# Question No. 17

- What are the spatial boundaries of the biota (in kilometers)?
- Answered 1 October 2007.

Question author: Maxim.

Asked 28 September 2007.

Biota is spread over entire surface of our planet, which is equal to 5.1 x 10^{8} km^{2}, or 510 million square kilometers. Considering the
*volume* occupied by the biota, we should take into account depth of the oceans (~ 4 km on average) and height of the atmosphere, where living organisms can
still be found (up to 6 km). Taking oceanic depth 3.6 x 10^{8} km^{2}, we obtain that the volume occupied by the biota is equal to atmospheric volume 5.1
x 10^{8} km^{2} by 6 km, plus oceanic volume 3.6 x 10^{8} km^{2} by 4 km. This gives 4500 million cubic kilometers in total.

**Biota is vast**