Microclimatic interslope differences of illuminance, temperature, and humidity were measured on the "African", south-facing slope and "European", north-facing slope in the "Evolution Canyon" microsite, Lower Nahal Oren. Mt. Carmel, Israel. There were two measuring stations on each slope. Preliminary results show that (a) illuminance of the "African", south-facing slope was significantly higher than on the "European", north-facing slope during April-October 1997, (b) mean daily temperatures, as well as daily temperature ranges, were higher on the "African" than on the "European" slope, and (c) except under the high summer sun, relative humidity was 1-7% higher on the "European" slope. We concluded that microclimatic stress is responsible for the drastic interslope biodiversity divergence across life.