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Tardigrades, “Little Water Bears”

What are tardigrades?

Tardigrades are microscopic aquatic animals that are known because of their highly tolerant nature. Tardigrades were discovered in 1773 by the German zoologist Johann August Ephraim Goeze, who dubbed them “little water bear.” Three years later, Italian biologist Lazzaro Spallanzani named the group “Tardigrada,” or “slow stepper.” Tardigrades are also called “moss piglets.” These are invertebrates belonging to the phylum Tardigrada. Like roundworms, they have a fixed number of cells in their bodies. Like insects, they have a tough cuticle that protects them from their environment, and periodically shed their cuticle in order to grow.

Tardigrades water bears
Image Credit- Phillip Barden-Harvard - NJIT

What do tardigrades look like?

These aquatic animals have small, plump bodies that measure between 0.008 and 0.018 inches (0.20 to 0.45 mm). They have a well-developed head region and a short body formed of four body segments that are fused. Each body segment bears a pair of short, stout, and unjointed limbs. The limbs end in sharp claws. Their flat head has a mouth that is surrounded by spear-like structures. This helps these animals to feed by piercing.

What makes tardigrades special?

The most remarkable feature of the tardigrades is their ability to withstand extreme conditions. Some species can survive exposure to -272.15°C, while others can withstand temperatures of up to 150°C, although only for a short time. Tardigrades can also survive immense pressures, up to six times that on the ocean floor, or even being boiled in alcohol. When exposed to dehydrated conditions, they lose up to 99% of their water content and start looking like glass! In its dehydrated state, it is known as a “tun.” A tun’s metabolism lowers to as little as 0.01 percent of its original rate. This means a tardigrade can shut down its biological activities while managing to stay alive. Therefore, from volcanic vents to icebergs, these animals can withstand everything.

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Can tardigrades survive in space too?

Yes! In 2007, it was found out that these tiny water bears can also survive the vacuum condition of outer space! A European team of scientists had sent a group of living tardigrades to orbit the Earth for 10 days. After 10 days, when the rocket returned to Earth, 68% of the tardigrades survived!!

Why are tardigrades in the news these days?

Some scientists have found quantum entanglement in tardigrades, but others disagree and think more research is needed. According to this phenomenon, particles which show quantum entanglement are linked to each other. This means that actions performed on one of the particles will affect the other, no matter the distance between them. Tardigrades are possibly the first-ever multi-celled animals that are quantum entangled. 

Apart from this, the fossil of a 16-million-year old water bear was found trapped inside a chunk of Dominican amber. The new species is called Paradoryphoribius chronocaribbeus, combining the Greek word for time, “Chrono,” and “caribbeus” for the Caribbean region in which it was found.

After reading the above information, answer the following questions:

    1. “Tardigrade” means:
     
      • Tired stepper
      • Slow stepper
      • Tired animal
      • Slow animal
      Ans: b  
    1. What does a tun do?
     
      • Dies due to dehydration
      • Dies due to pressure
      • Shuts down all biological processes
      • Shuts down 99.9% of biological processes
    Ans: d  
    1. In which surroundings can tardigrades survive?
     
      • Volcanic vents
      • Under water
      • Outer space
      • All of the above
    Ans: d  
    1. What are tardigrades currently in the headlines for?
     
      • They are the first quantum entangled animals
      • A 16-million-year-old fossil of a tardigrade species new to science has been found
      • Both a and b
      • They can exist in the tun state
      Ans: c

Suitable for ages 12-14 (According to Flesch reading scale )

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