Hybrids=new species?

From: "Julius Boos" <ju-bo at msn.com> on 2007.02.25 at 23:50:18(15355) Reply-To : Discussion of aroids Sent : Saturday, February 24, 2007 5:58 PM To : "Discussion of aroids" Subject : RE: [Aroid-l] Hybrids? Excellent discussion and explanation, Christopher, thanks! Just yesterday Dr. Croat, Joep Moonen, Enid, Sam and myself were discussing this topic at Enid`s home while examining her wonderful collection of aroids, particulalrly her amazing Philodendrons, and Tom was speculating almost exactly along the lines you bring up, that by certain species in nature seem to have crossed, and by so doing produced a hybrid, which in certain cases may turn out to be a 'more sucessful' plant in the envioroment than the parents, which has 'become' a new species (over hundreds/thousands/hundreds of thousands of years??) and has been described as such! Julius +More Howdy! I am not a botanist, but I am a professional zoologist and a taxonomist at that. In zoology, hybridizability is the defining character for genera; if the gametes from two species can form a zygote, whether that zygote develops into a sexually viable or inviable (sterile) adult, then the two species belong to the same genus. There are of course separate rules for parthenogenic organisms. Obviously this definition will not work for plants where, for example, in the orchids, hybrids between genera, tribes, and subfamilies occur, even though the plants are from opposite corners of the globe. But something that all taxonomists need to keep in mind is that unlike the species (or specific) designation, which is an exclusive concept, all other taxonomic categories (genus, tribe, subfamily, family, on up) are inclusive categories. If we keep emphasizing the differences between groups we run into the problem of putting each species in its own genus, each genus in its own family, and so on. At that point the taxonomy become meaningless. So, in nature there are natural hybrids. This means that there is gene flow within genera. There are also entities called stabilized hybrids. These are reproducing populations of hybrids that have a stabilized set of characters, and are capable of continued existence without input of new genetic material from either parent taxon. Every once in a while, I hear of a species that has been discovered to be in actuality a stabilized hybrid of two other taxa. But they are functioning independently of the two parent taxa. Stabilized hybrids typically appear not because the two species are overlapping in distribution, but because they very rarely meet. In someplace remote to both species, but rarely colonized by each, they have few mate choices, and often choose the congener. These resulting hybrids often have all the best characteristics of both parent taxa, maybe giving them the characteristics they need to survive in a peripheral habitat. This can be a source of speciation. I hope my ramblings are of some use, Christopher D. Christopher Rogers<< Invertebrate Ecologist/Taxonomist ((,///////////=====< EcoAnalysts, Inc. (530) 406-1178 166 Buckeye Street Woodland CA 95695 USA ? Invertebrate Taxonomy ? Invertebrate Ecological Studies ? Bioassessment and Study Design ? Endangered Invertebrate Species ? Zooplankton ? Periphyton/ Phytoplankton Moscow, ID ? Bozeman, MT ? Woodland, CA ? Neosho, MO ? Selinsgrove, PA www.ecoanalysts.com ___ _______________________________________________ Aroid-l mailing list Aroid-l@gizmoworks.com http://www.gizmoworks.com/mailman/listinfo/aroid-l

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