There are two kinds of adaptation, one
is by evolution, which takes generations.
So animals that are active at night (nocturnal
animals) have evolved eyes that see well at
night. Another type of adaptation is a
temporary change in one individual,
usually in a short time. These changes are not
passed on to their offspring. For example,
getting used to hot or cold temperatures is this
kind of adaptation.
One evolutionary adaptation for seeing at night
is having big eyes Big eyes trap more light,
just like a bigger window takes in more light.
Another adaptation is having more light
receptors that work in dim light (rods). The
light receptors that let us see color (cones) need
bright light to work. That’s why everything starts
looking gray in dim light.
Another adaptation is having a sort of
mirror at the back of the eye that bounces
light by the light receptors again. If you look at
most flashlights they have a mirror behind the
bulb for the same reason. You can tell whether an
animal has this “mirror” because their eyes seem
to glow when light shines on them.
An important temporary adaptation is the pupil
of the eye getting bigger. The pupil
is the hole that light goes through to get to the
light receptors. It looks black. The iris
is the colored ring around the pupil. Your iris
might be black, brown, blue, green, or other
colors like that. The iris controls how big the
pupil is. If it opens up, more light gets in.
So pupils get bigger in the dark when the iris
If we only saw in black and white, we could see a
lot better at night. Why do you think being
able to see color might be an advantage?
Thanks for asking,