Why did nature select phosphate for its dominant roles in biology?

Evolution has placed phosphate mono- and diesters at the heart of biology. The enormous diversity of their roles has called for the evolution of enzyme catalysts for phosphoryl transfer that are among the most proficient known. A combination of high-resolution X-ray structure analysis and 19F NMR definition of metal fluoride complexes of such enzymes, that are mimics of the transition state for the reactions catalysed, has delivered atomic detail of the nature of such catalysis for a range of phosphoryl transfer processes. The catalytic simplicity thus revealed largely explains the paradox of the contrast between the extreme stability of structural phosphate esters and the lability of phosphates in regulation and signalling processes. A brief survey of the properties of oxyacids and their esters for other candidate elements for these vital roles fails to identify a suitable alternative to phosphorus, thereby underpinning Todd's Hypothesis "Where there's life there's phosphorus" as a statement of truly universal validity.