Hydra: Octopus of the Microscopic World

Biology
[caption id="attachment_6105" align="alignright" width="440"] Hydra oligactis - CCA Share Alike 3.0 Unported by Lifetrance[/caption] Resembling a cross between an octopus and a sea anemone, tiny hydra lives in fresh water. It would make an excellent subject for a Japanese sci-fi movie. H. oligactis, seen at left, has a central stalk from which a number of tentacles radiate. The Real Deal Waving its tentacles in search of prey, the tiny creature thrives in among loose weeds. The creatures are carnivores. Scientists find them of special interest because of their great ability to regenerate. They are capable of living a long time. The base of the stalk secretes an adhesive that enables the miniature "octopus" to stick to surfaces. The tentacles contain nematocysts or stinging cells with neurotoxins that paralyze a victim.…
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Daphnia Pulex: The Water Flea

Biology
[caption id="attachment_6098" align="alignright" width="440"] Daphnia - photo by Paul Hebert[/caption] Although there are other species, Daphnia pulex comes to mind when one thinks of the water flea. The tiny crustacean. D. pulex is cosmopolitan. That word means it is found throughout the cosmetic (surface) layer of the planet. The National Institutes of Health informs us that the water flea is “a versatile model system to investigate” biological systems. Also to investigate matters such as immunity, disease, and cellular function. Appearance Variability The image with this article, reveals the great beauty of this tiny creature. Enjoy this instructive one minute video. Another video, one-half minute in length, displays daphnia in an aquarium. The water flea's name comes from its appearance and jerky motions controlled by its antennae. These resemble arms with…
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