Tardigrades
Tardigrades or people usually call them as "Water Bear" or "Moss Piglet" are a water-dwelling eight-legged micro-animals. They were first discovered by a German Zoologist Johann August Ephraim Goeze in 1773. But the one who gave them the name "Tardigrades" were not him, It was an Italian Biologist Lazzaro Spallanzani. He called it "Tardigrada", which means "slow steppers".
The length of a normal Tardigrades are generally 0.5 mm. Their bodies are short plump looking with 4 pairs of legs and sucking disks on each end. Tardigrades are prevalent in mosses and lichens and feed on plant cells, algae, and small invertebrates. When collected, they may be viewed under a very low-power microscope, making them accessible to students and amateur scientists.
The length of a normal Tardigrades are generally 0.5 mm. Their bodies are short plump looking with 4 pairs of legs and sucking disks on each end. Tardigrades are prevalent in mosses and lichens and feed on plant cells, algae, and small invertebrates. When collected, they may be viewed under a very low-power microscope, making them accessible to students and amateur scientists.
Tardigrades are one of the few groups of species that are capable of suspending their metabolism (see cryptobiosis). While in this state, their metabolism lowers to less than 0.01% of normal and their water content can drop to 1% of normal, and they can go without food or water for more than 30 years, only to later rehydrate, forage, and reproduce. Many species of tardigrade can survive in a dehydrated state up to five years, or in exceptional cases longer. Depending on the environment, they may enter this state via anhydrobiosis, cryobiosis, osmobiosis, or anoxybiosis.
They have been found everywhere, from mountaintops to the deep sea and mud volcanoes and from tropical rain forests to the Antarctic. Tardigrades are among the most resilient animals known, with individual species able to survive extreme conditions—such as exposure to extreme temperatures, extreme pressures (both high and low), air deprivation, radiation, dehydration, and starvation—that would quickly kill most other known forms of life. Tardigrades have survived exposure to outer space. About 1,150 known species form the phylum Tardigrada, a part of the superphylum Ecdysozoa. The group includes fossils dating from 530 million years ago, in the Cambrian period.
Questions:
1. Where can we find them?
2. What is "Crytobiosis"?
3. Who is Lazzaro Spallanzani?
4. if Tardigrades are 0.5mm in size, it means they are?
5. How can a Tardigrade survive through extreme condition?
For more detailed information about Tardigrades, you can watch this video
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