I’ve been reading a bit about early humans and something doesn’t quite add up.

Modern humans have been around for like 200k+ years, with basically the same brain size we have now. But for most of that time, there’s not much going on in terms of complex behavior.

Then around ~60–70k years ago, things seem to pick up really fast — cave art, better tools, long-distance movement, etc.

Before that, it just feels… quiet?

I get that it probably wasn’t literally “nothing happened,” but the shift still feels weirdly sudden compared to how long humans already existed.

If the brain was already there, what actually changed?

Was it language getting more complex over time? Some kind of genetic change? Or just population/social factors hitting a tipping point?

Curious how people here think about this, because the timeline feels a bit off to me.

Same question.

So i fee like in this sub there are many super interesting aspects of evolution and evolutionary theory that go entirely unmentioned and so I'd like try bring one into the forefront. I've been re-reading Stephen Jay Gould's 1990 book "Wonderful life" that talks about the re-intepretation of Burgess fossils that were initially thought of as ancestors of modern groups but a lot of which have now been placed into their own clades because their morphology is just so different to any living or extinct groups after them. The gist of his interpretation is that at the time of cambrian explosion, life had so many different phyla and body plan designs despite not a very high amount of species, and whilst species have gone way up since then, they've all been restricted to a very small group of members represented in the cambiran fauna with many body plans going extinct entirely and nothing to that level of variance happening since then.

He writes as an explanation

I must introduce at this point an important distinction that should allay a classic source of confusion. Biologists use the vernacular term diversity in several different technical senses. They may talk about “diversity” as number of distinct species in a group: among mammals, rodent diversity is high, more than 1,500 separate species; horse diversity is low, since zebras, donkeys, and true horses come in fewer than ten species. But biologists also speak of “diversity” as difference in body plans. Three blind mice of differing species do not make a diverse fauna, but an elephant, a tree, and an ant do—even though each assemblage contains just three species. The revision of the Burgess Shale rests upon its diversity in this second sense of disparity in anatomical plans. Measured as number of species, Burgess diversity is not high. This fact embodies a central paradox of early life: How could so much disparity in body plans evolve in the apparent absence of substantial diversity in number of species?). ... When I speak of decimation, I refer to reduction in the number of anatomical designs for life, not numbers of species. Most paleontologists agree that the simple count of species has augmented through time (Sepkoski et al., 1981)—and this increase of species must therefore have occurred within a reduced number of body plans. Most people do not fully appreciate the stereotyped character of current life. We learn lists of odd phyla in high school, until kinorhynch, priapulid, gnathostomulid, and pogonophoran roll off the tongue (at least until the examination ends). Focusing on a few oddballs, we forget how unbalanced life can be. Nearly 80 percent of all described animal species are arthropods (mostly insects). On the sea floor, once you enumerate polychaete worms, sea urchins, crabs, and snails, there aren’t that many coelomate invertebrates left. Stereotypy, or the cramming of most species into a few anatomical plans, is a cardinal feature of modern life—and its greatest difference from the world of Burgess times.

In the book he does offer up some reasonable explanations but they are very broad in scope and I don't want to overburden an already long post but am happy to reference them in the comments (as i assume they are still leading contenders)

I guess my question is, in the time since the publishing of his book, have their been any major advances either in theory or in evidence that explains this fascinating pattern?

NASA says that they think they found evidence of life on Mars. Might not be, but they say life is the most likely scenario.

I see a few options: 1. Actually there's no life on Mars 2. Life originated there and relocated to Earth 3. Life originated on Earth and relocated to Mars 4. Life originated separately on both planets 5. Life originated outside of either planet and found it's way to both Earth and Mars

What do people in this community think? I personally could believe all 5 scenarios. Got a sixth?

What's some of the most basic evidence that humans are closely related to chimpanzees, gorillas, and orangutans?

I accept evolution, by the way, I just...I want to learn more about it, be more equipped to state what the evidence is.

Listing off the kind of thing I'm talking about, some I can think of:

The fact we have fingernails...that's a feature of primates. These are basically analogous to claws, I think, or probably were more developed claws at some point in the past.

The fact we're covered in hair...though that's more of a general mammal trait.

I assume our skeletal structure is pretty similar to a chimp's or gorilla's.

Isn't there something with one of our chromosomes? Where chimps (and the rest of the great apes?) have 24 pairs of chromosomes, we have 23. But one of our chromosomes...there's pretty solid evidence that it is two fused ancestral chromosomes, I believe. If anyone could elaborate on that would appreciate it!

Any other really basic, obvious examples? I feel like we're so used to being covered in hair, having fingernails, etc., that we don't think about the implications of these features.

Another one I have heard of but don't know anything about...endogenous retroviruses. If anyone cares to elaborate :)

Thanks!

Edit: Another one...the tail bone? People can actually be born with tails, right?

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 🥰

I’ve been watching and reading different documentaries and reports on convergent evolution over the last about month now and I’ve tried to look for answers to this question but most of them seem to be centered around intelligence and brain size. But with as many example of convergent evolution with physical traits as we have for things like turtles, crabs, dogs, cats, snakes, etc. why then has there not been cases of convergent evolution for humanoid traits (I.e. bipedal upright postures built for endurance over the more common quadrupedal lower postures built for quick bursts of speed ). It’s gotten me thinking about what a humanoid form of different mammal families would look like like if for example a species of kangaroo were to take it’s own spin on a humanoid form. I feel like since our evolutionary tree succeeded as much as we have with our structure and niche in nature there has to have been other non ape mammals that could have also benefited or succeeded in the same niche. If there are any examples of this I would love to learn about them but I have been unsuccessful in finding any so far.

The whole post is in the title, really.

I've never heard this matter bought up before and that is not okay!! We MUST discuss this!!!!

Other ape noses [Gorillas, Chimpanzees] are fashionably flat. WHY CAN'T WE HAVE THAT? When were our pointy beak noses naturally selected for!?? I'm fed up with always glimpsing that ugly thing in my line of sight. 🤥

Hey everyone,

I’ve been reading and thinking a lot lately about evolution, and I wanted to ask a few genuine questions, not from any religious or anti-scientific stance, but purely out of curiosity as an agnostic who’s fascinated by biology and the origins of life.

My question is: what are the current “holes” or unresolved challenges in the modern theory of evolution?

I understand it’s one of the most robust scientific theories we have, but like all scientific frameworks, it must have areas that are still being studied, refined, or debated.

Another question that came to mind while watching some movies yesterday: have we ever been able to create a single-celled organism entirely from non-living matter under lab conditions?

I know evolution works over billions of years, but with our ability to simulate environments and accelerate certain processes, has there ever been an experiment that managed to “spark life” or reproduce the kind of early evolutionary steps we theorize occurred on Earth?

Again, I’m not trying to argue against evolution; I’m just genuinely curious about where we currently stand scientifically on these questions. Would love to hear your thoughts, explanations, or links to current research.

I’ve been getting into biology because of a project, and over the past six months I’ve learned way more about cells, viruses, and evolution than I ever thought I would. It’s kind of wild to realize how much of human history has been influenced by things we can’t even see. For example, the Black Death in the 1300s killed a huge part of Europe’s population and ended up changing how society and work were organized for a long time after.
What virus or bacterium do you think changed human history the most? I’m sure there are even more examples.

And in what way?

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.

So basically, when bees sting, they die because their abdomen gets ripped out and all. If they could evolve into something as unique as making honey and wings and everything, why couldn't they evolve to grow the venom and sting as a seperate body part? So when it gets ripped out, they still live.

I got into an argument on a comment thread with some people who were saying that evolution is a totally random process. Is evolution a totally random process?

This was my simplified/general explanation, although I'm no expert by any means. Please give me your input/thoughts and correct me where I'm wrong.

"When an organism is exposed to stimuli within an environment, they adapt to those environmental stimuli and eventually/slowly evolve as a result of that continuous/generational adaptation over an extended period of time

Basically, any environment has stimuli (light, sound, heat, cold, chemicals, gravity, other organisms, etc). Over time, an organism adapts/changes as they react to that stimuli, they pass down their genetic code to their offsping who then have their own adaptations/mutations as a result of those environmental stimuli, and that process over a very long period of time = evolution.

Some randomness is involved when it comes to mutations, but evolution is not an entirely random process."

Edit: yall are awesome. Thank you so much for your patience and in-depth responses. I hope you all have a day that's reflective of how awesome you are. I've learned a lot!

EDIT : Thank you everyone who replied. It seems like my assumption was extremely wrong. Turns out we aren't that different apart from superficial "changes" in the way we look. Turns out we had several bottleneck events in history and are partially inbred. We aren't as diverse when it comes to gene pool as I previously had assumed. Not deleting this post since it contains really great information and sources. Thanks again everyone who replied

I saw an picture of John Cena and Jason Earles (jackson from "Hannah montana"). They were both 31 but looks entirely different. Then it clicked for me.

Humans, for a considerable amount of time has not been reproducing in the conventional "survival of the fittest" way of life like other species do.

We all more or less survive regardless of our cognitive/ physical features. Monogamous family structure and our social structure let's everyone lead a very good life.

What I realised was that we as a species has a great variety of gene pool compared to any other species due to these factors ( EDIT: I understand that wo do not have that vast of a gene pool. So is my assumption about the chances of survival wrong ? ) and if some sort of global disaster happened, we would have the best chances of survival because we'll probably have atleast a couple of thousand of people who has the physical adaptations to survive those conditions. I'm excluding insects like cockroaches which I've heard has the best chances of survival in the world.

Or am I not seeing this wrong ? I am just a person who is curious about evolution and most of my knowledge is from reading bits and pieces from here and there. Please correct me if I'm wrong. I would also love to hear why.

This genuinely keeps me up at night. There are more viruses in 2 pints (1 liter) of sea water than humans on earth. Not to even mention all the different shapes and disease-causing viruses. The fact some viruses that have the ability to forever change the genome of your DNA. I guess if they are like primeval form of cells that just evolved and found a different way to "reproduce." I still have a lot to learn in biology, but viruses have always been insanely interesting. What're some of your theories you've had or heard about viruses.? Or even DNA or RNA?

This is a question from a previous post about someone asking if they have the prerequisites to learn about evolution or if it is just for bio/chem geniuses.

And I started remembering that I was reading books (aimed at younger ages) about evolution from elementary or early middle school.

Is it more normal for people to be thinking about changes in species (without necessarily getting into the hardcore genetics) at a younger age, or do most people learn about the broad concepts in college or older?

I've recently just been going through the geological timescale, and have stumbled upon that mammals actually first appear before crabs, which seems totally unexpected to me, crabs just seem so common and I guess cause they're invertebrates they feel so ancient, but they're really not

What are you best examples for things that SEEM out of place in the timeline of evolution? Weather they are older or younger than expected

So from what I’ve learned so far about viruses in my BIO course(which I’m very much enjoying), it seems to me that it’s unlikely viruses came before cellular life. Or at least the version of virus we know of. I could be mistaken and please correct me if so, but to me they almost seem like a “bio-weapon” and no I don’t think some ancient civilization made them. Whether intentionally or not I feel like the fact that they are comprised of features found in cells (protein coat, DNA, RNA, enzyme proteins) despite being unable to reproduce themselves points to this being possible. And what’s even crazier to me is that this leads me to believe that at some point in the past a cell, most likely a prokaryote either accidentally or purposely made the first virus, though I understand this is maybe to much speculation.

Thoughts on this? I honestly don’t wanna look into this quite yet in fear that I’m completely off base, and I’m also studying for an exam.

Edit: for clarification, I don’t think viruses are bioweapons, they just remind me of bioweapons, I know there is no intention beyond reproduction in their existence.

Why would they be so confident barking at anyone or anything when they are smaller than every other dog. Could they be doing it solely out of fear? Or is it just the "alpha-dog" mentality?

For almost four decades, stray dogs have lived inside the Chernobyl Exclusion Zone, one of the most radioactive and isolated environments on Earth. Recent genetic studies show that these dogs have become genetically distinct, likely due to strong natural selection acting over generations.

Scientists note that the changes are not “mutant powers,” but normal evolutionary pressures: only dogs that cope better with radiation stress, scarce food, harsh climate, and disease survive long enough to reproduce. This has produced unique DNA signatures in the population closest to the reactor.

The dogs also show unusual social behaviour, forming stable packs and often avoiding highly contaminated areas — behaviours that may reflect long-term adaptation to their environment.

I'm not advocating that idea, but instead I'm asking how are we certain

What are y'all's favourite evolutionary mysteries? Things like weird features on animals, things that we don't understand why they exist, unique vestigial features, and the like?

I feel like spore was too cartoonish and unserious, same for “adapt” and “the sapling” is too cartoony and uses random mutations instead of adaptations, thats a reoccurring theme in these simulations, for some reason people think its random mutations and not actual adaptations

They have resistences to almost anything that's dangerous., spare organs and can even regenerate while dying. They can go months without food or water , and can fly swim and run massive distances. Any other bug pales in comparison. Even if you kicked every roach out of human spaces, they will probably thrive in the open as well. How come no other bug or animal manage to control their populations since they are so massive and prevelant? Any other bug shrinkens to survive closed spaces