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by thinkingtoilet
603 days ago
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I highly doubt birth control has altered the selection process in humans in the span of two or three generations. I think you're right for the wrong reasons. Correlation does not equal causation. I think it's very clear it's our modern lifestyle. Our diet. Many of us are over weight. Most of us are sedentary. We're consuming higher percentage alcohol and weed. We're consuming other drugs. There are microplastics in our blood stream and the food we eat. There are chemicals like BPAs that were in our products for years before we removed them. Pollution. The list goes on. I would rule out these factors first before ever considering the idea that evolution is at play. |
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The fact that you have said this makes me think you have misunderstood my point.
I am not arguing that genetic differences are responsible for any change over the past couple generations. I am strongly arguing that there is now an enormous new selection pressure, i.e. a new factor that strongly affects fertility rates, and over time (and, perhaps a very long time) that genetic inheritance will respond to that selection pressure. That is inherently how evolution works.
People love to say "correlation is not causation", but all evolution really works with in the first place is correlation. That is, the environment changes, and then organisms that happen, through "the genetic lottery", to not be able to reproduce in that new environment are outcompeted by those organisms that do. My argument is that the environment that determines whether humans reproduce has changed drastically over the past ~100 years or so, and that this will affect which genes are likely to be more prevalent in the future. I am not arguing this genetic change has already happened.