Think about what you said...."a gene gets
copied with
an error".[.quote]
Yep. Most of them don't do much of anything. You and I have dozens that weren't present in either parent. Some are harmful, and tend to be removed from the gene pool. And a few are useful, and tend to be preserved and to spread through the population.
That alone confirms the theory.
unless you can offer how DNA gets copied in error.
Same way that organic syntheses produce some unwanted isomers. It's a matter of probabilities. How much do you know about kinetic theory of chemical reactions?
No. Amoebae are too evolved to become animals.
No. Monkeys are too evolved in their own direction to become hominids. These are some of the weird misconceptions that we see among creationists. When they think they hate evolution, it's mostly their own imaginations that scare them.
It's really more of a problem of not knowing things. As Everette Dirkson remarked, "people are usually down on things they aren't up on."
I wonder how with all that sickness we even exist as a higher form based on evolution.
Evolution isn't about "higher" and "lower." Another misconception.
Sickness (error)is a precursor to extinction in any environment.
Turns out, that's demonstrably wrong. As you see, error can even prevent sickness, such as the Milano mutation discussed above. When there are very few mutations in a population genome, the population is in danger of extinction. Cheetahs have so few mutations that you can usually do viable tissue grafts between them. And they are almost certainly on the way to extinction.
Though being able to receive an organ donation from any individual in your species might sound appealing, being so excessively inbred can lead to an increase in the expression of deleterious recessive alleles. This can lead to a decrease in fitness in the entire population, a phenomenon known as inbreeding depression. A potential example of this inbreeding depression is that cheetahs have little success with reproducing, likely due to the fact that cheetahs have a high proportion of malformed sperm. The scientists responsible for the new research suggested that this is related to the accumulation of excessive deleterious mutations in genes tied to reproduction. Being inbred also means that the lineage is less likely to evolve in response to new environmental conditions or pathogens. For natural selection to work, it requires genetic variation to act on. So if variation is absent, the species simply cannot adapt. It may only take a novel virus or a changed climate to wipe out the cheetah for good.
https://evolution.berkeley.edu/evolibrary/news/160201_cheetahs