In the 1980s, scientist J.L. Marx conducted a series of experiments in Xenopus (an aquatic frog native to sub-Saharan Africa) and found that “mundane” biophysical events (like chemical reactions in the cells, mechanical pressures inside and on the cells, and gravity) can switch genes on and off, determining cell fate. Animal bodies, he concluded, result from an intricate dance between genes, and changing physical and environmental events.