In a teleological (purposive) model of evolution I have inferred that there must be governing entities that shape evolution in order to overcome the destructive effects of entropy and short-termist and ultra-selfish natural selection, in order to enable long-term survival and reproduction to be pursued.
In general, teleology seems to be required for the imposition of a background level of cooperation and coordination between similar entities and across the different levels of organization.
If this is accepted, and some kind of general mechanism for teleology is devised - such as the hierarchy of governing entities - then the question arises as to how teleology is imposed?
There seem to be two possibilities - purpose could be imposed from outside by the operation of some kind of field, force or form; or purpose could be built-in.
While I think it likely that external forms/ fields/ forms have a role - they strike me as radically too simple, too lacking in dynamic complexity, to perform the necessary job in biological entities - although perhaps they suffice for the mineral world such as atoms, molecules, crystals etc.
My instinct is that purpose is most likely to be built in, specifically that, as an entity is formed, its purposive nature is built into the structure and organization (by the action of its governing entity) such that there is a degree of agency and self-regulation directed at the overall purpose.
For example, in multicellular organisms there may be the mechanisms of cell-suicide or apoptosis - such that if a cell experiences a mutation that may endanger the organism - perhaps by a neoplasm such as cancer - then the cell destroys itself (for the good of the whole organism).
There is considerable altruism built-in at the cellular level - white blood cells (some of which closely resemble free living amoebae) will kill themselves in the process of defending the organism against microorganism invasion (these dead soldiers are found in pus): this purpose is apparently built-into them.
Another example is reproductive self-suppression; which is found in some social animals. For instance, when a male orangutan fails to become the alpha, he remains as a partly developed adolescent. Now, in one sense he is biding his time and hoping for sneaky coercive sex with a female - but in another sense he is preserving the cohesion of the group by removing himself from competition.
Similar behaviours are seen in primates in relation to submission - a defeated male will submit and accept the dominant male - on the other side the dominant male will refrain from killing the defeated opponent.
In humans, there is considerable altruism and risk taking among young men in defending their group. Of course, this behaviour - once established, may be sustained by the advantage of protecting genetic relatives - but the behaviour had to occur and be stable before such advantage could be established; and it is consistent with observation that such motivations are built-in.
The primary reliance upon built-in teleology also makes it easy to understand the existence, indeed often at high rates, or the opposite - of behaviours which are non-functional, free-riding, parasitic. The teleology - including traits that are long-termist, altruistic, cooperative and coordinated - are vulnerable to subsequent, later events that disrupt or destroy these built-in mechanisms: such as damage or mutations during the life of the entity - mutant mitochondria in a eukaryotic cell, cancer in a multicellular organism, the effects of mental illness in human society.
Therefore, I think it most likely that governing entities work to impose teleology at the point where entities are being formed - either originally and/ or when being reproduced. The teleological behaviours are part of the design specification built into the entity.