Other than cases of inclusive fitness, could there be cases where biological fitness is lowered by natural selection due to other compounding mechanisms?
Also I read before cavemen used to trim nails by biting them but how to trim toe nails??
Edit: I do read the replies. It seems fingernails does have many uses from tweezers to scratchers.
Now toe nails? What if we had claws for toes? Then we won’t be afraid of accidentally kicking doors or logs and can manually use our fingers to use toe claws when needed.
I've been doing research on fast food. I want to know if its possible that humans could make cellular adaptations to deal with emulsifiers and preservatives many companies blatantly put in cheap food? I know that after eating heavily industrialized foods, our bodies trigger an inflammatory response to it. And I know it's because our bodies see it as an alien substance that needs to be removed, but it can't discern harmful microbes from harmful chemicals, so it treats them both the same. This can cause chronic inflammation which leads to worse conditions. But I wonder, generation after generation of this happening, is it possible for the body to eventually come up with a way to metabolize these harmful chemicals, to make them less harmful ? Or for there to be some sort of cellular changes that can resist these substances? Like if someone was living paycheck to paycheck and had nothing but family dollar food to eat for years on end. How would this affect the body over generations? Would there be any adaptations to these harsh chemicals that are often used as cheap way to preserve something? Like sodium benzoate or even blue 1 lake for example? MSG? I know its pretty much impossible to answer now, but what do you educated lads think of this?
I’m not very smart and pretty uneducated in anything regarding science so I’m sorry if this is a silly question. I just want to know why we as a species evolved to feel emotions so strongly. Sometimes it’s great but when it comes to negative emotions like sadness or grief it becomes debilitating. Some people just stop functioning due to their emotions/mind- nothing physically wrong with them. I can’t see how emotions to this level would be beneficial. Some days all I can do is be consumed with anxiety.
I’ve heard it’s losing genes and getting smaller over the years
I was blown away when I started learning more about evolution because I thought most traits happened only once and everyone who had them necessarily had a common ancestor that came up with said trait (I believe there is a special name for them but I couldn't find it)
I however discovered this is not the case at all and that not only the traits appear more than once due to the environmental pressure but it also made me understand a lot better how evolution works.
Like, it's so much more like a big tree spreading and experimenting and having fun with all the possibilities of life. Makes me feel like we are all connected somehow, all forms of life appearing and vanishing from/to the same material like solar flares. I mean, I could be a whale 100 million years from now, who knows.
I was shocked learning that eyes, wings, viviparity and other traits that were to me so complex and elegant were in fact convergent in many species. I'd love to know more examples of both convergent and unique traits, tell me your favourites!
Two cases that have been on my mind lately as I've been delving into this research program.
Pinotti et al. 2025 in Nature paired ancient-genome sequencing of Picuris Pueblo individuals with Picuris oral-traditional accounts of lineage continuity back to the Chacoan era. The two converged. Lineage-group identity, migration narratives, and place-name continuity preserved across roughly a thousand years. Specific named individuals from the deeper end — their biographies, what they did, who they were — largely didn't.
Burley's 1998 paper on Tongan archaeology documents a cleaner version of the same pattern. The early Tu'i Tonga sacerdotal genealogy preserves position-ordinals and names back to ~AD 950, supported by institutional priestly recitation. The names are there. But Burley's exact phrase: "Little is known of these individuals beyond their names."
Two regions with no methodological connection. Same within-tradition pattern. Institutional infrastructure preserves the names but not the people.
The standard cumulative-culture story (Henrich, Boyd & Richerson) tells us high-fidelity transmission preserves cultural content but doesn't specify what enables high fidelity for some content and not others. The cultural-attraction story (Sperber) tells us drift goes toward cognitively easy forms but doesn't explain why some content resists that drift for millennia. Kelly's mnemonic-architecture story actually predicts that institutional infrastructure should preserve named-individual content. The Pinotti and Burley anchors suggest it doesn't, at least at this granularity.
Curious whether anyone here has worked on the granularity question explicitly. Within-tradition contrasts (named ancestors vs. lineage segments, ritual formulas vs. ritual explanations, named founders vs. named offices) seem like the cleanest empirical test — same source, same institution, same time depth, different granularity. Are there other case studies in the literature beyond Pinotti and Burley?
Wondering if here are any theories as to why there are no saber toothed cats (e.g. Smilodon, etc) alive? Or conversely, why no current cats have such long canines, but previous felines evolved them. Was there some environmental/evolutionary benefit that existed then but not anymore?
I wasn’t exposed to evolutionary theory much till college and even then only learned about population biology. Now I have to learn more about it for the biology CLEP. Speciation makes solid sense to me (I’m mostly self-educating through YouTube) but having not deeply studied common ancestry, I don’t really get it. I know that it’s commonly accepted based on evidence, but I’m trying to grapple with it myself as well. Anybody go through a similar reckoning?
Edit: thanks everyone for the resources 🥰
Varga, Zsombor, and Máté Varga. "Gene expression changes during the evolution of the tetrapod limb." Biologia Futura 73.4 (2022): 411-426.
https://doi.org/10.1007/s42977-022-00136-1
For the caption: https://link.springer.com/article/10.1007/s42977-022-00136-1/figures/2
PNAS Commentary:
S.N. Manivannan, & C.B. Ogbunugafor, Maynard Smith’s analogy, realized: Common ancestry constrains evolutionary percolation through protein space, Proc. Natl. Acad. Sci. U.S.A. 123 (21) e2610113123, https://doi.org/10.1073/pnas.2610113123 (2026).
The study:
L.H. Isakova, E. Streltsova, O.O. Bochkareva, P.K. Vlasov, & F.A. Kondrashov, Descent from a common ancestor restricts exploration of protein sequence space, Proc. Natl. Acad. Sci. U.S.A. 123 (14) e2532018123, https://doi.org/10.1073/pnas.2532018123 (2026). (open access)
From the commentary:
> In a new study published in PNAS, Isakova et al. address an old, unsolved problem in evolutionary biology: of all the protein sequences that could plausibly function in living cells, how many has evolution explored (1)? The answer, drawn from an analysis of thousands of protein families across vertebrates and bacteria, revisits this puzzle. The region of functional sequence space occupied by natural proteins is orders of magnitude smaller than models of protein evolution predict. Why is this so? What is the dominant constraint on how far evolution has percolated through the space of possible proteins? It turns out to be neither the difficulty of traversing the embedded fitness landscape, nor the efficiency of natural selection, but descent from a single common ancestor. The leash of shared origin, the authors demonstrate, matters more than any property of the landscape, or force of evolution.
Humans started collaborating in large numbers when evolution provided a developed prefrontal cortex for them. But short beaked echidnas also have highly developed prefrontal cortex. Then why don't they collaborate in large numbers?
What is the evolutionary purpose of the proteins that ultimately make gluten in bread? As I understand, they are only prevalent in wheat, rye, and a few other cereals. What specific purpose do they serve that other seeds and grains don't cover?
Here's a working definition of a crustacean that I think would be intuitive for a lot of people: a crustacean is any animal more closely related to a crab than to a centipede or a dragonfly.
So what does that include? Crustacea is now widely understood to be a paraphyletic taxon, wikipedia explains, because about three of its classes are more closely related to hexapods than to any other crustaceans, and one of its classes is an outgroup that is less closely related to hexapods than the other crustaceans.
(Those three classes that form a clade with hexapods are about 39 species of remipede, about 13 species of cephalocarida horseshoe shrimp, and about 2,476 species of plankton-like branchiopods, not to be confused with the mollusc-adjacent brachiopods. The one class that is an outgroup is about 7,909 species of seed shrimp, tongue worms, and fish lice. These numbers are from opentreeoflife.)
But here's the thing: about 50,910 species do in fact seem to be part of a single monophyletic clade, including just about every animal you might think of as a crustacean: crabs and hermit crabs, lobsters and crayfish, prawns and shrimp, krill, mantis shrimp, barnacles. Another 15,774 species of copepods might belong here, too.
So why have researchers from 2005-2023 sought to describe this clade (and various different formulations of it in each new study) with new titles (e.g., multicrustacea, vericrustacea, communostraca) and taken pains in the meantime to reeducate the public that crustaceans aren't a valid clade?
Wouldn't it be clearer to just call this large clade "Crustacea" and instead argue over whether copepods and remipedes and fish lice are or aren't crustaceans?
In a more general sense, I'm asking whether the practice of using new names for each new cladistic hypothesis in order to preserve the definitional continuity of taxonomic grades is actually better for public understanding than just updating the definition of old taxa as phylogenetic research advances.
Whenever I see podcast clips, read articles/books, or listen to interviews with evolutionary psychologists and evolutionary psychology, whether it's regarding mating strategies, infidelity, or how women and men approach relationships and the other sex, no matter what it is, it seems that men are portrayed in the most negative light imaginable.
Some examples (these are apparently common findings in ev psych): When it comes to infidelity, men are more concerned with sexual infidelity, women are more concerned with the emotional infidelity. When men cheat, it's simply because of sexual desire/horniness/variety; when women cheat, it's for actual meaningful reasons (although cheating is wrong either way). Men are more shallow and more focused on a woman's looks and have a stronger physical desire and stronger sociosexuality and have a more carnal, inferior sexuality, whereas women are more relational/narrative/contextual, and they are far more selective and just aren't nearly as sexual or carnal as men and their sexualities inferior superior in that way and virtuous. Men are more focused on physical pleasure and the physical bodies when it comes to sex. Women are more interested in personality and traits and kindness and intelligence and other non-physical traits, which portrays women to be superior in my view.
Then, of course, there's the theory of sexual conflict within reproduction and how it basically portrays men as just wanting to have sex as much as possible and chasing after physical pleasure and not wanting commitment, whereas women are driven by commitment, raising children, stability, and are not carnally inclined, which, of course, portrays women as morally superior. I can go on, but you get the idea. No matter what it is, whatever the topic is within mating or human sexual behavior or whatever evolutionary psychology teaches us about those things, it always degrades men and places women in a comparatively better light, or it makes men out to be shallow. And I see this everywhere within evolutionary psychology.
Is there another way to look at all this? Are the aforementioned findings within ev psych overwhelmingly true or is there a large overlap between the genders (like do many women care more about sexual infidelity, do men care about emotional infidelity, etc)?
There are theories large brains also entail a immune system more susceptible to neurodegeneration, are there examples of something like this even more extreme leading to extinction?
This study, cited in the Wikipedia article on Synapsids hints that the Synapsid-style configuration might have been ancestral to Amniotes, with Synapsids keeping this configuration while Sauropsids evolved additional fenestrae, and "anapsids" being non-crown Amniotes.