Main conclusions

  1. The working assumption on which this website is based is that published phylogenetic trees (equivalent to family trees) represent valid hypotheses of relationships between ancestor and descendant fossil organisms. This assumption implies that common descent applies in the specific clade being considered, but not necessarily that there is a single tree of life representing all living organisms.
  2. Stem-group fossils identified from published phylogenetic trees show changes with time that are generally gradual and lead to stem-to-crown transitions (the period of time between the oldest-known stem-group fossil and the oldest-known fossil representing the corresponding crown group) that are long, with average durations of 123 and 120 million years for the vertebrates and the vascular plants, respectively. Such fossils can be considered as transitional fossils.
  3. Fossil images shown in this website illustrate how the characteristics of transitional fossils representing a stem group exhibit change through time. This is evolution. However, the data presented here provide no evidence that such evolution was the result of natural selection.  I believe that the evolutionary process, down to the most detailed genetic causes and effects, was directed by God.
  4. Using published phylogenetic trees it has been possible to assemble data from more than 1,700 transitional fossils.  (Data on all of these can be found in the Data page under the "Other Information" tab of the website.) 
  5. I therefore consider that the opinion, expressed by some of my fellow Christians, that transitional fossils do not exist is disproved by the data presented in this website.
  6. However, of the 195 vertebrate and vascular plant clades examined for this website, 100 (51%) provide no unequivocal evidence that they contain stem-group (i.e. transitional) fossils.  The most obvious reason for this would be that   stem-group fossils do exist but have not yet been discovered. Alternatively,   it could be a result of the fact that most of the taxa lacking  stem-group fossils were defined by molecular rather than morphological data, thus rendering recognition of stem-group fossils difficult or impossible. A further possibility is that  for some of the 100 taxa, the published phylogenetic trees are incorrect, such that there is no way of identifying stem-group fossils that have a coherent relationship with the corresponding crown group.
  7. Of the roughly 30 animal phyla that are extant at the present day, 17 appeared during a period of 21 million years from the beginning of the Cambrian period. This corresponds to an average time of 1.2 million years per phylum, much shorter than the average duration of 123 million years for the stem-to-crown transitions of all the vertebrate clades analyzed, each of which represent a component within a single phylum, the chordates. This episode of apparently very rapid evolution represents the "Cambrian explosion".
Page last updated August 24th, 2026.
Photo credit
Charles Darwin in 1881: Public domain, Wikimedia Commons