Before anyone comes for me, I grew up southern baptist – went to a private christian school & was homeschooled for a few years. The extent of my “science” education when it came to evolution & the origin of the universe was “if we came from monkeys why do monkeys still exist?” and “look at this galaxy that’s shaped like a cross, isn’t god amazing!!” I’m an atheist now and would like to have some sort of understanding of how our world came to be, but trying to figure it out as an adult with no real foundation has been incredibly difficult, and none of it’s making sense. I also know I’m asking a lot as all 3 of those subjects are pretty extensive, so if you know any good videos or books I’d love some recommendations!
In: Biology
Non-scientists tend to get a lot wrong about evolution, and that leaves a lot of questions that can seem to make for contradictions.
A lot of people have the idea that evolution is about trying to build a genetically perfect individual that can be replicated across the population. That’s not right. Evolution doesn’t even operate at the level of the individual, it operates at the level of entire populations. It’s not trying to build a perfect individual, it doesn’t “want” anything, evolution is just observing a tendency of populations to build resiliency over time.
This means that the population will live on, not any particular individual. If you are in a particularly “evolved” population, that means you have a higher chance of taking on whatever environment stresses come at you, but in order to build that resilient population, there have to be a lot of experiments going on with variation, and a lot of those are going to be failed experiments.
Also, in order to be resilient, there may be a lot of characteristics that are hidden away and only come into the picture when the environment changes. It’s the latent *variation* in populations that allows them to adapt to new situations. Keeping those variations means that an organism might not be perfectly adapted to the current situation, but as long as it’s good enough to pass on those genes along with all that latent variation, then the genetic line will survive. Then when things change, it can adapt.
One final bit of this evolution preamble: Don’t confuse *evolution* with *evolution theory*. Many, many people use these terms interchangeably. Evolution is an observable **fact**. You can see that evolution happens with some bacteria and a mild toxin. We see pathogens become antibiotic resistant, etc, etc. There is no more disputing that evolution exists than there is disputing gravity. *Evolution theory* is a scientific model based on the fact of evolution that makes all sorts of predictions, and it’s changed over the years. The first theory was Darwinism, but as time goes on and we learn more, we keep improving the theory (there was punctuated equilibrium for awhile, then that got replaced, up to the modern day theory). This is no different than any other theory, we had Newtonian physics get updated with relativity, for instance.
Okay, so what about abiogenesis? Well evolution doesn’t care about life. It is highly correlated with life, but to evolution, there’s nothing particularly special about life. So if you think about the primordial soup with all these compounds running around in a high energy environment, constantly getting zapped with lightning and all these things going on, you can imagine that this soup is just chaos. There are different compounds forming and breaking all the time.
If any of those compounds happen to be an enzyme that operates on other compounds, then you might start to see the population of different compounds shift. At first, there might be a bunch of compound A and compound B, but in the presence of enzyme E, which turns A into B, the balance of things will naturally shift so there’s not many A and lots of B. What happens if B happens to itself be an enzyme that makes enzyme E? Well now as long as you have a steady supply of A coming in, there’s going to be a lot of B and E floating around. Or you might have an enzyme X that makes more of itself, a self-replicating enzyme.
Both of these things might seem improbable, but if you think about this soup just sitting there getting zapped all the time, once you realize that this process only has to take hold once and suddenly the populations will shift toward these substances that tend to replicate themselves, it doesn’t seem that farfetched. (Think of a terrible dart player playing darts. If they throw a dart, it’s highly unlikely they’ll hit a bullseye. If they throw 100 darts an hour for decades, they’ll almost certainly hit a bullseye a bunch of times.)
In this simple primordial situation, evolution is already in play. The enzymes and self-replicators that are more robust and adaptable will end up “metabolizing” all of the inputs they need more successfully to outcompete all of the other enzymes and self-replicators that aren’t as fast or as stable or adaptable.
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