Re: does a species from one genus evolve into a species from another genus ... yes
Not quite - my "aliens did it" theory is an example of sublime science produced by the mind of a deadset genius.
The problem with using aliens or an intelligent designer or any of their variants to explain anything is that it establishes there's only so much we are capable of understanding, which happens to be the level of knowledge we have currently acquired and that we can't take it any further. Some explanations even suggest we have over-reached and have to rein in our knowledge. If all you are looking for is an answer then these explanations are probably sufficient, but where do we go from there?
Science also is very good at providing answers, but I would argue that is not its greatest strength. What makes science important is that it provides a means to ask more questions. This leads to more answers which allows more questions, and so our knowledge grows.
Re: Another useful application of evolutionary theory
It's also an observable fact that after thousands of years of animal and plant breeding, using even unnatural methods such as inbreeding to produce gross mutations, it never occurred to anyone that plants and animals could be breed to became something radically different to the original species
Iâ€™m not trying to get all Shelbyville Manhattan, but why do you describe inbreeding as unnatural? Yes as Taq correctly pointed out this reduces genetic variation, which means that there will be an increased probability that detrimental traits will be expressed, as well as beneficial traits. The reason this is a problem when we look at modern humans is that dying from a genetic disorder is a tragedy that could be avoided. Similarly, in terms of livestock, food plants (I donâ€™t know the technical term for that) and I suppose pets, the detrimental effects can be mitigated by how we manipulate the environment that these organisms live in. Itâ€™s also worth pointing out that inbreeding doesnâ€™t create mutations, since they happen all the time, but the environment we create allows the detrimental mutations to propagate at the same time as we try to maximise our artificially selected preferential mutations. It is for these reasons that our perception of what genetic mutations can accomplish can become skewed
But in nature for plants and animals, including us not too long ago, things are different. All things being equal, a significant majority of offspring in each generation will die from lack of resources, predation or disease. Individuals held back by their genes will die off, freeing up resources that those individuals who have an advantage through their genes can use to thrive. Sometimes this differential between advantage and disadvantage can occur within a single brood. This means advantageous mutations can propagate through a population more quickly, while disadvantageous mutations can be removed without lingering, like in the artificial environments we create.