My theory says all the genetic material for variation is built in, and because nonselected traits must be lost for the selected traits to emerge at those loci, over time there is a trend to loss of the genetic stuff that would make further evolution possible.
And your theory is refuted by observation. We see mutations producing new genetic diversity in populations all of the time. We see the evidence of these mechanisms being active in the past in the form of sequence conservation and nested hierarchies.
We don't just assume that the differences between species is due to mutations. The patterns of both differences and similarities demonstrates that they were produced by evolutionary mechanisms, including mutations.
The divergence of phenotypes is due completely to new combinations of preexisting alleles, and the divergence is limited by the necessity for loss of competing traits.
This claim is disproven by examples such as the pocket mice and peppered moths. It is also disproven by classic experiments like the Lederberg plate replica experiment and the Luria-Delbruck fluctuation experiment. All of these examples demonstrate the emergence of a new mutation which changes phenotype and increases fitness.
You can get two populations evolving in entirely different directions but only up to the point that they no longer have genetic diversity for further variation or evolution.
Then please explain what mechanism prevents mutations from accumulating. We can directly observe mutations happening in every human generation.
"Here we present, to our knowledge, the first direct comparative analysis of male and female germline mutation rates from the complete genome sequences of two parent-offspring trios. Through extensive validation, we identified 49 and 35 germline de novo mutations (DNMs) in two trio offspring, as well as 1,586 non-germline DNMs arising either somatically or in the cell lines from which the DNA was derived."
Variation in genome-wide mutation rates within and between human families | Nature Genetics
They sequenced a child's genome and the genome of that child's parents. They found that the child is born with DNA changes not found in either parent, otherwise known as mutations, around 35-50 per person per generation. What natural mechanism removes these mutations? What mechanism stops these mutations from accumulating in each and every generation? What mechanisms cause chimps to have the same mutations in their genomes?
Yes, that's the theory but it's not the reality and you have no evidence that it ever did our could happen, it's ALL theory, ALL assumption.
It is all evidence. For example, the genetic evidence:
"First, the distribution of provirus-containing loci among taxa dates the insertion. Given the size of vertebrate genomes (>1 109 bp) and the random nature of retroviral integration (22, 23), multiple integrations (and subsequent fixation) of ERV loci at precisely the same location are highly unlikely (24). Therefore, an ERV locus shared by two or more species is descended from a single integration event and is proof that the species share a common ancestor into whose germ line the original integration took place (14)."
Just a moment...
Out of the more than 200,000 retroviral insertions in the human genome, all but ~100 are found at the same exact location in the chimp genome. This is undeniable proof beyond any reasonable doubt that we share a common ancestor.
We also have transitional fossils. We have the matching phylogenies. We have all of the evidence.
Edited by Taq, : No reason given.