I should teach the world that all living things are self-organising communities of molecular machines, devices and constructs. The parts kit that life uses to build living things contains mainly the atoms of carbon, hydrogen, oxygen, nitrogen, sulphur and phosphorous.

The basic organisational unit is the single cell, which is usually about a tenth to a hundredth of a millimetre in diameter. Microorganisms, such as bacteria and archaea, are just single cells, in which myriads of molecules constantly encounter and either 'ignore' or 'recognise' each other. Molecules interact to build bigger molecules, or they break down into smaller molecules, with the effects being registered through a complex network of molecular feedback loops - all in microseconds. Each molecule is inanimate, yet the whole is alive!

Chemicals are taken in from the immediate environment, through the cell's outer molecular membrane, and are processed, to gain energy and to sustain life processes. Even in a single bacterial cell, there are several thousand different types of molecular machine - comprised of proteins, polysaccharides, polar lipids, etc. All of these machines have been assembled and manufactured, directly or indirectly, according to the instructions encoded in the genes of the DNA - the central file of the molecular genetic machinery. These machines range in size - from small clusters of a few tens of atoms bound together, like the vitamins; to huge chains and network structures, such as DNA and enzymes. Most of these machines have specialised functions - serving, for example, as partitioning, protection, repair, catalysis and storage devices; and as coding, transcription, recognition, communication and transport systems.

More advanced multicellular organisms - like plants, worms, mice, or people - are elaborate, genetically controlled assemblages of billions of single cells, each cell with its own particular sets of molecular machinery. Many cells benefit the whole organism, providing movement, digestion, excretion, repair, reproduction, memory and thought. Using genetic analysis - genomics - we can now see how closely each living thing is related to each other living thing, and how differences in gene complement characterise individuals of the same species.

Even so, when we read out the full sequences of the thousands of genes in their DNA, we can rationalise the patterns - in terms of all organisms, unicellular and multicellular, being descended from a common ancestor. Many types of molecular machine are universally present in cells, often differing only very slightly in their precise structures, from one species to another. This is particularly so, where the molecule has some essential biochemical function to perform, such as catalysis of reactions fundamental to life - for example, the building up of complex carbon compounds.

Indeed, all life forms are largely assemblages of standard parts. Evidently, most of these key molecular machines were invented far back in time, on the young Earth, and have been conserved through the eons of biological competition ever since.

Some of the mechanisms by which evolution occurs can now be seen at the molecular level. Small changes in the DNA template - mutations - or even whole gene transfer can occur, which then results in different new copies of the DNA of the organism. These copies may then be more or less successful, in coping with the environment - the survival of the fittest.

There is molecular evidence of early unicellular life forms, that is discernible in sedimentary rocks that are two and a half billion years old. Here, we find chemical fossils, in the form of hydrocarbons bearing the same carbon skeletons as some of the biomolecules in today's organisms, persisting as trace components locked in rocks over all that time.

We need to recognise and better appreciate the breathtaking complexity of our molecular makeup. Above all, the uniformity of living things is truly awesome. The Native Americans had it right - we are one with nature, and we should nurture and respect it.