Our drive from Arizona into California was an opportunity to see the desert as three unique biomes. From Sonoran to Colorado to Mohave. As we had already discovered, the desert wasn’t as desolate as we imagined, and these different deserts didn’t disappoint with their individual characteristics.
From the giant Saguaro, Palo verde trees and large Ocotillo shrubs we entered the Colorado desert. It wasn’t so much that it was barren compared to the Sonoran, as less diverse. Instead of the varied desert flora, it felt like all we could see were two kinds of shrubs, the creosote bush and smaller saltbush. If felt like we could see forever on some stretches of road with the creosote bush neatly growing alongside the roads with the saltbush everywhere else, as far as the eyes could see.
The creosote bush is one of the more prolific plants of the desert and one of the oldest. Apparently, the king clone as it is known could be almost 12,000 years old. This is a great example for our students about vegetative reproduction or cloning where new plants are formed from roots or branches of an existing parent. We talk about this in class, but now we can relate it to this ancient organism.
Another interesting fact about the creosote is how we found it arranged neatly along the highway. These prominent lines are an example of edge effect or an ecological transition zone. That narrow band of dirt alongside the road can maintain a bit more water and keeps the dirt slightly warmer during the early mornings and late afternoons, allowing for just that much more growth. Cool eh?
This monotone landscape continued until we started to climb into California and the Mohave desert of Joshua Tree. We were planning to climb among the massive granite boulders there but were also excited to see the Joshua trees as well. These funny looking trees looked more at home in a Dr. Seuss book with their spiky leaves and almost fur like exteriors than the desert. Again, the desert changed showing us its multi-faceted landscape.
The Joshua tree is actually a yucca plant and is the largest of the species. It can grow upwards of 40ft and live over 150 years. Because the wood had no real economical value, it wasn’t threatened by harvesting and can be found in large numbers throughout the park. Besides it’s unique look, we discovered some interesting details about how it interacts with the yucca moth. The tree relies on a single organism, the pronuba moth for pollination. This is an elegant example of coevolution that has probably occurred over millions of years. The female yucca moth has evolved special organs to collect and distribute the pollen while the Joshua tree provides nutrients for the moth larva, while still growing seeds. This relationship also represents a symbiotic one and demonstrates to our students mutualism, an example where both organisms benefit.
Another cool science moment for us and our students! Now off to the Salton Sea to learn how a dying lake might teach us a lesson on water conservation.
And if you were wondering the climbing was awesome.