1. Biodiversity involves diversity of species, genetics and habitats. But there is a fourth source of biodiversity – molecular biodiversity – without which evolution cannot occur, either in the origin of a new species, its survival and development, or its eventual extinction.
2. Molecular biodiversity is distinct from genetic diversity, though both ultimately depend on inheritable DNA. It occurs within one individual, between individuals of the same species, between related species, within and between phyla and ecosystems, and throughout evolution. There is also a crucial evolutionary role for ‘hidden’ molecular biodiversity in ‘bad’ genes. These highlight what Darwin and Wallace missed, the origin of a biological process, or a species.
3. Genetic engineering of bioluminescence, coupled with molecular imaging, has given us a wonderful technology for lighting up the molecular biodiversity of individual living cells, and even whole organisms. This has highlighted a major challenge – when is a biological process analogue or digital?
4. Synthesis and applications. The care of our planet, and ecology in the 21st century, depend on a new thinking based on molecular biodiversity. My go-home message is that ecologists must grasp the opportunities presented by advances in molecular and cellular biology. But, although molecules are at the centre of modern biology and medicine, science begins and ends with a curiosity about the whole – the cell, the organ or the individual organism, within a particular ecosystem.