From UPSC perspective, the following things are important :
Prelims level : Tardigrade
Mains level : Not Much
- On this April 11, the Israeli spacecraft Beresheet attempted to land on the Moon, but crashed on the surface.
- It was carrying a number of items — including thousands of specimens of a living organism called Tardigrade.
- The Tardigrade, also known as water bear, is among the toughest and most resilient creatures on Earth.
- The Tardigrade can only be seen under a microscope.
- Half a millimeter long, it is essentially a water-dweller but also inhabits land and, a 2008 study found, can survive in the cold vacuum of outer space.
- It derives its name from the fact that it looks like an eight-legged bear, with a mouth that can project out like a tongue.
- Its body has four segments supported by four pairs of clawed legs.
- A tardigrade typically eats fluids, using its claws and mouth to tear open plant and animal cells, so that it can suck nutrients out of them.
- It is also known to feast on bacteria and, in some cases, to kill and eat other tardigrades. Although they are famed for their resilience, they are destructible too.
- Should a human being swallow a tardigrade with her food, her stomach acid will cause the flesh of the tardigrade to disintegrate.
- In 2017, a study found that if all other life were to be wiped out by a cataclysmic event — a large asteroid impact, a supernova or a gamma-ray bursts — the tardigrade would be the likeliest to survive.
- It can endure extreme hot and cold temperature levels.
- Although the tardigrades on the Israeli spacecraft were dehydrated, the organism is known to “come back to life” on rehydration.
- In fact, they themselves expel water from their bodies and set off a mechanism to protect their cells, and can still revive if placed in water later.
- However, there is no evidence of liquid water on the Moon, although there is ice.
- Without liquid water, it is possible that the tardigrades will remain in their current state, unless future astronauts find them and revive them in water.