>>In summary: no species ever evolved directly into another without first adapting to become separate breeds & sub-species.<<
The process is called stochasticism FWIIW. Many confuse “random” with “stochastic” although they are quite different.
Not for your benefit: I figure you already know this. More for participants and lurkers. Extending the lesson, the categorization process, as you know, is called “taxonomy.”
Although we can be talking millions of years, we have seen evolution in subway flies in NY which cannot breed with outdoor flies and thus become a sub-species or arguably a different species altogether. This become a matter of categorization using specific criteria, which is why I pointed out that words like “form” or even “species” (don’t get me started on “kind”) are not scientific without proper context.
(/Schoolhouse rock)
:-)