The notion of the “biological individual” is crucial to studies of genetics, immunology,
evolution, development, anatomy, and physiology. Each of these biological subdisciplines …

In the last two decades, the widespread application of genetic and genomic approaches has
revealed a bacterial world astonishing in its ubiquity and diversity. This review examines …

Over the past decade, advances in both molecular developmental biology and evolutionary
ecology have made possible a new understanding of organisms as dynamic systems …

Today, the three classical biological explanations of the individual self––the immune system,
the brain, the genome––are being challenged by the new field of microbiome research …

Resident microbiota do not just shape host immunity, they can also contribute to host
protection against pathogens and infectious diseases. Previous reviews of the protective …

The theory of evolution by natural selection is, perhaps, the crowning intellectual
achievement of the biological sciences. There is considerable debate, though, about which …

Most epithelia in animals are colonized by microbial communities. These resident microbes
influence fitness and thus ecologically important traits of their hosts, ultimately forming a …

The swimming larvae of many marine animals identify a location on the seafloor to settle and
undergo metamorphosis based on the presence of specific surface-bound bacteria. While …

Holobionts are multicellular eukaryotes with multiple species of persistent symbionts. They
are not individuals in the genetic sense—composed of and regulated by the same genome …

The paper links discussions of two topics: biological individuality and the simplest forms of
mentality. I discuss several attempts to locate the boundary between metabolic activity and …