Goal 4
Understand the interactions between life
on Earth and its planetary and Solar System environment
Investigate the historical relationship between Earth and its biota by integrating evidence from Earth history, organisms, and modern environments.
We must understand how the planetary environment influences the evolution of life and changes as a result of biological processes. Such interconnections, especially if they reveal repeated patterns, will help predict how life evolves on other planets and will help to develop strategies to detect extraterrestrial life. Given the knowledge of how life has altered diverse environments throughout Earth history, we will be better prepared to detect remnant biosignatures on other planets, even in cases where life has become extinct. In pursuit of this goal, we need to reconstruct major aspects of the evolutionary tree and time scale of life on Earth, the history of change in biomolecules and organisms (fossils), and the history and timing of environmental change. We seek patterns emerging from a synthesis that will guide us in our searches for life elsewhere.
- Objective 4.1—Earth's
early biosphere. Investigate key
biological processes and their environmental consequences during the
early history of Earth through molecular, stratigraphic, geochemical,
and paleontological studies.
- Objective 4.2—Foundations
of complex life. Study the origin
and early evolution of complex life and its planetary context to understand
better the foundations of the modern biosphere and the initial steps
leading eventually to intelligence.
- Objective 4.3—Extraterrestrial effects on the biosphere. Examine the response of Earth's biosphere (both the habitable environment and biota) to extraterrestrial events.