Examples of bad "design" in humans

[Blue Mountain]

The intelligent design crowd says humans are far too advanced to have evolved, and therefore must have been designed, and that thus implies a designer. While there are a couple of logical fallacies in that conclusion, I'm more interested in the assertion that humans are designed.

Off the top of my head, I can think of two parts of the human body that do not seem to be well designed at all:

• The spinal column: On a recent episode of The Skeptic's Guide to the Universe, Dr. Steven Novella noted that the spinal column works quite well for quadrupeds, where it is normally horizontal. However, stand it upright (as we humans have it), and there are some problems, notably slipped discs and lower back pain.
• The punchline to an old joke: Who would run a septic line through a recreational zone?

What other example of bad design can others think of here?

 

[AbleSugar]

There are a lot of things I would have added if I were designing a body. Eyes in the back of my head for starters.

 

[robinson]

Better question, if you could design it, how would you run the plumbing?

 

[devnull]

breathing and eating through the same orifice is a commonly quoted one.

 

[rjh01]

Why do people have their brains in the head? I would have thought it would be more logical to have such a critical part of the body in the chest zone next to the heart.

 

[Frozenwolf150]

I would have included more, but the rest were kind of pervy.

• Eye lenses that invert the image, forcing the brain to compensate for the upside-down image. Compare this to the eyes in cephalopods like squid, who can see quite well without inverting the image. Additionally, they have photoreceptors facing towards the light, whereas we have them facing away.
• Nerve tissue that does not regenerate from injury. The evolutionary reason for this is that if an animal were to sustain such a severe injury, such as to the brain or spinal column, it would be costly to repair and thus better for the population as a whole if the individual just died.
• A cardiovascular system that increases blood pressure to an open bleeding wound, causing you to bleed out.

 

[robinson]

I know this isn't the intent of the topic, but I love a challenge.

The spinal column: On a recent episode of The Skeptic's Guide to the Universe, Dr. Steven Novella noted that the spinal column works quite well for quadrupeds, where it is normally horizontal. However, stand it upright (as we humans have it), and there are some problems, notably slipped discs and lower back pain.

The trade off for being able to outrun anything, as well as many other benefits, favors the upright stance. Most healthy people never have back problems.

The punchline to an old joke: Who would run a septic line through a recreational zone?

The same design is used in most animals, so it is the best there is. Besides, some people consider it all recreation zone.

There are a lot of things I would have added if I were designing a body. Eyes in the back of my head for starters.

That is what other people are for. We are social animals, so we don't need eyes everywhere. Ears are often enough to know what is going on behind you as well.

breathing and eating through the same orifice is a commonly quoted one.

You should breath through the nose, and eat with your mouth.

Why do people have their brains in the head? I would have thought it would be more logical to have such a critical part of the body in the chest zone next to the heart.

The brain needs cooling, it can't be buried deep inside the body.

Eye lenses that invert the image, forcing the brain to compensate for the upside-down image. Compare this to the eyes in cephalopods like squid, who can see quite well without inverting the image. Additionally, they have photoreceptors facing towards the light, whereas we have them facing away

See these pages for extensive commentary
http://www.pandasthumb.org/archives/2006/11/denton_vs_squid.html
http://www.pnas.org/content/94/6/2098.full

Nerve tissue that does not regenerate from injury. The evolutionary reason for this is that if an animal were to sustain such a severe injury, such as to the brain or spinal column, it would be costly to repair and thus better for the population as a whole if the individual just died.

Some nerve tissue does regenerate.
http://www.eurekalert.org/pub_releases/2008-05/asfb-bch052708.php

A cardiovascular system that increases blood pressure to an open bleeding wound, causing you to bleed out.

If blood pressure did not increase, you would die right away. Elevated blood pressure maintains brain function so you have a chance at survival. Stopping bleeding isn't that hard, but you have to be awake long enough to do it.


Next?

 

[Freethinker]

How about the kludged night vision system in the eye? Since the eye is often used by the ID nuts as an example of something too complex to have come about by evolution, how come the designer of the universe gave us such a half-assed system to let us see in low light situations. He could have given us infrared vision, or better yet, design the universe such that we could have eyes that enabled us to see without light, but we are stuck with a system that performs very poorly when transitioning from a brightly lit environment, and which doesn't give us color vision. On top of that, it's really bad at seeing what we are looking at, and performs best on seeing things that we aren't looking directly at.

Wow, what a great design!

 

[robinson]

How about the kludged night vision system in the eye?

We evolved to sleep at night. Or to have fire to see with. Fire good.

how come the designer of the universe gave us such a half-assed system to let us see in low light situations.

Actually we have a pretty good mix of vision, both in very bright light, and very low light. If you wear a patch over one eye you can switch between almost pitch black and brilliant sunlight with no problem. Just switch the eye the patch is on. (Rrrr, thanks be to me pirate friends for that tip).

He could have given us infrared vision, or better yet, design the universe such that we could have eyes that enabled us to see without light, but we are stuck with a system that performs very poorly when transitioning from a brightly lit environment, and which doesn't give us color vision.

Considering the dangers of the jungle (or grasslands) at night, evolution favored those who stayed in the cave at night. By the fire.

On top of that, it's really bad at seeing what we are looking at, and performs best on seeing things that we aren't looking directly at.

Being able to see things out of the corner of the eye, in lowlight situations, is a survival skill. But again, it is all about staying by the fire, not tramping around in the dark. At night. There may have been some ancestors with good night vision. They were eaten while young by bears.

 

[six7s]

A birth canal that is so small/inflexible that our (big skulled) young are born prematurely (cf many (most?) other (terrestrial) mammals that can walk within minutes of their first breath)

 

[SezMe]

You should breath through the nose, and eat with your mouth.

Orifice was probably not the word he wanted to use. What is bad design is having the same pipe feed the lungs and belly because it allows for choking.

 

[SezMe]

Why do people have their brains in the head? I would have thought it would be more logical to have such a critical part of the body in the chest zone next to the heart.

Because you want the processing engine (brain) as close as possible to the sensors to minimize transmission time.

 

[robinson]

A birth canal that is so small/inflexible that our (big skulled) young are born prematurely (cf many (most?) other (terrestrial) mammals that can walk within minutes of their first breath)

This is due to our large brains, which are not fully formed at birth. The long period from birth to walking allows greater brain development. It is a trade off.

Orifice was probably not the word he wanted to use. What is bad design is having the same pipe feed the lungs and belly because it allows for choking.

There are two pipes. The connection between them allows speech. If it was hardwired so you couldn't choke, you also couldn't sing.

 

[kallsop]

What use is the funny bone? I could do without an exposed nerve there.

 

[e-sabbath]

Blind spots caused by blood vessels passing over the retina.

 

[robinson]

What use is the funny bone? I could do without an exposed nerve there.

OK that one I have to agree with. It is right up there with soft exposed reproductive organs hanging out at just the right level for a swift knee to the family jewels. If there is a God, he has a sick twisted sense of humor, and must really laugh it up each time somebody gets a groin shot.

Blind spots caused by blood vessels passing over the retina.

Needed to reduce heating from intense light conditions.

 

[SezMe]

There are two pipes. The connection between them allows speech. If it was hardwired so you couldn't choke, you also couldn't sing.

We have only one throat. If there were two, there is no reason the vocal cords couldn't be in the air pipe.

 

[Herzblut]

Crappy mammalian eyes that pale compared to many birds' or reptiles' eyes.

 

[phantomb]

OK that one I have to agree with.

Why don't you agree with some of the others? You've provided insight into why some of these things evolved to be the way they are, but that doesn't mean that they aren't still examples of bad "design", as most of them are serious detriments to Humans today.

 

[TjW]

Terminating a waste disposal line in a major recreational area.