The man made fruit fly experiments are quite precisely the opposite of natural selection, which is what I'm looking for.
As for the birds, there was never observed a time when that genetic anomaly was not present, so no evolution has been observed. Regardless, it isn't the case that the species has bifurcated itself into two subspecies, rather there are 4 genders in the single species and each gender only mates with a particular partner gender.
How is this different from speciation? Easy: any organism can produce offspring of any gender, but they will all be the same species.
Evolution is a theory that is parsimonious to the data at hand. We proved speciation in a lab. As you and I are part of nature, their speciation is natural even if at our will. We isolated a species long enough that they could no longer mate, subjected to separation of environments. Ergo, separation of populations leads to speciation. QED.
But if you decide that only random events cause the effect you're looking for, first restate your hypothesis as such then do your homework on a very well studied field.
Why a restated hypothesis? Because it is intellectually honest to say your first hypothesis is completely answered by the fruit fly experimentation. There is no clear distinction between speciation from random events causing separation and researchers doing so in a laboratory.
Sure, I believe there is no evidence to support the hypothesis: "the species we encounter derived exclusively from random genetic mutations competing via natural selection", or even the weaker form: "random genetic mutations have been responsible for the development of new functionality in Life".
I used to buy into the Evolutionary Theory, or at the very least believe there was actual observational Science behind it commensurate to the scale of the claims atheists make. Hell, I even studied biology at a top university. I suspect you may be less familiar with the opposing view, I recommend the "Creation vs Evolution" lecture here: https://www.thenarrowpath.com/topical_lectures.php#Creation_... . While the site as a whole is rooted in Christian fundamentalism, the lecture itself makes no arguments based on Scripture or Faith.
Now, I believe in the parts of evolution we have observed. Which, in CS terms is something along the lines of: "the backing data-vectors of life forms are subject to stochastic gradient decent mechanics which can result in population-level changes tending towards local maxima in fitness, via a process we call `Evolution`". That said, I have seen no evidence to support the claim that those data-vectors were initialized randomly, or that Evolution is capable of optimizing past these local-maximas.
> Has science ever observed speciation via natural selection amongst a sexually reproducing cohort?
Theories of speciation do seem to lean toward asexuality.
I mean, at an extreme, we can consider asexual-reproduction through cloning -- where genetic-mutations simply get cloned along different lines, allowing for increasingly divergent genetics.
But even when we're talking about sexual-reproduction, [theories](https://en.wikipedia.org/wiki/Speciation#Modes ) often focus on [bottlenecks](https://en.wikipedia.org/wiki/Population_bottleneck ) (e.g., an isolated population on an island) -- which, while nominally "sexual" in the sense of individuals still engaging in sexual-reproduction, is asexual in the sense of the isolated-population disengaging from sexual-reproduction with other populations.
Where, generally, greater population-level asexuality might be expected to lead to greater divergence -- with full-blown individual-level asexuality being an asymptotic-limit.
I'll grant that this example is more compelling than any others provided. The fact that they needed to redefine "species" to find the first example of speciation in the wild is certainly a weak point.
What's interesting with this example is that the changes come from hybridization, not the typically stated evolution mechanism of "tiny random little changes that somehow overtime make brains". Accordingly, this provides no "origin of life" answers, as the life was only able to develop from hybridizing existing life.
Fossil record demonstrates evolution at most. Even then there are plenty of large gaps.
Fossils don’t tell us about speciation, as that’s a concern of reproductive capabilities not physical features. They certainly don’t tell us anything about the selection process being “natural”. (aliens from Tralfamadore coming over in hovercraft to explicitly select for the features they want would leave the same fossil record)
> Has science ever observed speciation via natural selection amongst a sexually reproducing cohort?
posits a world where we can iteratively ask-and-answer questions if scientists are paying attention to speciation. The fossil record provides many many snapshots of different beings, from which we can infer speciation. By seeing the split _as it happens_, we can test hypotheses.
It seems to imply a dichotomy in value between seeing "as it happens" and the fossil record.
Some of the most definitive proof of speciation is the actual fossil record, while simulations or purpose constructed experiments typically achieve the desired results of their authors.
Has science ever observed speciation via natural selection amongst a sexually reproducing cohort?