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| Although it is commonly called the giant shipworm, this organism is actually a type of clam. https://www.sciencenewsforstudents.org/article/weird-mega-worm-found-have-odd-diet |
Scientists have known about the giant shipworm for the last 300 years but it wasn't until recently that the species was dissected for the first time. These mollusks aren't worms at all but get their name from their long, thin bodies. The ship part comes from their close cousins, much smaller, that eat the wood of ships or trees that have fallen into the ocean. Not only are giant shipworms larger, they have a very different anatomy from them and other mollusk: they posses a much smaller digestive system than expected because they don't use it. These organisms have evolved to be fed by the chemical compounds produced by bacteria living in their gills that thrive off of the hydrogen sulfide, the same compound that gives rotting eggs their smell. Scientists from the US and Philippines that harvested a few individuals from their remote, muddy habitats determined that their smaller-than-expected digestive system evolved 1 million years ago as an adaptation that was more energy efficient than eating wood.*
There is some evidence that can be pulled from the article about the last statement since these shipworms are much larger than their closest cousins that have a very different diet. One might conclude from this alone that the giant shipworms diet allows it to grow larger but there are likely a few other factors in play. The reduction in digestive system and its upkeep may also allow the shipworm to grow larger without putting energy towards organs they do not use. I do wonder if they did other tests to see if the digestive system is still functional? Do they have the ability to eat anything other than what the bacteria provide or is their digestive system still present because it is difficult for larger traits to just disappear in a species (is the digestive system a vestigial system)?*
Oosthoek, S. (2017, May 26). Weird mega-worm found to have odd diet. Science News for Students. Retrieved from: https://www.sciencenewsforstudents.org/article/weird-mega-worm-found-have-odd-diet
*Paragraph 1 is a summary of the article without additional input, Paragraph 2 contains my thoughts and questions. You can do one paragraph or 2 or more (whichever you think will make it easiest to read)
