> The fossil record shows that biodiversity in the world has been increasing dramatically for 200 million years and is likely to continue. The two mass extincti

> The fossil record shows that biodiversity in the world has been increasing dramatically for 200 million years and is likely to continue. The two mass extinctions in that period (at 201 million and 66 million years ago) slowed the trend only temporarily. Genera are the next taxonomic level up from species and are easier to detect in fossils. The Phanerozoic is the 540-million-year period in which animal life has proliferated. Chart courtesy of Wikimedia. The fossil record is incomplete, of course. We keep finding new fossils, of new species, many of which are very incomplete. It can be hard to determine if two fossils are the same species or not, depending on what you find. Plus, not all organisms leave fossils, like animals with soft bodies (no bones) or hard shells. If anything, that first graph looks pretty fishy to me, just with the rapid explosion of growth in the last 200 million years. Of course, those are the fossils that are also on top. When stamp collecting (or fossil finding) you're at the mercy of luck and statistics.