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Origin and Evolution of Life on Terrestrial Planets by Brack, Hornet et al. Cristina Retamoza Richard-Jacob Corona. Overview of the Origin of Evolution of Life. The paper addresses the question:
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Origin and Evolution of Life on Terrestrial Planets by Brack, Hornet et al. Cristina Retamoza Richard-Jacob Corona
Overview of the Origin of Evolution of Life • The paper addresses the question: Is is possible for life to evolve on other Earth-like exoplanets that exist outside of our Solar System?
Key ingredients are Organic Molecules (i.e. carbon) and Liquid Water Though only a small amount of amino acids are yielded An other possible theory is Hydrothermal vents A lot of Organic matter on Earth was extraterrestrial in origin. The Chemical Evolution of the precursors of Life
Organic matter in the interstellarmedium and comets • Dust grains can form in to complex organic molecules or become carbonized through UV irradiation. • Comets and Meteorites contribute to the Cosmic Dust Connection
The RNA world and RNA ancestors • Some people think that the first forms of life were cell-like in organization • Others claim it is a step in the evolutionary process. • PNA is a potential candidate for a prebiotic polymer.
Phylogenetic tree of life • 16s RNA Molecule diverges into 3 domains, Archaea, Bacteria and Eukarya • The common ancestor was likely to have been chemolithoautotrophic hyperthermophilic in nature. • A hypothesis about life is that life appeared in a semi thermophilic environment that created catalytic reactions but was was cold enough to inhibit degradation.
Appearance of Life: Terrestrial Life as a Referencefor Habitable Exoplanets
Oldest fossil record • Do to biosynthesis some scientist believe that Earth may have been active 3.9 GYR. • These are the only places with sediments older than 3.3 GYR the greenstone belts of Isua in southwest Greenland, The Barberton area east of South Africa, The Pilbara area of northwest Australia.
The role of radiation and particle-induced stresson the evolution of life • UV radiation can be responsible for evolutionary processes • Selective factors against UV • Mutations • Secondary Energetic Particles
Environmental Limits to Extreme Life-Forms • Most life forms are suited for normal environment conditions, while others can live in extreme environments. • Temperature • pH • Pressure
Points of Interest • Life could of appeared as soon as there was a stable body of water covering Earth. • Many planets are assumed to have similar evolution to Earth, thus could have life too. -No geodynamic process? Can live from underwater active volcanoes’ energy. • Life had time to become complex and adapt to a diverse range of environments, so it should be hard to end it all, even if planets evolve to one extreme.