Suzana Herculano-Houzel

Behaviour without a nervous system depends on diffusion

All actions, and therefore behaviors, require energy transfer. Behaviors happen as potential energy is dissipated, channeled through natural or man-made circuits, networks, or natural paths of least resistance. Ultimately, the source of energy is external to the system, and transferred to it in an original explosion (case of the solar system), through a power line or induction (appliances), or fuel (vehicles and…...

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Behavior is any observable action

We usually equate nervous systems with behaviors, but as it turns out, a nervous system – that is, an ensemble of organs and tissues made of excitable cells that carry signals rapidly across the body – is actually not necessary for behavior. If behavior is defined simply as sets of observable actions in a given context, then plants have behaviors, like orienting to sunlight; so do single-cell…...

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Life 101: Larger bodies are made of more cells, not larger cells

If life is self-organizing work at the expense of metabolism, then the cell is the membrane-bound unit of life: it is the building block that contains all the enzymes that promote the chains of reactions that transfer energy and matter that constitute metabolism. Bodies are made of cells that stick together to one another and…...

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