nd in so doing invented posynte,posyntedly t important single metabolic innovation in toryof life on t”—and it ed not by plants but by bacteria.
As cyanobacteria proliferated to fill o ternation of t found it poisonous—ually useoxygen to kill invading bacteria. t oxygen is fundamentally toxic often comes as a surpriseto t so convivial to our t is only because it. to ot is a terror. It is urns butter rancid and makes ironrust. Even olerate it only up to a point. t atentmosphere.
tages. Oxygen oproduce energy, and it vanquisitor organisms. Some retreated into ttoms. Ot ter (mucer)migrated to tive tracts of beings like you and me. Quite a number of tities are alive inside your body rigo digest your food, but abiniest of O2. Untold numbers of oto adapt and died.
teria first, tra oxygen taccumulate in tmosp combined o form ferric oxides, tom of primitive seas. For millions of years, terally rusted—a ps t provide so mucoday. For many tens of millions of years not a great deal more t back to t early Proterozoic find many signs of promise forEarture life. Perered pools you’d encounter a film of livingscum or a coating of glossy greens and broherwise life remainedinvisible.
But about 3.5 billion years ago sometic became apparent. ructures began to appear. As t tines, teria became very sligacky, and t tackiness trappedmicroparticles of dust and sand, o form slig solidstructures—tromatolites t ured in ter on VictoriaBennett’s office romatolites came in various simes times like fluffy mattresses (stromatolite comes from ttress”), sometimes tens of metersabove ter—sometimes as ers. In all tations, ted tcooperative venture, ies of primitive organism living just at t underneataking advantage of conditions created by ts first ecosystem.
For many years, scientists kne stromatolites from fossil formations, but in 1961t a real surprise y of living stromatolites at Se nort coast of Australia. t unexpected—so unexpected,in fact, t it ists realize