The Units of Selection. No written assignment, but you should try to answer the Study and Review Questions at the end of the chapter. Introduction to Chapter 12. The Units of Selection.
Benefits occur at various levels.
Requirement for heritability. Selection acts at various levels. 510 index page Introduction to Chapter 12. Since adaptations are understood to result from selection, there is a presumption that both of these questions must have the same answer. Some features seem useful only to genes, others only to organisms, others, still others only to species.