Evolution and Limits Our Canadian critic, John, has said that our characterization of the theory of evolution is false. This is continually fueled by mutation, crossover, drift, gene duplication, horizontal transfer, etc. More individuals are born than are able to reproduce. This, along with environmental changes, reproductive isolation, founder effect, etc., is the basic mechanism by which the gene pool of a population changes over time. There is no known limit to this process.
All current species do in fact share a single common ancestor.
This is shown by the genetic relatedness of all living species, as well as their geographical distribution and the fossil evidence of now-extinct ancestors. 1a through 4a. We don t know of any creationists who don t agree with those statements. 4b though 5b. Specifically, we believe there are limits.