chemistry

Tardigrades tarde grade

In my presentation I am going to talk about creature that has most endurance in the planet.

It called Tardigrades, often called water bears or moss piglets, are near-microscopic animals with long, plump bodies and scrunched-up heads. They have eight legs, and hands with four to eight claws on each. While strangely cute, these tiny animals are almost indestructible and can even survive in outer space.

Tardigrade is a phylum, a high-level scientific category of animal. (Humans belong in the Chordate phylum — animals with spinal cords.) There are over 1,000 known species within Tardigrade.

Size

These creatures look like the hookah-smoking caterpillar from "Alice in Wonderland." They can range from 0.05 millimeters to 1.2 mm long, but they usually don't get any bigger than 1 mm long.

Habitat

Water bears can live just about anywhere. They prefer to live in sediment at the bottom of a lake, on moist pieces of moss or other wet environments. They can survive a wide range of temperatures and situations. 

Research has found that tardigrades can withstand environments as cold as - 328 degrees Fahrenheit (-200 Celsius) or highs of more than 300 degrees F (148.9 C), according to  Smithsonian magazine . They can also survive radiation, boiling liquids, massive amounts of pressure of up to  six times the pressure of the deepest part of the ocean . A 2008 study published in the journal  Current Biology  found that some species of tardigrade could survive 10 days at low Earth orbit while being exposed to a space vacuum and radiation. 

In fact,  water bears could survive after humanity is long gone , researchers found. Scientists from Harvard and Oxford universities looked at the probabilities of certain astronomical events like Earth-pummeling asteroids, nearby supernova blasts and gamma-ray bursts, to name a few — over the next billions of years. Then, they looked at how likely it would be for those events to wipe out Earth's hardiest species. And while such catastrophic events would likely wipe out humans, the researchers found little tardigrades would survive most of them.

Strong:

The most 'indestructible' animal on Earth. tardigrades can survive up to 30 years without food, live in volcanoes, and endure the vacuum of space. Researchers say they could even survive an asteroid impact like the one that led to the extinction of the dinosaurs.

Habits 

Tardigrades were discovered by a German pastor, Johann August Ephraim Goeze, in 1773. He named them Tardigrada, which means "slow stepper." In 1776, Italian clergyman and biologist Lazzaro Spallanzani discovered that water bears survive extreme conditions by making a transformation. 

How they do it:

In many conditions, they survive by going into an almost death-like state called cryptobiosis. They curl into a dehydrated ball, called a tun, by retracting their head and legs. If reintroduced to water, the tardigrade can come back to life in just a few hours.  

While in cryptobiosis, tardigrades' metabolic activity gets as low as 0.01 percent of normal levels, and their organs are protected by a sugary gel called trehalose. They also seem to make a large amount of antioxidants, which may be another way to protect vital organs. Water bears also produce a protein that protects their DNA from radiation damage, according to research by the University of Tokyo.

In cold temperatures, they form into a special tun that prevents the growth of ice crystals. 

They also have another defense for when they are in water. When the water they live in is low on oxygen, they will stretch out and allow their metabolic rate to reduce. In this state, their muscles absorb oxygen and water well enough that they can survive. 

In 2016, scientists revived two tuns and an egg that had been in cryptobiosis for more than 30 years. The experiment was reported in the journal Cryobiology. 

Reports from an experiment in 1948 claim that a tun over 120 years old had been revived, but this research has never been duplicated, according to the BBC. 

Diet

Tardigrades eat fluid to survive. They suck the juices from algae, lichens and moss. Some species are carnivores and even cannibals — they can prey on other tardigrades, according to the BBC.

Classification

Here is the classification for tardigrades, according to ITIS:

Kingdom: Animalia Subkingdom: Bilateria Infra kingdom: Protostomia Superphylum: Ecdysozoa Phylum: Tardigrada

Survived:

They are not on any other endangered list and have survived five mass extinctions over the course of around a half a billion years, according to National Geographic.

In The space:

IN APRIL 2019, the Israeli Beresheet spacecraft crash-landed on the Moon. Along for the ride were thousands of tiny creatures, which scientists now think may have spilled out and littered the lunar surface.

Beresheet had some unusual cargo. In an attempt to document life on Earth, a non-profit organization by the name of the Arch Mission sent a library to the Moon aboard the craft. The library of life included a stack of disks archiving 30 million pages of information about Earth, a copy of the entire English-language Wikipedia, human DNA samples, and a mega-payload of thousands of tardigrades.

They may also now be the only (potentially) alive organisms on the Moon.

Beresheet's strange occupants were dehydrated tardigrades, a process that essentially slows their metabolism down and suspends them in a near-life state. The idea was that, if they were to be rehydrated by someone or something, then they would come back to life, ostensibly telling future lunar explorers about life on Earth today.

THERE'S JUST ONE PROBLEM — But the spacecraft carrying the tardigrades didn’t land according to plan and crashed on the lunar surface, losing contact with ground control.

Despite the impact, scientists believe that if anything survived the crash intact, it may well have been the tardigrades. The microscopic creatures were sandwiched between micron-thin sheets of nickel and suspended in epoxy, a resin-like preservative that acts like a jelly — potentially enough to cushion their landing.

This is not a totally new idea. Tardigrades have been shown to survive the harsh conditions of space in the past.

In September 2007, two species of dehydrated tardigrades were exposed to the vacuum of space, solar radiation, or both onboard NASA’s Foton-M3 mission. Back on Earth, after they were rehydrated, the tardigrades exposed to the vacuum of space survived as though nothing had happened.

If they did stick the landing, the tardigrades would have a hard time finding liquid water on the lunar surface to revive them. Everything We Know About Tardigrades, the Only Animal That Can Survive in Space.

Citation:

Bradford, A. (2017, July 14). Facts about tardigrades. Retrieved March 02, 2021, from https://www.livescience.com/57985-tardigrade-facts.html.

Rabie, P. (2020, December 24). Why tardigrades spilled all over the moon in 2020. Retrieved March 02, 2021, from https://www.inverse.com/science/tardigrades-may-have-taken-over-the-moon