The goals of this chapter are to offer a brief overview of the origin and evolution of organic molecules in astrophysical environments, and further, to provide a broader context to the task of understanding the origins of the materials that made up the original biosphere, particularly the cryosphere, on Earth. Much of the chemical reservoir for prebiotic and biotic chemistry in the early biosphere was likely delivered from space by comet, asteroid, and meteorite impacts. The compositions of comets and meteorites include complex organics, even molecular species as complex as amino acids and polycyclic aromatic hydrocarbons (PAHs). These materials and their precursors originate in the cold, vast interstellar clouds of gas and dust from which the Sun and other solar-system bodies were formed around 5 billion years ago. Organic molecules observed in these interstellar systems include complex hydrocarbon chains and branched structures, simple sugars, and PAHs. Finally, we will discuss the observation that if complex hydrocarbons including PAHs were present from the time life appeared on Archean

Earth, then it is not unexpected that we nd microorganisms ef ciently degrading petroleum hydrocarbons and even using them as a metabolic resource in remote polar ecosystems.