An intervening variable facilitates a better understanding of the relationship between the independent and dependent variables when the variables appear to not have a definite connection. They are studied by means of operational definitions and have no existence apart.
Difference between Microevolution and Macroevolution. â¢ Micro evolution refers to visible changes in a population of the same species over a period of time. â¢ Macroevolution is what evolution is as described by the theory of evolution by Darwin.
An example of macroevolution is the appearance of feathers during the evolution of birds from theropod dinosaurs, when now viewed at a distance from the future, although as they arose the developing changes would be deemed microevolution.