 Biological evolution, in its most general construal, is modification by descent, that is, change over time in frequency of observed traits or forms in a population or a taxonomic group derived from a common ancestor. A narrower definition, however, arose with the rise of a genotypic conception of heredity, namely, only with changes in frequencies of genes is evolution deemed to be happening. The barrier to so-called inheritance of acquired characteristics is held to make irrelevant any changes in forms without changes in gene frequencies. Exponents of extended inheritance disagree, including in their definition of evolution the changes in the developmental system and its constructed niche (Griffiths &amp; Stotz 2013). Adjudication of the disagreement comes down, in part, to a matter of quantity: How significant are resources other than the genotype (in the sense of the DNA of the whole genome) in development of traits that influence survival and reproductive success? Significance may depend on the number of generations that the resources are transmitted. The disagreement, however, becomes qualitative, even radical, if attention is given to the dynamics of development in an ecological context that had been abstracted away in demonstrating the original genotype conception of heredity. Reintegrating developmental dynamics entails more than noting the existence of developmental noise, such as when Drosophila individuals are not symmetric in the number of bristles on each side. The next subsection elaborates.