It is the assumption that it is natural selection that preserves traits that favor survival and reproduction that are more prone to persist that is the issue.
-_- tell me, in what universe do the individuals in a population better at surviving in a desert die more frequently and reproduce less than organisms less suited to that environment when the whole population lives in a desert? True, the reproduction aspect matters more, hence why traits which benefit reproduction at the cost of reducing survival chances persist, but the pattern remains nevertheless. In order for this "assumption" to be wrong, organisms which have a harder time surviving and reproducing should have their traits persist equally well or better than organisms that reproduce and survive easily. You might be able to find individual examples of that happening, but you'll never see that as a general trend in nature.
There is no evidence for this apart from the assumption that natural selection being an all powerful creative mechanism based on some simple examples.
It's far from all powerful; for example, as long as a trait doesn't outright prevent survival/reproduction, it has the capacity to persist even if it is detrimental. Especially if the detrimental effect begins after the organism has already reproduced (an example of this in humans is Huntington's disease).
Furthermore, natural selection can only act on traits that appear within a population, it cannot force mutations to go in a specific direction. As a result, what usually persists amounts to "good enough", not ideal traits for survival. This is why the majority of species have gone extinct.
In reality there are limintations.
-_- many creationists have suggested as much, but no actual limitations on how much mutations can change a genome have ever been presented. The closest you can get to that is knowing that specific mutations on specific genes will result in death or infertility if they occur by themselves in a specific species.
The idea that a blind and random process can reproduce consistently the same outcomes right down to the genetic level regardles of the relationship between creatures or their environmental circumstances calls for massive coincidence and odds.
-_- I've mentioned before that it isn't random. Even mutations, the most random aspect of evolution, are not truly random, because certain segments of DNA are far more prone to mutation than others, and true randomness demands that all possibilities be equally probable. For example, one of the most mutation prone segments of DNA in humans is a region related to brain development, while the HOX genes almost never mutate by comparison.
What mutations do not do, however, is ensure a population will end up with genes that will benefit survival well enough to prevent eventual extinction. Which is why most species have ended up going extinct.
It is better explained by mechanisms that are designed to produce certain forms over and over again and are self organising and predictable through processes like development and self directed change.
Such a mechanism would not explain genetic defects and extinction outside of human interference very well. Plus, the "repeating forms" can very easily be explained by the fact that despite environmental changes over time, many traits which are beneficial for specific niches remain as such (for example, body shapes that reduce drag in water in aquatic organisms). If there was really such a framework as you imply, then why aren't identical genes the result of these reappearing traits? Why are the genes that shape a dolphin so dissimilar to the ones that shape a shark despite the immense similarities in their bodily shapes and the environment in which they live?
There are certain genes which program for certain features that are the same for all living things such as eyes.
This isn't true. All vertebrates have great similarity in terms of the eye relevant genes, but this is not the case with invertebrates. Certain traits are so beneficial for survival that they will appear multiple times in a very similar fashion despite having entirely different genes contribute to them. Last I checked, it was estimated that eyes evolved independently more than 1000 times.
The variation is just a matter of those genes being switched on or off. This genetic info was already there to produce these features.
-_- by that logic, all humans have genes for all eye colors, and which one you end up with is a matter of chance and environment. This is not the case. Gene activation and inactivation is not sufficient to explain variety in phenotype in populations completely. Furthermore, we have sequenced the genomes of large populations of our own species and thus know for a fact that many of the variations within our species are a matter of genetic differences, not differences in genetic expression.
Consider identical twins, including ones that were separated at birth. Exactly how different do those people end up being, even if they end up in entirely different environments? Usually not very different at all. All differences between such twins would have to be the result of environmental influence and differences in genetic expression, yet, how they develop is mostly the same no matter what, generally amounting to making them just different enough that you could tell them apart and little more.
