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Water Bears belong to a lesser known phylum of invertebrate animals, the Tardigrada. The first tardigrades were discovered by Goetz in 1773. Over 400 species have been described since that time.

Tardigrades grow only to a size of about 1mm, but they can easily be seen with a microscope. Tardigrade bodies are short, plump, and contain four pairs of lobopodial limbs (poorly articulated limbs which are typical of soft bodied animals). Each limb terminates in four to eight claws or discs. They lumber about in a slow bear-like gait over sand grains or pieces of plant material.

Tardigrade facts.

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coloured scanning electron microscopy by steve gschmeissner (and sixth photo by nicole ottawa). an electron microscope uses a particle beam of electrons, which have much shorter wavelenghts than photons (visible light) and produce a greatly magnified image of the illuminated specimen (up to 10 million times).

dyk: the tardigrade, or water bear, seen in the last photo, can survive in temperatures of one degree kelvin and tolerate pressures six times that of the deepest oceans. despite preferring simple ground dirt, these creatures (which aren’t technically extremophiles) were shown in one experiment to have survived ten days in the vacuum of space. they can also endure heavy doses of radiation and hibernate for a decade. 

dy-also-k: the maggots of the bluebottle fly (the goofy looking dude in the first photo), are used medicinally to clean wounds. once sterilized, they are placed in a wound where they feed on dead tissue and leave healthy tissue untouched. their saliva contains anti bacterial chemicals which maintain sterility in the area.  

click pic for a description of other photos. see also: previous microscopy posts

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You guys might recognize some of the thumbnails and a preview from a post awhile back… here’s the finished piece! :D

Done for the charity artbook Memorieal which recently gave us the go-ahead to upload the illustrations we did earlier this year. As a kid I had a flying/gliding bear species based off this stuffed animal (I named them “Pinky Bears” since I was an original precious snowflake). They were the mortal enemies of eagles, and they primarily ate fish — which they stored underground in burrows. Since that’s what bears do.

Is this one about to grab one or shake its fin? WE MAY NEVER KNOW.

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Tardigrades (Water Bears/Moss Piglets): 

These ambling, eight-legged microscopic “bears of the moss” are cute, ubiquitous, all but indestructible and a model organism for education

by William R. Miller

The young woman in my office doorway is inquiring about the summer internship I am offering. What’s a tardigrade? she asks…

Tardigrades, I reply, are microscopic, aquatic animals found just about everywhere on Earth. Terrestrial species live in the interior dampness of moss, lichen, leaf litter and soil; other species are found in fresh or salt water.

They are commonly known as water bears, a name derived from their resemblance to eight-legged pandas. Some call them moss piglets and they have also been compared to pygmy rhinoceroses and armadillos. On seeing them, most people say tardigrades are the cutest invertebrate.

At one time water bears were candidates to be the main model organism for studies of development. That role is now held most prominently by the roundworm Caenorhabditis elegans, the object of study for the many distinguished researchers following in the trail opened by Nobel Prize laureate Sydney Brenner, who began working on C. elegans in 1974. Water bears offer the same virtues that have made C. elegans so valuable for developmental studies: physiological simplicity, a fast breeding cycle and a precise, highly patterned development plan…

(read more: American Scientist)

images: Eye of Science/Photo Researchers and Dr. David J. Patterson/Photo Researchers. Illustration at bottom by Tom Dunne, adapted from a figure by the author.

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