THE QUALITY OF THE FOSSIL RECORD - POPULATIONS, SPECIES, AND COMMUNITIES

Paleontologists have always been concerned about the documentary quali ty of the fossil record, and this has also become an important issue f or biologists, who increasingly look to accumulations of bones, shells , and plant material as possible ways to extend the time-frame of obse rvation on species and community behaviors. Quantitative data on the p ostmortem behavior of organic remains in modern environments are provi ding new insights into death and fossil assemblages as sources of biol ogical information. Important findings include: 1. With the exception of a few circumstances, usually recognizable by independent criteria, transport out of the original life habitat affects few individuals. 2. Most species with preservable hardparts are in fact represented in th e local death assemblage, commonly in correct rank importance. Mollusc s are the most durable of modern aquatic groups studied so far, and th ey show highest fidelity to the original community. 3. Time-averaging of remains from successive generations and communities often prevents the detection of shortterm (seasons, years) variability but provides a n excellent record of the natural range of community composition and s tructure over longer periods. Thus, although a complex array of proces ses and circumstances influences preservation, death assemblages of re sistant skeletal elements are for many major groups good to excellent records of community composition, morphological variation, and environ mental and geographic distribution of species, and such assemblages ca n record temporal dynamics at ecologically and evolutionarily meaningf ul scales.