The human race in its current evolutionary incarnation, Homo sapiens sapiens, has been present on planet Earth for approximately one hundred and ninety-five thousand years. During this time the species has survived ice ages, volcanic eruptions, global climate shifts, epidemics and a veritable myriad of other upheavals, many of which in recent times it has brought upon itself. Some would argue that by sheer virtue of surviving this long without any drastic changes in its biological makeup, the species has in some way proven itself to possess a infinite longevity.
Questions to ask about Survivability
Is the present human animal a peak of evolution, neither requiring nor subject to further improvements? Is the survivability of the species dependent solely on its own intellect; limited only by an apparently limitless capability for internal conflict and, as a result, the increasingly cunning ways in which new means to destroy itself are developed? And is it then possible, or even plausible, to predict the progress of this intellect in order to look into the future survivability of the species as well as the past?
The Longevity of Previous Human Species
Human physical evolution from the first recognisable hominid, Ardipithecus ramidus, to the modern incarnation of Homo sapiens, has taken somewhere in the region of five million years. During this time various subspecies have evolved and died out depending on their particular characteristics and ability to survive. The longevity of the present genus cannot be considered incontrovertible proof of its position as an evolutionary apex; until out competed by more modern human species, Homo neanderthalensis enjoyed over two hundred thousand years of dominance yet now remains only in fossil evidence, and the original bipedal species, Homo erectus, was the most highly evolved of its type for one and a half million years before it was outcompeted by Homo heidelbergensis, so by comparison Homo sapiens is a mere juvenile race.
Natural Selection and Survivability
Natural selection, whether aided or hampered by artificial interference, may well cause humanity’s genetic material to survive long into the future even if it is eventually barely recognisable to modern man as humanat all in physical appearance or cultural values. Olaf Stapledon notes in one of his most famous science fiction novels that “If one of the First Men could enter the world of the Last Men, he would find many things familiar and much that would seem strangely distorted and perverse,” in describing a world of the future inhabited by supremely evolved forms of the human animal.
In reality, there is also just as much probability that the species will de-evolve, or perhaps evolve ‘sideways’ into a different incarnation. For instance, in many populations it is possible to note an inverse relationship between intellectual ability and fertility. If this trend is exacerbated the species may well develop into a less intellectually capable but more fertile species (Homo philoprogenitus, meaning lover of many offspring). Increased reproduction could mean increased survival prospects in the long term, but would current humankind consider these descendents as truly human as themselves?
How We Evolve
Any such evolution, even considering artificial intervention or gross mutation, would take place on a far large scale than a single millennium, and so a more pertinent consideration is the destruction of the species in its current form due to various events, be they accidental or deliberate, malicious or benign in original intent. What is certain, however, that the length of a species’ survival up to any given point cannot be taken as any indication of how long it will (or will not) persist afterwards.
Resources
First and Last Men by Olaf Stapledon (Gollancz of the Orion Group, SF Masterworks edition)
Bostrom, Nick, 2002, "Existential Risks: Analyzing Human Extinction Scenarios and Related Hazards" at nickbostrom.com Accessed 22/02/10.
Archaeology Info Team, 1998-2008, "Human Evolution" at Archaeologyinfo.com accessed 22/02/10.
