Most scientists describe biodiversity in terms of the number of species that have been discovered and described in scientific journals. Roughly 1.8 million species have been described, although most scientists think there could be as many as 50 million species or more currently living on Earth. However, in the video, Craig Venter seems more interested in the total number of discovered genes (he gives a total number of 20 million genes in the video) than the total number of discovered species. Why is that