A biological continuum

[DARBYSHIRES at NCCCOT.AGR.CA]

Curtis Clark wrote:

>George Garrity wrote:
>>species density in a readily comprehensible form. What we are learning from
>>this approach is that the species of microorganisms we normally refer to are
>>merely points along a biological continuum.  I rather suspect that higher
>>organisms will behave in an analogous manner, provided that a sufficiently
>>large sampling is done with enough characteristics.  Rather than focus on
>
>There biological reasons why multicellular sexually-reproducing eukaryotes
>would not be expected to form a continuum.  Perhaps with enough characters
>we could force them into a continuum (certainly it has been tried in the
>past), but this could well obscure important patterns.

Mammals and birds are the only major groups of eukaryotic organisms
that reproduce exclusively by sexual means (a rather small proportion
of eukaryotes), and even they are not free from phylogenetic
reticulation.

As J. K. Veldkamp has pointed out: All plants are hybrids, but some are
greater bastards than others.

There is a continuum between taxon pairs where the taxa are discretely
distinct and pairs where the taxa are continuously variable.

Stephen Darbyshire