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What is an individual? Biology seeks clues in information theory.

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  1. mundane_and_naive
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    [...] [...] [...]

    Now, a few groups of scientists are [...] formalizing the concept of the individual according to a set of principles and measurements that they hope will guide biology into a new era.


    At the core of that definition was the idea that an individual should not be considered in spatial terms but in temporal ones: as something that persists stably but dynamically through time. “It’s a different way of thinking about individuals,” said Mitchell, who was not involved in the work. “As kind of a verb, instead of a noun.”


    Their formalism, which they published in Theory in Biosciences in March, is based on three axioms. One is that individuality can exist at any level of biological organization, from the subcellular to the social. A second is that individuality can be nested — one individual can exist inside another. The most novel (and perhaps most counterintuitive) axiom, though, is that individuality exists on a continuum, and entities can have quantifiable degrees of it.


    [...] the Santa Fe team distinguishes three types of individuality. The first is the organismal individual, an entity that is shaped by environmental factors but is strongly self-organizing. Nearly all of the information that defines such an individual is internal and based on its own prior states. “This is a lens that, if you wore it, would allow you to see humans and mammals and birds,” Krakauer said.

    The second type of individuality is the colonial form, which involves a more complicated relationship between internal and external factors. Individuals in this category might include an ant colony or a spiderweb — distributed systems that are “partially scaffolded” by their environment but still maintain some structure on their own.

    The third type is driven almost entirely by the environment. “If you remove the scaffolding, the [entity] would fall apart,” Krakauer said. It’s like a tornado, which dissipates under the wrong temperature and moisture conditions. The very first life to arise on Earth was probably like this, Krakauer added.

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