Tag: evolution
![Adapted from fig. 1.8 of [2]. Modern protein synthesis; the anticodon at one end of a tRNA molecule binds to its complementary codon in mRNA derived directly from the genome. Sequence-to-sequence translation is not highly parallel, in this model, and the process can be characterized in terms of the Shannon uncertainty in the transmission of information between codon machinery and amino acid machinery. -- biorxiv.org](https://astrobiology.newspackstaging.com/wp-content/uploads/2025/06/Biochemical-‘Cambrian-explosion.png)
![Phylogenies inferred under the gradual+abrupt clock model. The three-point estimates summarize their respective tree posterior distributions using the conditional clade distribution 0 method [57]. Median estimates of branch spike sums are shown. -- Proceedings of the Royal Society B](https://astrobiology.newspackstaging.com/wp-content/uploads/2025/06/Evolution-Is-Coupled-With-Branching.png)
![The original role of proteins was to stabilize RNA, rather than to act as enzymes. (a) The peptidyl transferase center of the Escherichia coli ribosome [96]. The figure shows the RNA that forms the catalytic site, as identified by [97], with the three proteins that form the closest association with it: the large subunit proteins L2 (red), L4 (green) and L15 (magenta). All of these have substantial non-globular parts, which are the parts in contact with the RNA. The catalytic center is in the middle of the RNA helix. (b) The human 17S U2 snRNP involved in the first step of RNA splicing [98], showing the RNA core and the protein most closely associated with it (splicing factor 3b). Again, the part of the protein in contact with the RNA is lacking in regular secondary structure. -- LIFE via PubMed](https://astrobiology.newspackstaging.com/wp-content/uploads/2025/06/Autocatalytic-Selection-As-A-Driver.png)
Posted inAnalog Studies, Arctic / Antarctic / Alpine, Atmospheres, Climate, Weather, Biogeochemical Cycles & Geobiology, Biosignatures & Paleobiology, Extremeophiles and Extreme Environments, Gaia - Planetary Perspectives, Habitable Zones, Icy Worlds, Water/Hycean Worlds & Oceanography
During Snowball Earth Early Life May Have Sheltered In Meltwater Ponds
Posted inAtmospheres, Climate, Weather, Biogeochemical Cycles & Geobiology, Extinction events, Fossils & Paleontology, Gaia - Planetary Perspectives, Habitable Zones, Impact events, Mapping, Geodesy, Cartography, Origin & Evolution of Life, Water/Hycean Worlds & Oceanography