[apinstein]

The outcome of a mutation on the biology isn’t binary.

Some mutations are so bad that they are fatal to the organism (don’t compile). Where a gene isn’t that important, the mutation will just confer a fitness change.

this is mediated through a variety of mechanisms. Some mutations just alter the performance of a protein, or the expression dynamics (when, for how long, and how much) of the gene expressed as protein. Many proteins don’t act directly on things but are part of complexes of proteins that perform a function, or are receptors that trigger other things, and thus many genes are “meta” in this way.

Imagine a complex sequence if gene expression during vertebrate development. At one point during elongation, a series of enzymes alter how this process starts and stops. Small variations in the performance and availability of the genes involved in this will nudge the outcome of elongation to result in a longer (or shorter) necked animal. If that is helpful for that individual, the gene will survive and flourish.

This gets more complex as in animals w sexual selection we have multiple versions (alleles) of each gene. There is also a huge realm of epigenetics and modulation (methylation, promoters, antisense, etc).

It’s really stunningly beautiful and amazing.

[titzer]

Also, many mutations are completely benign and don't influence anything right now. They confer genetic diversity to a population. Later, if a selective pressure appears via a rapid change in the environment, such as the introduction of a disease, a new predator, or climate change, what was a benign mutation might suddenly confer a survival advantage, and will begin being selected for.

This is why genetic diversity is important. Populations aren't just more copies of a single genome. They are in fact reservoirs of genetic diversity which makes ecosystems more resilient to change. This partly explains why there are so many species of insects. As the recyclers at the bottom of the foodchain, they are the boots on the ground that do the heavy lifting and are subjected to the first shocks. They evolve into many species not only to specialize, but to guard against rapid changes at the bottom of a food web.

[codedokode]

Cannot evolution theory be validated by calculations?

We know the size of genome of an animal, we can estimate the maximum possible number of mutations throughout history. And then calculate if it is possible to create such genome with this number of mutations or not.

For example, if a mutation happens once per K animals, if one successful mutation happens once per L mutations, and there have lived M animals then maximum number of successful mutations is M / K / L. We can compare this number to size of a genome and verify whether it could be created as a result of an evolution.