Does natual selection create new alleles in the gene pool?

Question

the earliest discovery fossils are......... dating back to ............ yrs ago?

Answer 1

natural selection does not create new alleles, it just works on alleles already in existence (by changing frequencies of these alleles).  new alleles are created by random mutation in DNA

Answer 2

No.  Only mutation can create new alleles.  Natural selection can remove them from a population, but not create new ones.

The earliest bacterial fossils are from the Pilbara rocks and are 3.5 billion years old.

Answer 3

No the new alleles are created by mutation and not by natural selection. Natural selection helps to maintain the selected gene pool.  

Answer 4

In addition to mutation, sometimes a copying mistake can make changes.  Say a gene coding for a protein gets copied.  One copy might remain stable, while the other morphs into something else that may eventually become useful.  Also, you can get DNA transfer via viruses, and even bacteria.  And natural selection then decides to keep the changes, or not.  And the genome itself seems to have a good idea if something is important or not.  There are mechanisms in place so that certain regions of DNA are guarded carefully, and others are allowed to drift.  So, for example skin color may change quickly, while certain basic cell functions are kept stable.

The oldest fossils?  The oldest insect fossil is 400 million years old. Stromatolites date back to 3.5 billion years old.  Some say there are fossil carbon mattes that date to 3.7 billion years ago, but this is somewhat controversial.