Complex Order, Life, and Intelligence
The chlorophyll molecule is like a hand on a long, flexible stem. The “hand” is a cage that holds a single magnesium atom in a special orientation. Chlorophyll uses the magnesium atom like a magnet to pick up and transfer parts of one molecule to another as the cage moves back and forth on the long stem. Chlorophyll is an ingenious molecular machine, but it doesn’t operate in isolation. Other structures have to bring the raw materials or molecules up to the chlorophyll, and carry the molecular products away. The hemoglobin in our blood uses an iron atom in a similar cage to carry oxygen to all our body cells, and to remove carbon dioxide. If chlorophyll is the result of an extremely lucky accident that occurred in a “warm little pond” one day on the Earth’s surface, how is it possible that a similar extremely lucky accident produced the identical design in hemoglobin, substituting iron for magnesium? But creative designers often reuse their most elegant solutions.