Evolution is Happening all the time
We are what we eat. Evolution is one of those things where the implications are not really realised, as it is a continually ongoing process. Humans up until recently had an omnivorous diet, so we can eat most things within reason. More specialised animals eat particular things, some backing themselves into a dead and end extinction, but most eating what there is a lot of and that food altering them in a way to accommodate eating those things.
When you try and force ‘out of type’ nutrition on an animal it usually has a lot of problems associated with it. Take bulking up cattle with animal proteins. All well and good, the animal puts on more weight and value, but there is always the problem of unsuitable additions. One of those things is bovine spongiform encephalitis or BSE.
Scrapie has been long known since the 1700’s, affecting sheep, and linked to prions in the sheep’s body not folding correctly. It seems to be passed from mother sheep to offspring but can appear anywhere in a flock and is very hard to get rid of. Most of the transmission seems to be from ingestion of placental or allantoic fluids, but during lambing the flocks form closer groups, and this stray material can contaminate the field that they are in, the flocks eating the contaminated grass.
With the similar BSE, you have a similar contamination, but in many cases the herd as fed with contaminated feeds, some it quite possibly from contaminated sheep, crossing the species barrier.
Cattle and sheep are an almost vegetarian species, not noted for their carnivorous behaviour, unlike birds, so their systems are not designed to exclude, or have lost the ability to exclude, animal material based problematic proteins.
Birds are usually omnivorous, some being carrion eaters that have a higher level of acid in their stomachs to deal with more troublesome pathogens.
Humans also have some of this ability, it being likely that humans have eaten sheep and cattle material that has been contaminated with rogue prions, but their systems dealing in most cases with it. But if we adopt a different diet arbitrarily will we have problems re-adapting or lose digestive or defensive abilities, backing ourselves into a dead end?
The diet defines the person. We have over the past 60 years been restricting to certain diets and choosing to reject or accept certain types of foods. Typical ones being nuts, lactose based products, products with gluten in them, low fat, low sugar, high fat, high sugar, sweeteners and other sugary chemicals, high doses of vitamins, etc. But in doing so we risk effects from them or not having them. The lack of exposure to nuts may produce severe nut allergies, no lactose where it is not problem for a person, producing lactose intolerance, lack of gluten in people who are not gluten intolerant producing a gluten intolerance. We see now shelves full of specialist products designed for people who have problems, but people who do not have the problems choosing them. There is not likely to be a problem of supply for a while, but it may be that people who do this may be closing down an area or selection of foods, just waiting for a problem to occur when they may need to eat them.
But there are other effects of the change in human practices and locations. Humans developed in a warmer tropical environment, so our bodies are attuned to that circumstance. But with the move north and into colder climes we have been changing. Colour becoming paler due to decreased sunlight, bodies accustomed to operating at lower temperatures, fat buffering, and frames becoming larger and more bulky. This has all added to an increase in stature and a lower but more cold efficient metabolism. For people who have moved in the opposite direction, they have become darker in colour, lighter and smaller, the move of the body to operating in higher temperatures and sunlight. This view suggests neanderthals and denisovans were not so different as everybody thinks and may just be the same as homo sapiens that their environment adapted through millenia of effect. Are we slowly becoming or reverting to neanderthals through environment?
We live in a time of plenty for most, logistics and financial status preventing plenty for all. All around the world we are seeing ‘I’ve got many times what I need, but I’ll only give you a bit if you pay for it with money you haven’t got.’ The celebration of greed being the highest status in the world.