If natural selection is true should n't we humans have organs/parts that are not useful to our existence ?

Question

This is for experts on Evolution theory. Since natural selection remove negative mutations, we should have neutral and beneficial mutation carried forward. Based on what I understand from our body parts/organs everything is of use to us. Is there any thing in our body that is not harmful nor beneficial ?

Answer 1

Appendix,
wisdom teeth,
tailbone,
embryonic tail,
embryonic gill slits,
male nipples,
extrinsic ear muscles,
the "third eye lid",
goose bumps (leftover erector pili muscle fibers used for puffing up the fur for insulation, useless without fur)
For many other examples, see article (Discover Magazine) "Useless Body Parts":
http://www.discover.com/issues/jun-04/features/useless-body-parts/?page=2


But one that I love to point out: the plantaris muscle.

This is a long thin muscle in the human calf. It serves no purpose in humans. In fact it is often removed by surgeons harvesting muscle tissue for use elsewhere (as in heart surgery). It is so useless that is is absent from 9% of the human population.

Then what is it for? In other primates, the very same muscle is used for ... wait for it ... grasping with the feet.

Answer 2

I can think of two thing: the appendix, which serves no purpose, and the coccyx, or tailbone, which is the very bottom of our spine. All of the vertebrae of our spine up to the lumbar area are fused, and the little bone sticking out serves no purpose. It is, in fact, just bone buried in tissue. It is believed to be the remains of what was once, long ago, the spinal bones which led to a tail. If you look at an x-ray of an animal with a tail, such as a cat, you find that the tail is just an extension of the spine. We humans still have that bone which serves no purpose, and which is, actually, often detrimental. It can be broken, and while it does not cause harm, it does cause a lot of pain. We no longer need it, but we still have it :)

Answer 3

There are standard cases people put forth as neutral adaptations, i.e., features we possess not because of any positive benefit, but just because it doesn't hurt us. E.g., male nipples and the appendix are such standard cases. (Whether these really are neutral is not entirely obvious. They could have a function that is just not understood yet.)

Generally speaking, though, any "neutral" organ sitting there and not doing anything is not really neutral at all, for it has to be built and maintained, which requires energy. The animal would be better off without it, and so neutral organs will be selected against.

I suppose a "true" neutral organ would be one that provides just enough positive benefit to offset the costs of its construction and maintenance. But trying to empirically determine whether an organ is "truly neutral" in this sense is quite tricky.

Answer 4

Nature is economical: it doesn't create useless parts of any living organism. Something we can do without now is our appendix. But this organ was necessary for our ancient ancestors to help facilitate the digestion of many of the "rough" foods they ate. Now, as we no longer need this organ, it is slowly diminishing in size over the generations, and eventually will be gone.

Answer 5

g'day Searching wisdom,

Yes. Our appendix is a vestigial organ.

Currently, the function of the appendix, if any, remains controversial in the field of human physiology.

There have been cases of people who have been found, usually on laparoscopy or laparotomy, to have a congenital absence of their appendix. There have been no reports of impaired immune or gastrointestinal function in these people.

One explanation has been that the appendix is a remnant of an earlier function, with no current purpose. I had my appendix removed in 1974 and haven't missed it at all.

I have attached sources for your reference.

Regards

Answer 6

The appendix - it is generally determined to be a vistigial organ. It has been equated to the ceacum - but is no longer used with humans. It now just has a marginal immunity function for the body.

Answer 7

The Appendix is the remains of a hindgut and serves no purpose, harmful or beneficial.

Answer 8

Damn .......people were quicker than me. Not only appendix, and tail bone, but tonsils are proving to be more harmful than useful in most.

Question to you........it is found we only really utilize 10% of our brain. Did it de-evolve or is still evolving?

Answer 9

Our appendix

Answer 10

appendix