If you have allergies and want to blame your sneezes on someone or something, try sex. 520 million years ago, giant societies of single-celled organisms dared to harness nature’s wrath. These cheeky micro-beasts had the audacity to live on seacoasts and in ponds. Formally these risk-takers are called cyanobacteria. We know them more colloquially as blue-green algae and