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Abstract The search for extraterrestrial life hinges on identifying biosignatures, often focusing on gaseous metabolic byproducts as indicators. However, most such biosignatures require assuming specific metabolic processes. It is widely recognized that life on other planets may not resemble that of Earth, but identifying biosignatures “agnostic” to such assumptions has remained a challenge. Here, we propose a novel approach by considering the generic outcome of life: the formation of competing ecosystems. We use a minimal model to argue that the presence of ecosystem-level dynamics, characterized by ecological interactions and resource competition, may yield biosignatures independent of specific metabolic activities. Specifically, we propose the emergent stratification of chemical resources in order of decreasing energy content as a candidate new biosignature. While likely inaccessible to remote sensing, this signature could be relevant for sample return missions, or for detection of ancient signatures of life on Earth itself.
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Thinking outside Earth’s box—how might heredity and evolution differ on other worlds?
Abstract Scholars and the public conceive of extraterrestrial life through the lens of life as we know it on Earth. However, assumptions based on centuries of study around heredity and evolution on Earth may not apply to life truly independent forms of life, and some perspectives accepted or ruled out in the nineteenth century may need to be re-evaluated for life outside of Earth. In honor of the 200th birthday of Mendel, and to provide raw material for the creativity of storytellers, filmmakers, and the public, this thought experiment essay revisits a handful of classic concepts and approaches, as well as some unusual forms of life on Earth, to posit whether different types of genetics and evolution may exist in truly independent extraterrestrial forms. While fundamental evolutionary processes like natural selection and genetic drift are likely to still apply at least similarly in independent life forms, inheritance may be quite radically different from that envisioned by Mendel and others since.
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- Award ID(s):
- 2019789
- PAR ID:
- 10372862
- Publisher / Repository:
- Springer Science + Business Media
- Date Published:
- Journal Name:
- Evolution: Education and Outreach
- Volume:
- 15
- Issue:
- 1
- ISSN:
- 1936-6426
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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