Evolution of Collective-level Darwinian Properties

Life has a nested structure where lower level entities are embedded in higher level collectives (genes in chromosomes, organelles in cells, cells in organisms, organisms in eusocial groups). All levels are subject to evolution by natural selection. This arises from the fact that at each level the focal entities are Darwinian, that is, they are discrete and vary one to another, they replicate and give rise to offspring that resemble parental types. The emergence of a new level of organisation is a relatively rare event in the history of life, and requires the de novo evolution of level-specific properties that allow the new level of organisation to participate directly in the process of evolution by natural selection. In this manuscript I explore, using mathematical models, the idea that Darwinian properties can be exogenously imposed (scaffolded) by the environment. I show how natural selection can build upon those scaffolded properties to promote the emergence of endogenous traits underpinning collective-level reproduction and heredity.