not sure about random myself, i think evolution is all about being able to survive a new threat, the survivors pass this skill or characteristic on to the next generation, there was a program a few years ago on tv explaining how evolution can happen in a few years, a few decades ago white butterflies in London where becoming extinct, they realised this was because the air in London had become darker due to all the fumes being pumped into the air, the white butterflies stood out in the dark air and where easy for prey to see, so in a short space of time they where becoming extinct and only dark butterflies where surviving in London, the black butterflies had a defence against a new threat, this was given as a simple example of how evolution can happen very quickly for simple reasons
This is actually an excellent example of the con-trick pulled by DNA. Organisms breed to pass on their genes, but in reality these genes are thoroughly diluted after a few generations. It is only unintended mutations of some kind in conjunction with environmental change that make a big difference in evolution.
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