10 Worst Evolutionary Designs

JamJam writes "Besides my beer gut, which I'm sure has some purpose, Wired is running a story on the 10 Worst Evolutionary Designs. Ranging from baby giraffes being dropped 5-foot during birth to Goliath bird-eating spiders that practically explode when they fall from trees."

Comments

Humans

[Kittenman]

1) Knees

2) Windpipe close to channel to stomach - choking hazard

3) Walking upright leads to distended colon, piles, etc

4) As my wife says, playground close to a sewage works

And first post, BTW...

Re:Humans

[Bertie]

Ah, but...

The design of our breathing/eating apparatus may be a choking hazard, but it gives us the ability to do a neat trick that no other animal can: speak.

Ever noticed how babies can feed and breathe at the same time, but you can't? This is because of the shape of their vocal tract, which is more like an animal's than yours at that point. Babies need to get a lot of food down their necks as quickly as possible, because they're busy growing. Speaking can wait.

After a few months, things start to move around - the larynx drops, the back of the throat curves round into a right-angle, and all of a sudden they have to choose between eating and breathing. But the reshaped vocal tract allows them to form configurations of the speech organs which weren't previously possible, and so they learn to speak.

Re:Humans

[ceoyoyo]

1) Don't listen to some article writer at Wired to learn what is or is not a bad birth process. Several of the ones he mentioned seem silly until you know more about them, then they make sense. Other things that continue to seem silly may do so because we just haven't figured them out yet. Similarly, lots of irreducible complexity arguments that originally seemed convincing have famously fallen to new insights.

2) Evolution doesn't produce "perfection" or even necessarily approach it. Evolution is an optimization process. It can certainly get stuck in local minima.

Re:Humans

[ucblockhead]

It's cost/benefits. Imagine an animal. Now tweak it slightly. That tweak may increase the incidence of some sorts of death and decrease the incidence of other sorts of death. Does the one outweigh the other? If so, over time, there will be more and more animals with that tweak.

That's evolution in a nutshell.

Evolution means that if a change that makes humans 10% smarter and therefore much more successful hunters and therefore less likely to starve but means a 4% increased infant mortality then that change will spread throughout the population.

Remember that it is not about individuals...it is about populations. Look at how the human mind and body works and breaks down and tells me if it looks like something designed to be optimal, or something randomly created that balances efficiencies and deficiencies to maximize broad statistical success of reproduction. In which worldview does cancer make sense?

Re:Humans

[SilverEyes]

If that individual doesnt reproduce, then that mutation (benificial or adverse) is lost.

Yes.

When a mutation of significance happens, which might be once every few hundred generations, that individual is the only one that can pass it along. It has to reproduce so much more than normal that it has enough offspring that the mutation is preserved through not only the first generation, but the second, third and so on. Remember, each generation it goes through, there is only a 50/50 chance that the offspring will have it too.

Many animals will have multiple generations of offspring. There may be a 50/50 chance for a specific mutation (that is only linked through one gene) to be passed on, but if the offsprings chances improve, they will be more successful at reproduction, and their offspring as well.

Mutations in genetics during reproduction are actually pretty rare. Note that mutations later in life dont matter because they no longer have the ability to affect the entire organism. It is a localized mutation, like cancer.

Rare for a particular part of the gene. Even one mutation in a million base pairs works out to some mutations per generation for any sizable genome. Animals have lots of DNA. I'm assuming you're talking about a mutation rate in terms of base pairs. If you're talking about encoding proteins and so forth, then obviously it's much lower and I apologize for pointing this out.

Even considering the age of the universe and the earth, there isnt enough time for random chance to have created life as we know it. For the slightest change to a species as a whole, it would require not one, but many individuals to have the same mutation (requiring untold generations to pass), and for them all to reproduce so much more than normal that it spreads to the entire offspring population.

Not enough time for random chance -absolutely-, but evolution is a higher order function. It occurs in subtler ways, and in parallel across every species.

Re:Humans

[holmstar]

How does their breathing tract move from their mouth, to another orifice?

It didn't! Most animals breath mostly through their noses, not their mouths. The nostrils of the proto-dolphins migrated from the tip of the nose to the top of the head, presumably because being able to breathe while keeping your head level/pointed downward has a survival benefit... easier to see enemies/food/whatever swimming through the water, probably.

Re:Gut bacteria

[jonored]

The apparatus to ferment cellulose into digestibles internally is rather large and high-maintainence. There's the multiple 'stomachs' before the main one where the bacteria breed, the cow routinely vomits up some to mechanically reprocess, and occasionally when venting becomes blocked for any reason a cow dies becuase their lungs were crushed by the expanding gasses in their stomach. termites get away with a lot because of being small. Additionally, there was that study that indicated that developments in the human intellect were associated with us starting to use cooking as an external digestion method - might not be the best thing for us in particular to add digesting some of the hardest foodstuff to use when we already diverted that energy to brainpower. And if we use cows properly we get the best of both worlds anyways - fueling ourselves off of cellulose with only the effort of keeping a few cows to eat. Of course, we don't, and use them as an inefficient step between stuff we /can/ eat and us, but that's another issue.

design!

[fermion]

There are so many bad "designs". baby butterflies dying because they can't get out of the cocoon. Reasonable from an evolutionary perspective, but what designer would want to kill baby butterflies.

Or what about pain that will never go away. What is the purpose of have a burn victim still feel pain days after the injury. Or lifelong back pain. What kind of design relishes in making organisms suffer for no apparent reason?

Then of course there is sex. From a procreation point of view, one would the process to be as simple as possible, not a few to several minutes of interaction. One could have designed us so the interaction was separate from reproduction. That way we could couple as needed, to have orgasms, but then make babies only when it was useful. The combination of the two is obvious trickery, and it says something about the design.

Re:Spartan Giraffes

[skine]

Yes, but what GP was specifying was that evolution, mutation and natural selection are not the same thing at all. It's similar to how hydrogen and oxygen atoms are essential parts of a water molecule, but it's crucial not to just lump the three together as being one in the same.