in the development of modern man, many of the
useful functions and parts of the human body
become unnecessary. What is most fascinating is
that many of these parts of the body still remain in
some form so we can see the progress of
evolution. This list covers the ten most significant
evolutionary changes that have taken place –
leaving signs behind them.
10. Goose Bumps: Cutis Anserina : Humans get
goose bumps when they are cold, frightened, angry,
or in awe. Many other creatures get goose bumps
for the same reason, for example this is why a cat
or dog’s hair stands on end and the cause behind a
porcupine’s quills raising. In cold situations, the
rising hair traps air between the hairs and skin,
creating insulation and warmth. In response to fear,
goose bumps make an animal appear larger –
hopefully scaring away the enemy. Humans no
longer benefit from goose bumps and they are
simply left over from our past when we were not
clothed and needed to scare our own natural
enemies. Natural selection removed the thick hair
but left behind the mechanism for controlling it.
[b]
9. Jacobson’s Organ: Vomeronasal organ : [/b]
Jacobson’s organ is a fascinating part of animal
anatomy and it tells us a lot about our own sexual
history. The organ is in the nose and it is a special
“smell” organ which detects pheromones (the
chemical that triggers sexual desire, alarm, or
information about food trails). It is this organ that
allows some animals to track others for sex and to
know of potential dangers. Humans are born with
the Jacobson’s organ, but in early development its
abilities dwindle to a point that it is useless. Once
upon a time, humans would have used this organ to
locate mates when communication was not
possible. Single’s evenings, chat rooms, and bars
have now taken its place in the process of human
mate-seeking.
[b]
8. Junk DNA: L-gulonolactone oxidase : [/b]
While many
of the hangovers from our “devolved” past are
visible or physical, this is not true for all. Humans
have structures in their genetic make-up that were
once used to produces enzymes to process vitamin
C (it is called L-gulonolactone oxidase). Most other
animals have this functioning DNA but at some point
in our history, a mutation disbled the gene – whilst
leaving behind its remnants as junk DNA. This
particular junk DNA indicates a common ancestry
with other species on earth, so it is particularly
interesting.[b]
7. Extra Ear Muscles: [/b]Auriculares muscles : Also
known as the extrinsic ear muscles, the auriculares
muscles are used by animals to swivel and
manipulate their ears (independently of their head)
in order to focus their hearing on particular sounds.
Humans still have the muscles that we would once
have used for the very same reason – but our
muscles are now so feeble that all they can do is
give our ears a little wiggle. The use of these
muscles in cats is very visible (as they can nearly
turn their ears completely backwards) –
particularly when they are stalking a bird and need
to make the smallest movements possible so as to
not frighten its future meal.
[b]
6. Plantaris Muscle : [/b]The plantaris muscle is used
by animals in gripping and manipulating objects with
their feet – something you see with apes who seem
to be able to use their feet as well as their hands.
Humans have this muscle as well, but it is now so
underdeveloped that it is often taken out by doctors
when they need tissue for reconstruction in other
parts of the body. The muscle is so unimportant to
the human body that 9% of humans are now born
without it.
[b]
5. Wisdom Teeth : [/b]Early humans ate a lot of plants –
and they needed to eat them quickly enough that
they could eat a sufficient amount in one day to get
all of the nutrients they needed. For this reason, we
had an extra set of molars to make the larger mouth
more productive. This was particularly essential as
the body lacked the ability to sufficiently digest
cellulose. As evolution made its selections, our
diets changed, our jaws grew appropriately smaller,
and our third molars became unnecessary. Some
human populations have now all but completely
stopped growing wisdom teeth, while others have
almost 100% likelihood of developing them.
[b]
4. Third Eyelid : [/b]If you watch a cat blink, you will
see a white membrane cross its eye – that is called
its third eyelid. It is quite a rare thing in mammals,
but common in birds, reptiles, and fish. Humans
have a remnant (but non-working) third eyelid (you
can see it in the picture above). It has become quite
small in humans, but some populations have more
visible portions than others. There is only one
known species of primate that still has a functioning
third eyelid, and that is the Calabar angwantibo
(closely related to lorises) which lives in West
Africa.
[b]
3. Darwin’s Point: plica semilunaris : [/b]Darwin’s point
is found in the majority of mammals, and humans
are no exception. It is most likely used to help focus
sounds in animals, but it no longer has a function in
humans. Only 10.4% of the human population still
has this visible left-over mark of our past, but it is
possible that a much larger number of people carry
the gene that produces it as it does not always
cause the ear tubercle to appear. The point (shown
in the picture above) is a small thick nodule at the
junction of the upper and middle sections of the ear.
[b]
2. Coccyx : [/b]The coccyx is the remnant of what was
once a human tail. Over time we lost the need for a
tail (as tree swinging was replaced by hanging out
at the local water hole grunting neanderthal gossip),
but we did not lose the need for the coccyx: it now
functions as a support structure for various
muscles and a support for a person when he sits
down and leans back. The coccyx also supports the
position of the anus.
[b]
1. Appendix : [/b]The appendix has no known use in
modern humans and is often removed when it
becomes infected. While its original use is still
speculated on, most scientists agree with Darwin’s
suggestion that it once helped to process the
cellulose found in the leaf-rich diet that we once
had. Over the course of evolution, as our diet has
changed, the appendix became less useful. What is
particularly interesting is that many evolutionary
theorists believe that natural selection (while
removing all of the abilities of the appendix) selects
larger appendices because they are less likely to
become inflamed and diseased. So unlike the little
toe, which may eventually vanish and is equally
useless, the appendix is likely to stay with us for a
long time – just hanging around doing nothing.
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