The fossil record of extinction: Analysis of extinction

摘要

Virtually all plant and animal species that have ever lived on earth are now extinct and there is ample evidence that solar system and/or galactic events have played a role in species death. Inspired by this record, the research carried out under NAG2-237 investigated a wide variety of issues dealing with the geologic history of biological extinction. Critical questions included: Can the link between the evolution of advanced life and earth's cosmic environment be confirmed If so, how has the cosmic influence affected the course of biological evolution And what does this tell us about the possibilities for life elsewhere in the universe and how should NASA's search strategies be modified Some progress was made on these questions and we now know a lot more about the extinction phenomenon than ever before. Many of the analyses were statistical in nature and were based on data compiled with NASA support. But the research ranged rather widely to include cognate problems such as the association between the extinction record and the earth's magnetic reversal history and the record of impact craters.