Darwin and Brantz
The excerpts of Darwin’s writing seem to have a sort of haughty air to them. The English breeders’ version of pigeons are far superior to the Indian or Java, and each time that a breeder wishes to change the bird he’s making “improvements.” According to Darwin birds in the past were considered inferior compared to the present day version, and it is assumed that those birds in the future will serve as improvements on those birds of the present day. This bias towards mutations constantly resulting in better versions of animals is contradictory to most of what we now know about the way mutations work, and leads me to wonder whether Darwin’s attitude was an offshoot of his slightly nationalistic tendencies (seeing England as superior to the rest of the world) or if it’s just because he hadn’t realized/considered the possibility that most changes are deleterious.
In the nineteenth century the mutations or changes Darwin described are all clearly visible to the naked eye: changes in tail feathers, coat color, beak length, etc. However, most mutations that occur are on the microscopic level, and they probably are never noticed because they result in death to the organism. For example, a mutation that changes the structure of a ribosomal protein may result in a lack of protein synthesis, which would prove fatal to an organism. However, we rarely see such mutations not because they don’t occur, but because when they do occur the offspring of an organism rarely survives long enough to reproduce even a single cell cycle. I’m wondering if perhaps Darwin experienced this same bias, and that those mutations that would be harmful to a pigeon actually never showed up because they were so harmful that the pigeons never made it to birth.
Brantz mentioned the idea of domestication as an act of civilization, and that concept may be part of what gave Darwin his (in my view) bias. According to Brantz’s research, thinking at the time ran that domestication caused animals to become more civilized, and that colonizing foreign lands and introducing domesticated agricultural plants was civilizing that area. In addition, Brantz went on about the nature of pets in high society and the concept that domesticating animals carried with it a certain air of power or arrogance.
Page 86 on Brantz: “Despite some major criticisms, Darwin’s ideas about variability through natural selection were quickly accepted on both sides of the Atlantic not least because they offered a new model for how to think about the relationship between humans and animals.”
I’m a bit confused by that passage because Darwin’s theories were not accepted quickly on both sides of the Atlantic, especially on the American side. There were all sorts of counter theories and schools of thought that argued against Darwin or argued for different versions of his theories for decades after he published his work.
I’m not sure how much I agree with your first paragraph. Darwin’s writing can be quite dense with excessive numbers of clauses, so I may have misinterpreted. But, it seemed to me that he was not conveying that earlier versions of adaptations and organisms are inferior. If he was, I think he was referring to inferiority in terms of an organism’s successful adaptation to an environment. For instance, woodpeckers with longer beaks tend to get more food, and in this sense their adaptations are “superior,” not because there is some innate quality of superiority to having a longer beak, but because it is more successful and is more likely to be past on. If using this definition, any adaptation can be inferior or superior depending on the constraints of the surrounding ecosystem. Evolution DOES tend to improve on adaptations, not because beneficial mutations are really common, but because unsuccessful organisms die off, leaving those who are relatively more successful to reproduce. Also, I don’t believe most mutations are deleterious. My impression is that most have no effect on an organism’s survival. Most variability that occurs makes little difference to an organism’s success until a happenstance change in the environment selects certain individuals and reinforces those variations.
He does use the word “lower” to refer to organisms less successful than humans. He may be implying a sort of evolutionary direction toward “higherness” that doesn’t necessarily happen with evolution, but I can’t say he’s incorrect in conceptualizing species this way. There is degree of accuracy in calling us (or at least our minds) higher than other organisms.
In the long run yes evolution improves on adaptations. But I’m saying if you look at it from a pure numbers standpoint the vast majority of mutations are not helpful and I’d argue are actually harmful. Variability makes a huge difference. Mutations occur at the level of DNA, which encodes RNA, which gives the blueprints for proteins. You’ll certainly get mutations in the DNA that have no difference in the end result of the proteins, but I believe it’s more common to get a mutation that does alter the amino acid sequence of a protein and that can have big effects because proteins are so specific.
With Darwin I’m talking about the tendency to talk about superiority of the domesticated pigeons as opposed to those that aren’t, especially in regards to England vs India or Java. They’d certainly be superior in the sense that they have traits that are prized by English breeders, but they are not superior in the sense that if released into the wild they might end up killed off far more quickly than the less domesticated or inferior versions produced in India or Java. It’s all relative to what you’re using as a measure of fitness