One thing you have missed here though, is some microbes have the ability to take DNA from another species of microbe and use it themselves.

https://en.wikipedia.org/wiki/Horizontal_gene_transfer

This still isn’t Lamarkian evolution, and they would’ve evolved this ability with Darwinian means, but evolution is stupidly complex and intricate. There is still fear of a “superbug” (though the media does fearmonger about it far more than they should, of course) as one antibiotic resistant bacteria could transfer their genes to another, deadlier one.

This isn’t supposed to be a “gotcha” or anything, just a bit of extra information, as there is just so much to cover.

Anti-biotics causing super bugs is still in line w/ darwinism: anti-biotic kills off bacteria, stopping an anti-biotic regiment early means whatever survivors will be the most resistant one who can then spread, thereby creating a resistant strain. The worry about superbugs comes from people not finishing regimens (giving a bacteria the chance to survive and propogate) or over prescribing (an anti-bacterial used on a virus wont do anything, but any benign bacteria present could develop resistance and might become deadly later)

Is lamarckism still a thing?

While Lamarckian evolution is categorically incorrect for genetics, is somewhat accurate for the field of epigenetics. While genetics studies your genes, epigenetics studies how those genes are expressed, “turned up or turned down” using various chemical markers on the DNA.

For example, each cell in your body has all the DNA to become any other cell in the body (pluripotency). This is how one fertilized egg can divide into the myriad cells of your body. How come your skin cells don’t turn into neurons after you’re fully grown? Epigenetics. As your cells specialize into the various functions of the body, they disable the genes they don’t need via a variety of chemical markers. So your skin cells will disable the genes for neurons, heart, stomach, etc.

Epigenetics is also at fault for cancer. When you are a fertilized egg, your body needs to divide and grow as quickly as possible. The genes that up-regulate the division rate are turned on at first. Once you are finished growing, said genes are disabled. However, cancers arise when the chemical markers that disable those genes are damaged, accidentally turning up growth speed. For example, when you smoke a cigarette, not only can the cigarette smoke mutate the genes in your lungs, they can also damage the epigenetic markers (epigenome) in your lung cells. Both can lead to lung cancer.

Epigenetics play the key role in the nurture side of the nature-nurture dichotomy. For example, epigenetics helps regulate your metabolism (how fast you burn calories). If someone gets very little food for much of their life (like in much of the developing world), their epigenome will change, instructing cells to burn less calories and conserve energy. However, if you suddenly give this same person tons of calories (like developing countries with fast food), their body will initially be unable to keep up with the influx, as their epigenome is still designed for a low-calorie environment. This is partially the reason why developing countries tend to have dramatic increases in obesity and diabetes as food availability increases.

Your epigenome can even be passed on to your kids via epigenetic markers on egg and sperm DNA. Using our previous example, properties of your parents’ metabolism can be passed onto you via their epigenome, affecting your own likelihood of obesity and diabetes. In this way the environment, not just the genes, of your ancestors affects you and your descendants.

Not all hope is lost however! In the same way the environment of your ancestors changed their epigenomes, your own environment and behavior can change your epigenome too. As an example, if you eat healthy with good nutrition, over time it can change your epigenome for the better, and you can pass these improvements to your descendants. In this way Lamarckian evolution is still kinda true!

If you want to learn more, here is a great list of introductory resources:

• quick explainer by Amoeba Sisters
• Lecture at the Royal Institution by researcher Nessa Carey
• Epigenetics Chemical Visualization by WEHI
• Role of epigenome in aging by Veritasium

I don’t really think Lamarckian evolution of genetics is a very prominent belief today. Rather, when we talk about organisms and physical phenomena, we like to ascribe them some form of agency because it makes explaining easier, not because they actually have agency.

For example, in the phenomenon of osmosis, water tends to flow towards areas of high solute concentration and away from areas of low solute concentration. When explaining to less scientific people, we usually say: “water flows towards the solute to find a balance”. Does the water actually, consciously choose to flow? NO. It’s just easier to say that then to explain, “it is more thermodynamically and entropically favorable for the water and solute to disperse evenly”.

Similarly, bacteria do not consciously choose to evolve antibiotic resistance. It’s just easier to say, “they evolved resistance after repeated antibiotic exposure” than it is to explain, “every time you took antibiotics, all the bacteria without a resistance mutation died until only resistant ones were left”.

Initially I was pretty annoyed about this too. It’s just a limitation of language and the human tendency to ascribe consciousness and agency to inanimate things.

What? That first like makes no sense whatsoever. That’s exactly how evolution works in terms of antibiotic adaption.

If you have a population of 100, then kill off all but 2 with a pesticide or antibiotic, their offspring will carry the genes that make them resistant. Continue this process hundreds, thousands, or millions of times, and you get evolution as the entity now has a near perfect defense.