dant@tekla.UUCP (03/03/87)
I have cross-posted this to sci-bio. Please followup there as well. From: "Joseph_F_Stephany.WBST128"@Xerox.COM >The Mushroom theory is based on the observation that the Mushroom is >highly ill-adapted to our planet. It spends most of its time dormant. >It gows during a brief interval, then goes dormant again even though >there is no reason for it to do so. > >The holders of the Mushroom viewpoint think that the Mushroom was >brought to Earth either on meteors or on the boots of interstellar >travelers. They point out that it is obvious that the system that the >Mushroom originates in, is at least a double star system where most of >the time the home planet is frozen and cloud covered. After long >intervals of time, a second star in the system periodically approaches >near, thus warming the planet and allowing the Mushroom its brief few >days of activity after which it again goes dormant. This Planet must be >very cloudy since the Mushroom requires no light to complete its >life-cycle. > >It is thus seen that if one constructs the conditions underwhich the >Mushroom thrives, he arrives at very different planetary conditions >than we find on our own planet. Since life adapts to the conditions of >its enviroment, it follows conclusively that live exists on at least >another planet. > >You are correct, that this argument would have contradicted my viewpoint >that only one life supporting planet exists in our Galaxy. > > Joe [First of all, note that Joe does not claim to ascribe to the Mushroom Theory. I'm following up merely because it seems like an interesting theory, albeit a bit off-the-wall.] There seem to be several potential problems with the Mushroom theory. 1. Mushrooms currently live off of decayed organic matter. On a world with long periods with no light, there would be no plants which produce this organic matter by photosynthesis. This isn't fatal to the theory; one could imagine a planet of mushrooms with the bottom of the food chain being bacterial digestion of rocks. (In fact, someone did: "Omnivore", a Science Fiction book by Piers Anthony, I think.) 2. Mushrooms have the same kind of DNA as most other plants and animals. This one seems more likely shoot the theory down. I'm sure others can think of other flaws in the theory. --- Dan Tilque dant@tekla.tek.com I used to work for a company which used the Mushroom Theory of Personal Management: 1. Keep the employees in the dark. 2. Feed 'em a bushel of manure. 3. Then CAN 'em.
felsenst@entropy.UUCP (03/04/87)
The difficulty with the theory that "mushrooms" are extraterrestrials is that, not only does their DNA turn out to be like other earth life's, but more specifically when a part of their DNA or RNA is sequenced and compared with that of other earth life forms, one can construct an evolutionary tree (phylogeny) which places them in an unexotic position. It seems there are three major multicellular forms of life: animals, plants and fungi. The details of cell ultrastructure support the conclusion that fungi are eukaryotes (proud possessors of ordinary nucleated cells) like ourselves, plants, and protists. Mushrooms are the fruiting bodies of certain kinds of fungi. They disappear during periods when the rest of the organism is happily making its living growing underground. No amount of astronomy is going to explain the enormous diversity of life styles of fungi (an extraterrestrial explanation of bread mold life styles, anyone?). -------------------------------- Joe Felsenstein, Dept. of Genetics, University of Washington, Seattle, WA e-mail: uw-evolution!joe%entropy.ms.washington.edu@wally.cs.washington.edu