Figure 2.

Commonly used depictions of empirical evidence for the Developmental Constraints (DC; §2a) and Predictive Adaptive Response (PAR; §2b) hypotheses. (a) As adult environmental quality improves, health and fitness outcomes improve. However, organisms that started in low-quality developmental environments always fare worse than peers that started in high-quality environments. (b) Organisms that experienced similar-quality developmental and adult environments have better outcomes than organisms that experienced ‘mismatched’ developmental and adult environments. These depictions manipulate both the starting point (e₀ in table 1, the variable that DC theory is concerned with) and how well the developmental and adult environments match (Δe in table 1, the variable that PAR theory is concerned with) simultaneously. This approach makes it difficult to distinguish between these two hypotheses. Moreover, the x-axis shows variation in the adult environment, which is the key variable of interest for the Adult Environmental Quality (AEQ) hypothesis (e₁ in table 1).