Tardigrades
Have you ever heard of the moss piglet? What about the water bear? Maybe you are more familiar with its technical name, the tardigrade, which means “slow stepper.” Or it might be that you have never heard about this microscopic marvel. Well, my dear reader, you are in for quite a treat, because this tiny little wonder is one of the most amazing creatures God ever designed.
Even though the tardigrade is teensy, several big words accurately describe it. First, it is known as a micrometazoan. Micrometazoans are animals that are generally less than one millimeter in length, and most can only be seen through a microscope. There are several kinds of these little critters such as rotifers or nematodes (which are super cool as well, but we will not have room in this Discovery to discuss them). Our subject, the moss piglet (so named because it often lives on moss), can be between one-tenth of a millimeter and a little more than a millimeter, but many are about half a millimeter long. To get an idea of that size, imagine a ruler that is divided into centimeters and millimeters. The millimeter lines are the smallest on the ruler. You could fit two tardigrades end-to-end in the small space between two of the millimeter lines.
The word “extremophile” is another rather long and somewhat strange word used to describe the little water bear. This word is used for living things that “love” to live in extreme environments, such as very hot or extremely cold places. The word itself means “one that loves extremes.” There are several varieties of extremophiles. Thermophiles can survive in very hot places such as burning deserts, or in deep, hot water ocean vents. Acidophiles are creatures that can live in areas that are highly acidic. Halophiles can thrive in areas with lots of salt. And psychrophiles handle cold very well.
So, which of these terms describes our cute little slow stepper? It turns out that several of them do. You see, the tardigrade is the toughest animal in the entire world. It can live in places as cold as -457 degrees Fahrenheit or as hot as 302 degrees. It does fine in the salty water of the ocean, and at the very bottom, where the water pressure is six times more powerful than the atmospheric pressure on the surface of the Earth. It can live in extremely dry areas and go for more than 30 years without water. Furthermore, the tough tardigrade can get hit with thousands of times more radiation than a human could handle and live through it.
In 2007, astronauts put into action the TARDIS plan (Tardigrades In Space), and sent several out into the cosmic radiation and crushing vacuum of space. These micro masterpieces, sometimes referred to as the most “unkillable” animal on Earth, survived space’s deadly vacuum unscathed.
You might be wondering how these miniscule marvels can accomplish such death-defying feats. God designed tardigrades with the ability to almost completely stop all functions of life in their bodies. When they perceive a threatening environment, they go into a process called “cryptobiosis.” In this state, they pump 98-99% of all the water out of their bodies. They then replace the water with special sugars that harden almost like glass and “freeze” the tardigrade in a suspended state like hibernation, only much more effective. When the environment becomes more suitable for normal life, just add water, and the tardigrade rehydrates back to its normal self.
simulated image of a tardigrade in cryptobiosis
While cryptobiosis is one way God designed the moss piglet to be so hardy, it is not the only survival trick it has up its sleeve. If our sturdy little specimen is subjected to radiation, it has a special protein known as the Dsup (Damage Suppressor) protein that is used to protect its DNA. This protein creates a protective shield around the animal’s DNA that lessens the effects of radiation. Think about it like one of those bubble soccer suits people squeeze into when they play “bumper soccer.” Brilliant scientists who study this protein are experimenting with ways it can be used to help humans. They believe that it may help lessen the destructive effects of radiation or harmful chemicals on human cells. These scientists have put the protein in with human cells in lab experiments, and the human cells were able to withstand much higher levels of radiation. Isn’t it amazing how God designed such a little animal with abilities that even our most brilliant scientists do not completely understand?
Another survival tool God equipped the tiny tardigrade with is the ability to reassemble its badly damaged DNA. Most cells in most living organisms need water to live. For instance, we humans can go for several weeks without food, but we can only live about three days without water. When an organism loses water, it gets dehydrated. Dehydration normally shatters the DNA inside living cells in a way that it cannot be repaired. Think of a strand of DNA in a cell as a very large book of information that tells the cell what to make in order to stay alive. Then imagine that book being sent through a huge paper shredder and being shredded to tiny pieces. Then imagine a big dog coming in and tearing the pieces up even further. That is an illustration of what happens when a cell dehydrates. As you can imagine, without readable instructions for what to do, most cells simply die.
When the water bear dehydrates and then is given water, its body realizes that the DNA in its cells has been shattered. Instead of dying, however, the tardigrade’s cells begin to put the pieces of DNA back in order and reassemble the instructions. Scientists are still baffled by how this happens, but special enzymes in tardigrade cells work to piece parts of DNA back together, end-to-end, like working a puzzle. Other enzymes work on broken pieces of DNA and repair (or rewrite) the information in it. Imagine walking into a room and seeing that huge book torn to shreds. Then you watch as tiny little robots pick up the little scraps, study them, and start putting them back together how they are supposed to fit until the entire book is fixed, with each sentence perfectly written as it was before! That is what God designed the tough tardigrade to be able to do. Imagine how this technology could help humans if we were able to understand it and use it to repair human cells.
Psalm 148 explains that God created the entire Universe. The text says, “For He commanded, and they were created.” It then talks about the “great sea creatures” and all the “beasts and cattle, creeping things and flying fowl,” and how every creature on Earth was made to bring glory to God. During the time the psalm was written, they did not have microscopes, and the readers could never have known about the marvelous miniature moss piglet. Today, however, when we zoom in on tiny tardigrades, we can be amazed that even the most micrometazoans prove to us, in a very big way, that God is the most brilliant Designer of all.
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