Evolution Canyons I and II are found in Israel in the Carmel and Galilee mountain ranges (the image above shows Evolution Canyon I (ECI) in Lower Nahal Oren, Mount Carmel, Israel). These areas are ideal for the study of evolution because each range has a north-facing slope with relatively temperate environmental conditions and a south-facing slope with relatively extreme UV radiation (the south-facing slopes receive 200--800% more solar radiation than north-facing slopes), daily temperature variation, and arid conditions.
Scientists are interested in exploring how these different environmental conditions lead to evolutionary changes in organisms. An example of an evolutionary change is a change in coat color in mammals. Many mammals, particularly prey organisms, have evolved coat coloration that matches their environment in order to provide camouflage from predators. Singaravelan et al (2010) investigated how hair melanin content of spiny mice (Acomys cahirinus) has evolved in response to alternative selection pressures inflicted by contrasting colored habitats of Evolution Canyon. There are two main forms of melanin: pheomelanin results in yellow to brown hair color and eumelanin results in gray to black hair color.
- Based on this information, do you expect mice that live on the “African” slopes to have higher pheomelanin content in their hair or higher eumelanin? What do you expect of mice living on the “European” slopes?
- Explain how a change in environmental conditions can result in an evolutionary change in a population.
Singaravelan N, Pavlicek T, Beharav A, Wakamatsu K, Ito S, et al. (2010) Spiny Mice Modulate Eumelanin to Pheomelanin Ratio to Achieve Cryptic Coloration in “Evolution Canyon,” Israel. PLoS ONE 5(1): e8708. doi:10.1371/journal.pone.0008708