Theory:Doctor Who television discontinuity and plot holes/The Hungry Earth


 * The central concept of this episode — that the miners have achieved a record by drilling to 21 km, thus threatening the Silurian habitat — is inconsistent with both Inferno and Journey's End. The Inferno Project achieved a depth of at least 20 miles, and the Osterhagen Project placed their nuclear devices beneath the crust of the Earth, which varies between 20 and 70 km in thickness. Humans should therefore have aggravated the Silurians long before this episode. The Osterhagen Project should have been particularly incendiary to Human/Silurian relations, according to the underlying logic of this episode.
 * The Silurians don't live underneath every square inch of the surface. Presumable the Inferno and Osterhagen projects just happened to not be anywhere near any Silurian encampments (and likewise for the Daleks' later attempt to drill all the way down to the Earth's core to remove it so they could take the planet for a joyride), while this one was directly over a major city.
 * Of course that still doesn't explain how 21km could be a record. The Osterhagen project may have deliberately chosen the thinnest parts of the crust (which is actually well under 5km in some spots, especially on the ocean floor--the real-life Project Mohole, the inspiration for Inferno, planned to drill off-shore for exactly this reason). But Inferno was intending to drill all the way to the core, and got as far as 20mi (32km).
 * Maybe Inferno was a well-kept secret. After all, most scientific projects aren't guarded by UNIT.
 * And of course, Torchwood have dug right to the core, and exposed the Racnoss
 * Linking in with the above point both inferno and the osterhagen project were (presumably) secret. So the going by this logic the drilling in this episode will be the deepest official drilling of the earths crust.
 * I don't see how it is inconsistent with the Osterhagen Key, the Inferno Project or the Dalek attempt to hijack the earth's core. These may have plunged the crust nowhere near Silurian settlements. Or perhaps the Silurians are aware of them and choose not to mention them. Or(to use a tired-old device to explain discontinuities) these different events occur in differing timestreams or alternate universes.According to the Doctor, travel to other universes was freely possibly before the fall of Gallifrey.
 * Could the season five crack be responsible for the apparent inconsistency? It has been repeatedly shown throughout this season that key events from the Doctors past never happened as those involved were never born. Could it be that brains behind Osterhagen and Inferno were caught up in the crack? In which case this site in Wales is the deepest hole drilled as the other never happened.
 * In Inferno it wasn't in the welsh village above the silurians.


 * Why would a female Silurian have breasts when reptiles don't give their children milk?
 * They aren't reptiles if they are homo reptilia....
 * Under the cladistic system, mammals are just a kind of reptile, so some reptiles do give their children milk.
 * Mammals aren't reptiles. That isn't how it works. Birds are one specialised group of dinosaurs, which means they are sauropsids, what people mean when they use the Linnaean classification Reptilia. Mammals are descended from the early synapsids. Both split off from the very first amniotes so mammals and reptiles are two quite distinct groups.
 * A number of features have been invented multiple times on separate lines. Eyes evolved more times than we can count. Bats developed flight separately from birds. Warm-bloodedness evolved on at least two reptile lines (the one that led to mammals, and the one that led to birds). Bipedalism evolved multiple times. Obviously, in the Whoniverse, intelligence and vocal cords also evolved at least twice on separate lines. So, why couldn't lactation have evolved on another reptile line?


 * Why are they called "Homo reptilia" in the first place? Homo is a genus within the Primate order--in other words, apes. And the Doctor can't just be speaking figuratively--he gives "Homo reptilia" as a more accurate name than the inaccurate "Silurian" or "Eocene". Really, if 300 million years is anywhere close to accurate, attaching them to a 2-million-year-old ape genus is a lot farther off than Silurian, which is at least a period in the same era that they came from, if not the right one.
 * Technically the name 'homo' is latin for wise/clever so their name actually means wise/clever reptile, it doesn't necessarily have to apply to humans it has just been used this way as we view ourselves as wise. As the silurians bear such similarities to us socially it is likely they named themselves wise reptiles in a route language of their own (like our own latin) and the TARDIS simply translated it for the Doctor.
 * No, because it is the sapiens part of our latin name that means wise, not the homo part. The 'homo' part is our genus (homonids). They should be called Reptilia Sapiens, as that would be wise reptile. Perhaps the Doctor uses this name because they are humanoid in structure? But this is unlikely as hundreds of species across the universe are vaguely or strongly humanoid in shape; so why doesn't he call Sontarans 'Homo Spud-head' for example?
 * The basic point is accurate, except that "hominid" isn't our genus; it's our subfamily (Homininae), which includes all of the great apes. The word for members of genus Homo is "humans".
 * Also, we didn't name ourselves "wise mammals", but "wise humans". Even if they didn't invent the same classification system as us, they certainly would have distinguished themselves from all of the other reptiles at a higher level than the species.
 * Perhaps they really have evolved into a species of human, though I suppose that would imply they shared a common ancestor with Homo sapiens, which seems unlikely.
 * I don't think the Doctor anywhere says Homo reptilia is their real scientific name. After all, scientific names have been invented by humans, and the humans haven't been aware they were there, let alone studied them. It's more likely that the Doctor is using the term 'Homo' as an analagous concept, referring to human-like reptiles. Of course, from the Silurian point of view, humans are reptile-like apes.
 * He doesn't say it's their real scientific name, but he does say that it's a more accurate name than "Silurian" or "Eocene". Was he saying, "Just for fun, I'm going to make up a horribly inaccurate name that sounds scientific but isn't, but not quite as inaccurate as the other two inaccurate names I've given them in the past?"
 * The Doctor deliberately avoids designating them. This is because of continuity. In Doctor Who and the Silurians they are referred to as 'Silurians', in the belief they originated from the Silurian Period of Earth history. But this is too early for reptiles, so the Third Doctor corrects the mistake in The Sea Devils, saying they might be called Eocenes. But the Eocene Period is too late, for the creatures were contemporaries of dinosaurs, which had died out by the Eocene. So the issue of naming them is confused. In Warriors of the Deep they are again called Silurians, even by themselves, with what justification it is hard to fathom. And their cousins, the Sea Devils, who had not been named at all in the story of that name, call themselves Sea Devils. So the writers seem to think it is better to avoid definitively naming them. And we also have to remember that the Doctor says they are unlike the 'Silurians' previously seen. They are a different branch and obviously more human-like.
 * We never hear them call themselves "Silurian" or "Sea Devil" in their own language. We don't even hear them speak their own language. In every case, someone (significantly, often the TARDIS) is translating, so an English name had to be invented as part of the translation. (The same must be true with most alien races. Even the Judoon, who we do hear speaking their own language, can't call themselves "Judoon", because every syllable in their language ends in "o".)