Forest scene photo: Edward Parker

The sheer variety of species on Earth—from microscopic bacteria to blue whales the length of a city block—is pretty impressive on its own. But biodiversity isn’t limited to the numbers and kinds of organisms.

Biodiversity also includes Earth’s ecosystems: its savannas, rain forests, oceans, marshes, deserts, and all the other environments where species evolve and live.

And it includes genetic diversity, which refers to the variety of genes within a species. All three are critical to understanding the interconnections that support all life on the planet.