That depends on what you mean by "bad mutations" or "good mutations"

I mean, in my view a prehensile tail would be an awesome mutation, but the doctors at the birthing of your incestuous lovechild would probably violently disagree.

Anyway, your understanding of what "evolution" means is a huge failure. I just wanted you to know that. LET'S ALL HUMP OUR SISTERS, IT'S A RACE TO THE EVOLUTIONARY OMEGA POINT

By restricting the size of the breeding population, you will likely see a drastic change in the new population through rapid genetic drift and the founder's effect (rather than natural selection). The new population may exhibit traits that seem at odds with their survival. If the population doesn't grow over the generations, genes will become fixed and the genetic variance suffers. Not a good thing, as a single genetic weakness may wipe out an entire population.

That's because evolution does not favor success. For every success or helpful mutation there is literally millions of harmful mutations that occur. Evolution isn't always one step upwards towards "progress".

Watts, I think you're confusing evolution with one of the processes behind it.

Evolution is the end result of mutation and natural selection. A lot of mutations aren't benefitial, but the ones that are benefitial are passed on and eventually become widespread among a population. That is evolution.

I think it's one of those terms like 'accelerate'. Generally, when you think of acceleration, you think of something speeding up. But, by the definition of the world, slowing down is also acceleration and words like 'deceleration' are pretty much pointless.

Thus, evolution does not favor success. Nor does evolution equal "progress". Yet everybody, including yourself generally assumes this. Why?

Are you some kind of believer in eugenics? Harmful mutations are passed on just as beneficial ones are. The only way they are not passed on is if they're breeded out of somebody's heritage. Or we just isolate or exterminate people with harmful mutations so they can't pass their DNA onwards.

That's why evolution is a product of natural selection and mutation. An organism is born with a benefitial mutation, with regards to its environment, that organism is more likely to survive and breed. A number of its offspring will have this mutation as well, meanwhile, the ones without the benefitial mutation or ones with harmful mutations might breed, but probably won't encounter much net reproductive success because they're not suited for the environment.

Generally, when harmful mutations express themselves on the phenotype it is selected against, whether it's environmental or, in the case of humans, social pressures.

Harmful mutations may be passed, yes, but they generally don't express themselves in the majority of the population.

You're confusing evolution with simple genetic mutation. Yes, mutations occur, but typically they're selected against. Evolution occurs when a trait becomes dominant in a population. Harmful mutations, because they're harmful generally don't have enough reproductive viability to reach that point.

That's scientific hyperbole. There's a multitude of hereditary and genetic diseases that while aren't considered beneficial, do not impede a person from living a healthy fufilling life. Like colorblindness. That's just eugenics thinking at work. It isn't always the healthy or smart that survive. Humans are not like animals that have to adapt to their environment. Humans can fundamentally change their environment. And we have. And we will.

Meanwhile you have genetic diseases like cancer that do impede with a person's longevity, yet still most people are able to breed and pass on their DNA before the mutations causing damage to their DNA kills them.

Social pressure only exists in certain cases. Usually most parents are worried about downs syndrome. This doesn't necessarily stop them from breeding, but it's a factor in considering it. However, parents would rarely choose not to have children because their children might be colorblind.

The number of harmful mutations outweighs the beneficial mutations by far. Cancer has proliferated nicely since the 1920's when it was hardly heard of or known about. Much less as common per capita. I bet that someday in the future 1/3rd of the population will have cancer.

No, I'm not. Look at the dictionary definition that RR posted. Evolution is the process of change that results in more complexity, and only sometimes (as in rarely) results in beneficial traits. Again, you're just assuming that evolution is a step upwards.

Take a good look at a list of genetic diseases. Most of which you'll find were completely unheard of 100 years ago, 200 years ago, and so on. And not because we didn't know anything about it. But because they became more common in the general population as time passed.

From what I can tell, the same environmental factors that are somehow poisoning us with such a high amount of cancer lately might also be causing an excess of genetic mutations to us humans and also increasing genetic diseases.

I don't know any specific data on whether we are more healthy now or 100 years ago though, but from what rumors I have heard, we are coming down with more defects now. So don't take my word for it!

My parents are second cousins and I was born with mild autism.... weither the blood was the cause... I am not sure. My mother had a learning disability, but my father is a genius mathematician... so who knows.

Take a look at expected mortality rates from 100 years ago and compare them to today's and tell me that we're worse off.

Sure, we may be dying from getting fat when we're 65 instead of living until we're 75, but how many people do you know that have died of smallpox or influenza?

Think of it this way: suppose being taller gives you an edge. If two tall people marry, they get to push for tallness while having that gene-checking to get rid of some horrible mutations.

I'm pretty sure this is due to diet. I'm 70% sure I remember reading this somewhere: people used to be taller, got shorter when agriculture first started out (humans turned to it out of desperation and weren't that good at it), and now with excellent nutrition during childhood, we're catching up again.

It can result in less complexity too.

Food for thought.

It is still in current practice to marry first cousins in Iraq (I believe most other middle eastern countries do this as well).

The parents choose who their daughter marries, they look for any available cousins first (preferably first cousins) and only if there is no possible cousins available for marriage do they look outside of their family for a candidate for their daughter. The daughter has the final say whether or not to marry the possible candidate.

Quite a bit different from the way we do things here in the western world, at least on a large scale.