I think the skepticism warrants more work than that. Darwin's finches are an entry-level concept to learn when learning about biochemistry and genetics. Separate planets would act to separate groups into distinct genetic populations which would then have different selection pressures put upon them. Even without selection pressure, genetic drift in both populations would result in differences compounding over time.
Humans aren't the endpoint of evolution. Something will come after us, and if we're spread out on a ton of planets, there would need to be explicit counteracting forces (genetic modification, tremendous volumes of interstellar human travel, etc.) to make sure whatever comes after us is uniform among our interstellar backyard.
No, most genetic drift that ends up being reflected in wildtype populations happens during those periods, because small errors taking up a sizable percentile of the allelic distribution is easier when there are less alleles.
When it comes to neutral mutations, we can literally see constant variance creation in plenty of non-coding areas of DNA over time.
Drift occurs at a fairly consistent rate that reflects the intrinsic error rate of the particular replication machinery that a given organism uses. You can measure the statistical error rate of different ribosomal complexes.
Different planets are going to have different selection pressures. They'll have different conflicts. Different crises. Different cultures. Different reproductive preferences. Imagining that these populations will converge on the same wildtype by sheer chance is lunacy.
I think the skepticism warrants more work than that. Darwin's finches are an entry-level concept to learn when learning about biochemistry and genetics. Separate planets would act to separate groups into distinct genetic populations which would then have different selection pressures put upon them. Even without selection pressure, genetic drift in both populations would result in differences compounding over time.
Humans aren't the endpoint of evolution. Something will come after us, and if we're spread out on a ton of planets, there would need to be explicit counteracting forces (genetic modification, tremendous volumes of interstellar human travel, etc.) to make sure whatever comes after us is uniform among our interstellar backyard.
Most genetic drift happens during 'bottleneck' periods where >80% of the population dies due to selective pressure.
No, most genetic drift that ends up being reflected in wildtype populations happens during those periods, because small errors taking up a sizable percentile of the allelic distribution is easier when there are less alleles.
When it comes to neutral mutations, we can literally see constant variance creation in plenty of non-coding areas of DNA over time.
Drift occurs at a fairly consistent rate that reflects the intrinsic error rate of the particular replication machinery that a given organism uses. You can measure the statistical error rate of different ribosomal complexes.
Different planets are going to have different selection pressures. They'll have different conflicts. Different crises. Different cultures. Different reproductive preferences. Imagining that these populations will converge on the same wildtype by sheer chance is lunacy.