Researchers at the University of Leeds in the UK think they may have uncovered the energy source for the first forms of life on Earth.
Because this involves that critical time on earth when life was just getting a foothold, it’s also closely related to abiogenesis, which is the development of life from nonlife or put another way, the game-changing transition on earth from chemistry to biology.
All theories of abiogenesis have had to address two key components: replication and metabolism. Pinning down exactly what that thing called life is has always been harder than it sounds. It’s kind of like indecency…..you know it when you see it.
Every definition of life I’ve come across agrees though that life at an absolute minimum needs to replicate itself somehow and metabolize. Some think metabolism came first, modern thinking seems to be pointing towards theories in which replication came first.
Intertwined with these two components though is another critical factor that often disappears into the background: Energy.
All biology requires an energy source to support all the squishy activities it engages in.
For the first lifeforms on earth though this is a problem. Much of biology today uses an energy source that the earliest liforms probably didn’t use. I’m talking about one of the most important molecules for life on the planet. ATP otherwise known as Adenosine Tri-Phosphate.
ATP is basically the energy currency of the cell. It stores and transports chemical energy within cells to do little things like making proteins and contracting muscles. Right now you have 250 grams of ATP in your body which is roughly equivalent to a AA battery. Not much you might think but this amount of ATP is made and used every second of every day. In fact, you make and consume your body weight in ATP every day.
I did a quick calculation to find out how many AA batteries a person would use up in a day just going about normal activities. What’s your guess?
A 200lb man would need about 363 AA batteries a day to live. Imaging replacing all those every day.
ATP though is a problem for the first life on the planet. As research lead, Dr Terry Kee from the University of Leeds said:
“You need enzymes to make ATP and you need ATP to make enzymes”
How then did biology use energy before these two things existed?
This is the new discovery made by these scientists. They realized that a molecule called pyrophosphite could fit the bill. This molecule is similar to ATP but it could potentially transfer energy without using enzymes.
If you put it all together then, the idea is that meteorites possibly brought phosphorus to the young earth. The acidic and volcanic conditions turned it into pyrophosphite which may have supplied the constant energy needed when basic chemistry transitioned to biology. This then would give the ATP and the enzyme partnership time to evolve its intertwined relationship which could then take over from the pyrophosphite.
Perhaps in a century or two, our robot conquerers powered by nano fusion reactors will be looking over the remains of humanity and wonder what inefficient form of chemical energy we used.