[cross posted at TSZ A Question for those that doubt Common Descent] Mark wrote Recent posts by Sal remind me that there are some intelligent educated people who doubt Common Descent. What I don’t understand what they think the alternative is. Put simply I take Common Descent as the position that : * At one time there was only very simple unicellular life on earth (this is not a debate about how that unicellular life originated) * Complex life forms (eukaryotes) are created by slight modifications from other life forms (which are their parents). We have never observed them being created any other way! * All complex life forms are the descended from a very small number of simple life … Continue reading Mark Frank’s question on common descent and some responses