For Charles Taylor, the first Axial Age resulted from the “great disembedding” of the person from isolated communities and their natural environment, where circumscribed awareness had been limited to the sustenance and survival of the tribe guided by oral narrative myth. The lifting out from a closed-off world, according to Taylor, was enabled by the arrival of written language — the stored memories of the first cloud technology. [ -- Nathan Gardels ]
There is an analogy to biological evolution that may be instructive. When all reproduction was asexual, gene variants/mutations were “embedded” in the genome in which they arose, and their spread depended largely on the fitness of their “host genome” (vertical/clonal reproduction). With the arrival of sexual reproduction and recombination roughly two billion years ago, genes could now free themselves from their native soil and spread (horizontally) to new genomic lands. Sexual reproduction also brought a new form of selection—sexual selection—that depended less on the physical environment and more on the composition of the gene pool.
But sexual selection means the gene is more constrained, more “embedded”, not less, than it was under natural selection.
For asexual, species-less organisms, a gene codes for a thing and that’s pretty much it. It probably happens to be more advantageous in some lineages of organism than others, and it’ll be selected for in those more than others, but it won’t end up having wildly different effects on different types of organism, because their genotype-to-phenotype pathways just aren’t that complicated-and-mutually-contingent yet.
Sexually-reproducing species have “alleles”; a random substitution of a single nucleotide can become a problem for an organism so intricately typed. If you manage to find a mutation that helps one species, it won’t help others. It’ll screw with large parts of the hill they’ve delicately climbed.
There’s a lot to disentangle here, but I think you’re conflating embeddedness/constraint and I’m not sure what you are saying that invalidates my original point.
- re: embeddedness—the allele in a sexual species is shuffled into a wildly different background every generation whereas it the allele finds itself in a background which is almost the same every generation with the rare exception of horizontal gene transfer. A new mutation is very much embedded in a specific genetic background in a way that it is not in a sexual organism. For a mutation to be beneficial in a sexual organism, it needs to be beneficial on average across the vast pool of genomic combinations for that species—it can’t just be beneficial in the one genotype of the organism in which it occurred like it can in a clonal species. The mutation in a sexual organism also needs to be sexually beneficial in that particular gene pool, i.e. - a gene for red feathers is only good in a gene pool where the allele for attraction to red feathers is at a high frequency.
- there are still “species” in asexual organisms, i.e. clusters in genotype space. Genes that jump to another cluster (a human pathogen → a soil bacteria) can certainly have a wildly different effect on that new cluster/species (there is something like reproductive isolation for asexual species with horizontal gene transfer).
- the diploidy and genotypic/phenotypic complexity of sexual reproducing organisms makes them much more robust to mutations. I’m not sure why you think a single nucleotide mutation can’t have a massive effect on a bacteria. They have less genes and less phenotypes but the map is still incredibly intricate and continent.
But sexual selection means the gene is more constrained, more “embedded”, not less, than it was under natural selection.
For asexual, species-less organisms, a gene codes for a thing and that’s pretty much it. It probably happens to be more advantageous in some lineages of organism than others, and it’ll be selected for in those more than others, but it won’t end up having wildly different effects on different types of organism, because their genotype-to-phenotype pathways just aren’t that complicated-and-mutually-contingent yet.
Sexually-reproducing species have “alleles”; a random substitution of a single nucleotide can become a problem for an organism so intricately typed. If you manage to find a mutation that helps one species, it won’t help others. It’ll screw with large parts of the hill they’ve delicately climbed.
There’s a lot to disentangle here, but I think you’re conflating embeddedness/constraint and I’m not sure what you are saying that invalidates my original point.
- re: embeddedness—the allele in a sexual species is shuffled into a wildly different background every generation whereas it the allele finds itself in a background which is almost the same every generation with the rare exception of horizontal gene transfer. A new mutation is very much embedded in a specific genetic background in a way that it is not in a sexual organism. For a mutation to be beneficial in a sexual organism, it needs to be beneficial on average across the vast pool of genomic combinations for that species—it can’t just be beneficial in the one genotype of the organism in which it occurred like it can in a clonal species. The mutation in a sexual organism also needs to be sexually beneficial in that particular gene pool, i.e. - a gene for red feathers is only good in a gene pool where the allele for attraction to red feathers is at a high frequency.
- there are still “species” in asexual organisms, i.e. clusters in genotype space. Genes that jump to another cluster (a human pathogen → a soil bacteria) can certainly have a wildly different effect on that new cluster/species (there is something like reproductive isolation for asexual species with horizontal gene transfer).
- the diploidy and genotypic/phenotypic complexity of sexual reproducing organisms makes them much more robust to mutations. I’m not sure why you think a single nucleotide mutation can’t have a massive effect on a bacteria. They have less genes and less phenotypes but the map is still incredibly intricate and continent.
Hope this helps.