10 Worst Evolutionary Designs 232
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."
Spartan Giraffes (Score:5, Interesting)
Seriously though, evolution does not provide traits that are advantageous, it simply removes those that are disadvantageous, relative to other traits. That is a subtle but important difference. Eating your brothers and sisters in-utero sounds pretty gross, but unless it hurts the reproductive rate of those who carry that gene, there is no reason to weed it out.
It's fun, but don't draw conclusions from it. (Score:5, Interesting)
Oh isn't this a great parlour game! Did you know that the retina is backwards, which is why we have a blind spot? How horrible, how inefficient!
These types of things are all very fun to discuss. But please oh PLEASE do not draw any inferences from them. They don't mean ANYTHING, from a philosophical or theological perspective.
(Example) The vagus nerve in giraffe's neck is as long and ungainly as it is because of the way it develops in the fetus. To make it more efficient in the adult would require a change in the course of fetal development. And depending on how you change the course of fetal development, other things need to change, too. This is a very large and complex system of interconnected dependencies. To look at one isolated phenotypic feature and say, "Hey, I could have designed that better!" bespeaks of a total lack of knowledge about what all is involved in development.
I will say for the record that I believe in evolution, not intelligent design. But whenever I heard people "on my side" using examples like this as "evidence" for NOT intelligent design it frustrates me. You have absolutely no idea the entire bredth of changes -- on every level, from genetics to protein synthesis to overall development -- that would be required to make whatever "inefficient design" work better. It isn't as simple as looking at the adult and saying "this nerve should go here, instead!"
So, that's my little rant. Examples like these are fun. They're entertaining. They're cute.
They are "evidence" of absolutely nothing.
Re:Humans (Score:2, Interesting)
4) As my wife says, playground close to a sewage works
That's usually the voters at work actually. Parks require large plots of land and are very expensive most places besides flood planes and near sewage treatment plants where property values are very low. And so that's where you find 95% of parks because no one would vote for a park if the price went up tenfold by a change of venue.
Re:Spartan Giraffes (Score:3, Interesting)
I think perhaps we all have a difference of symantics between "evolution", "mutation", and "natural selection".
natural selection will select those most fit for survival within a species, thereby weeding out those with undesirable traits in relation to the rest.
mutation provides the grist of the natural selection mill, giving it new material to select from.
Evolution is the overall process of species adapting genetically and eventually forming new and more numerous species.
Thats how I view it, but IANAEB.
Re:Spartan Giraffes (Score:5, Interesting)
"...evolution does not provide traits that are advantageous, ..."
Yes it does.
Possibly more correct to say that evolution continuously offers random features which may or may not be advantageous, and the features which are detrimental to its survival tend to be removed from the gene pool.
OP is correct in saying that evolution in itself doesn't provide anything specifically helpful. It does encourage traits that happen to be beneficial though. Evolution is not the process of trying improvements, that's what heterosexual reproduction is for. The purpose of evolution is to improve on the survival of the accidentally better designs.
There are an insane number of good examples, but I'll toss out a good one now. Sickle Cell Anemia. Sucks if you have it, has a variety of nasty side effects and no visible benefit. Except if you live in say, Nicaragua, and are exposed to malaria-bearing mosquitoes all the time. Something about the cell shape defies the virus, SCA sufferers are immune to malaria. So the SCA expression there is very very high because although it grants a disadvantage, it also grants an advantage. Interesting thing about SCA is you only need one gene to have immunity, and require both to get the nasty side effects. But it's advantageous enough to be kept.
On the other hand, there is pure genius. (Score:3, Interesting)
For those that want to look at nature, there's plenty of male chauvinism to go around for bitter old men to look at. One example of pure chauvinistic genius is one animal, and I think its the giraffe, whose schlong goes and mashes up whatever giraffe baby might already be in there, just to make sure that he knocks up the lady giraffe with his own seed. Then, there's the lion, who, after killing off a rival, causes the lady to spontaneously miscarry, and she then mates with him to carry his seed.
Re:Old (Score:5, Interesting)
Re:Humans (Score:3, Interesting)
As long as we're both being speculative, here's a shot (and I guarantee my shot in the dark here is wrong, but it's an attempt). Perhaps elephant ancestors have a gene that regulates expression of a protein that controls cartilage. Due to a random mutation, an extra promotor for this protein uncovered from 'junk DNA', and this ancestor expresses the gene in far greater quantities. As a result, a species of pig-sized elephant ancestors develops large noses and ears. Complete with more area to develop on, more olfactory nerve clusters are in the nose, and the ears provide a greater area to gather sound. The mammalian brain, being a malleable enough organ to learn new patterns, identifies the extra sensitivity to sound and smell and can detect more predators easily. Over time, subsequent species find that directing their noses with a finer degree of muscle control (the protein to promote growth of muscle attaching to cartilage has been exapted from the muscles controlling the ears for better directional hearing) allows them to more accurately sniff out delicious tubers, which they dig using their newly evolving tusks. Suddenly, during a drought, proto-elephants (or whatever you want to call them) are able to retain enough water by digging for roots, whereas their less fortunate relatives die off. This new behaviour and trunk-like appendage becomes increasingly useful, acquiring more and more encoding genes and proteins causing a sort of runaway evolution.
Re:Humans (Score:4, Interesting)
Your examples are only confounding because
Just because you can't think of a reproductive advantage, doesn't mean there isn't / wasn't one. The details of the selective pressures that drove most evolutionary changes are lost to unrecorded history.
You assume that snouts can only evolve 0.2cm in a single generation but, perhaps they can, with the right mutation, lengthen 20cm within one generation.
You assume that blow holes moved fractions of centimeters per eon from some other uncertain location, but perhaps they simply erupted from the back of the existing breathing apparatus in one evolutionary jump.
To be sure, the evolutionary evidence for most dramatic body plan changes seems to support the slow and incremental, but there is evidence that evolution can take dramatic steps in shorter periods of time.
Just because an idea makes you feel uncomfortable, doesn't mean you should reject it. Most great steps in human thought were initially rejected as untenable because they challenged the existing belief systems.
Re:Humans (Score:4, Interesting)
You're thinking from an engineer's point of view, but evolution simply does not work like that. Evolution is, at its core, the concept of differential reproduction. Very few traits are absolutely beneficial, and even if they were, the environment can change quickly. In fact optimization can be downright bad for a species. Species that are too tightly bound to specific environments can be thrown into serious trouble when environmental change happens.
If environments were static, maybe you could reach a permanent equilibrium, but environments are not. There are constant pressures on populations, and that makes optimization pretty much impossible.
Evolution is really a statistical science. An trait's survival isn't so much a yes-no, but more a trend. Think of human birth. Yes, it's true, we're born far more prematurely than most mammals, and even at that, passage through the birth canal can lead to death in both the infant and mother. But the survival advantages of having a large brain are so great that the trade-off of higher infant and mother mortality rates is more than offset. You also have to consider that traits don't exist in isolation. Yes, it would be better if the birth canal were widened so that passage of the infant were easier, or maybe even allowing a longer gestation period to permit the birth of more mature offspring, but now you would start intruding on pelvic size, and that means severe disabilities as far as mobility. Since bipedalism also confers substantial benefits on our species, it means there is a physical limit on how large the pelvic area can get before females would no longer be effectively upright. Thus you have two competing traits, and what you ultimately get is the trade-off, that women can still walk, although the center of gravity is different, a sacrifice to some degree of mobility and strength.
Re:Humans (Score:3, Interesting)
He isnt saying poor design. He is saying there are a whole lot of traits that would have had/have zero reproductive advantage, yet are clearly evident in modern animals.
The problem here the whole notion of "reproductive advantage" which gets evolution arse-end round. Rather we should be looking for reproductive disadvantages. The real question is "will this change increase the chances of the animal dying before it has had a change to reproduce."
My example is the elephant. The first animals (presumably like a pig) had a short nose. Some random member of the species gets born with a slightly longer nose. Not much mind you, because they cant have very much variation in only one generation, so this nose is barely noticeable to be longer, yet it has so much reproductive advantage that generations later the short snout has evolved to a long trunk? It doesnt make sense.
A great example. Will the long nose kill the animal before it has a chance to mate? No. Make sense now?