Fig. 3: Scenarios of causal relationships between temperature and developmental time.
Dashed arrows show the correspondence between stages, components and mathematical functions. F: functional components of the organism interacting with temperature at a given stage and leading to the developmental time at the same stage. The example is based on three stages, S1–S3 that occur either sequentially (a, b: black arrows) or defining alternative pathways (c: blue arrows). a Component conserved along development: All stages share the same functional component, leading to a single function. b Stage-specific components: functional components (and functions) are stage-specific. Organisms develop through a fixed pathway. c Plasticity: Stages do not necessarily coincide with morphological stages. The manifestation of a given functional component (F2 or F3) depends on the temperature (indicated as T2, T3) experienced in the previous stage (S1) and interacting with an 'operator component' (O). Hence, organisms develop through alternative pathways (blue arrows), also reflected in a sequence of functions driving the effect of temperature on developmental time.
