Here’s what you’ll learn when you read this story:The organization of life on Earth follows a simple, hidden rule known as “core-to-transition organization.”Hypothesized by biogeographers for centuries, a new study finally finds empirical evidence of this phenomenon using geographic dispersion data across five separate taxa. This shows how a majority of species originate from “core regions,” but those species suitable to heat and drought often colonize areas beyond those regions. The Earth is home to incredibly remarkable and diverse biomes that host millions of species worldwide. First, there is a core area where life appears to flourish, and from there, species tend to radiate outward—hence “core-to-transition” organization. “From that core, species expand into surrounding areas, but only a subset manages to persist.