Editing Unit of selection (section)

=== Cell ===

[[Leo Buss]] in his book ''[[The Evolution of Individuality]]'' proposes that much of the [[Evolutionary developmental biology|evolution of development]] in [[animal]]s reflects the conflict between selective pressures acting at the level of the cell and those acting at the level of the multicellular individual.  This perspective can shed new light on phenomena as diverse as [[gastrulation]] and germ line sequestration.

This selection for unconstrained proliferation is in conflict with the fitness interests of the individual, and thus there is tension between selection at the level of the cell and selection at the level of the individual.  Since the proliferation of specific cells of the vertebrate immune system to fight off infecting pathogens is a case of programmed and exquisitely contained cellular proliferation, it represents a case of the individual manipulating selection at the level of the cell to enhance its own fitness.  In the case of the vertebrate immune system, selection at the level of the cell and individual are not in conflict.

Some view [[cancer stem cell]]s as units of selection.<ref>{{cite journal | author=Greaves, Mel  | volume=6 | issue=1 | title=Cancer stem cells as 'units of selection' | journal=Evolutionary Applications | pages=102–108 |doi=10.1111/eva.12017| pmid=23396760 | pmc=3567475 | year=2013 | bibcode=2013EvApp...6..102G }}</ref>