Vital Question: Energy, Evolution, and the Origins of Complex Life

by Nick Lane

the acquisition of mitochondria and the origin of complex life was one and the same event.

Erwin Schrödinger’s book What is Life? in 1944. Schrödinger made two key points: first, that life somehow resists the universal tendency to decay, the increase in entropy (disorder) that is stipulated by the second law of thermodynamics; and second, that the trick to life’s local evasion of entropy lies in the genes. He proposed that the genetic material is an ‘aperiodic’ crystal, which does not have a strictly repeating structure, hence could act as a ‘code-script’ – reputedly the first use of the term in the biological literature. Schrödinger himself assumed, along with most biologists at the time, that the quasicrystal in question must be a protein; but within a frenzied decade, Crick and Watson had inferred the crystal structure of DNA itself. In their second Nature paper of 1953, they wrote: ‘It therefore seems likely that the precise sequence of the bases is the code which carries the genetical information.’ That sentence is the basis of modern biology. Today biology is information, genome sequences are laid out in silico, and life is defined in terms of information transfer.

The earliest large fossils – up to a metre in diameter – are a mysterious group of symmetrical frond-like forms that most palaeontologists interpret as filter-feeding animals, though some insist are merely lichens:

We now know that eukaryotes all share a common ancestor, which by definition arose just once in the 4 billion years of life on earth. Let me reiterate this point, as it is crucial. All plants, animals, algae, fungi and protists share a common ancestor – the eukaryotes are monophyletic.