Fire and Fitness: A Summary of the Evidence
Surely there could not be an equivalent ensemble of fitness in nature for some other type of life.
For Fire, Nature Obliges Us with Rapid Reflexes
One area where very fast nerve conduction is vital is vision, more specifically, in keeping the eyes fixed on some object in the field of vision while in motion.
For Fire and More, Humans Are Designed to Have Just the Right Strength
How is it that an ant appears proportionately so much stronger than a trained human weight lifter?
Remarkably, Humans Are Just the Right Size to Make and Master Fire
Only an organism of our dimensions and android design — 1.5 to 2 meters in height with arms about 1 meter-long ending in manipulative tools — can handle fire.
How Man Became the Fire-Maker
Being terrestrial is one obvious requirement. No fully aquatic species could master fire and thus develop metallurgy.