{"id":3570,"date":"2022-07-01T07:47:22","date_gmt":"2022-07-01T07:47:22","guid":{"rendered":"https:\/\/thepoetryofscience.peachpuff-wolverine-566518.hostingersite.com\/?p=3570"},"modified":"2022-07-01T07:47:22","modified_gmt":"2022-07-01T07:47:22","slug":"ancient-life-off-earth","status":"publish","type":"post","link":"https:\/\/scienceblog.com\/thepoetryofscience\/3570\/ancient-life-off-earth\/","title":{"rendered":"Ancient Life Off Earth"},"content":{"rendered":"

Beneath the cool embrace
\nof bygone waves
\nyou grew.
\nNot gasping,
\nbut rather
\nsearching, for air.
\nYour signature
\nevolving in the
\nshifting pigments
\nof your many-coloured coat.
\nBlues and greens
\ntransformed to
\nyellows,
\npinks,
\nand reds –
\nperipheries
\ntinged with purple
\nas we turn our gaze
\nto the stars.<\/p>\n

\"\"<\/a>
Ancient microbes, such as the Chlorobium phaeoferrooxidans pictured here, played an important role in the development of Earth’s early atmosphere (Image Credit: Katharine Thompson).<\/figcaption><\/figure>\n

This poem is inspired by recent research<\/a>, which has found that ancient microbes may help us to find extraterrestrial life forms.<\/p>\n

As Earth\u2019s atmosphere first developed it was rich in methane, ammonia, and water vapour but lacking in oxygen. As such, whilst life probably began in the ocean at least 3.5 billion years ago, it was in the form of simple microorganisms that existed anaerobically (i.e. without oxygen). It took hundreds of millions of years for enough oxygen to build up in the atmosphere and ocean, which in turn led to the development of the more complex life we observe today. Understanding what life was like for some of Earth\u2019s earliest microorganisms can thereby help us to better understand the evolution of our planet. Doing so can also provide us with clues for what signs of life might look like on other planets, whose atmospheres may more closely resemble that of our pre-oxygen Earth.<\/p>\n

These early microbes are known to have evolved something called rhodopsins, a special type of protein related to the rods and cones in human eyes, and which possess the ability to turn sunlight into energy. This energy can in turn can be used to power cellular processes such as repair and replication, and early microorganisms used this to harness the power of the sun without the complex biomolecules that are required for photosynthesis. Using machine learning, researchers in this study have now analysed rhodopsin protein sequences from all over the world and tracked how they evolved over time, creating a family tree that has enabled them to reconstruct rhodopsins from 2.5 to 4 billion years ago, and the likely conditions that they encountered. Understanding how and why these rhodopsin-possessing microorganisms have changed over both time and environment, will in turn help us to better recognise what life might look like on planets that more closely resemble the Earth of a distant past, rather than how it appears to us today.<\/p>\n