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.
Macroevolution: Change above the species level NABT 2006 Evolution Symposium Introduction The basic concept of evolution â change over time â can be examined in two different time frames. The first, which considers the time period covering a few generations for a population, is microevolution. There are many examples of microevolution that are handy for teaching, such as drug resistance (NESCent 2006a) and changes in beak size of finches in the Galapagos (NESCent 2006b).