This all came to mind while watching this video by Anton Petrov.
It’s a great video about the group of archaea that we seem to be descended from, in part. Look at those cellular appendages!
To summarize life, cellular life comes in 3 major groups: bacteria, archaea, and eukarya. The first 2 are single celled and the last one can be single or multicellular. We are eukaryotes.
What are eukaryotes?
The way we talk about this bugs me. An archaea engulfed a bacteria and the bacteria became modern mitochondria as the endosymbiotic theory goes. From there complex membrane systems evolved like the nuclear membrane and the endoplasmic reticulum. But when you look at the circular genome in the mitochondria it’s tiny, most of the genes for everything including mitochondrial ribosomes have moved to the nuclear genome.
We are bacterial-archaeal composites. The 2 earliest branches of the tree of life combined into the 3rd. We are just as evolved from an archaea as we are a bacteria. Identifying with the outside membrane and main genome is a kind of bias. We are both.
What was the nature of the evolution of 1 group of cells to 2?
Since there is evidence that the chemistry of alkaline hydrothermal vents is involved in the evolution of life, I wonder how that relates to the evolution of 2 major groups of cells before eukarya showed up? Archaea are extremophiles. They seem to like things like high temperature systems and other extreme conditions. Since the alkaline vents are like internal cellular chemistry cellular life likely evolved there first. But there are 2 kinds of hydrothermal vent systems, alkaline and magmatic.
I’m of the view that this life, maybe bacteria, then seeded the magmatic hydrothermal vents which resulted in archaea as the populations became separate. The 2 kinds of vents is what makes sense to me as a means of evolving bacteria and archaea and eventually the 2 met again allowing for eukarya.
Maybe I’m wrong but it’s an interesting thought.
that is an interesting thought. how did i miss this post when it came up? thanks.
FTB put me down at the bottom of the recent posts. *Shrugs*
(Disclaimer, my writing ability is somewhat impaired at the moment, I hope word catches my mistakes and I make general sense and not a wordsalad)
Hey there again! Eukaryot symbiosis is such an fascinating topic, I love it. The video is really good, i did not know about the actin and tubulus discoveries in asgardians.
But. You wrote “I’m of the view that this life, maybe bacteria, then seeded the magmatic hydrothermal vents which resulted in archaea as the populations became separate. The 2 kinds of vents is what makes sense to me as a means of evolving bacteria and archaea and eventually the 2 met again allowing for eukarya.”
If I understand you correctly you say Bacteria became Archaea (if not, then here is something cool anyway). That is a question that was solved a while ago. Archae and bacteria evolved from a common ancestor pool (genetic drift thingy), because one turning into the other chemically pretty impossible due of the chirality in their respective membrane molecules*! One order is exclusively righthanded, the other exclusively lefthanded. Membranes with mixed chirality inherently are less stable and they slowly de-mix when they move/combine. Unguided processes result in a 50-50 mix of left and righthandedness. The distinction between the two orders came from evolving different enzymes that facilitated the monochiral assembly of membrane molecules. Both bacterial and archae live evolved under the same extreme conditions, but one group was, for reasons I don’t know, better prepared to move away from them, so they spread differently. They still interacted though and it is very probable that they formed many different symbiotic relation ships before the event that causes the “final” eukariote merger.
The Geochemistry of vents can change quite rapidly with the changes in volcanic activity, I’d wager early live could cope with both.
*(Yes I know the use different kinds of membrane molecules, bacteria use esters vs ethers of the archae, but that is not a big hurdle, biochemically speaking)