The trouble or problem with “evolution” is that it had no master plan.
It was a method whereby “life” solved problems on a trial and error basis; life encountered a problem and began to try to resolve it using small steps and trial and error.
Because this didn’t involve a Master Plan, it took a long time at every step, and many side-roads had to be explored before a final solution could be settled on and put into action. Those “side roads” sometimes can be seen as strange life forms, things like odd animals and insects that appeared with specialised powers that more often than not are not needed for survival. Those attributes may have been considered possible survival mechanism when the original problem arose, but became redundant when a different solution came into being, and showed itself to be far superior to help the life form survive. But you can take this one step back and assume that All Life, itself, originated from the evolutionary process, meaning there was no Creator and therefore no Master Plan, and that Life’s evolution also took a long time and often explored avenues of Trial and Error to see which way to proceed to further survival.
That’s the key to Evolution. Survival.
And if you believe in it, it can explain how the Immune system came into existence, or how Nerves and Muscles appeared. Or even how the brain and Higher Consciousness came into Being.
But the problem with Trial and Error is that it only attacks small steps of a larger problem. If there were a Master Plan, then every issue would be solved with a Long Term View type of solution, but in real life, those issues were resolved a small step at a time. Meaning that once the issue had been just about completely resolved, ages had passed and the organism didn’t see any reason to develop along that path any more.
Take Modern Medicine as an example of a Trial and Error solving process.
Quite often it attempts to fix a problem which in the short term, endangers the Life Form, and it often does so, without insight. It just tackles the specific problem with everything it can muster, and with Drugs used in this manner, there are often Side Effects that are just as bad as the problem being treated. The original problem may get resolved, or toned down enough to no longer be a threat to actual survival, but the treatment itself may have endangered the life form, through what are these days called “side effects.”
Side effects from Drugs, particularly those used to treat Mental Illness and Cancer, as well as Side Effects from surgeries which attempt to resolve problems by the physical re-arrangement of the physical organism. With this I mean anything from Cancer surgeries, through to Organ Transplants. Such treatments may be effective in the very short term, but often in the longer term are a clear and present danger to Survival.
Plus, when you begin to add “capitalism” into the equation, you come up with some really crazy solutions. Not that there was ever any “system” that didn’t have profit and exploitation as its backbone! But Capitalism in its refined forms of this and the last century, quite literally put profit over survival itself. That’s why some types of experimental drugs were shelved while others were given lots of research money and promoted heavily. “Traditional” medicines, such as the Mushrooms and naturally occurring LSD and Marijuana plants were discarded for being (1) natural (2) not profitable enough to be researched further.
You’d think the same would have happened to alcohol and tobacco, but just look at the profit potential of each drug, and you’ll see why society used them so heavily and in many places still does. To that “mind” any addictive drug is better than no drug etc.
So where do we go from here?
As this is a result of evolution, there’s no turning back and there’s literally no going forward. Evolution only supplies a “path” when an anti-survival problem is encountered and once it is 90% defeated, evolution stops exploring its trial and error solutions and applies all its energy to adapting the “new” solution, which can take many many years without synthetic interventions..
Again, that’s more or less the position taken with Drug side-effects, in particular those used to “treat” mental illness. (Which you should try to understand was “created and defined” through Trial and Error also.)