Answering Questions About...

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Human Evolution

Monkeyman wrote:

Why did humans evolv the way we did? Waking on two legs causes a lot of problems, eg, lower back pain, and tougher pregnancies for one, so why did we evolve to two legs? I doubt that's an answerable question though? deal with it.

As Jardel said, it was a successful random mutation. All mutations that occur in nature occur at random, but pressure from the environment tends to select those that are best fit for a particular environment/niche. In the case of bipeds, the mutation that gave them the ability to stand on two legs was a successful one because it freed two of its limbs to do other stuff besides walk. Previously, one walked with four limbs; doing stuff like procuring food and meat, and eating, etc mainly involved the mouth only (think of lions and dogs and paws; cows and horses and hoofs). And when your upper limbs are freed from the task of walking, dexterity skills are developed; one begins creating things. (and yes, in case you're asking, apes have been found to 'invent' primitive tools that aided them in their everyday lives) In an environment where dexterity in manipulating objects, such organisms would flourish.

For example, the Utahraptor (mistakenly called the Velociraptor in Jurassic Park) was a predator whose sharp-clawed forearms were used to kill prey - as opposed to its earlier cousins, who used claws in the foot - had large braincases and were in all probability highly intelligent, and were most likely the most successful killers of their day. (Unfortunately the KT extinction killed them off) And apes and monkeys are certainly more developed socially and intellectually than most of the other land animals (we'll talk about ants another time). The elephant probably never evolved to become biped because of the impracticality involved, but they *do* have a highly versatile limb - the trunk. Sea creatures today have mostly either 'replaced' their original limbs with vestigial ones or those suited to moving through the water because having normal limbs was simply impractical - and not genetically successful - in water.

All these creatures are suited to their environment through natural selection. And as for your question, why develop two legs.... I'm sure that had we been brought up in gravity-free space, that over time our greatgreatgreatetcgrandchildren would evolve to have four arms/hands (or at least four highly dextrous limbs) instead of two arms and two legs.

Black Holes

Evil wrote:

I also read that the way we are able to detect a black hole is by x rays. So, I would assume that since nothing can escape the event horizon, how are we able to detect them? Is it by their great density or perhaps we can tell by a star or gases being sucked into the hole?

Re: detection of black holes - well, because black holes are immense, collapsed stars of incredible mass, they have very intense gravitational fields. Of course, you can't *see* gravitational fields, but you can observe and measure its effects upon neighbouring objects, like for example if there astronomical bodies orbiting a massive but unseen object, or if there were a visible companion star whose mass is mysteriously being sucked by something invisible. Because of intense gravitation, the mass that's being sucked heats up to very high temperatures, and emits X-ray and other electromagnetic radiation which may be observed (and therefore the temperature can be measured). Because normal stars don't normally give off radiation in such great amounts, such findings usually indicate the presence of a black hole.

An aside, as Stephen Hawking put it, black holes ain't so black . According to Hawking's calculations, not *everything* goes into a black hole, that a black hole actually *radiates* (this is called the Hawking Radiation); the energy that black holes get to radiate comes from their rest mass energy. A black hole that does not accumulate mass from outside will gradually lose mass and 'evaporate'.

And in case you're asking what Hawking Radiation is all about, the theory states that virtual particle-antiparticle pairs are sometimes created outside the event horizon of a black hole (the point of no return, to borrow cliches). If one member of this particle pair is sucked into the black hole and the other does not, the 'escaped' particle therefore must become real, and therefore becomes observable. I think there's still a great deal of debate on this whole theory, though.

(I hope I'm not oversimplifying things. If I am - sorry! And Jardel, I'm so sorry for butting in)

IQ Tests

Monkeyman wrote:

so tell me about IQ ratings. As in what is considered "average" what is considered "lower" then average and what is considered "higher" than average.

Also, is thee a PROPER IQ test on the net anywhere. And also, what the frig is MENSA?

An intelligence quotient is a statistically derived number that tells you about how well you score in an intelligent test relative to others in your age group. It is usually standardised to an STD (standard deviation, NOT that other thing) of 15 so that the distribution is in a bell curve, with 100 as the mean (average) score. By mathematical calculations, about 68% of the population will score between 85 and 115; about 95% will score between 70 and 130. (different sources give slightly different numbers and percentages)

So for example, if you were to score 100, it would mean that half of the population did better than you did, and the other half did worse.

To interpret the scores:

1. If your score is no more than one STD (15) away from the mean (100), it means that your IQ is average;
2. If your IQ is between one and two STDs (up to 30) away from the mean, it means that your IQ is either low (less than 85) or high (more than 115);
3. If your IQ is more than two STDs away from the mean, it means that you're either mentally challenged (less than 70) or very smart (more than 130).

The thing with IQ tests, though, is that many IQ tests are designed to suit a certain group of people (eg. English-speaking; Americans, education level etc) - that is to say, some of these tests deal with things that certain people in certain walks of life would have an advantage over others - hence it's not practical to compare the intelligence of two different people if they have drastically different backgrounds. (I did all of Hans Eysenck's tests back when I was in school, and among other things, they tested a person's ability to unscramble words - in this case, the names of trees in temperate countries. It's just as well I knew all of the names - otherwise I'd probably have scored something like 20 lower!!!)

You can find plenty of tests on the internet - just type 'IQ'. I think emode.com has a couple of decent ones. It would be a good idea to do the MENSA one as well, though.