Evolution and Survival of the Fittest
Questions from reading The Gene by Siddhartha Mukherjee
I am in the process of reading The Gene by Siddhartha Mukherjee, and I keep finding super insightful information about the process of life and biology. In my experience, biology is one of these fields (maybe another being Math) where depending on how you were originally introduced to it, you may either love it or hate it. In high school, I HATED it—and that might be an understatement. However, both in college and through reading this book, it may have become one of the topics I’m most fascinated by. So, take it from someone who absolutely hated biology: this book is a must read.
I plan on writing a more comprehensive review of the book, but let’s talk bout this morning. I just finished reading the chapter “The Hunger Winter”, which provides some insights into the question of how come twins, who largely share the same exact genes, end up leading two different lives? If genes are the blueprint of our identity, twins should become exactly the same person, but that is obviously not the case—why?
While I found that question fascinating (and the insights the book provided), one question I asked myself when reading one of the 17 sections in this chapter was around evolution. Section 1 through 15 basically answers the chapter’s question—essentially describing the process through which “information” is encoded within the genome and how this information can even be transmitted through generations with the purpose of evolution and survival [*]. Section 16 of the chapter is a segway into the next chapter, and it kind of says, “before moving forward, let’s talk about how this entire system of genes and cells even got started”.
I excerpted Section 16 below if you want to read it to get some context! Then, here are my thoughts as I was reading it.
The section describes how genes could start in a test tube. The entire process is quite complex and involves a lot of lucky events to lead to having genes, cells, and life.
Now, what I know from years of being in school, from reading about and learning science, is that evolution can help explain a lot of things. I wrote an article a while ago explaining where loss aversion comes from for example, and the answer has to deal with evolution and the whole survival of the fittest.
Where Does Loss Aversion Come From?
Reflections from reading Thinking Fast and Slow by Daniel Kahneman
Literally, a lot of human behavior, when put through that lens of “how would evolution theory lead to humans having this behavior”, end up having a logical reason.
With that said, I kind of asked myself, what happens before we get to this “survival of the fittest”?
Why does biology inherently want that? Why does it have to be this way? Honestly, I feel like this article is more about me asking this question than answering anything. Let me navigate through what my thoughts are about it but I would be super curious if you (the reader) have any insights!
How Evolution and Survival of the Fittest Came About
Section 16 describes the lucky set of events that had to happen to hypothetically lead to the development of genes and this entire process of reproduction. From there, we kind of take it for granted that all of the basic, physics process exist (answering where those came from is obviously a whole other ass hard difficult question). That is, we have all the basic building blocks (protons, electrons, and their makeups), we have all the various atoms and their processes, and somehow we have this earth planet where there is not living beings but we have everything else: this earth is rotating around the sun, which leads to a bunch of climate stuff (rain, earthquakes, lighting, etc) and everything. Then, the process from section 16 (excerpted below) happens, and now we have living cells that can reproduce.
What we have, so far, is an inherently random process. So, perhaps, these cells aren’t choosing to survive per se, but through this random process, the cells that are best equipped to live in this harsh earth environment are those that end up reproducing and surviving. Not just that but also the fact the earth has different climates in different areas means that in some places, cells are in an environment where their chances of survival are higher.
It’s like, imagine spawning a bunch of baby humans equidistantly all over earth—like 1 human every 10 square mile around the earth (no other living species). Some humans will spawn right above the oceans and they’ll basically die right away because they can’t breathe in the water. Others will spawn on freaking north or south pole, and they’ll basically die right away due to the extreme cold weather. Others might spawn in the middle of an erupting volcano, and they’ll basically die right away due to the extreme burning heat. However, other humans will spawn in nice ish areas, and they might encounter other humans and start forming communities and survive like that. But even then, they will be subjected to random events—like an extreme weather event, and maybe the humans that choose to stick together will have a better chance of survival. If you top that with animals, those who are more afraid of death will have a better chance of survival (because they’ll do everything they can to avoid death, which is roughly what leads to loss aversion).
People in different places may have different degrees of these though. In some places, maybe you don’t need to be that afraid of death (because there’s not that much danger around). This could lead them to behave differently, and that will create this insane diversity we have on earth.
Those are my Saturday morning thoughts into how this “survival of the fittest” comes about. It’s not that nature wants the fittest to survive. It’s that that’s just how it is—the fittest survive. But I’m curious as to what other people think on the subject. All in all, this book, The Gene, makes me think and wonder so much about the world, and I find it super fascinating.
Excerpt from The Gene: The Hunger Winter, Section 16
There might be errors in my copy below. Get the book for a clean version 😜!
But before we leap into the genome’s future, allow a quick diversion to its past. We do not know where genes come from, or how they arose. Nor car we know why this method of information transfer and data storage was chosen over all other possible methods in biology. But we can try to reconstruct the primordial origin of genes in a test tube. At Harvard, a soft-spoken biochemist named Jack Szostak has spent over two decades trying to create a self-replicating genetic system in a test tube—thereby reconstructing the origin of genes.
Szostak’s experiment followed the work of Stanley Miller, the visionary chemist who had attempted to brew a “primordial soup” by mixing basic chemicals known to have existed in the ancient atmosphere. Working at
the University of Chicago in the 1950s, Miller had sealed a glass flask and
blown methane, carbon dioxide, ammonia, oxygen, and hydrogen into the
flask through a series of vents. He had added hot steam and rigged an electrical spark to simulate bolts of lightning, then heated and cooled the flask
cyclically to recapitulate the volatile conditions of the ancient world. Fire
and brimstone, heaven and hell, air and water, were condensed in a beaker.
Three weeks later, no organism had crawled out of Miller’s flask. But
in the raw mixture of carbon dioxide, methane, water, ammonia, oxygen,
hydrogen, heat, and electricity, Miller had found traces of amino acids-
the building units of proteins — and trace amounts of the simplest sugars.
Subsequent variations of the Miller experiment have added clay, basalt,
and volcanic rock and produced the rudiments of lipids, fats, and even
the chemical building blocks of RNA and DNA.
Szostak believes that genes emerged out of this soup through a fortuitous
meeting between two unlikely partners. First, lipids created within the soup
coalesced with each other to form micelles-hollow spherical membranes,
somewhat akin to soap bubbles, that trap liquid inside and resemble the
outer layers of cells (certain fats, mixed together in watery solutions, tend to
naturally coalesce into such bubbles). In lab experiments, Szostak has demonstrated that such micelles can behave like protocells: if you add more lipids to them, these hollow “cells” begin to grow in size. They expand, move
about, and extend thin extrusions that resemble the ruffling membranes of
cells. Eventually they divide, forming two micelles out of one.
Second, while self-assembling micelles were being formed, chains of
RNA arose from the joining together of nucleosides (A, C, G, U, or their
chemical ancestors) to form strands. The vast bulk of these RNA chains
had no reproductive capability: they had no ability to make copies of
themselves. But among the billions of nonreplicating RNA molecules,
one was accidentally created with the unique capacity to build an image
of itself-or rather, generate a copy using its mirror image (RNA and DNA, recall, have inherent chemicals designs that enable the generation of mirror-image molecules). This RNA molecule, incredibly, possessed the capacity to gather nucleosides from a chemical mix and string them together to form a new RNA copy. It was a self replicating chemical.
The next step was a marriage of convenience. Somewhere on earth—Szostak thinks it might have been on the edge of a pond or a swamp—a self copying RNA molecule collided with a self-replicating micelle. It was, conceptually speaking, an explosive affair: the two molecules met, fell in love, and launched a long conjugal entanglement. The self-replicating RNA began to inhabit the dividing micelle. The micelle isolated and protected the RNA, enabling special chemical reactions in its secure bubble. The RNA molecule, in turn, began to encode information that was advantageous to the self-propagation not just of itself, but the entire RNA-micelle unit. Over time, the information encoded in the RNA-micelle complex allowed it to propagate more such RNA-micelle complexes.
“It is relatively easy to see how RNA-based protocells may have then evolved” Szostak wrote. “Metabolism could have arisen gradually, as … [the protocells learned to] synthesize nutrients internally from simpler and more abundant starting materials. Next, the organisms might have added protein synthesis to their bag of chemical tricks.” RNA “proto-genes” may have learned to coax amino acids to form chains and thus build proteins—versatile, molecular machines that could make metabolism, self-propagation, and information transfer vastly more efficient.
[*] One thing to be careful about here, which the chapter does note, is that this idea that information from a person’s life experience is somehow “encoded” into their genome and transmitted (when they reproduce) has led to junk science where people start to extrapolate from it without any scientific basis. For instance, someone might say that the experience of one’s parent, say, the parent being unfaithful, can lead to their children also being unfaithful, and they might claim this biological fact as “proof” of that when it really is not the case. The book explains the nuance here, and it is that information is encoded and transmitted in the genome with the purpose of evolution and survival. The example it gave, which was that Hunger Winter, was that 3 or more generations of people from Netherlands who had suffered a prolonged, Nazi-Germany-induced famine from September 1944 to 1945 had physiological consequences from that famine—including having higher rate of obesity and heart disease. What had happened was that the original Dutch victims’ physiology had to drastically change in 1944 in order to survive the famine, and information about this was encoded in their genome to allow their children and grandchildren to survive living in a place where getting nourished was difficult. Overall, that’s a fundamentally survival thing—it’s not some behavior (e.g., being unfaithful) that is encoded and etched into the genome that the future generations will be prone to do. It’s more like the genome saying, “we got to be prepared to survive a famine”. Honestly, I’m probably butchering this a little bit too but that’s my understanding of the nuance of this subject. 😅
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