Question

After completing the "Beginner," "Intermediate," and "Expert" exercises in the Biostratigraphy Simulation, think about the logic you used. Today we know that the reason why fossils occur in an ordered succession in the fossil record (rather than being randomly distributed throughout) is because of evolution. Different species evolve, live, and go extinct, only to be replaced by others through time.

However, when William Smith discovered fossil succession in the eighteenth century, the idea that organisms evolved was still in its infancy. It wasn't until the mid-nineteenth century that evolution became widely accepted among scientists.

In recreating the fossil succession based on your outcrops, did you ever need to think about the fossils' "evolutionary position" relative to one another, or did you ever place a more "highly evolved" fossil above a "less evolved" fossil? Is knowledge of evolution necessary to reconstruct a stratigraphic reference section using the principal of fossil succession?

Answer 1

Knowledge of evolution is not necessary to utilize the principle of fossil succession in stratigraphy, as demonstrated by its use prior to the acceptance of the evolutionary theory. Nevertheless, understanding evolution provides valuable context for the progression of fossils through the strata over time.

Step-by-step explanation:

When William Smith discovered the principle of fossil succession in the eighteenth century, he observed that different fossils could be found in different geographical layers, and used this method to predict rock and fossil types when digging canals.

However, with our current understanding of evolution, it is clear that fossils are not randomly distributed but are ordered in the stratigraphic record due to the evolutionary lineage of species. Fossils show gradual evolutionary changes over time, and fossils of more “highly evolved” species might be found in newer strata than those of “less evolved” species, reflecting the chronological appearance and extinction of these organisms.

The task of reconstructing a stratigraphic reference section using the principle of fossil succession does not expressly require knowledge of evolution. However, such understanding does enrich the process and can provide additional context for why certain fossils are found in certain layers.