Updated project metadata. How the fertilized egg develops the anatomy of an adult ultimately must be explained at the biochemical level. Deeply connected to the anatomy is the complement of proteins and RNAs expressed during embryogenesis. The relationship of mRNA and respective protein expression dynamics during development has never been systematically explored. Here we present a comprehensive characterization of protein and mRNA dynamics across early development in Xenopus, between unfertilized egg and early tadpole stage. Surprisingly, most proteins change very little; there is an inverse correlation between abundance and rate of change. While the correlation of mRNA and protein expression is poor, a simple mass action kinetics model connects protein to RNA. Parameterized by two fixed parameters the median protein synthesis and degradation rates, the model depends on RNA dynamics, and initial protein concentration. Associated mRNA datasets in GEO: GSE73905 and GSE73870.