The life-functions, life-forms, and life-force are closely related. 

The life-functions each correlate with a specific life-form.  Any given life-function requires a specific physical or mental system to operate.  That system arose at a particular moment in evolutionary time, namely the emergence of a new life-form.  Each new form simultaneously innovated a new structural system and its associated life-function.  The new function constituted the new life-form's distinctive way of being in the world.  By the same token, the life-form which originated a life-function remains an eternal reference point for that function.  By definition, a new life-function was the highest modality available to its originating life-form.  Accordingly, the life-form manifests that life-function with a certain purity and absolutism.  Later life-forms added new functions, but necessarily at the expense of cluttering the operation of earlier life-functions, as compared with their expression by their originary forms.  Nature has not improved upon locomotion since inventing it with insects. 

The life-force is responsible for the great transitions between life-forms.  Contrary to Darwinian orthodoxy, those transitions -- that is, the changes defining the major chapters of life -- are not gradual, but disjunctive, or "saltational."  Unlike the slow modulations between species, the appearance of a new life-form displays sudden and dramatic alterations of physical structure.  This remarkable phenomenon arises from the fact that the factor driving saltation does not really inhere in the individual at all, but in the social structure of the life-form -- that is, in the life-force.  Each life-form displays a unique social ethos governing the relation between the individual and the society of its co-organisms.  The individual organism is always operating within a programme of defined contributions to the social whole.  It is this social system which may "tip" abruptly into a new mode, generating a new life-form.  The phenotype of the individual tags along, as it were, modifying to suit the new social mechanism.  Phenotype is simply the physical apparatus enabling participation in the new mode.  In short, it is the differences between social worlds which are the differences which make a difference.

Finally, the life-functions and life-force are also intertwined.  Fundamentally, a life-function is an operation upon the external world.   Each life-function harnesses aspects of the objective world in order to generate the activity of life.  As it were, the individual builds itself out of the materials of the world.  This phenomenon has been dubbed "autopoiesis," self-making.  The paradox of autopoiesis is that the individual's enactment of its life-functions -- seemingly the very essence of the individual soul -- is also the least distinctive thing about the individual.  Our life-functions are what we have most in common with every other member of our life-form.  Thus the individual's performance of a life-function is simultaneously life's own working-out of a generalized process.  While we perform the life-functions, the life-functions also perform us.  Thus we find ourselves in the midst of the life-functions, as it were – borne up by them even as we execute them.