speciation hi to all, would it be true to say that every species has a sister species, and to be a truly different species of the same genus, premating isolation would be a major factor, also would the chemotype effect the genus of a sister species?
No, it would not be true to say that every species has a sister species. There are modes of speciation (e.g., hybridization, polyploidy) that do not fit a model where species "B" branches off of species "A" by a mutation event and become conceptually the sister species to it. Reproductive isolation is one requirement of some species concepts (e.g., the Biological Species Concept), but it is by no means absolute (see above re: hybridization). Other species concept do not use reproductive isolation (by the way, reproductive isolation can either be prezygotic (something which prevents formation of the zygote or "fertilized egg") or postzygotic (e.g., a functional physical individual but sterile so no chance of reproductive success)). Please clarify the question regarding chemotype - it's not an oft-used term (only 3250 hits on Google!).
Thank you for the clarification Daniel, What I mean by chemo type. As phenotype is to growth characteristics, leaf shape, plant size, branching characteristics, ECT, so chemo type would relate to the chemical composition of the plat.
Sorry, I was asking for a clarification of the question. "Would the chemotype effect the genus of a sister species?" I'm not sure what you mean by it. Do you mean, "Are chemical properties sufficient to say that two similar-appearing species are in different genera?"
Hi Stevi: If you are still looking into these forums can you tell me which particular question in relation to which organism you are asking about? If your original, so far unasked, question is in regards to Algae then I may know what you are alluding to. Cytological studies years ago suggested that some species of Algae may indeed be a form of or have undergone some sort of speciation. We know it was perceived likely in Chlorella, for example, in which one organism was a light green in color, one was a darker green in color, yet they both had the same chemical make up. Thus, it was tentatively proposed years ago that one form could be a sister of the other. The only real difference in the two organisms was the phenotype (what we see). Just a few quick thoughts. Jim
