March 2004 Unknown |
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LAST MONTH'S WINNERS: Four people submitted a correct answer to our March unknown. (There were also a few mis-identifications). The three prize winners for this month are:
Correct answer but too late for a prize:
Please note: Prize winners are now drawn each month from the total pool of correct answers for that month. Thanks to all of those who submitted an entry to this contest. |
Not Found on Most Oak Trees - Saccoglossus sp. We're not sure how Hemichordate worms get the name "acorn worms" but this photo of a species belonging to the genus, Saccoglossus, seemed to be enough to drive our audience nuts. Also called proboscis worms, or tongue worms, hemichordates like this species live burrowed in soft muddy sediments or in shell sand where they feed by probing out from their burrown with their soft flexible proboscis. The mucus-generating organ traps detritus particles which are transported up the proboscis to the mouth on the front edge of the collar (the brighter red section in this photo). Behind the collar, the worm's body has a series of gill slits. Hemichordates are relatives of the Echinoderms and the Chordates; all are placed together on a major branch of animal life, the deuterostomes. Many evolutionary biologists think that modern Hemichordate worms resemble some of the ancient ancestors to chordates - a split that took place at least 500 million years ago. | |
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For a concise and revealing teaching video about Arthropods, get our video/DVD: Branches On the Tree of Life: Arthropods. For a rich overview of marine intertidal ecology, see our program: The Biology of Seashores. |
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