Humans consider themselves the epitome of evolution: spanning the globe in its entirety and even threatening to spill over into space. Most people consider evolution to be like a linear progression: creatures constantly getting better and more adapted to their circumstances. Unfortunately, both of those assumptions are wrong, and not only are humans not the epitome of evolution, but our very survival isn’t even guaranteed past the next 150 years.
Evolution is not a “getting better,” but is more of a “good enough to not die”. To make this more understandable: picture the span of the complexity of life as spanning between two walls, but only the left wall is static. The static (non-moving) wall represents the most simple niches: their environmental needs are relatively non-complex. The niches towards this wall have long since been filled by the most effective organisms able to do so, and have remained relatively constant for at least hundreds of millions of years (think e.coli or nematodes), and the ability of a newcomer to unseat them is almost non-existent. So the newcomers are almost always more complex, but that doesn’t make them in any way “better” or even more able to adapt.
This means that the available niches always stretch out towards the moving right wall: that of increasing complexity. These more complex organisms are not necessarily better: they are just filling otherwise empty niches, as their interaction with their surroundings have reached new levels of complexity not encroached on by existing organisms. At the same time, ineffective mutations which have an evolutionary disadvantage disappear over time, leaving the individuals who best (or at least successfully) filled the new niche.
That said, humans appear to be the most complex life-forms currently stretching themselves towards the ever-moving wall of complexity. We have made a lot of physical sacrifices in the name of our niche (mainly hyper flexible cognitive processing and the ability to learn and recognize new patterns), and it is questionable if these adaptations offer more than a geologically short term advantage over other existing organisms. I will return to this after explaining a little about how evolution works.
One of the central things to remember about evolution is that mutations do NOT react to the problems the organism faces. Mutations are random, and to a large extent their relative number is a function of homeostasis (physiological stability and balance). Higher levels of environmental instability yield an increased mutation rate, which pushes the species towards extinction, but also opens the door for macro-evolution. This means that a consistently unstable environment makes the inheritance of existing genes less likely, both preventing existing adaptations from being successfully passed on and increasing the likelihood of drastic changes in the genetics of the offspring (if they are able to survive or reproduce). So the species that survives is that which managed to maintain its positive adaptations against the forces of instability, but mostly species just tend to go extinct as the probability of keeping advantageous genetic mutations decreases with an increased mutation rate.
The reason we cannot find “missing links” between related species is the same reason that the IPCC estimates 15-40% of existing species will go extinct by 2050. This is the same reason the UN estimates we are losing 150-200 species a day. There exist physiological tipping points in terms of genetic stability, based on the concentration of Heat Shock Proteins (HSPs), which determine the likelihood of being able to pass on existing adaptations to the next generation, or even being able to reproduce at all. These tipping-points can be applied again to ecosystems and their ability to react to or resist change; collapsing into a different stable state when this line is crossed. This can again be applied at a higher level to the biosphere (or world ecosystem).
To sum this up: a little instability increases the likelihood of positive adaptations developing without the organisms’ entire genetic code being otherwise screwed up, but quick and intense changes lead to extinction. Selectionary pressure from the environment helps separate the maladapted from the well adapted, and over time the species changes and “evolves”. When instability crosses a critical threshold (when meiotic -reproductive- DNA is no longer repaired) then extinction becomes far more likely than any form of adaptation, especially since any positive evolutionary change in the next generation would have little chance of remaining within the gene pool.
Humans have gotten this far because of our genetic sacrifices in the name of quick adaptation, and the fact that our relative homeostasis within civilization has provide conditions which allow for adaptations to persist within the gene pool. By genetic sacrifices I am referring to our relatively large heads (creating an astounding number of child birth complications), our relatively weak necks (leading to potentially fatal injuries from falls other organisms would survive), our high calorie intake (our brain alone uses roughly 20% of our energy), and our relatively slow maturation both physically and mentally.
All the above disadvantages were taken on in the name of the neocortex: the most plastic and dynamic part of the brain. Despite every node of the neocortex operating using the same algorithms, it is capable of piecing together information from any of the other parts of the brain and then recognizing even isolated pieces of said patterns in other contexts. The neocortex is where concious decisions are made, where language and art is processed, and where humans today even process many of our physical movements (which were earlier processed by the cerabellum, responsible for instinctual or non-concious physical movements, and possesses about half the brain’s neurons).
The neocortex is evolutionarily the newest brain region and is present only in mammals. The fact it uses the same universal algorithms to process so many different types of data is the reason that it is so able to adapt to whatever is needed, even able to take over processing for other parts of the brain which become damaged. It has, in combination with our thumbs and limbic system (emotions), enabled us to create artificial and social systems spanning the entire planet.
But, since it is only conditioned to react to that which it experiences, or is taught, we are only able to react to problems that we notice. Part of being so far towards the moving evolutionary wall is that our niche is not necessarily stable, and can very easily become vacant; waiting to be filled by the next species. The farther one is towards the side of complexity, the less established the species is in its niche, and the more the species needs from its environment in order to survive.
So, far from being the “epitome” of evolution, humans actually rest on a precarious position which we have only reached by making biological trades that left many mothers dead before the advent of modern medicine. We have only managed to keep this position due to our ability to learn quickly, dynamically, and because the environment has allowed us relative homeostasis. Our actual survival, as high level consumers, is dependant on the survival of a huge swath of other life forms, including bees.
With the coming biosphere collapse, we are not only risking being taken largely unprepared, but we are especially unsuited for dealing with extreme environmental unpredictability. Our already high mutation rate (partially responsible for cancer rates, along with our modern diet), our difficult birthing procedures, lower fertility due to xenohormones, and the high calorie diets we requires to reach our cognitive and physical potential almost guarantee that unless we are prepared and reacting before the biosphere switches states, that there will be no humans left to talk about it within 1000 years.
The problems facing us are so much bigger than global warming or “climate change” that it is insane to describe them in such banal terms. The hope is that our neocortex, along with the amazing tool that is the internet, can help us reach the 10% needed to inform 90% about our situation.
If evolution has prepared us for anything, it is being able to react to such abstract but dangerous threats as global biosphere collapse. Like every species, we are a mix of advantages and their associated costs. But unlike many other species: we have exchanged many physical advantages for fast and dynamic learning abilities. We didn’t “evolve from apes”, but that won’t stop us from going extinct alongside them. Doesn’t it make more sense to stop ourselves from going over the cliff, than to try to adapt to free fall?
Kurzweil, Ray. 2012. How To Create A Mind