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.
The terms macroevolution and microevolution were first coined in 1927 by the Russian entomologist Iuri'i Filipchenko (or Philipchenko, depending on the transliteration), in his German-language work VariabilitÃ¤t und Variation, which was an early attempt to reconcile Mendelian genetics and evolution.