Halting evolution insofar as "organisms that possess heritable traits that enable them to better adapt to their environment compared with other members of their species will be more likely to survive, reproduce, and pass more of their genes on to the next generation." no longer applies where "organisms" = humans in developed countries. You can now be less fit for your environment and still survive just as well as someone who is more fit. You can reproduce the same as or more than someone who is more fit, and pass on more of your less-fit genes. Your random mutations don't matter much since we've solved survival pretty well for the vast majority of people. One finger being half an inch longer won't help you much in modern society.
This is just wrong. Do bears not make homes in caves? Do monkeys not use tools? Parasites co-evolve with who ever they're leeching from. Plants, insects, and bacteria are still evolving in greenhouses and petri dishes. Natural selection is determined in many ways, you can go read about it (most definitely not just with "random mutations"). None of those reasons exclude humans on earth just because we live in concrete walls. A lot of animals and whole species are "less fit" by your definition and still pass on their genes just fine. Or are "fit" by your definition and don't.
Once again, I have no idea what you mean by halting, or "less fit" or anything else in your rambling comment. The fact that you focus on the traits you think matter, makes the comment even more idiotic. People who have no fucking clue what evolution is, should not be a part of this conversation and should be ridiculed and ignored.
Evolution is not survival of the fittest, it's natural selection. It is working on earth, on humans, and will continue to work with or without genetic engineering. Like I said, the decrease in natural genetic diversity from unchecked genetic engineering will hurt every species on earth. What we've done to cultivated plants in reducing biodiversity, should be more than enough evidence of what will happen with genetically engineered humans if we ever get there.
