Researchers Explain How Rotifers Thrive Despite Forgoing Sex

Posted on February 21, 2010  Comments (1)

Bdelloid rotifers haven’t had sex for at least thirty million years. Most asexual animals are doomed to extinction. The excellent show, Science Friday, looks at the extraordinary adaptations that allow rotifers to thrive sex-free.

For millions of years, the rotifers have reproduced asexually, flying in the face of an idea known as the Red Queen Hypothesis, which states that without the advantage of sexual reproduction, more-rapidly evolving parasites and predators will eventually doom the asexual species. Now, the researchers studying the tiny organism say that its ability to dry up and blow away to greener pastures may have given the rotifers a hidden tactical edge in this evolutionary war.

The webcast provides a nice overview of the research. Every week Science Friday provides many such interesting reviews of recent scientific research.

What Are Rotifers?

Rotifers are small, mostly freshwater animals, and are amongst the smallest members of the Metazoa — that group of multicellular animals which includes humans, and whose bodies are organized into systems of organs.
Most rotifers are about 0.5mm in length or less, and their bodies have a total of around a thousand cells. This means that their organ systems are a greatly simplified distillation of the organ systems found in the bodies of the higher animals.

A typical rotifer might have a brain of perhaps fifteen cells with associated nerves and ganglia, a stomach of much the same number, an excretory system of only a dozen or so cells, and a similarly fundamental reproductive system. They have no circulatory system. It is an anomaly that despite their complexity, many rotifers are much smaller than common single-celled organisms whose world they share.

they are able to survive long periods — even perhaps hundreds of years — in a dried or frozen state, and will resume normal behaviour when rehydrated or thawed.
Secondly, they exhibit what biologists call cell constancy — they grow in size not by cell division, but by increase in the size of the cells which they already have.

Related: Bdelloid Rotifers Abandoned Sex 100 Million Years AgoFungus-gardening Ant Species Has Given Up Sex CompletelyAmazon Molly Fish are All Female50 Species of Diatoms

One Response to “Researchers Explain How Rotifers Thrive Despite Forgoing Sex”

  1. Nature Uses Stem Cells from Fetus to Repair Health of Mother » Curious Cat Science Blog
    November 23rd, 2011 @ 3:24 am

    Scientists have learned mice use stem cells from the fetus to repair damage to the mother in the event of things like heart attacks. And there is evidence people do the same thing…

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