What does it mean "form follows function?"

What does form follow function mean in physiology?

Pretty much the same things as "putting a square peg in a round hole".

The FORM (shape or arrangement) of something will usually indicate its "purpose" in some way.

For example, fingers can grasp, but so can a tentacle. Fingers are kinda like tentacles. But SEVERAL fingers, working in unison, can grasp AND control at the same time.

The eyes of a hunting animal are usually on the front of the head for better stereoptic (3D) vision. The eyes of a prey animal are more often on the sides of the head for a better range of vision as protection against enemies.

Frankly, a penis is long and round for the purpose of fitting into a vagina.

That the shape and structure of a thing evolves from the benefit to that function provided by that shape and structure.