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The size of life: the differing scales of living things

posted by Jason Kottke   Aug 10, 2017

In the first in a series of videos, Kurzgesagt tackles one of my favorite scientific subjects: how the sizes of animals governs their behaviors, appearance, and abilities. For instance, because the volume (and therefore mass) of an organism increases according to the cube of the increase in length (e.g. if you double the length/height of a dog, its mass roughly increases by 8 times), when you drop differently sized animals from high up, the outcomes are vastly different (a mouse lands safely, an elephant splatters everywhere).

The bit in the video about how insects can breathe underwater because of the interplay between the surface tension of water and their water-repellant outer layers is fascinating. The effect of scale also comes into play when considering the longevity of NBA big men, how fast animals move, how much animals’ hearts beat, the question of fighting 100 duck-sized horses or 1 horse-sized duck, and shrinking people down to conserve resources.

When humans get smaller, the world and its resources get bigger. We’d live in smaller houses, drive smaller cars that use less gas, eat less food, etc. It wouldn’t even take much to realize gains from a Honey, I Shrunk Humanity scheme: because of scaling laws, a height/weight proportional human maxing out at 3 feet tall would not use half the resources of a 6-foot human but would use somewhere between 1/4 and 1/8 of the resources, depending on whether the resource varied with volume or surface area. Six-inch-tall humans would potentially use 1728 times fewer resources.

See also The Biology of B-Movie Monsters, which is perhaps the most-linked article in the history of kottke.org.