The types of factors are different because there are different set conditions for each ecosystem. A cactus is built for it's hot, dry ecosystem. If it were to move to a polar ecosystem it would not survive there. Same for the polar bear. It's built for polar regions. It has white fur to blend with the white ice to help it blend in and it's adapted to swim to get it's food source.
Alright bud the best answer to this question would be that one of the first scientists of the Renaissance to advance taxonomy through first hand observations was Cordus
