This is not the time to be starting a new project. I’ve got stuff I gotta do. And yet here I am, playing with tectonic.js.
I give you *Middle-Layer, an earthlike world. I mean really earthlike. So earthlike that as a science fiction setting it would be unacceptable. As a fantasy setting however…
*Midde-Layer is 4.5 billion years old, but for our purposes, we only need to start 173 million years ago, at the beginning of the *Middle-Life era, when the supercontinent *Great-North began to break up. This break-up coincided with a mass extinction, which left terrestrial vertebrate life restricted to two main clades, the *No-Shelled (present only around the coast of *Great-North) and the *Shelled (whose range extended further north). *Shelled animals (which laid eggs with shells) are further divided into the *Feathered and *Furred clades, the latter of which might already have produced the first *Milk-Givers.
It is probably also around this time that a stem-*Milk-Giver became the host of the Laplace bacterium, ancestor of the Laplace Bodies now found in the cells of all *Milk-Givers. Laplace bodies can measure the speed of water molecules in the surrounding cytoplasm and allow only fast-moving molecules to pass through their membranes, creating a heat gradient the Laplace body uses to drive proton pumps, which produce ATP. This (hideously physics-breaking) process is most efficient in cold external temperatures, which is unfortunate because shortly after its evolution, the entire continent of *North-Land began to break up and move south.
*Middle-Layer, 157 million years ago.
North-south channels split *North-Land into *Before-South (to the east), *Before-North (to the west) and *Before-East (to the east), allowing equatorial water to flow to the north pole. In the period of global warming that followed, the *Feathered and *Furred clades became relegated to minor niches, while the scaled and mucus-skinned *No-Shelled animals dominated continental ecosystems. Some *No-Shelled animals, such as the *Non-Toad-Lower-Layer-Salamanders, became truly monstrous in size.
The age of the *Lower-Layer-Salamanders came to an end in an extinction event, leaving only the burrowing, mucus-skilled *toads (the “scales” of some modern *No-shelled animals are actually constructions of mucus, rather than true scales). *Toads quickly radiated to fill the recently-abandoned niches, but so did the flying *feathered and tree-climbing *furred animals.
*Middle-Layer 54 mya
Although often called the “Age of *Furred animals,” the first ten million years of the *Recent-Life age was a hot, wet world where if anything *furred animals were at a disadvantage. Large flightless *feathered *birds hunted them, as did giant, running *toads. However, the major clades of *furred animals were established at this time: the *North-beasts (including the large-brained, tree-dwelling *Human-likes and huge *thick-skinneds), the *South-beasts (including *sharp-tootheds and *hooveds), and the *West-beasts (including *fur-salamanders and the enigmatic *mound-gods).
*Middle-Layer 2 mya
In the most recent Ice Age, ice-caps formed around southern *South and the north pole. By this time, most of *Middle-Layer’s megafauna was *furred, although there were (and continue to be) some large *toads and large flightless *birds on islands and in equatorial *North and *West.
Humans evolved around this time in the rift valley of eastern *North. They were terrestrial *human-likes, whose ancestors had descended from the trees when the central jungles of southward-drifting *North became savannas. Several species evolved and spread from this area, including the early human species-complex, about one million years ago. This species-complex, able to make tools and use language, wiped out all of its relatives (except those still living in the jungles and uplands of central *North), and quickly spread across *Middle-Layer.
Fossils of several subspecies of early human allow us to trace the spread of these speaking tool-users across glaciated *Middle-Layer. The *A group, of which modern humans are a part, spread south from the rift valley and colonized *South, producing the gracile *A2s and the robust *A3s. The *A1s, more similar to modern humans, nonetheless produced some outre dwarf and swimming forms in the *Before-West islands, some of which may have survived until just before historical times.
The more divergent *B group is famously distinguished by its manual claws, but was certainly not as savage as popular media usually depicts. Although larger and stronger than *As (including modern humans), *Bs also possessed large brains and made complex tools, including boats.
Genetic studies show that modern humans interbred with many local human subspecies when we expanded out of *North about 50 thousand years ago, at the beginning of the current interglacial period. Most of the genes passed on by these archaic humans have to do with disease resistance, but some physical features, such as claws, belly-horns, and dayglow hair may indeed be products of these interbreeding events. As well, local variation in magical ability is almost certain to, at least in part, be a relic of those long-lost cousins.
More to come…some day. If you want to contribute or change something, feel free to make your suggestions.
(The *s indicate words I need to generate when we get to the linguistic state of the world building. If I can sustain this project long enough, I’ll be back.)