Loading video... VIDEO: Authors explain the message of their Science paper from January 2021: The importance of soil biodiversity and functioning beyond agricultural needs must be acknowledged in all nature conservation strategies. To... view more Credit: Carlos Guerra If you asked people which group of animals is the most abundant on earth, hardly anyone would know the right answer. Ants? Fish? No, and not humans either. The answer is nematodes, also known as roundworms. Four out of five animals on earth belong to this group, and the reason hardly anyone is aware of the fact is that they live underground, invisible to us. Together with thousands of other soil organisms, they quietly, discreetly and constantly perform enormously important services for the world above them.