>Let me throw in my two cents by now...
>If the switch from lecitotrophic to planktotrophic is controlled by some
>environmental variable, like e.g. population density, then it could go forth
>and back from one generation to the next, depending on the environmental
>conditions. An animal issued from a planktotrophic egg will probably come to
>another location, where it could lay lecitotrophic eggs (provided it finds a
>mate; land pulmonates, which I mostly deal with, are not so demanding. OK,
>dispersal of land snails would be another thread).
>The mate could also be the descendant of a local, currently lecitotrophic
>population. As long as there are no mechanisms restricting the gene flow
>between different subpopulations, there will be no species split.
>Greetings from Germany
>Michael


My point exactly.
--
Andrew Grebneff
Dunedin, New Zealand
64 (3) 473-8863
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Fossil preparator
Seashell, Macintosh & VW/Toyota van nut
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I want your sinistral gastropods!
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