Observations On Linear Incarnations

Life forms. Life forms form from life.

Life eats life to live. And so on, and so on,..

So how are linear incarnations of life NOT possible, if not probable?

On the surface it may seem impossible, but doesn't most phenomena seem impossible when we first hear of them? 

The atomic bomb. Black holes. Gravity. Space travel. Radio waves. Language. Instinct. Insemination. Eternity.