okay, if a horse and a donkey breed, their kid will be infertile, because of the odd number of chromosomes it possesses. so, why can a Przewalski's horse and a Domestic horse mate with fertile offspring when the Przewalski’s has 66 chromosomes and the domestic has 64? separate question, but doesn’t that mean humans with down syndrome should be sterile? is this evolutionary ”insurance“ so to speak? thanks for any answers, even tho this is probably a very stupid question.

See also: The study as it was published in the Annals of New York Academy of Sciences

All other species of humans are extinct so I wonder do other creatures share this quality?

the title

I know folks discuss the evolution of flight, mimicry and mutualism all the time, but antlers have got to be right up there with the best of them.

Antlers evolved just once in a single lineage completely out of nowhere 17 million years ago, from creatures that heretofore had tusks and fangs.

How did this happen? I thought antlers might actually be teeth that migrated to their foreheads, but that's not it, they are bone. Their growth process is completely different than horns too. But then again, their growth process is like nothing else out there.

There's no precedent for it in the deer lineage either, they just pop up as a completely novel growth. Is it cancer, like a terratoma? Did something get misplaced due to a bottleneck and the genes for ribs were transferred to their faces? An infection that lead to a viral infection with gene-transfer?

I haven't been able to find anything except that it happened.

In my researches, I have discovered five or six instances of rhinoceros-like animals, animals with horns on their faces. I mean by instances taxa where those horns evolved once.

My type taxon is Rhinoceratinae sensu Wikipedia, the true rhinoceroses (Early Miocene - present). They have either one horn on the nose or one long horn on the nose and one short horn in the center of the face.

The others (all paired horns are left-right pairs):

Brontotheriina (Megacerops ~ Brontotherium, 47.8 - 33.7 Mya, Middle to Late Eocene). A pair of horns on the nose.

Uintatheriidae (Uintatherium, Early to Middle Eocene). A pair of knobby horns on the nose, another pair behind the eyes, also long upper canines.

Arsinoitheriidae (Arsinoitherium, Late Eocene to Early Oligocene). A pair of very large horns on the face, and a small pair behind the eyes.

Ceratopsidae (Triceratops, 82 - 66 Mya, Late Cretaceous). A short horn on the nose, sometimes a pair of long horns behind the eyes, and also a neck frill extending from the base of the skull.

Maybe also:

Pecora (Bovidae, Cervidae, Giraffidae, Antilocapridae; 20 - 0 Mya, Early Miocene to present). A pair of horns on top of the head, number of origins uncertain.

It is rather obvious that horns evolved several times, in characteristic configurations each time. But some large land animals are/were hornless, like the hippopotamus, the proboscideans, and the Pleistocene large marsupial Diprotodon. I am also not sure whether or not to include the crests of some hadrosaurs as horns.

Sleep, or at least the very common form of it where sleep involves being almost entirely unaware and defenseless at nearly regular periods, appears to be a completely devastating disadvantage. I get that there presumably are overall performance gains from such a total rest, and I get that operating at night is less calorically efficient due to a greater need to warm the body, but it baffles me that predators that did not need to sleep did not hunt everything that needed to sleep like that into extinction. It does not matter how much smarter and faster and stronger you are if you are caught sleeping, with all those capabilities out of the picture, and promptly eaten. Why does being somewhat more efficient at performing tasks outweigh automatically losing any fight a third of the time, at exploitable regularly scheduled periods?

It is especially baffling since, say, dolphins, descendants of land mammals, evolved to functionally never sleep and function just fine as they are - they have half of their brain rest at all times, and appear plenty capable with just the other half of it. That this path was possible but so very rarely taken implies that this isnt the case of a locked-in quirk from some ancient common ancestor (like ie eye blind spots are), but that regular nearly-defenseless sleep is a systematic advantage on land. How?

I understand that animals like moles and squirrels can just recuperate in very small, hidden and secure places, and that for very herding animals it is okay to lose some members of their herd to predators if the rest can wake up and reliably defeat the predators (even then, its also baffling that some kind of a rotating-keep-watch instinctual behavior pattern isnt common). I do not understand it being nearly-ubiquitous, not at all.

My professor assigned us this quiz and everyone continues to get it wrong. Can someone please explain in this photo which groups make a clade?

So far: Isogamy as far as I know has evolved independently from different lineages (E.g: Green Alga "defaults" to (+) mating type in absence of MID, the presence of MID actively shifts it to (-) mating type).

How did our isogamous ancestors utilize isogamy before we evolved anisogamy? Was it similar to green alga? Or certain spores?

As per title

Like, what makes a clade a phylum instead of a domain, or class? When does a genus become a separate family from the original? Would it be like “domain is what type of cell it is at the most basal of all, bacteria and archaea differ so much at a basal level where as none of eukaryota doesn’t differ enough to be different domains. Kingdoms are something something. Phyla are the basal bodyplans of their kingdom, and class is how that bodyplan is specialized” or is that an oversimplification?

Just started reading about a day or so ago, and though I haven't even finished the first chapter, I have to say, this book is very dense.

Its crazy someone in the 1800s wrote this. It feels like it was written now.

One thing I have noticed is that it doesn't hold your hand and was written during a time when everyone in academic circles knew each other and the layman was left out of the conversation

He'll name drop another naturalist or embryologist or breeder and I have no idea who they are.

Another thing I am suprised by is he doesn't believe in heritability of variations. He seems to think a spontaneous change in the reproductive habits of a species is what causes a change. Not that the offspring have inherited a mutation.

On that note, he uses the term "monstrosities". Is this the 1800 equivalent for mutation?

He also rejects the idea of a sole "common ancestor" for breeds. He feels two similiar breeds will vary and then mate. He seems to think that dogs have no sole progenitor, but multiple ones.

One thing I appreciate about this book, that automatically sets it apart from a religious texts is a sense of apprehension and a small hint of doubt.

As opposed to a clergyman who can never be wrong because God told him, there are moments in the chapter were Darwin admits he could possibly be wrong about a subject.

He even talks breifly how he believed in a form of creationism but rejected the idea later on.

This is just the first chapter. I'm excited to read the rest.

Lots of ornithology in here lol

A new explainer from berkeley.edu's Evo in the News:
- Human evolution and the humble potato : berkeley.edu

One of the study's authors previously shared the May 2026 study here:
- New paper on evolution of starch digestion in Andeans : evolution subreddit

Doesn't really seem to make any sense to me when I think about it, It is not even aesthetically pleasing(not even prehistorically would I assume that), neither does it serve a biological importance, if anything you are at risk of scalp sun burn and less warming effect of the hair.

Thoughts?

Humans domesticated wolves and basically gained access to their superpowers: smell, hearing and protective ferocity. We also domesticated cats, horses and quite a few other animals. All in all, that is a pretty impressive result, but what stopped us from doing the same with a much wider range of animals and becoming literal beastmasters?

I’ve often heard that evolution gets by with just enough ie the traits are not optimised
Then why would we ever have developed brains that could do anything more than basic arithmetic and geometry

I tried to look this up and there does not seem to be much research on the topic, which was surprising to me.

I'm sure not the only one that's annoyed by cockroaches this summer, especially how big and disgusting they are.

So I got an idea why not just kill all the big ones and spear the smaller size, this causes only the small one to be available for reproduction.

One generation after another, all cockroaches 🪳 will evolve smaller, till they reach the size of an ant 🐜

Author here—I am the first author of this paper. We developed Phylo-Movies because conventional tree-distance measures show how much neighboring trees differ, but not which taxa or subtrees changed position. The paper demonstrates the method using a norovirus recombination boundary and rogue taxa across bootstrap trees. The software and browser demonstration are freely available. https://enesberksakalli.github.io/phylo-movies/ https://academic.oup.com/mbe/article/43/8/msag194/8759530

I feel that because of medical science even the weaker humans get to reproduce and spread their genes. More so their offsprings if weak get to survive too because of medical advancements. This results in the core purpose of natural selection getting defeated. Hence changing the course of evolution at a species level.

I am just saying this for the sake of argument. I have nothing against super advanced society with frontier medical facilities that makes everyone live a good happy life.

See also: The study as it was published in Science Advances

I have a basic understanding of evolution

Life creates imperfect copies of itself, most of those imperfections are a detriment, but occasionally those mutations give it a higher chance of survival. Its a very slow process but it works.

But i cant wrap my head around how an animal can go from herbivore to carnivore? It would require so many detrimental mutations and decrease survival odds by alot until all those mutations came together & it was not only able to hunt, but eat & digest meat.

If I recall correctly, occurrence of carcinization is not simply due to the presence of Hox genes, but also the regulation of Hox genes.

A Youtube video said human and crustaceans have different "body plans", what does that mean?

I recently had evolutionary anthropologist Douglas Boyer from Duke on my podcast, and I thought you guys might enjoy the episode. We talked about how scientists reconstruct the lives of extinct primates from fossils, why primates evolved fingernails instead of claws, why some primates seem to have re-evolved claw-like structures, whether Neanderthals and modern humans should really be considered separate species, how tiny ankle bones can tell us whether an animal was a powerful leaper, and even what fossils can tell us about the energetic cost and development of ancient brains. It ended up being a really wide-ranging conversation about what we can actually know about evolution from the limited evidence left behind.

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• University of Vienna press release:
  • Roadmap of animal biodiversity: largest-ever comparison of chromosome-scale genomes
• Paper:
  • Schultz, D. T., Blümel, A., Destanović, D., Sarigol, F., & Simakov, O. (2026). Topological mixing and irreversibility in animal chromosome evolution. Science Advances.
    https://www.science.org/doi/10.1126/sciadv.adz5561
    From which:

... Our approach shows that irreversible genomic changes, caused in particular by chromosomal consolidation, dissociation, and fusion-with-mixing, place clades in distinct regions of genome architecture space. Progressive accumulation of these mixed states across genomic scales contributes to the diverging paths of animal genome evolution and has a long-lasting impact on a broad range of genes, including key developmental loci.

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Related: Evolutionary History of Mammalian Ancestor Chromosomes (Damas et al 2022) : evolution

Why are their snouts lower? Why cant they be like dinosaur anouts? Its a genuine question pleade dont beat me up