Hi, there is a common trend among people in both physical and online circles: the idea that not reproducing means less reproductive success, so it means less "evolutionary success" for the...
Hi, there is a common trend among people in both physical and online circles: the idea that not reproducing means less reproductive success, so it means less "evolutionary success" for the individual. On an isolated level, the first part is true. However, a lot of people attach value-judgements to this, and wonder whether they are betraying the species by choosing not to reproduce. A lot of intellectual people even consider if they're "dumbing down" the species. And a lot of people think this must constitute some kind of paradox: more intelligence means less reproduction.
There's a lot to be said about this. First is the good ol' (and kind of boring) idea that evolution is not going toward "higher" beings, but simply a change in inherited traits in a population among generations. However, this is not my point in this post.
What I want people to consider is how much variety there is between individuals: only 0.1% of DNA differ between two individuals from the species Homo sapiens. This means the other 99.9% is the same. Despite however much media, intellectuals, and individuals might focus on differences between people, the genome is 99.9% the same.
But what if the 0.1% is so vital that it exerts an outsized influence on the rest of the genome? Well, first of all, at some level it doesn't matter. There is a reason the phrase "evolution by natural selection" is often used, instead of just using the term natural selection. It's because evolution and natural selection are not interchangeable. As stated before, evolution is a change in inherited traits in the population between generations. This includes four forces: selection, mutation, migration, and genetic drift.
Selection, as is known, tends to preserve traits that are more adapted to their environment. Mutation is the spontaneous origination of a new variation in the genome. Migration is individuals migrating to or out of a population. And genetic drift is random variation that happens between generations due to chance.
These mechanisms, taken together, determine the change of inherited traits between generations. However vital, natural selection is by far not the only means.
But-wait?! You were talking about populations, and not individuals. Why?
Well, it's because evolution makes the most sense at population level. You can't really examine the change of traits on an individual level. It's micro of the micro of the microevolution. Furthermore, at macro level (species to species evolution; speciation) it's populations that evolve, not individuals.
This is another key takeaway: in evolution, populations matter the most, not individuals.
Other than the 99.9% sameness in DNA, you can also see this in the genome structure. For the most part, we share the same number of chromosomes, structured in the same way, with genes interspersed at places that are mostly at the same part.
Supporting this, here are the current known numbers of genes in the genome, according to different sources. There is no evidence that the number of these genes differ significantly between individuals. Sure, the variations (alleles) of the exact content change very often. But not the existence of the genes themselves.
So, we not only share vast majority of the same DNA, but the way DNA and genes are structured is also almost exactly the same.
Let's summarize what I've said so far.
- Population level evolution matters the most in evolution.
- We share 99.9% of our DNA.
- We have almost the exact same genome structure.
- We have virtually the same genes (but not alleles).
Why have I said all this? Created this topic?
It's to counter the perspective that is so pervasive in culture, including intellectual spaces. The idea that not reproducing somehow makes you "unnatural", or "against laws of nature". There is, of course, already the ethical rebuttal against these claims: that natural doesn't mean good. However, what I've laid out here is also a different side of nature that is rarely talked about: in evolutionary terms, we are almost the same.
Following this logic, it can be seen that, even if you don't personally reproduce, contributing to the well-being of the population or the species means you are contributing to the inheritence of 99.9% of your DNA, its overall structure, and its gene structure. After all, your contributions make it so that other people can reproduce, and pass on these commonalities they share with you. You are not, in normative terms, "an evolutionary failure". It can even be argued that, at the current connected level of internationality where populations are quite dependent on each other, and exchange DNA with each other frequently, a global cooperative approach can even be considered the most succesful strategy.
As with most things in culture, when interpreting biology, the role of competition and dissimilarity is overemphasized, and the role of cooperation and similarity is overlooked, even when it runs counter to a lot of scientific findings. Funnily enough, Peter Kropotkin, who lived most of his life in the second part of the 19th century, realized this. Of course, he didn't have even remotely enough scientific evidence. But looking at nature, he had realized how much the role of cooperation was ignored, due to a fixation on competition. So, this is not a new problem, and my reasoning is not entirely new.
Further reading on this topic could be made by searching for "evolution cooperation" on the search engine of your choice, and on Google Scholar.