Abstract
Whether natural selection can operate above the level of individual organisms is a controversial matter, especially when the units at issue do not reproduce in the same way as organisms do, or do not seem to reproduce at all. In this contribution, I will consider the possibility of ecosystems being units of selection following two different lines of reasoning, i.e. understanding fitness as differential persistence, and understanding it as differential reproduction. In the conclusion, I will explore the hypothesis that human beings are favouring ecosystems’ becoming units of selection through ecological engineering.