
An ecologist who wants to map everything - diaphanous
https://www.nature.com/articles/d41586-019-02846-4
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mlthoughts2018
When I was in middle school I first learned the basic idea of the fundamental
theorem of arithmetic and my instantaneous first idea was that we should
assign a unique prime number to each attribute that a biological entity can
have, and then multiplying together the prime factors for all the
characteristics would give the unique integer ID for that biological entity.

So if having a limb is “7” then some creature with three limbs gets 7^3 in its
prime factorization, and so on.

Obviously it is an incredibly stupid idea, but 12-year-old me was quite
impressed by the thought of it.

~~~
pvaldes
species complex, hybrids, mimicry, evolutive convergence, chimaeras... Life is
too complicated and exhuberant to reduce it to a math formula

~~~
adrianN
No it's not. It is likely too complicated to reduce to a formula that you can
evaluate in reasonable time, or too complicated to measure with sufficient
accuracy to even know what numbers to put into that formula, but life still
follows the laws of physics and to the best of our knowledge they can be
expressed in mathematical language.

------
mncharity
> the error margin for the estimate [of number of trees on Earth] ranged
> between one trillion and ten trillion

A moment's googling gives primary forest being 1/3 of Earth land area and 40M
km^2 ("world forest square km"), and primary forest tree density being 50k to
100k trees per km^2 ("trees per square km"). So there are at least 1T trees,
as forests alone have more. And exceeding 10T would require non-forests to
average at least half the tree density of forest, which seems unlikely.
Suggesting bounds of 1T and 10T trees.

Just a reminder that rough quantitative reasoning and Fermi problem solving
are powerful. Especially when approached as an exercise in order-of-magnitude
bounding, rather than point estimate.

"How many trees are there in the world, is it more like 1, 10, 100, 1k, etc?
Can anyone suggest a low bound?" "There's a tree outside the window. So one
tree." "How confident are we? Should we consider that a hard or soft bound?"
... "Ok, a hard lower bound of 1 tree." "Can anyone suggest an upper bound?"
"Ok, sigh, Jim?" "There can't be more trees on Earth than atoms in the visible
Universe, because all Earth trees are part of the Universe, and each is made
of lots of atoms! So a hard upper bound of 10^80 trees!" "Ok, is everyone ok
with a hard upper bound of 10^80?" ... "Can anyone suggest some narrower
bound?" ...

The phrase "I've _no idea_ how many/much/etc" seems said far more often then
it's true. You may not know it to some needed accuracy. But even young kids
can be taught to estimate bounds. Which often turn out quite narrow enough to
move on with.

~~~
Iv
If I recall correctly the main problem for evaluating the amount of trees on
earth is in the tress density of forest which may vary by quite a lot more
than we initially believed. And of course that numbers can easily vary by a
factor on 100 if you vary the criterion you use for counting a plant as a
tree.

