Let's blow up the little piece of the spectrum that we see,
of the electromagnetic spectrum that we see, and look at it in more detail.
So the wavelengths that we see, range from
about 400 nanometers to 700 nanometers.
And that's really a tiny range, but this is the range that normally we can see.
Other animals can see more into the ultraviolet,
more into the infrared,
for the purposes of the niches in which they exist.
But in our niche, this is the range that we have evolve to see and
in fact, all animals with visual systems don't go very far away from
the kinds of spectral light that we're capable of seeing.
Because the energy out here, begins to damage cells and
the energy here, is really heat.
And detected better as, for example some snakes do with heat detectors than with
vision and light detectors.
So that's the range that we see and
its colored because as we'll come back and talk about in a later module.
Of course we see colors and how we see colors,
I've already introduced you to the anomalous way that we see them.
And we're going to talk much more about that, but
all of these things are again critically important.
For how we think about vision, what its demands are and
how we're solving those demands.