Editing Last and First Men (section)

== Species of humans ==
* '''First Men'''. (Chapters 1–6) The First Men are our own species. Beginning in the early twenty-first century, several increasingly devastating wars take place in Europe, which result in the United States and China becoming the two dominant superpowers on Earth. In the twenty-fourth century, the US and China go to war, and the war concludes with the formation of the First [[World State]]. Two centuries thereafter, all religions and secular science consolidate into a religion based on the worship of motion whose god is Gordelpus, the Prime Mover. Four millennia after the formation of the First World State, humans [[Peak oil|deplete Earth's supply of fossil fuels]], resulting in the total collapse of civilization. 100,000 years later, the [[Patagonia]]n Civilization emerges. One feature of the Patagonian civilization was a cult of youth. One day, a riot occurs at a mine, and the rioters inadvertently cause a colossal subterranean explosion, rendering most of the Earth's surface uninhabitable for millions of years save for the poles and the [[Far North (Russia)|northern coast of Siberia]]. The only survivors of the disaster are thirty-five humans stationed at the [[North Pole]], whose descendants eventually split up into two separate species, the Second Men and some sub-humans. The First Men do not become completely extinct until shortly after the emergence of the Second Men.
* '''Second Men'''. (Chapters 7–9) The Second Men came into existence ten million years after the fall of the First Men. "Their heads, indeed, were large even for their bodies, and their necks massive. Their hands were huge, but finely moulded&nbsp;... their legs were stouter&nbsp;... their feet had lost their separate toes&nbsp;... blonde [[hirsute]] appearance&nbsp;... Their eyes were large, and often [[Shades of green#Jade|jade green]], their features firm as carved [[granite]], yet mobile and [[wikt:lucent|lucent]].&nbsp;... not till they were fifty did they reach maturity. At about 190 their powers began to fail&nbsp;..." Unlike our species, [[egotism]] is virtually unknown to them. At the acme of their highly advanced civilization, just as they are about to create a superior human species through "[[Genetic engineering|artificial evolution]]", a protracted war with the Martians finally ends with the Martians extinct and the Second Men gone into eclipse.
*'''Third Men'''. (Chapter 10) "Scarcely more than half the stature of their predecessors, these beings were proportionally slight and lithe. Their skin was of a sunny brown, covered with a luminous [[Halo (religious iconography)|halo]] of red-gold hairs&nbsp;... golden eyes&nbsp;... faces were compact as a cat's muzzle, their lips full, but subtle at the corners. Their ears, objects of personal pride and of sexual admiration, were extremely variable both in individuals and in races.&nbsp;... But the most distinctive feature of the Third Men was their great lean hands, on which were six versatile fingers, six [[Antenna (biology)|antennae]] of living steel." They were deeply interested in music (to the point of developing a religion based on the worship of music) and the [[genetic engineering|design of living organisms]]. The Third Men eventually split into two factions: one that sought to create a subspecies of [[Mediumship|mediums]], and one that focused on designing humans that consist almost entirely of [[brain tissue]].
*'''Fourth Men'''. (Chapter 11) Giant brains bred by one faction of the Third Men. For a long time they help govern their creators, but eventually their rule becomes oppressive and the Third Men rebel. The Fourth Men prevail by recruiting as servants a subspecies of Third Men prone to [[hypnotic suggestion]] (the ultimate product of the effort to breed a mediumistic subspecies). The docile subspecies of the Third Men exterminate the original subspecies, save for a few individuals to be used as lab specimens. After the war, the Fourth Men eventually reach the limits of their scientific abilities and discover that emotions and body are also necessary for complete understanding of the cosmos.
*'''Fifth Men'''. (Chapters 11–12) An artificial human species designed by the Fourth Men. "On the average they were more than twice as tall as the First Men, and much taller than the Second Men&nbsp;... the delicate sixth finger had been induced to divide its tip into two [[Lilliput and Blefuscu|Lilliputian fingers]] and a corresponding thumb. The contours of the limbs were sharply visible, for the body bore no hair, save for a close, thick [[wikt:skullcap|skull-cap]] which, in the original stock, was of ruddy brown. The well-marked eyebrows, when drawn down, shaded the sensitive eyes from the sun." After clashing with and finally eliminating the Third and Fourth Men, they develop a technology greater than Earth had ever known before. When Earth ceases to be habitable, they [[Terraforming of Venus|terraform Venus]], committing [[genocide]] on its marine native race which tries to resist them. The Fifth Men do not cope well after the migration and eventually [[Devolution (biology)|devolve]] and diverge into two species: the Sixth Men and a [[Pinniped|seal]]-like subhuman species.
*'''Sixth Men'''. (Chapter 13) "Sadly reduced in stature and in brain, these abject beings&nbsp;... gained a precarious livelihood by grubbing roots upon the forest-clad islands, trapping the innumerable birds, and catching fish&nbsp;... Not infrequently they devoured, or were devoured by, their [[Pinniped|seal]]-like relatives." After [[Plate tectonics|tectonic changes]] provide them with a promising land mass, they fluctuate like the First Men and repeat all their mistakes.
*'''Seventh Men'''. Flying humans, "scarcely heavier than the largest of terrestrial flying birds", are created by the Sixth Men. After 100 million years, a flightless pedestrian subspecies appears which re-develops technology.
*'''Eighth Men'''. "These long-headed and substantial folk were designed to be strictly pedestrian, physically and mentally." When Venus becomes uninhabitable, about to be destroyed along with the entire [[inner Solar System]], they design the Ninth Men, who will live on [[Neptune]].
*'''Ninth Men'''. (Chapter 14) "Inevitably it was a [[dwarfism|dwarf]] type, limited in size by the necessity of resisting an excessive [[gravitation]]&nbsp;... too delicately organized to withstand the ferocity of natural forces on Neptune&nbsp;... civilization crumbled into savagery." After the Ninth Men's civilization collapses, the Ninth Men themselves devolve into various animal species.
*'''Tenth to Thirteenth Men'''. (Chapter 14) "Nowhere did the typical human form survive." About three hundred million years after the colonization of Neptune, a rabbit-like species evolves into the Tenth Men. The Tenth Men are sapient but primitive. After a plague wipes out the Tenth Men, several other primitive human species rise and fall.
*'''Fourteenth to Seventeenth Men'''. The Fourteenth, Fifteenth, and Sixteenth Men are essentially Neptunian versions of the First, Second and Fifth Men, respectively. The Fourteenth Men create great civilisations and destroy them, frustrated with their own imperfections. The Fifteenth improve upon that, creating a spirituality based on "a devotion to the fulfilment of human capacity". They eventually create the Sixteenth Men – the first Neptunian artificial species. Thus the cycle of rise and collapse of civilisations ends, and steady progress takes its place. The Sixteenth Men achieve the highest level of civilisation possible "to the individual [[human brain]] acting in physical isolation" and to avoid stagnation create the Seventeenth Men, with an ability for "mental fusion of many individuals" to succeed them; however, the Seventeenth Men are "flawed" in some unspecified way, unimagined by the 16th due to their lesser awareness, and last only a short period of time before being replaced by the Eighteenth Men.
*'''Eighteenth Men'''. (Chapters 15–16) The most advanced humans of all, essentially a perfected version of the 17th species. A race of philosophers and artists with a very liberal sexual morality. "Superficially we seem to be not one species but many." (One interesting aspect of the Eighteenth Men is that they have a number of different "sub-[[genders]]", variants on the basic male and female pattern, with distinctive temperaments. The Eighteenth Men's equivalent of the family unit includes one of each of these sub-genders and is the basis of their society. The units have the ability to act as a [[Group mind (science fiction)|group mind]], which eventually leads to the establishment of a single group mind uniting the entire species.) This species no longer dies naturally, but only by accident, [[suicide]], or [[Homicide|being killed]]. Despite their hyper-advanced civilisation, they practice ritual [[Human cannibalism|cannibalism]].<ref>Chapter 15, subchapter 1: "Whenever a human being has chosen to die, his body is ceremoniously eaten by his friends".</ref> They are eventually extinguished on [[Neptune]] after a [[supernova]] consumes the remains of the [[Solar System]], faster than any means of escape they can devise for their corporeal forms. This last species of man devises a method of [[panspermia]], a [[virus]] to broadcast life to other worlds and ultimately cause the evolution of new sentient species throughout the galaxy.

===Sub-humans===
*'''Baboon-like Submen'''. (Chapter 7) "Bent so that as often as not they used their arms as aids to locomotion, flat-headed and curiously long-snouted, these creatures were by now more [[baboon]]-like than human".
*'''Seal-like Submen'''. (Chapter 13) "The whole body was moulded to stream-lines. The lung capacity was greatly developed. The spine had elongated, and increased in flexibility. The legs were shrunken, grown together, and flattened into a horizontal rudder. The arms also were diminutive and fin-like, though they still retained the manipulative forefinger and thumb. The head had shrunk into the body and looked forward in the direction of swimming. Strong carnivorous teeth, emphatic gregariousness, and a new, almost human, cunning in the chase, combined to make these seal-men lords of the ocean".
*'''Period of Eclipse'''. (Chapter 14) "Man's consciousness was narrowed and coarsened into brute-consciousness. By good luck the brute precariously survived." Nature succeeds in colonising Neptune where sapient life fails. Human-derived mammals of all shapes come to dominate Neptune's [[ecosystem]] before adapting well enough for the vestiges of opposable thumbs and intelligence to become assets again.