title: Life on Earth is an individual.
abstract: Life is a self-maintaining process based on metabolism. Something is said to be alive when it exhibits organization and is actively involved in its own continued existence through carrying out metabolic processes. A life is a spatio-temporally restricted event, which continues while the life processes are occurring in a particular chunk of matter (or, arguably, when they are temporally suspended, but can be restarted at any moment), even though there is continuous replacement of parts. Life is organized in discrete packages, particular cells and multicellular organisms with differing degrees of individuality. Biological species, too, have been shown to be individuals, and not classes, as these collections of organisms are spatio-temporally localized, restricted, continuous, and somewhat cohesive entities, with a definite beginning and end. Assuming that all life on Earth has a common origin, all living organisms, cells, and tissues descending from this origin exhibit continuity of the life processes at the cellular level, as well as many of the features that define the individual character of species: spatio-temporal localization and restriction, continuity, historicity, and cohesiveness. Therefore, life on Earth is an ontological individual. Independent origins of life will have produced other such individuals. These provisionally called 'life-individuals' constitute a category of organization of life which has seldom been recognized. The discovery of at least one independent life-individual would go a long way toward the project of the universality of biology.
authors.affiliation: Interdisciplinary Centre of Marine and Environmental Research of Madeira, Edifício Madeira Tecnopolo, Caminho da Penteada, 9020-105, Funchal, Madeira, Portugal. margarida.hermida@ciimarmadeira.org.
authors.forename: Margarida
authors.initials: M
authors.lastname: Hermida
mesh_terms: D005075:Biological Evolution; D001695:Biology / Q000379:methods*; D018534:Earth, Planet; D018559:Exobiology; D053476:Extinction, Biological; D019369:Life; D008954:Models, Biological; D000069497:Origin of Life; D013997:Time Factors
keywords: Alien life; Historical individuals; Individuality; Life on Earth; Life-individuals; Spatio-temporal continuity