Living Fossils

Administrative assistant Rachel Garner talks about living fossils.

Campbell Hall

Charles Darwin coined the term “living fossil.” It describes a species that has survived with little apparent change over a great span of time. Paleontologists recognize the fan-shaped leaf of the ginkgo (Ginkgo biloba) and the fronds of the dawn redwood (Metasequoia glyptostroboides, south of the ginkgos) from fossils found in North America. But the trees themselves disappeared from this continent millions of years ago.

The two ginkgos and the dawn redwood that you see here derive from Asia, where both species were “rediscovered.” Dawn redwoods might still be considered extinct but for one man’s illness during World War II. It forced a traveling forester to stop at a rural school in China. He learned there about a large, unidentified tree three days’ journey away. Intrigued, he made the trek. Ultimately, it took five years, repeated visits, and a scientist familiar with the fossil record to identify this tree as the long-lost relative of our coast redwood and giant sequoia!

As for the ginkgo, sometimes called the maidenhair tree, this species is about 56 million years old. It is the sole surviving member of a family that is truly ancient, reaching back 200 million years to the dinosaur era. In the late 17th century, a German botanist traveling in Japan observed a ginkgo tree and collected seeds. Since then, ginkgos have been cultivated all over the world. Ours were planted in 1961 by a biology professor. They are locally famous for their extraordinary fall color, intensely yellow leaves that can drop to the ground on a single autumn night. But the most famous gingkos by far are the ones that survived the atomic blast in Hiroshima during World War II.

Autumn ginkgo photos are by Associate Dean of the College Jim Diedrick.