How do the evolutionary developments of the trilobites represent stability over the long term, and change over the short term? This is the paragraph-
Coevolution in the Fossil Record
Following the Cambrian–Ordovician extinction event, life became dramatically different. During the Ordovician, marine ecosystems expanded in a uniform climate, and high sea levels produced shallow seas all over Earth. These conditions favored Paleozoic marine invertebrates. Ecological diversity was expanded by the evolution of large predators. This evolution affected trilobites, which developed spines and other features that allowed them to avoid predation. This is an example of coevolution.