Length Scales
Laura Deming mentions how she thinks about biology with different mental models, to understand it numerically, in a fast way.
One grounding point in biology is a smple question: how big are all the different words we are talking about? In her “do your scales!” thought experiment video, Laura walks though mentally shrinking/growing objects by factors of 10, starting with objects we can intuitively understand, and then jumping down into a smaller biological scale.1 2
| Length ($10^x$ m) | Item |
|---|---|
| $x=0$ | 1m |
| $-1$ | Hand |
| $-2$ | 6-sided die |
| $-3 \text{, mm}$ | Bead |
| $-4$ | Oocyte |
| $-5$ | Skin cell |
| $-6 \text{, Micron}$ | E. coli. |
| $-7$ | Virus |
| $-8$ | 30 amino-acid peptide |
| $-9 \text{, nm}$ | 3 amino-acids |
| $-10 \text {, Angstrom}$ | Atom |
Note that E. Coli. would fit into a skin cell. Mitochondria may originate from prokaryotes forming a symbiotic bond with Eukaryotes - visualizing the length scale makes this clear.
E. O. Wilson also has an interesting visualization of these length scale differences, in the iPad book Guided Tour of the Living Cell. ↩︎
See also this visualization ↩︎