40654ac3c5227b0b760299124tardigrades in space

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water bears:

the animal that

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survived space!

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Meet a hardy little organism called the water bear.

Water bears, also known as tardigrades, are a wonder! They are tiny eight-legged creatures, known for their virtual indestructibility on Earth. They can survive almost anything: extreme temperatures, tons of radiation, the pressures of the deep sea, starvation, and nearly a decade without water. Now their legendary toughness has been put to the ultimate test. They've been sent into space!

In the past, some biologists have suggested that tardigrades may be the only animal to come back alive after a trip in real space. Scientists now decided to send them into space to find out if that is true.

Once in space, all the water bears were exposed to the vacuum of space, and some were even exposed to solar and cosmic radiation. After 10 days of exposure to space, the satellite returned to Earth. The water bears were rehydrated to see how their reproductive abilities were affec ted.

The vacuum itself seemed to have little effect on the creatures. But ultraviolet radiation , which can damage cellular material and DNA, did take its toll. Yet, a handful of animals even survived full exposure to the Sun's UV light, which is more than 1000 times stronger in space than on the Earth's surface.

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Water bears are a mystery. They have an unparalleled ability to cope with the extremely dry conditions of deep vacuum and the harmful solar and cosmic radiation up there, which has piqued scientific curiosity. Still, no one quite understands how they can be as resistant as they are. Besides, they are also challenging our traditional concepts of life, for instance that life depends on water, or that life is a continuous process.

Tardigrade QUIZ

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I. Are water bears bacteria or animals?

They have claws and eyes. They are real animals.
They are bacteria.
Neither, they are the largest known viruses.

II. How big are they?

Tardigrades are about the size of a fly.
Bigger adults are visible to the naked eye, reaching about 1,5 mm in length.
They can only be seen under a microscope.

III. How many legs do they have?

Tardigrades are six-legged.
Tardigrades are seven-legged.
Tardigrades are eight-legged.

IV. Where do they live?

They are found throughout much of Asia and Africa.
Tardigrades occur over the entire world, from the high Himalayas (above 6,000 m), to the deep sea (below 4,000 m) and from the polar regions to the equator.
They can only be found inside active volcanos in Peru.

V. How did they get their name?

The name water bear comes from the way they walk, reminiscent (=reminding) of a bear's.
The name is a reminder of their distant genetic relationship with bears.
The name reflects their ability to go into hibernation to survive extremes.

VI. How hot is too hot for them?

They can survive temperatures between -50 and 90 °C for a few minutes.
They can survive temperatures between -150 and 125 °C for a few minutes.
They can survive being chilled to -272 °C (absolute zero is −273.15 °C), or being heated to 151 °C for a few minutes.

VII. How long can they go without water?

Tardigrades can go without water for nearly one year.
Tardigrades have been shown to survive nearly one decade in a dry state.
Tardigrades can survive nearly one hundred years in a dry state.

VIII. How much radiation can they survive?

They can withstand (=survive) 17,000 rads of x-ray radiation. (1,000-2,000 rads could be fatal to a human).
They can withstand 57,000 rads of x-ray radiation.
They can withstand 570,000 rads of x-ray radiation.

IX. How do they survive extreme conditions?

They're capable of halting (=stopping) their metabolisms (=life functions) during times of extreme privation (=a lack of basic things), and can repair DNA damage caused by extraordinary doses of radiation.
They are supposed to be alien organisms that landed on Earth with an incoming meteor. Their native planet must have been much closer to the Sun, making them evolve resistance toward extreme heat and radiation.
They survive extremes by having a tremendously resilient (=resistant) shield that reflects heat and radiation.

Source URLs:

http://tardigradesinspace.blogspot.com/

http://blog.wired.com/wiredscience/2008/09/invertebrate-as.html

http://www.newscientist.com/article/dn14690?DCMP=ILC-hmts&nsref=news1_head_dn14690

http://en.wikipedia.org/wiki/Tardigrade

http://x1brettstuff.blogspot.com/2007/10/tardigrades-in-space.html

Tardigrade QUIZ

solutions

I. Are water bears bacteria or animals?

A. They have claws and eyes. They are real animals.

II. How big are they?

B. Bigger adults are visible to the naked eye, reaching about 1,5 mm in length.

III. How many legs do they have?

C. Tardigrades are eight-legged.

IV. Where do they live?

B. Tardigrades occur over the entire world, from the high Himalayas (above 6,000 m), to the deep sea (below 4,000 m) and from the polar regions to the equator.

V. How did they get their name?

A. The name water bear comes from the way they walk, reminiscent of a bear's.

VI. How hot is too hot for them?

C. Tardigrades can survive being chilled to -272 °C. (absolute zero is −273.15 °C), or being heated to 151 °C for a few minutes.

VII. How long can they go without water?

B. Tardigrades have been shown to survive nearly one decade in a dry state.

VIII. How much radiation can they survive?

C. They can withstand 570,000 rads of x-ray radiation. (1,000-2,000 rads could be fatal to a human).

IX. How do they survive extreme conditions?

A. They're capable of halting their metabolisms during times of extreme privation, and can repair DNA damage caused by extraordinary doses of radiation.