An individual's journey through life often is depicted as a pathway constantly dividing, a series of decisions over alternative routes, with destinations hidden in the mist of the future. And the choice taken at any division point changes forever the array of future pathways. And often, of course, the choices offered guide our decisions, an easy road to our left, a difficult path to our right. In many ways, the entire history of life is similar, though without the dubious benefit of free will.
As living things evolve, alternative routes appear—but the easier path
is always chosen. But just as in human lifetimes, the uncluttered road may lead to
disaster. In our Chihuahuan Desert, numerous birds and mammals took the route of
dependency for sustenance on the plentiful, ice-age large herbivores—mammoths, horses,
camels, and others. In so doing, they unknowingly took the pathway to extinction.
Unable to switch to other sources for food, the loss of the North American herds at the
end of the ice age wiped them out—doomed by the choices made ages before.
Contributor: Arthur H. Harris, Laboratory for Environmental Biology, Centennial Museum, University of Texas at El Paso.
Desert Diary is a joint production of the Centennial Museum and KTEP National Public Radio at the University of Texas at El Paso.
An early reconstruction of one of the now-extinct ground sloths. After Adams, 1872.
Adams, W. H. D. 1872. Life in the primeval world. T. Nelson and Sons, London. 335 pp.