🚀 go-pugleaf

Stanley makes an excellent point here, and the phenomenon to
which he refers has a buzzword name: "phenotypic plasticity".

Another example: in corals, classification used to be (and for
a lot of groups, still is, alas) based strictly on skeletal
characteristics. It turns out that a single colony may exhibit
multiple "shapes" during its life depending on the conditions
to which it is exposed; changing from a mound to a plate, and
back again, for example. These two forms - mounds and plates -
might well have been considered to be separate species in the
past. There are some wonderful plates showing gradation of
forms between two "species" of Pocillopora in the corals of
Australia collection.

The point is, the phenotype is often correlated with the
genotype, but not always. The genotype is strictly heritable;
the phenotype is ONLY if a) the relevant genetic material is
also transferred to the next generation, and b) similar environ-
mental conditions obtain for both generations.

I think there was a review of phenotypic plasticity in Annual
Review a few years back, but I only started taking it last 
year (couldn't afford it before... :-( ). I only urge readers
interested in current evolutionary thought to leaf through the
last few years' issues, where you'll find titles like:

Evolutionary Rates: Stress and Species Boundaries
Ecology of Parapatric Distributions
Canalization: Genetic and Developmental Aspects
Novelty in Evolution: Restructuring the Concept
Molecular Changes at Speciation

in the 1991 volume, and

Natural Hybridization as an Evolutionary Process
The Nearly Neutral Theory of Molecular Evolution
Artificial Selection Experiments
Behavioral Homology and Phylogeny
On Comparing Comparative Methods
Phylogenetic Taxonomy

in the 1992 volume, along with nine reviews related to the
subject of global environmental change. Great stuff. If only
_I_ could write like that.

Josh Hayes

--
  Josh Hayes, Quantitative Sciences HR-20 U of Washington
  josh@mowgli.cqs.washington.edu             206 543-5004
 That's one more kid that'll never go to school, never get
	   to fall in love, never get to be cool