coz i cant find that questions of the universe thread. can a mod move this and attach it to it if its not too much trouble (sorry!) the question i thought of today and would like answering is: u kno how we all got 2 parents. 4 grandparents. 8 great-grandparents. 16 great-great-grandparents. etc, etc, etc. so in theory the further back u go, the more people were needed just to make ONE person living in 2007? so, if it took, say 10,000 anscestors to make each person living today, how is it that the population is bigger NOW? this really puzzles me! sorry if its already been asked, i couldnt find the thread to check.

its got something to do with a mitochondrial eve. and a bottle neck in the population. confused? yeh me too slightly. here, read this: http://en.wikipedia.org/wiki/Mitochondrial_Eve and then this: http://www.bbc.co.uk/dna/h2g2/alabaster/A703199 its a lot of reading but it might help with your question it means that a lot of us are related aswell supposedly - all the descendents of mitochondrial eve.

That all assumes that each couple only produces one child. The average number of kids per couple was 2.0 in the seventies, which would have maintained the population (2 kids for 2 adults). Before contraception the average was a lot higher. Say a couple had produced 4 kids, when the parents die there are 4 people left in the population that those 2 people produced, therefore two more people in the population (4 kids minus 2 parents).