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
|
IAS on Facebook
IAS on Instagram
