Recurrent Laryngeal Nerve - what other poor designs to do we have?

[Charles Darwin]

http://www.youtube.com/watch?v=uW7NlkKaF38

 

It's an anti ID vid showing Dawkins and some others dissecting and talking about the recurrent laryngeal nerve in a giraffe.

 

Fascinating dissection to watch, especially from an evolutionary point of view because that nerve does not make sense from anything but an evolutionary point of view.

 

 

But as the title suggests, what other poor designs do we have, which are in the realm? I don't think Wisdom teeth really cut it.

[SH3RL0CK]

I heard that one problem is that our kneecaps would be much better if it were designed like our elbows. There would be less risk of injury to the supporting structures. I don't have a reference and I don't really know enough about anatomy to verify this however.

[Mokele]

We have 6 kidneys.

 

During early embryonic development, we form one pair, the pronephros. They never come fully "on-line" in humans, but are the kidneys of lampreys and hagfish.

 

Next, we form a second pair, the mesonephros, as the first begin to degrade. These are temporarily functional with ducts and everything, and become a portion of the kidneys of fish, frogs, etc.

 

In amniotes (mammals, birds, and reptiles), the mesonephros completely degrades, and is wholy replaced by the metanephros (which forms the posterior portion of the kidney in fish and amphibians).

 

 

 

There's also the fact that our retina is on backwards (making it easy to get a detached retina), that we've had to bend our knees in at a bizarre and damaging angle to function as bipeds, that the female reproductive system is open to the body cavity (allowing ectopic pregnancy and lethal infection), and that males have to stick our testes out through a hole in the bodywall (the inguinal canal).

[Charles Darwin]

We have 6 kidneys.

 

During early embryonic development, we form one pair, the pronephros. They never come fully "on-line" in humans, but are the kidneys of lampreys and hagfish.

 

Next, we form a second pair, the mesonephros, as the first begin to degrade. These are temporarily functional with ducts and everything, and become a portion of the kidneys of fish, frogs, etc.

 

In amniotes (mammals, birds, and reptiles), the mesonephros completely degrades, and is wholy replaced by the metanephros (which forms the posterior portion of the kidney in fish and amphibians).

 

 

 

There's also the fact that our retina is on backwards (making it easy to get a detached retina), that we've had to bend our knees in at a bizarre and damaging angle to function as bipeds, that the female reproductive system is open to the body cavity (allowing ectopic pregnancy and lethal infection), and that males have to stick our testes out through a hole in the bodywall (the inguinal canal).

 

I've never heard of the 6 kidneys.

[Sisyphus]

How about the same intake for food and air? Or dangling gonads? Or food cravings that would make us wildly unhealthy if fully indulged?

 

I'm sure you could name thousands of things that might be "designed" better, including the basis for pretty much any medical disorder.

[iNow]

Blind spot in our eye.

[Charles Darwin]

Blind spot in our eye.

 

The good ol' eye........ the disprover of IC.

[bascule]

The tidal motion of our respiratory system as opposed to the continuous unidirectional flow mechanism of birds is arguably inferior

[John Cuthber]

There's the punch line of the old joke...

"Three freshman-engineering students were sitting around talking between classes, when one brought up the question of who designed the human body.

 

One of the students insisted that the human body must have been designed by an electrical engineer because of the perfection of the nerves and synapses.

 

Another disagreed, and exclaimed that it had to have been a mechanical engineer who designed the human body. The system of levers and pulleys is ingenious.

 

"No", the third student said, "you're both wrong. The human body was designed by an architect. Who else but an architect would have put a toxic waste line through a recreation area?"

[Darwinsbulldog]

1. Biochemistry- not just humans, but every organism has complex biochemical pathways. They work, but they have every indication of the blind "design" by Natural selection.

2. Gene Regulatory Networks- again, they work [of course], but they show complexities and redundancies all over the place. Basically, the Hox cluster genes have been duplicated via polyploidy and some other mistakes. Cis -regulation [local, often just upstream], trans -regulation-is distal [like on another chromosome] . Positive and negative feedback loops, and stuff like repressors who repress more repressors. A designer would just have repressors and promoters. GRN's resemble complex circuit diagrams designed by a drunken idiot. Nevertheless, the logic works, and everything [usually ] happens at the right time and the right place in the embryo.

 

The work on Hox has given insight into how limb loss, limb gain and novelization occurs. How whales lost their legs, and gained flippers. How flight structures evolved in insects, reptiles, mammals and birds.