Hacker News Board Hacker News, browsed like a classic message board
Live data from Hacker News

Everyone on Earth is your cousin (2015)

qz.com

Post reply on HN
Print view View original

31–40 of 87 posts

Re: Everyone on Earth is your cousin (2015)

#31

Post by irrational »

abhishekjha wrote: post #27
irrational wrote: post #26

Earlier quoted context omitted.

I’ve read various studies that believe that our most recent common ancestor lives 2000-4000 years ago.

That seems a much shorter span of time for civilizations to spring up. Egypt, Iraq, India and Europe has history which was already divergent at that point of time.

Basically all you need is a single person traveling to a new area and reproducing and people travelled a lot more than our provincial thinking assumes. Just think of Assyria taking entire civilizations and transplanting them in new areas. The mongols, German hordes, Vikings, etc. raping and pillaging around the world. Polynesian sailors having contact with both SE Asia and South America. All the European colonization. Etc.

Re: Everyone on Earth is your cousin (2015)

#32

Post by ngngngng »

Pro tip, get the old folks talking, and take out your phone to record. Whatever they're talking about, even if they're talking about nothing at all. They'll all be gone soon, and having video of your boring everyday interactions with them is better than having only your memories of them.

Re: Everyone on Earth is your cousin (2015)

#33

Post by abc_lisper »

irrational wrote: post #26
tzs wrote: post #7

There are a few particularly interesting points when you go back up your ancestor tree. First, there is a point where some ancestor of yours is an ancestor of everyone else currently living (and so will also be an ancestor of everyone else to come). This is the "most recent common ancestor" point. Go farther back and you reach the "identical ancestors point" (also known as the "all common ancestors point" or the "gen…

I’ve read various studies that believe that our most recent common ancestor lives 2000-4000 years ago.

Not true. Australian aborigines split off 40k years ago. Now, if somehow we interbred with all of them, so that no pure aborigines are left, in a 100 years we move the line to a date that resembles what you suggest. We have to do that every remote tribe on earth. Or if for some reason they are killed.

Re: Everyone on Earth is your cousin (2015)

#35

Post by setr »

fastball wrote: post #28
tzs wrote: post #7

There are a few particularly interesting points when you go back up your ancestor tree. First, there is a point where some ancestor of yours is an ancestor of everyone else currently living (and so will also be an ancestor of everyone else to come). This is the "most recent common ancestor" point. Go farther back and you reach the "identical ancestors point" (also known as the "all common ancestors point" or the "gen…

Maybe I'm stupid but I'm not sure I understand the difference between most recent common ancestor and the identical ancestors point. Can someone explain differently?

From my reading of the above, the “most recent common ancestor” is a single individual who acts as a common ancestor to all alive today

Whereas “identical ancestors” is a time period where everyone alive is an ancestor to those living today. So a group of ancestors are being selected — rather than just the one. So this should generally always be closer to now than the “single recent ancestor”, simply by virtue of allowing the ancestor tree to be more splayed out.

However, my understanding of the latter must be wrong, because yesterday would always be the most recent time period holding true to that definition — or if it only counts if none of the people alive today are alive in the identical ancestor time period, then it’s always going to be today - current oldest human’s age - 1 day.

Re: Everyone on Earth is your cousin (2015)

#37

Post by ml_basics »

setr wrote: post #35
fastball wrote: post #28

Earlier quoted context omitted.

Maybe I'm stupid but I'm not sure I understand the difference between most recent common ancestor and the identical ancestors point. Can someone explain differently?

From my reading of the above, the “most recent common ancestor” is a single individual who acts as a common ancestor to all alive today Whereas “identical ancestors” is a time period where everyone alive is an ancestor to those living today. So a group of ancestors are being selected — rather than just the one. So this should generally always be closer to now than the “single recent ancestor”, simply by virtue of all…

My reading was that the “identical ancestors point" is the point at which every person is either: 1. an ancestor of all currently living people; or 2. an ancestor of no one currently living (ie their line died out).

Alternatively, it’s the time when all currently living humans have exactly the same set of ancestors.

Whereas “most recent common ancestor” means that the intersection of ancestries of all living people is non-empty. (That intersection being the common ancestor)

Re: Everyone on Earth is your cousin (2015)

#38

Post by jltsiren »

abc_lisper wrote: post #33
irrational wrote: post #26

Earlier quoted context omitted.

I’ve read various studies that believe that our most recent common ancestor lives 2000-4000 years ago.

Not true. Australian aborigines split off 40k years ago. Now, if somehow we interbred with all of them, so that no pure aborigines are left, in a 100 years we move the line to a date that resembles what you suggest. We have to do that every remote tribe on earth. Or if for some reason they are killed.

Isolated populations never remain fully isolated. If Aboriginal Australians managed to reach Australia tens of thousands of years ago, it makes no sense to assume that nobody ever followed them. It's far more likely that there was constant low-level contact with Austronesian peoples – even if it didn't occur in every generation or every century. And it's also quite likely that some lost sailors ended up in Australia over millennia, and some of them had children.

If the level of contact is low enough, it won't leave any measurable genetic traces. After all, if you go back sufficiently many generations, most of your biological ancestors are not your genetic ancestors.

Re: Everyone on Earth is your cousin (2015)

#39

Post by DoingIsLearning »

ngngngng wrote: post #32

Pro tip, get the old folks talking, and take out your phone to record. Whatever they're talking about, even if they're talking about nothing at all. They'll all be gone soon, and having video of your boring everyday interactions with them is better than having only your memories of them.

This is probably one of my greatest regrets with my grandmother.

I was planning to do exactly this for quite a while but life had other plans, she is gone now and although I have great memories of her, I do regret not having a video record of her story telling to be able to share with her great-grandkids.

Re: Everyone on Earth is your cousin (2015)

#40

Post by irrational »

abc_lisper wrote: post #33
irrational wrote: post #26

Earlier quoted context omitted.

I’ve read various studies that believe that our most recent common ancestor lives 2000-4000 years ago.

Not true. Australian aborigines split off 40k years ago. Now, if somehow we interbred with all of them, so that no pure aborigines are left, in a 100 years we move the line to a date that resembles what you suggest. We have to do that every remote tribe on earth. Or if for some reason they are killed.

Are you saying not true without even reading the studies, speaking from scientific knowledge, or speaking off the cuff?
Post reply on HN