Vestigial Structures
These are examples of human anatomy that
are no longer needed for us to survive or to
thrive, though in the past were much more
important.
Scientists believe the
appendix used to be
used as a storage place
for the vital bacteria that
help us digest our food.
When humans were
more spread out and
had less contact with
each other, they needed
this storage of bacteria in
case theirs was depleted
from sickness, etc.
A small fold of tissue
in the corner of the
eye is considered a
vestigial structure of
the nictitating
membrane, used in
animals to moisten
and protect the eye
Nictitating membrane of a chicken
Scientists believe that
early humans ate a
higher plant content
diet, which required a
large jaw, with more
teeth. As our diet
changed, the need for
such a large jaw
decreased, but the
extra teeth haven’t
evolved away yet.