What are the differences between a UIView and a CALayer?

Question

Both have most of the same attributes, both support different kind of animations, both represent different data. What are the differences between a UIView and a CALayer?

Answer 1

From the Ray Wenderlich blog (Tutorial)

CALayers are simply classes representing a rectangle on the screen with visual content. “But wait a darn minute,” you may say, “that’s what UIViews are for!” That’s true, but there’s a trick to that: every UIView contains a root layer that it draws to!