For many years evolutionists have been squabbling among themselves over a variety of issues. Not the least of these is how, and at what rate, the evolutionary process is supposed to have occurred.
Mutations are accidental alterations of the genetic code in a cell.
Natural selection is supposed to be nature's sorting mechanism. Those creatures with qualities best adapted for survival do survive, while the weaker are eliminated. Gradually, it is alleged, sufficient change is generated to effect a new type of biological organism. Of course if this scenario did occur, there is a perfectly good way to check it out. Look at the record that has been left by the fossil deposits in the various strata of the earth.