Kurtzgesagt has a video where they claim that genetically a baby born 10000 years ago could probably be transported to the modern world and grow up “normal”.
I think that parts of the evolution process goes much faster than most people think.
For example, to feed a baby well, it is an advantage to have big breasts. So for male individuals of the homo sapiens sapiens species it becomes an advantage to select female partners that have that feature. When those produce offspring, they combine the genes for “like big breasts” when male, and the “have big breasts” when female. Combine this with circumstances where these things provide a difference “offspring chances” and you quickly get a feedback loop. Women in South america have bigger breasts (on average) than in the rest of the world. Given that the original population was mostly wiped out, this happened in 4 to 5 centuries.
Another example is that in Europe, probably in the middle ages or maybe earlier, it influenced survival chances when you “liked beer or wine”. Probably something to do with water being contaminated. Those who didn’t stay drunk too long and didn’t go very drunk had better survival chances than those who didn’t have that gene. We nowadays see that difference in Asian people who handle alcohol less well than European people.
Similarly it is likely that some things we take for granted like being able to learn-to-read is something that we have genetic help for. Is it really just our “good education” that allows almost all of us to do a little math and read the papers? There probably is not a “reading” gene that only does that. It’s probably more complicated. So somehow, the last 5 centuries has selected for those people who are better at a few things including reading that has provided them with a slight advantage. It’s possible that a few percent of us are still running around without those genes. Those are the people with severe reading problems.
Sometimes genes that look good have disadvantages as well, or the other way around. Evolution is “optimized” to keep those genes around. For example, the sickle-cell anaemia gene helps against malaria. sickle-cell anaemia is not a fun gene to have: you die at age 20-30. But in an environment with a lot of malaria, not dying of malaria is more important than that and the incidence of the gene goes up measurably in just a few generations.
I’ll say some more about slow vs fast evolution in a future post.