These questions came in in the form of an interview from a science student doing a project on tardigrades:
- “What exactly are Tardigrades?”
- “Why did you decide to study them?”
- “What is your favorite part about Tardigrades?”
- “How do you think they evolved to this point?”
- “Why do you think Tardigrades needed to evolve these traits?”
- “If Tardigrades are seemingly so invincible what is a threat to them?”
- “Do Tardigrades pose a threat to humans?”
- By that I mean like could they harm us by say transfering diseases or getting inside our organs and harming them.
My answers here:
What exactly are tardigrades?
Tardigrades are microscopic creatures that are a maximum of one millimeter in size, but usually are found to be about half that size. They have a mouth, an alimentary tract, and they digest food and excrete it like we do. They have a nervous system and eyes (though primitive). How do they reproduce? They lay eggs. In fact, it is sometimes so difficult to identify types of tardigrades that you have to rely upon their odd shaped eggs. Many of their eggs have points like spikes.
Why did you decide to study them?
In the process of using a microscope to help my kids with their science projects, I did a lot of reading and observing of microscopic organisms. It became great fun to discover some micro creature and look it up to see what it was. When I came across tardigrades, I found that there had been none observed in New Jersey, not in any scientific paper anyway, so I decided to hunt them, and do a survey of the entire state of New Jersey and document it for science. When they were sent into space I became known as the Space Bear Hunter.
What is your favorite part about tardigrades?
What I like best is how they look and move. They have a cute cuddly appearance and they move in a lumbering gait like a bear. They are often referred to as “Water Bears” because they look like chubby little bears with six puffy legs, and they have claws that look like those a grizzly bear would have. Along with their two eyes, some tardigrades are brown in color, and with their hungry mouth, one is reminded of a bear.
How do you think they evolved to this point?
They seem to be related to either nematodes (for example: roundworms) or arthropods (such as crabs, water fleas, ostracods, or insects like ticks or mites). We don’t know how they evolved, but DNA studies are revealing more about that. We’re still trying to figure out how we evolved.
Why do you think tardigrades needed to evolve these traits?
This question implies that evolving is something active that a species does, and it’s misleading. Evolution happens to the organisms. In other words, a car doesn’t flat tire, but a flat tire happens to a car. In the case of tardigrades, those that could survive as their habitat alternated between dry and wet, dry and wet, continued to breed. So the result is a tardigrade that evolved to be able to go into cryptobiosis to survive. Tardigrades didn’t say – hey – we’ve got a problem with this rapidly changing environmental moisture thing -we need to evolve. No, most died and those creatures that over millions of years were able to still exist in the dry wet dry wet environments we call,,, tardigrades.
If tardigrades are seemingly so invincible what is a threat to them?
Tardigrades can easily be killed when submerged in alcohol or chemical fixatives for biological specimens. generally, however, they are hardy survivors in the natural environment and live out their lifespans normally. They can live a hundred years by going into cryptobiosis for long periods of time. A good experiment would be to see how long a tardigrade lives without going into cryptobiosis.
Do tardigrades pose a threat to humans?
They pose no threat to humans, and chances are you might have eaten a tardigrade on some vegetables at some point. There are no reported cases of any tardigrade causing harm to humans, livestock, or crops.
Could they harm us by transferring diseases or getting inside our organs and harming them?
This question seems to mention a threat such as that of a hookworm or tapeworm. Tardigrades are not parasites, and therefore pose no threat to our organs or bloodstream. They are probably destroyed by the gastric juices in the stomach long before they get much further in the intestinal tract. They are way too large to get into the bloodstream, and there is no evidence that they can carry any diseases that might affect us. A good experiment might be to see if tardigrades can survive the digestive system, but no such experiment has been performed.