Sarah at teleport.com wrote:
> Ontogeny being the stages in embryonic development and phylogeny the
> stages in evolutionary development. For instance: a developing embryo
> resembles a fish at one point because it has gill slits and at another
> stage an amphibian, both susposed stages in the evolutionary development
> chain.
The problem is that it's not really accurate to say that a developing
(mammalian) embryo resembles a fish at early stages of development. It's
more accurate to say that a mammalian embryo early in development resembles
a fish embryo early in development. This is more than a semantic
difference and it relates to the other misconception in your posting, the
"evolutionary development chain". The great chain of being notion, along
with ontology recapitulates phylogeny, lead to the idea that fish evolved
into amphibians which evolved into reptiles which evolved into mammals
which evolved into primates which evolved into humans. This is not how
evolution works. The ancestors of modern fish and the ancestors of modern
mammals diverged and went their separate ways several hundred million years
ago, with each group branching independently (after divergence) into
thousands of different species.
Keith Landa
Department of Biology
Marian College
Indianapolis, IN
http://darwin.bio.marian.edulandak at marian.edu