Starting with the base, or bottom, representing the equator, in terms of biotic factors, you would have more diversity of life. No where on Earth is life more plentiful and diverse that that situated around the tropical zones, from the equator to roughly 30 degrees north and south of the equator. For abiotic factors, the air has the largest concentration of oxygen available, and the temperature is the warmest, due to the air being the most dense at this level, which is closest to the Earth.
As you ascend, or go higher up, things begin to change. The air starts to become less dense, so it is cooler. The air also will contain less oxygen, making respiration more difficult. This will require a shift in the amount of diversification of life, to those forms with respiration mechanisms capable of existing on less oxygen. There is approximately 3 degrees temperature loss for every 1000 feet of elevation rise, so depending upon how high up you go, the temperature may drop significantly, necessitating organisms that are able to withstand the temperature shift.
When you get to the summit, 19,000 feet, things have drastically changed. The air is the least dense, with the least amount of oxygen available. The temperature has dropped significantly, from a humid 85 degrees Fahrenheit at the base, to around 28 degrees Fahrenheit at the summit (not counting wind chill factor). Only the hardiest organisms will survive here, able to withstand the extreme temperatures and low oxygen.