What is meant by "mode of existence"?

[Aafia]

According Zimmermann in 1953 "evolution is the transformation of the form and mode of existence" so I want want understand what is mode of existence ?

 

[DrClaude]

Definition of mode from the OED:

A way or manner in which something is done or takes place; a method of proceeding in any activity, business, etc.

 

[jim mcnamara]

Or - in more commonplace terms 'change in how or where an organism "makes a living" ' -- like foraging for food at different times of the day, or developing tolerance for drier environments. The change is a genetic change in a population as well.