Kind: captions
Language: en
[Applause]
have you ever noticed how badly people
behave when they're collecting their
luggage at the airport I mean they all
cluster right up against the carousel so
people behind them can't see their bags
and then when you do spot your bag you
have to push through all the other
passengers to collect it and usually
bump into them as you're grabbing your
bag off the carousel why is it that
people behave so badly it doesn't seem
to matter which airport you go to
anywhere in the world the problem is the
same and this problem believe it or not
is related to why trees are tall go with
me on this so why are trees this tall I
mean some of them are over 115 MERS they
are the largest organisms on the planet
now you might think that they're This
Tall so that they can capture sunlight
and to it agree that's true but anyone
who's ever walked through a mature
Forest knows that the lower part of a
tree has basically no branches and
leaves and that makes sense because not
enough light filters down through the
topmost branches to make it worth having
Sun capturing apparatus down here over
Millennia trees have evolved to put
their energy where it yields returns
that is in the canopy and not where it
doesn't but this then begs the question
why put all this energy into building a
trunk that's 10 or 20 M if you're never
intending to use this vertical space to
capture sunlight I mean it costs energy
for the tree to make this trunk plus it
makes it harder to transport water from
the roots up to the topmost branches and
it makes the tree more susceptible to
water stress so it's in every individual
trees best interest to be shorter to not
have this gigantic trunk and to use the
conserved energy to improve its seeds
and its branches to put its energy where
it pays a return but of course if there
was a mutation that allowed a tree to do
this you know what would happen to it in
a forest surrounded by all these taller
trees it would be shaded from the Sun
and so it would wither and die but what
if all of the trees develop the same
mutation what if they all created a
friendship pack a forest of friendship
in which everyone agreed not to grow
such a big trunk to start the leaves
right at the ground well that would mean
every individual tree would be better
off the trouble is this solution is not
stable because any tiny mutation that
results in a tree that's slightly taller
would advantage that tree it would be
able to capture more light and it would
shade its neighbors and so pretty soon
it would have more offspring it would
come to dominate the forest and then any
additional mutation down the line would
result in even taller trees this is how
trees got so tall I mean they would keep
getting taller until the cost of going
one more foot is exactly equal to the
benefits of collecting that additional
sunlight and that is why trees are as
tall as they are today I mean it's not
an optimal solution it's not like these
trees have the best use of their energy
but it is the one that is stable so the
point is although it's in every tree's
best interest to be a part of this
Forest of friendship it will never work
it'll never last because any individual
who get gets a little bit taller is
going to ruin it for everyone and it's
the very same thing where you go to
collect your bags I mean if everyone
could agree to stand a couple meters
away from the carousel everyone would
have a good view of their bags and be
able to easily step forward and collect
their luggage but of course one person
standing forward is going to block the
view of people behind them so everyone's
going to rush forward it's an unstable
solution just like the forest of
friendship so remember next time you
were frustrated collecting your bags at
the airport remember trees know just how
you feel
[Music]
I'll summarize the whole problem for you
here you
[Music]
ready