  The logistic equation is often considered as a simplification of the
chemostat (Kooi, Boer, Kooijman (1998)). However, the global qualitative
properties of the delayed single species chemostat are completely known, see e.
g. Smith (2011). Such properties still remain open for the delayed logistic
equation, see e. g. B{\'{a}}nheley, Czendes, Kristin, and Neymaier (2014)
despite that they have been announced a long time ago (Wright (1955)). We may
therefore ask whether the logistic equation really is a simplification and what
information about the chemostat actually is contained. We discuss the links
between these equations and conclude that they are less clear in the delayed
case than they are in the non-delayed case. We keep the presentation as
elementary as possible.
