When scientists examined fossils of Ordovician trilobites, they found that a sample from any given stratum was almost always intermediate in their morphology between samples from strata just above or below it, providing evidence of ____.
A) convergent evolution
B) rapid speciation
C) adaptive radiation
D) punctuated equilibrium
E) phyletic gradualism

Question

Quizplus · Accepted Answer

The observation that a sample of trilobites from any given stratum was almost always intermediate in morphology between samples from strata just above or below it supports the concept of phyletic gradualism. This concept suggests that species evolve through a gradual change of traits over long periods of time.

When Scientists Examined Fossils of Ordovician Trilobites, They Found That