when i was a kid, i always tried to figure out how we could all be decended from adam or noah and still be so different. it turns out our common ancestor lived as early as a couple thousand years ago. how bizzare!
http://news.yahoo.com/s/ap/20060701/ap_on_sc/brotherhood_of_man;_ylt=AljYWhXKss8Eulzka6QKBqUDW7oF;_ylu=X3oDMTBhZDhxNDFzBHNlYwNtZW5ld3M-"With the help of a statistician, a computer scientist and a supercomputer, Olson has calculated just how interconnected the human family tree is. You would have to go back in time only 2,000 to 5,000 years — and probably on the low side of that range — to find somebody who could count every person alive today as a descendant.
Furthermore, Olson and his colleagues have found that if you go back a little farther — about 5,000 to 7,000 years ago — everybody living today has exactly the same set of ancestors. In other words, every person who was alive at that time is either an ancestor to all 6 billion people living today, or their line died out and they have no remaining descendants."
this is how my geeky minds works: an accurate portrayal of time travel in a sci fi flick would show that if time travellers went back more than a few thousand years and killed anyone - everyone in the present day would have a completely different genetic makeup. different personality, different haircolor, everything - including all the folks that were time traveling.
and thats my non sequitur for the day