Earth Notes: Cryptic Species
You can't always tell a book by its cover - it's a cliche', but it's bearing out in the world of biology. As biologists peer ever more closely inside the book of life, they are learning there may be far more species of plants and animals than anyone previously thought.
They call them "cryptic species," ones that have "hidden" their identity, at least to human eyes. Outwardly, cryptic species look very similar. But molecular analysis, along with size and shape and a biologist's basic "gestalt" sense that something is different, reveals that some are actually two or more species.
Australian clams, African elephants, European vesper bats and Costa Rican butterflies have all proven to be more than the single species they were once believed to be.
Around here, the Grand Canyon is a hotspot for cryptic plants. Wendy Hodgson, research botanist at the Desert Botanical Garden, notes that agaves, blazing stars, and milkvetches in the Canyon have turned out to consist of multiple species. Other suspects are yuccas, prickly pears and beargrass.
This abundant biodiversity is partly the result of the Canyon's extreme elevation ranges, differing microclimates and special niches. Through isolation, hybridization and adaptation, plant genes are constantly being shuffled and selected, and new species develop.
Cryptic species are really ongoing experiments in evolution, and the Canyon is their laboratory. In a world of changing environments, biologists argue that it's vital to maintain genetic diversity - including multiple look-a-like species - so that plants and animals can continue to adapt and thrive.