![]() Some of the new copies of these molecules (which some would call “genes”) will have errors, or mutations, and some of these new mutations will improve the replication ability of the molecules. Once an information system can make copies of itself, natural selection kicks in. The “RNA world” hypothesis suggests that early life may have used RNA as material for both genes and replication before the emergence of DNA and proteins. DNA is more stable than RNA, but in contrast, RNA can be part of chemical reactions in which a compound makes copies of itself – self-replication. Importantly, nucleic acids - such as double-stranded DNA or its single-stranded cousin RNA - can store the information needed to build other molecules. Next, these simple molecules combined to form more complex ones, such as fats, proteins or nucleic acids. But if life emerged once, why not more times? But the current scientific consensus is that life emerged from non-living molecules in a natural process called abiogenesis, most likely in the darkness of deep-sea hydrothermal vents. Many lively beginnings have been suggested, from unsavoury primordial soups to outer space. This event took place four billion years ago, and it happened at a molecular level – meaning little fossil evidence remains. The origin of life is a central question in modern biology, and probably the hardest to study. Has all of life on Earth evolved only once, or are different living beings cut from different cloths? The question of how difficult it is for life to emerge is interesting – not least because it can shed some light on the likelihood of finding life on other planets. This leaves many questions open, and one of the most tantalising is how many times life magically emerged from non-living elements. The genesis of life is the oldest biological event, so old that no clear evidence was left behind other than the existence of life itself. From its humble origin(s), life has infected the entire planet with endless beautiful forms.
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