Adaptive radiation of marine invertebrates with skeletons

Adaptive radiation of soft-bodied marine invertebrates

4.6 billion years

Prokaryotic life only (bacteria and cyanophytes)

FIGURE 4.1. A. Time scale for Earth history and for life on Earth. The New York Paleozoic is from the early Cambrian to the end of the Devonian. Adapted from S. M. Stanley, Exploring Earth and Life through Time. New York: W. H. Freeman, 1989. B. Generalized geology and detailed scale for the Paleozoic rocks in New York. The vertical scale is linear and proportional to time; note that the dates of beginnings and ends of periods are given in millions of years before present. The right columns list the names of major unconformities and the names of Sloss supersequences. Most of the information is from a number of sources. The dates for the Cambrian are from Davidek et al. (2000) and Landing et al. (1998a,b). The T in the Cambrian time period indicates where trilobites first appear in the fossil record, 519 million years before present. The dates in the Epochs are the most current. The dates in the Stages have yet to be reconciled in the literature.

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