Geological evidence tells us that ancient Earth probably looked and felt very different from the planet we all recognize today. Billions of years ago, our world was a comparatively harsh place. Earth likely had a hotter climate, acidic oceans and an atmosphere loaded with carbon dioxide. The fact that manmade climate change, through carbon dioxide pollution, is re-introducing such hotter, acidified conditions demonstrates their intertwinement.
More recently, the life sciences have begun buttressing these notions of primordial Earth. Thanks to advances in a niche field called paleobiochemistry, researchers in the last decade have started to “resurrect” ancient proteins. Studying these proteins’ properties is offering us glimpses of what life was like in bygone epochs.
The results so far are compelling. Take, for example, beta lactamase proteins, which first evolved between 2 to 3 billion years ago. These ancient proteins actually remain more stable and work better in hot spring-like temperatures of between 130 and 150 degrees Fahrenheit (54 and 66 degrees Celsius) compared to their modern counterparts. Other proteins, called thioredoxins, originated 4 billion years ago at the time of life’s origin, and these ancient proteins stay active in acidities that would break down many modern proteins. Findings of this sort help paint a portrait of life prior to 500 million years ago in the vast era known as the Precambrian.