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?

The Precursors of Life

The Chemical Evolution of the precursors of Life 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.

Organic matter in the interstellar medium 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 Reference for 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 stress on 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.

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