The universe contains ~90 naturally occurring elements, of which about one third are known to be biologically relevant. Why that one third? Understanding the factors responsible for this selection could give us important hints about the processes involved in the origin and evolution of life on Earth and possibly elsewhere in the universe.
I will describe the abundances of the macro-nutrient elements (H, O, C, N, P, S), micro-nutrient elements (e.g. Na, K, Mg, Ca), and trace metals (e.g. Fe, Cu, Zn) in different eukaryotic and prokaryotic organisms.
I will discuss how average elemental compositions for different taxa can be used to examine changes in the abundances of bioavailable elements in response to environmental changes.
Our analysis may provide an indirect estimate of the relative abundances of elements in the Last Universal Common Ancestor and its environment.