What is life? : common patterns of organism function and species survival

The vast range of biological diversity evident on Earth masks a small number of essential ‘primary’ functions that determine survival: growth, maintenance and reproduction. Growth is linked with the ability to compete with other organisms, and may be maximized by large size and the monopolization of resources as part of an ‘acquisitive’ way of life. Maintenance of metabolic performance in response to environmental limitations (stress factors) may be optimized by a conservative way of life, depending on cellular protection/repair mechanisms and resource accumulation. Reproduction is central to the renewal of populations when individuals die, and thus the survival of the species despite the demise of the single organism. All species must perform these functions, but the importance of each one in any particular habitat depends on local conditions of productivity, stress and the occurrence of destructive disturbance events. The evolutionary trade-off between primary functions forms the basis of the CSR theory of plant strategies. I shall discuss recent developments in the practical application of CSR theory world-wide, born from a global collaborative effort lead by Italian and Brazilian research groups. Key examples from Brazilian and European ecosystems show how the method is starting to be used to investigate a range of plant community processes ranging from the co-existence of species at centimetre scales to understanding of the persistence and conservation of vegetation types across changing landscapes. I shall also discuss how this research on plants is relevant to communities of animals and microorganisms as part of the more general Universal Adaptive Strategy Theory (UAST).