Science!! Fucking magnets, how do they work?

The Ancient_sl said:

Jive Turkey are you arguing that evolution is no longer ocurring in humans due to the absence of natural selection?

Click to expand...

hodj_sl said:

As for sexual selection in regards to this issue, we could hypothesize several explanations, such as people are unconsciously selecting for larger brain capacity or there is a sexual selection advantage in terms of attractiveness of facial features in individuals who lack wisdom teeth versus those that don't, etc.

But really, its just more about the fact that, as our nutrition increased, our craniums and other anatomically relevant system altered to compensate. That linear trajectory continues today, the alleles which guide development of cranial features are already present in the population, and already pretty well dominate in it, so they're just getting shuffled and reshuffled around and the progression continues. Mutations which go in the other direction are selected against in part because they are now anomalous and the extremely large population drowns out their impact and drives them further towards extinction, so forth.

Click to expand...

Jive Turkey_sl said:

He still needs to explain how it impedes modern reproductive success. It doesn't.

Click to expand...

The Ancient_sl said:

Okay, but his earlier statement was that wisdom teeth could be tied to selective pressures that are.

Although now I'm wondering about the whole thing. In my experience it's the dumber people having more kids, so where is this pressure for increased cranial cavity?

Although that right there might be a grim explanation for the brain shrinkage point on the list.

Click to expand...

There are several different conclusions as to why this is: One group of researchers suspects our shrinking brains mean we are in fact getting dumber. Historically, brain size decreased as societies became larger and more complex, suggesting that the safety net of modern society negated the correlation between intelligence and survival. But another, more encouraging theory says our brains are shrinking not because we're getting dumber, but because smaller brains are more efficient. This theory suggests that, as they shrink, our brains are being rewired to work faster but take up less room. There's also a theory that smaller brains are an evolutionary advantage because they make us less aggressive beings, allowing us to work together to solve problems, rather than tear each other to shreds.

Click to expand...

Jive Turkey_sl said:

I'm not arguing for survival of the fittest! The opposite!

Click to expand...

Jive Turkey_sl said:

It's a flimsy argument and he has since stated that pretty much everyone reproduces at the same rate

Click to expand...

Jive Turkey_sl said:

I'm saying the populations will remain relatively stable because there is no survival of the fittest or selective pressure against wisdom teeth anymore.NO SELECTIVE PRESSURE.

Click to expand...

In the past it impacted reproductive viability, but not anymore.

Click to expand...

The way some people on this board are unable to follow an arguement blows my fucking mind sometimes

Click to expand...

Then you need to explain why people without them have greater reproductive success, or better yet, cite something showing that they do

Click to expand...

There was a time when our jaws could comfortably accommodate all 32 teeth, including the third molars. You have to go back about 100 million years ago, though, to the prehistoric version of man. Instead of walking upright, this guy got around on all four limbs, with a massive protruding jaw leading the way.

Early man's jaws were larger and more prominent because teeth played a vital role in survival. With the front appendages occupied with balance and running, teeth were prehistoric man's means of catching, dismembering and consuming prey. Our ancestors subsisted on a tough and chewy diet of leaves, roots and raw meat. Having 32 teeth's worth of chewing ability was a huge advantage at this point, especially because early man didn't visit the dentist with the regularity we do today; third molars might have played an important backup role when teeth were lost or worn down.

Then evolution had its way with prehistoric man, and teeth weren't so important anymore. Hominids began walking upright, and arms took on a greater role in obtaining food. After that, brains became larger and jaws became shorter. Researchers still aren't exactly certain which came first, though in 2004, a team from the University of Pennsylvania announced they had discovered a gene called MYH16. Mutations in this gene lead to shorter jaws, which may have been the factor which allowed early man's brain to grow [source: Wilford]. However it happened, the change lessened the amount of space available to teeth in the mouth.

As our heads and jaws were changing, some cultural shifts were taking place as well. Around the same time, man was creating the first tools, including cooking utensils (designed, of course, by primitive prototypes of Food Network hosts). With bigger brains, man got wise to fire and its ability to soften food. Overall, man's diet became much more processed; compared to the roots and raw meat our ancestors ate, we might as well be eating strained applesauce. In fact, we wouldn't necessarily need any teeth at all to survive today, though dining out would be a dull affair. As it is, though, we definitely decreased our reliance upon the third molar.

Opponents of evolution place greater weight on the dietary shift and dental hygiene in lessening our reliance on wisdom teeth, discounting the role of our evolving jaws and brains. But when you line up a prehistoric jaw and a modern jaw, the space is clearly smaller. Can evolution explain the shift? And if our evolutionary history has lessened the need for wisdom teeth and created conditions inhospitable to third molars, will we ever lose them completely?

For many of us, it may seem like our wisdom teeth didn't get the memo that our evolved jaws are lacking space. But some people never develop wisdom teeth; in fact, these teeth don't appear in about 35 percent of the population [source: Spinney]. Are we on an evolutionary track to losing them altogether?

Some experts say it's possible these teeth will eventually disappear [sources: Flam, Usbourne]. Still, there are a few unknowns in the equation. Scientists aren't sure of the role that DNA plays in creating teeth at the third molar position [source: Colf]. Third molars develop entirely after birth, the only teeth to do so. Because these teeth aren't present at birth, it may be harder for nature to select against them [source: LePage].For wisdom teeth to form, the tissue that starts the process of tooth building has to migrate back in the mouth to interact with the back jaw tissue. If this migration doesn't happen, then no tooth will grow there.

There may also be some environmental factors at work, including disease or head trauma, that stop the tissue migration [source: Silvestri, Singh]. It could also come down to differences in how various cultures use their jaws. For example, in the 1970s, researchers tied the larger jaw that was present in Eskimo women to their tradition of chewing leather to soften it. In parts of East Asia, it's more common to find people with fewer wisdom teeth, if any [source: Vines]. If people of a culture have reached the point where they don't use a trait, they may lose it.

But some scientists are beginning work on stopping the teeth from appearing altogether, so that we might bioengineer these teeth out of existence before evolution does it for us. Because there's a window of time in which there's no third molar, it might be possible to administer a laser or a chemical agent that would prevent the tooth growth. Preliminary studies have shown some success in dogs and rats [source: Silvestri, Singh].

Currently, the lack of wisdom teeth doesn't produce any great evolutionary advantage, particularly with the abundance of oral surgeons who can remove the wisdom teeth that do emerge. That makes it hard to say exactly how the trait might adapt in the future. Certainly, oral surgeons probably have their fingers crossed that these teeth continue to appear for a good long while. The rest of us will have to make do with lots of ice cream and the continuous exchange of surgery stories. Sure, those wisdom tooth lackers may claim they're more highly evolved because they don't have to go through a few days of misery, but what do they talk about at boring parties?

Click to expand...

For wisdom teeth to form, the tissue that starts the process of tooth building has to migrate back in the mouth to interact with the back jaw tissue. If this migration doesn't happen, then no tooth will grow there.

Click to expand...

Abefroman_sl said:

Click to expand...