Stripes are common in nature
even if the scale of landscapes.
Two centuries ago Alexander von Humboldt
noticed that plants in the Andes
occur in distinct altitude and zones
You can find similar  patterns on a smaller scale
at the beach. I invited Amy who is
an expert in marine ecology to come out
and help me understand why you tend to see
stripes of different colors
between the high tide and the low tide on the oceanside
One of the first stops we wanted to make was a tide pool
You find very different things
in a tide pool. Like you find on a rock right next to the tide pool
And you can tell that by looking at the colors
right at that edge of the tide pool.
Green and then immediately
when you're outside of the tide pool
brown.
The stripes  between low and high tides are
even more obvious at a broader scale. The bands of
color start with sort of a dark green
zone or a lighter green zone which is actually red algae
And then it starts with a dark brown zone that's your
rock weed zone.
And then there's a white band
that's where your barnacle.
All of the creatures living  on the rock
physiologically speaking
would prefer to spend more time in the water.
In a famous experiment ecologists
took animals and algae from the uppermost zone
and transplanted them farther down
Guess what happens when you do that. They will do better
they will grow better
they will make more babies
they will grow faster if they're actually lower down.
So why don't they occur farther down?
Two reasons: the species in the highest stripe
are not good at competing for space with species
lower down. And they're more vulnerable
to predation by snails, sea stars, and fish.
What they are good at is not drying
out during low tide.
On the other hand the species that make up
the bottom stripes are good predators
and can defend themselves from predators but they're prone
to desiccation and can't survive in the upper zone.
So the next time you're at the beach
check out the stripes
