This is a frequently repeated error. The single common tree of life of ribosomal RNA is strong scientific evidence for universal common descent.
There is also no evidence that random mutation and natural selection got us from a single cell creature to what we are today, but they teach that too.
You are quite well aware there is massive genomic and fossil evidence that we descended from single-celled creatures, and massive genomic evidence that the process was mutation coupled with natural selction.
Freqeuntly repeated error number 2.
I we are going to accept beliefs in science as valid theories, whose to criticize which ones get in there?
You can criticize what you want. However, you would, if you were smart, leave the teaching of biology to people who know some biology. If the above is any indication, your criticism would come from the standpoint of unusual ignorance and/or prejudice.
Ah God, not *this* again.
Talking to creationists is like a never ending conversation with Leonard Shelby from Memento.