Surface-area-to-volume ratio
Similar explanation appears in the literature: "Small size implies a large ratio of surface area to volume, thereby helping to maximize the uptake of nutrients across the plasma membrane",[10] and elsewhere.
Thus, the same linear relationship between area and volume holds for any number of dimensions (see figure): doubling the radius always halves the ratio.
A high surface area to volume ratio provides a strong "driving force" to speed up thermodynamic processes that minimize free energy.
The ratio between the surface area and volume of cells and organisms has an enormous impact on their biology, including their physiology and behavior.
The finely-branched appendages of filter feeders such as krill provide a large surface area to sift the water for food.
[14][15] Similarly, the small intestine has a finely wrinkled internal surface, allowing the body to absorb nutrients efficiently.
More contact with the environment through the surface of a cell or an organ (relative to its volume) increases loss of water and dissolved substances.
High surface area to volume ratios also present problems of temperature control in unfavorable environments.
Higher values are also correlated to shorter fuel ignition times, and hence faster fire spread rates.
A body of icy or rocky material in outer space may, if it can build and retain sufficient heat, develop a differentiated interior and alter its surface through volcanic or tectonic activity.
The length of time through which a planetary body can maintain surface-altering activity depends on how well it retains heat, and this is governed by its surface area-to-volume ratio.
The moon, Mercury and Mars have radii in the low thousands of kilometers; all three retained heat well enough to be thoroughly differentiated although after a billion years or so they became too cool to show anything more than very localized and infrequent volcanic activity.
[22] Venus and Earth (r>6,000 km) have sufficiently low surface area-to-volume ratios (roughly half that of Mars and much lower than all other known rocky bodies) so that their heat loss is minimal.
