Originally Posted by Duo Maxwell
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.
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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.
Originally Posted by Duo Maxwell
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..
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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.
Originally Posted by Duo Maxwell
Harmful mutations may be passed, yes, but they generally don't express themselves in the majority of the population.
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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.
Originally Posted by Duo Maxwell
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.
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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.
I was speaking idiomatically.