There are two types of classification, homology and analogy. Homology is the fundamental identity of structure, as distinguished from analogy, which incidental resemblance in form or function. Bat wing showing homolog and analogy.

Bat Wing

There are two types of classification, homology and analogy. Homology is the fundamental identity of…

There are two types of classification, homology and analogy. Homology is the fundamental identity of structure, as distinguished from analogy, which incidental resemblance in form or function. Bird wing showing homolog and analogy

Bird Wing

There are two types of classification, homology and analogy. Homology is the fundamental identity of…

There are two types of classification, homology and analogy. Homology is the fundamental identity of structure, as distinguished from analogy, which incidental resemblance in form or function. Fly wing showing homolog and analogy.

Fly Wing

There are two types of classification, homology and analogy. Homology is the fundamental identity of…

"The water in resovoirs A and B stands at different heights. As long as this difference of level is maintained, water from B will flow through the pipe R to A. If by means of a pump P the level in B be kept constant, flow through R will also be maintained. Here, by means f the work expended on the pump, the level in the resovoir is kept constant; and in the corresponding case of the electric current...a constant difference of potential is maintanied." -Hawkins, 1917

Analogy of Water Flow to Electric Current

"The water in resovoirs A and B stands at different heights. As long as this difference of level is…