Evolution Canyon: A Galapagos in Israel

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Professor Emeritus Eviatar Nevo, the founder and director of the Institute of Evolution at the University of Haifa in Israel, knows a thing or two about evolutionary biology, as his thousands of scientific publications will attest. Sit him down on a cool, yet sunny spring day at the base of a canyon on a slope of Mount Carmel near the University of Haifa, and knowledge will flow from his mouth like a resplendent fountain. This place in particular provides Nevo, who just celebrated his 91st birthday, with a special burst of inspiration. It's called Evolution Canyon.

It is "the best laboratory to study nature," Nevo insisted during an outdoor lecture he gave in 2018. “In a local environment, you have global phenomena.”

A layperson might stand at the base of the canyon, notice the lovely array of wildflowers dancing in the wind before them, the savanna-like, rocky slope to their left, and the lush, humid, and forested slope to their right, and think, "Wow, that's pretty." An evolutionary biologist would absorb the same picturesque scenery and think, "What a great place to explore the adaptation of organisms to their environment!"

Evolution Canyon is not only a model for biodiversity evolution, it’s also a model for adaptation evolution… speciation… global warming… host-pathogen interaction,” Nevo says.

That's because the two slopes of the canyon, separated by just 200 meters of open grassland, respresent drastically different biomes. The south-facing slope is almost tropical, receiving 200-800% more solar radiation than the north-facing slope, which is temperate and shady. It's like someone cut a small slice out of Africa's savanna and a piece from Northern Europe's forest and stuck them right next to each other.

This rare placement renders Evolution Canyon the perfect location to study sympatric speciation, the evolution of a new organism from a surviving organism while both species inhabit the same geographic area. This differs from allopatric speciation – evolution that occurs as a result of geographic separation.

A simplified diagram of sympatric speciation. Reproductive isolation evolves within a population without the aide of geographic barriers.

For decades, biologists debated whether sympatric speciation was even possible, but with dedicated observation, we now know that it does. Evolution Canyon provided a variety of examples. Bacillus bacteria, wild barley, fruit flies, beetles, and spiny mice were all found to diverge into novel species on the contrasting slopes, despite clear evidence of gene flow between the existing and new species.

Roughly 2,500 species, including bacteria, fungi, insects, and mammals, are known to dwell in Evolution Canyon. Neto says that lots of species new to Israel, Eurasia, and science as a whole have been discovered there. The "African" southern-facing slope is the most genetically and biologically diverse, as it fluctuates wildly in temperature from day to night.

There are three other similar canyons in Israel – in Galilee, Golan, and Negev, but Mt. Carmel is considered the best. Thus, it attracts the most scientific attention.

"The Evolution Canyon model represents the Israeli ecological equivalent of the Galapagos Islands," Neto wrote. [It] could potentially highlight many mysteries of evolutionary biology."


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