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.
Typically, observable instances of evolution are examples of microevolution; for example, bacterial strains that have antibiotic resistance. Microevolution over time leads to speciation or the appearance of novel structure, sometimes classified as macroevolution.