the ethnicity part I manage to figure out with a lot of digging and talking to the right people that are from terra.
not taking race mods so going from human to fox, like penny who before was Asian. just took my common scene to kick in.
i know that i worded the question wrong to what i meant, reading over it.
I guess it depend son how you define ethnic groups. I define them genetically, but I know most people do it cultural. I personally think ignoring genetically distinct groups of people is absurd when classifying people into groups. After all there's some really cool things IRL like this one Bedouin tribe that's immune to arsenic due to millennia of drinking from this one aquifer. Or how Kenyan tribe known as the Kalenjin really are genetically better than all other given ethnic groups as runners due to a combination of factors including longer thinner legs than average and better pulmonary systems on top of that to create the perfect storm of "human distance runner" traits outside of that one actual mutant who doesn't get lactic acid build up and thus cant get tired from physical activity.
I don't think these traits and others like them can be removed from classification systems without removing critical facts about the cultures that arise from the people with those traits. Take the Kalenjin who are a distinct ethnic group. All of them are great runners by the standards of other people, and because of that their athaleets are one of the biggest parts of their cultural identity and have been since as long as anyone can remember. It's a big part of their culture, and it's rooted in genetics. So what would happen if over the next 20 years people changed their genetics and the next generation of Kalenjin were not genetically advantaged as runners? I think that would begin to end the Kalenjin and start a new ethnic group as they adjust to new physical traits.
Things get even more messy once human colonies on other worlds come into account. We call people Asians because they come from Asia and share this culture that developed they way it did because of the specific people who lived in a specific place over a specific period of time. The world shapes us more than people think it does. American cities are so huge and sprawling on the west coast but cramped and messy on the east coast because cars were invited as the US spread west and western US cities were built for cars. Environment dictates culture. So if you take a few million Japanese people and send them to a planet which is nothing like Japan in climate and topography and let a few centuries pass... Are they really still Japanese, or do they have their own identity that's developed form adjusting to their new world?
I say they have a new one. It would have traces of Japanese culture... But it's different. Remarkably so.
As for TiTS Earth, the lore says that by like 2100 Earth is pretty much totally screwed. Over populated, out of resources... So take the global warming projections and use them to factor in forced migration. Every major city in Japan will be under water if most projections are accurate. We do not place cities randomly. We put them where we can do so and survive. Japanese people will move to the few places left in Japan that can support cities, that will fill up and they will then have to go elsewhere. Massive global refugee crisis. Everywhere will become like the USA, a huge melting pot of cultures. Stuff will intermingle and change each other.
I don't think the existing ethnic groups would survive that. The names would, but the cultures as we know them would not. The genetics as we know them would not. Right now Japanese people are generally pale, dark haired, short, and have those cool shaped eyes. But if most Japanese people had to flee rising sea levels for Russia or the USA, well... Things change over time. Crops that grew easily in Japan do not grow in Siberia, meaning traditional Japanese foods would die out over time. Japanese people would marry native Russian people and we'd start to see people of Japanese ancestry more commonly have fair hair colors and other different traits.
"Japanese" would refer to ancestry more than culture even just by 2300, when we started putting out Star Ships filled with colonists. Don't you think that those colonist's kids would identify as members of their colony world more than some place they've never seen before ever and was like destroyed for all intents and purposes before their grandparents were born? To me, yes. Yes they would. So only people from Terra would use old cultural identifiers and names.
When Penny says she's "Asian" I take that to mean she's form Terra and was born in the region refereed to as Asia, and that dosnt means she's Japanese or Chinese, or Korean, or Vietnamese. it means she's a Terran who was born within a given geological region and we lack the data to draw conclusions on what ethnic group and culture she belongs to. Especially since she's not like, typecast or anything. She's not eating rice, wearing a kimono, or carrying a katana or anything. She's not even doing anything subtly Asian that I know of... of course I'm not Asian so she might be. But she seems more American to me than anything else. FOr all we know in 10 years time in TiTS the USA decides "fuck it" and takes over Japan and China during WWIII and those cultures were completely consumed. Or maybe China takes over the middle east, so Penny is really distantly related to the Bedouins who were called Asians because of political reasons for so long that it just stuck and Asia includes the middle east now. Or mabey she says she's Asian in the same way my dad says he's Apache. IE she's like 4% Apache and the other 96% is a whole heap of random genes form everywhere on earth and he just likes one the most so he picked it to be even though he does nothing like the Apache did nor believes anything they did he just thinks its cool to "be" one. ALso he's not realy Apache... I did a DNA test. His family just THINKS they have Apache blood.
We just dont know enough about Terra to make any conclusions at all.