Their Evolution

At the molecular and cellular level, life on GJ-1214b is very similar to life on earth. Carbon chain molecules are still the key building-blocks of cells, with DNA and RNA encoding the information needed for the basic operations of reproduction and cellular repair. The proteins, metabolites and strands of DNA and RNA are suspended in a cyptoplasm that is surrounded by either a cell membrane or a rigid cell wall. So far, so good: even if you don’t know what all of those words mean, most of them should sound vaguely familiar from middle school science class.

A couple of billion years ago, however, evolution on GJ-1214b took a different turn. On earth, early microorganisms called cynobacteria discovered that they could make use of energy from the sun using photosynthesis. This produced oxygen as a by-product, which was at first absorbed by the iron in the ground but later started to build up in the atmosphere. This was the “Great Oxygenization Event” that started about three billion years ago on earth.

But on GJ-1214b, the light from the red dwarf sun was too dim, and the heavy atmosphere was too thick. Some light reached the surface of the planet, but not enough to give photosynthesis any kind of evolutionary advantage.

With so little light, there were no cynobacteria to carry out photosynthesis. Without photosynthesis, there was no source of oxygen. Without the Great Oxygenation Event, cells never developed mitochondria: the oxygen-based “power generators” that gave cells on earth the energy they needed to develop multicellular life.

As a result, almost all life on GJ-1214b has remained single-celled organisms that respire using sulfur, methane and organic compounds, instead of relying on oxygen. To this day, most of the organisms on GJ-1214b resemble the types of one-celled organisms that huddled in hot springs and around thermal vents on earth 3.5 million years ago: bacteria, algae, and archaea (single-celled ancestors of amoeba).

Mostly, anyway.

Evolution did continue on the planet, even without the Great Oxygenation Event. Without oxygen, the cells never developed an efficient enough energy source to support multicellular life the way we know it on earth; however, some species found a way to link cells together using horizontal gene transfer. Plasmids could be used as “messengers” to transmit information and commands between small groups of cells, coordinating their behavior so that they essentially operated as a single organism, even though the cells were not connected or even in physical contact with each other.

These species were multicellular, but not in any way we see on Earth: instead of collecting together to form a single body, cells evolved the ability to remote-control each other over short distances, and operate as a kind of distributed swarm organism.

In one of these species, the structure of the signals used to coordinate actions between these cells became so enormously complex that the organisms eventually developed both awareness and intelligence.

Or, to phrase it another way: the species evolved to the point where they stopped being creatures, and became people.