How Does Life Begin and Develop?
Goal
1
How
Life Arose on Earth
Goal
2
Organization of Matter into Living Systems
Goal
4
Coevolution of the Biosphere and the Earth
Does Life Exist Elsewhere in the Universe?
Goal
7
Signature of Life on Other Worlds
Goal
8
Life on Mars and Europa
What is Life's Future on Earth and Beyond?
Goal
9
Environmental Change on Earth
Goal
10
Terrestrial Life in Space
Question: How Does Life Begin and Develop?
Goal
3: Explore How Life Evolves on the Molecular, Organism, and Ecosystem
Levels
Utilize modern
genetic studies, the fossil record, and ecosystem analyses to understand
the processes of evolution, with emphasis on the development of microbial
communities.
Life is a dynamic process of changes in energy and composition that occurs at all levels of assemblage, from the molecular level to ecosystem interactions. Much of traditional research on evolution has focused on organisms and their lineages as preserved in the fossil record. However, processes such as the exchange of genetic information between organisms and changes within DNA and RNA are key drivers of evolutionary innovation. Modern genetic analysis, using novel laboratory and computational methods, allows new insights into the diversity of life and evolution at all levels. Complementary to such studies are investigations of the evolution of ecosystems consisting of many interdependent species, especially microbial communities.
Background
The powerful techniques of molecular biology and molecular phylogenetics are revolutionizing our understanding of the diversity of life and the relationships between organisms. Studies of RNA and other conserved gene sequences have revealed previously unknown kingdoms of organisms in unlikely habitats, and have led to new hypotheses about environmental conditions for the origins of life. However, an understanding of the evolution of primary lineages requires more detailed studies at the genome level. Indeed, initial studies indicate that, early in evolution, transfers of genes between organisms may have been common. Coupled with mechanisms such as gene duplication and gene rearrangement, these processes indicate that simple mutation and selection are not the only evolutionary drivers. Studies of individual gene families must be extended to previously undescribed microbial species. New research teams and methodologies are needed to develop and process genome data from key taxa. If gene transfer is indeed an ancient process, it will be important to determine when and how key functions arose and spread in genomic consortia. This effort will allow reconstruction of the development of genomic complexity. Coordinated studies of microbial diversity and of changes in microbial communities are required in order to identify genetic and environmental factors that influenced the spread of biological diversity and its influence upon biospheric change. For example, we must understand how organisms affect each other, and how ecosystems alter the environment through modulation of chemistry and the composition of the oceans and atmosphere. The study of Earth's global ecology is being transformed by new technology (remote sensing and geographic information systems), process-oriented and interactive system modeling, as well as new paradigms for thinking about the global ecosystem. Our understanding of evolution will also be altered by considering catastrophic environmental changes of external origin, including asteroid and comet impacts and the consequences of nearby stellar explosions. This research is linked to studies of the co-evolution of life and the planet (Goal 4), the ability of life to survive in extreme environments (Goal 5), and the search for biomarkers on distant planets (Goal 7).