 Besides distinguishing development and evolution in a qualitative manner as proximate and ultimate causal processes, a less common attempt is to quantitatively distinguish (or relate) the two. Here, especially distinctions based on the rates or time scales on which different developmental and biological processes occur have been made (see the entry  levels of organization in biology).  For example, Conrad H. Waddington (1957) developed a hierarchical model of time scales that includes biochemical processes on lower molecular levels of organization with a faster rate, medium paced processes of development on a medium level, and evolutionary processes on higher levels with a slower rate. According to such a view, evolutionary processes are simply processes occurring with a different rate and thus at a different level than developmental ones. Thus, they differ gradually rather than in kind. Rate-based distinctions have been described to be consistent with the ultimate-proximate framework (when interpreting it as one that distinguishes different timescales of phenotypic change; see Francis 1990; Haig 2013) or as different from proximate-ultimate distinctions (Baedke &amp; Mc Manus 2018). In addition, time-scale (or size-scale) conceptualizations have been applied for developing methodologies and multi-scale modeling that integrate, among others, developmental and evolutionary processes (S. Levin 1992; Green &amp; Batterman 2017; Duckworth 2019).