fungus from itself.

So rotifers can isolate themselves from the fungus in time. They can also do it in space. When they become dehydrated, they become little dandelion seeds (from an aerodynamics point of view anyway). That means that they are easily picked up by breezes and carried to a new, happy, fungus-free home.

One thing I didn't understand is that they program mentioned there are several hundred species of rotifers. But isn't sex and genetic variation the driving force behind evolution and speciation? Any thoughts?

South Korea Turns Off the Lights

One Wednesday a Month, offices in South Korea will shut off their lights early in the evening. No, they're not trying to look like North Korea when viewed from space. Instead, they want all their office workers to go home.

Why? Well, I've written how some countries have high birth rates that lead to food and resource shortages. South Korea has the opposite problem, with the world's lowest birth rate. At only 1.2 kids per couple, their population is actually in decline. This means that a comparatively large portion of the population are elderly, and there will be greater pressure on people of working age. And of course with less workers, the country has less manufacturing capacity. Therefore, the Ministry of Health hopes that by getting people out of the office, they might go into the home and make babies.

In order to make this truly successful, I think that the government also needs to shut down all TV broadcasts on those same evenings, at least based on the Indian government's assumption that getting people to watch television at night will stop them from making babies.

Birth Control Pills Might Alter Mate Selection

Yahoo News runs a story about some studies which may indicate that the birth control pill influence women's choice of mate. Researchers at the University of Sheffield in England predict that "offspring of pill users are more homozygous than expected, possibly related to impaired immune function and decreased perceived health and attractiveness." The idea is that women who are ovulating tend to be attracted to Manly Men, but women on the pill are hormonally in a state similar to perpetual pregnancy. Therefore, the claim goes, that women on the pill will be less likely to date the captain of the football team, and instead hook up with president of the role-playing club. It is important to note that the "impaired immune function", et cetera, of the predicted offspring are not a result of the woman actually taking the pill, but because of the 'less reproductively sound' mate she chose because the pill clouded her judgment.

Not everyone agrees, however. Dr. William Hurd of Case Medical Center is skeptical:

If you don't take into account society maybe we're all animals, but in social situations I don't think there are many women who change who they would mate with at different times of the month. It might change desires or perceptions but, gee whiz, that's a long stretch to changing who you would date, or even who you would go to dinner with.

Also, I may be wrong here, but I would think that many women taking the pill are doing it because they are already in a relationship (and therefore have chosen their "mate").

Population Control

The Columbia University magazine has an interesting article about overpopulation in this season's issue. On the one hand, population control seems like a good thing:

Now, after decades of unprecedented population growth, the land is running out. In southern Uganda, as in many parts of sub-Saharan Africa, farm communities are bumping up against one another and against dry lands, mountains, and rain forests... Other farmers are subdividing their parents’ land, reducing the typical-sized farm plot in some parts of Africa to half an acre.

“That’s too small to feed a family,” says economist Jeffrey D. Sachs, who directs Columbia’s Earth Institute. The only way to break this cycle of overpopulation and misery, Sachs writes in Common Wealth, is for wealthy nations to provide birth control to the world’s poor.

However, any mention of population control is immediately going to bring up memories of the last time large-scale birth control was attempted, during the '60s and '70s. China's "one-child" policy was one of the most innocuous methods used.

Western family planners in the 1960s and 1970s, in their zeal to slow population growth and to spur development in Asia, supported forced sterilizations, slum demolitions, and other abuses.

The article has a lot of details the sudden population increase in Africa and Asia, the history of the birth control agencies and processes, and how more kindly methods of birth control (for the purpose of slowing population growth rather than focusing only women's rights) may become a major issue again.

In a different news story, India is looking into an untried birth control idea: having Indians watch more television.

In rural India where birthrates are high, many people live in homes without electricity. Health and Family Welfare Minister Ghulam Nabi Azad has called the country to redouble its efforts to bring electricity to the rural population so these people can plug in TV sets and watch late-night soap operas rather than have sex.