[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index][Subject Index][Author Index]

Re: More on the genus problem



I don't get why this one was truncated -- "text/plain", no "format=flowed" --, but it still was:

Date: Sat, 19 Sep 2009 23:45:40 -0400
Reply-To: jstea003@odu.edu
Sender: owner-DINOSAUR@usc.edu
Precedence: bulk
From: James Stearns <jstea003@odu.edu>
To: dinosaur@usc.edu

--000e0cd37202f693f40473fa3253
Content-Type: text/plain; charset=ISO-8859-1

To be honest, I see the "fertile offspring" species concept as sort of a
convenient textbook definition and nothing more, as there have been plenty
of cases in which members of two different species (or even genera) have
successfully produced fertile offspring while still remaining within
seperate genera/species, _Bos taurus_ and _Bison bison_ being one example.
There just seem to be way too many exceptions to the rule for the "fertile
offspring" definition to hold water.

--000e0cd37202f693f40473fa3253
Content-Type: text/plain; charset=us-ascii
Content-Transfer-Encoding: 7bit

* * * * * * * * * * * * * * * * * * * * * * * * * * * * * *
*         ---REMAINDER OF MESSAGE TRUNCATED---            *
*     This post contains a forbidden message format       *
*  (such as an attached file, a v-card, HTML formatting)  *
*    This Mail List at USC.EDU only accepts PLAIN TEXT    *
* If your postings display this message your mail program *
* is not set to send PLAIN TEXT ONLY and needs adjusting  *
* * * * * * * * * * * * * * * * * * * * * * * * * * * * * *

--000e0cd37202f693f40473fa3253--

Or, alternatively, a lot of taxa currently recognized as species simply aren't species, and a lot of names we're used to have to be sunk into synonymy, because nothing but blind tradition is holding them up. :-|

There are _actual arguments_ against the two "biological species concepts"*, however: the ability to interbreed is a plesiomorphy; loss of it is usually selected against (more potential breeding partners = higher chance to pass genes on); and that loss is a gradual affair -- occasionally it happens that a mule is fertile.

* Yes, two: one where they have to do it in the wild, one where it's enough when they can do it under laboratory conditions.