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2004 Annual Science Report

Harvard University Reporting  |  JUL 2003 – JUN 2004

The Planetary Context of Biological Evolution

4 Institutions
3 Teams
0 Publications
0 Field Sites
Field Sites

Project Progress

The Harvard NAI team was constituted in 1998 as an interactive group of biogeochemists, paleontologists, sedimentary geologists, geochemists, and tectonic geologists assembled with the common goal of understanding the coevolution of life and environments in Earth history. In Year 6, the final year of NAI activity for the Harvard group, the team completed research in its core areas of inquiry: environmental evolution in the early Paleoproterozoic (2400-2200 Ma) when oxygen began to accumulate in the atmosphere and surface ocean; the terminal Proterozoic and Early Cambrian intervals (750-525 Ma) when animal life radiated; the Permo-Triassic boundary (251 Ma) when mass extinction removed some 90 percent of Earth’s species diversity, permanently altering the course of evolution; the recognition and interpretation of molecular and isotopic biomarkers; and the astrobiological evaluation of a terrestrial analog for iron oxide and sulfate rocks recently discovered at Meridiani Planum, Mars. Our efforts in Earth history and evolution highlight the importance of Earth’s physical development for the course of biological evolution — the planetary context of evolution is likely to be a major theme of astrobiological inquiry wherever life may be found. Our paleobiological and geochemical analyses of ancient rocks and our research on the generation of molecular and isotopic biosignatures further provide the tools by which the search for life beyond the Earth will be conducted. Finally, our research on iron/sulfate rocks on Earth will help to guide continuing astrobiological investigation of the Martian surface, including projected sample return.

    Andrew Knoll Andrew Knoll
    Unspecified Role
    Objective 1.1
    Models of formation and evolution of habitable planets

    Objective 1.2
    Indirect and direct astronomical observations of extrasolar habitable planets

    Objective 2.1
    Mars exploration

    Objective 4.1
    Earth's early biosphere

    Objective 4.2
    Foundations of complex life

    Objective 6.1
    Environmental changes and the cycling of elements by the biota, communities, and ecosystems

    Objective 7.2
    Biosignatures to be sought in nearby planetary systems