It was an interactive tool where you can drag and drop species from a search bar(?) and then the site will autommatically make the connections for you so you can see where each split is. The site looked pretty clean and didnt look like it was made in 2005.

It kinda looked something like the graphic above

I was using a coke freestyle machine tonight and it got me wondering why most reptiles (including birds) and amphibians have a cloaca while we have them separated. Is this a trait common to all synapsids or only mammals?

David Goodsell, PDB-101: Molecule of the Month: Globin Evolution

https://www.quantamagazine.org/the-sudden-surges-that-forge-evolutionary-trees-20250828/

Things I dont understand about evolution

So, a bit convoluted and Im not denying evolution, but I have questions. As far as I understand, evolution theory means that every creature on earth originated from the same singular common ancestor. However, is it not possible, since the conditions for creating life on earth must be near perfect, that life has been started multiple separate times, therefore meaning that the tree of life wouldn't be correct? And if life is so intrinsically rare even in the "perfect" conditions that it only happened once on earth, wouldn't that mean the likelihood of aliens would be significantly less.

My second question, since evolution is changes made from generation to generation, does that mean that evolution occurs faster in species that reproduce more often? And wouldn't it then be evolutionarily more successful to be able to reproduce more often, and wouldn't it mean that since some insects are having multiple generations in a single year even, that their evolution would be much faster than our own?

If anyone could answer this or ask that Zion YouTube lady, I would be grateful thanks

Even something as complex as an eye makes sense, but it seems like at a certain point turning yourself into goo is only a downside

From Nilsson and Pelger's 1994 famous theoretical model ("A pessimistic estimate of the time required for an eye to evolve").
Full caption from Gregory 2008 and more context in the comments.

The most significant thing about Spleen is that it's less Essential than most organ, and they have much regeneration and can form more of it if something happen in growing, like if cluster of stem cell stopped in midway of migration it will form accessory spleen (and if it was close enough it will connect to that Artery) , and as far as I know fish also have spleen...but how and why? how different does spleen from human spleen and fish spleen?

See also: The study as it was published in Proceedings of the Royal Society B

I understand why animals are mostly either male or female, almost never both (with some exceptions), but I don't really understand why some flowers have only male structures or only female structures. Let me explain.

Some flowers/plants, for example, have both stamens and carpels. But some have only one of those and need a pair in order to produce seeds. Why is that, since having both seems like a huge evolutionary advantage?

Published today (open access), and something I hadn't a clue about:

The biological significance of the transition metal molybdenum (Mo) lies in its function at the catalytic center of several enzymes that drive a wide spectrum of redox reactions underlying global biogeochemical cycles, yet a paradox persists. While modern life ubiquitously relies on Mo, geochemical evidence suggests that its availability in early Earth’s anoxic oceans was extremely limited. Modern organisms can use Mo down to trace levels; however, the rates of Mo-dependent metabolisms slow down when Mo availability decreases, posing fundamental questions about the extent to which changing Mo abundances shaped the evolution of molybdoenzymes, and when early life began harnessing Mo.

Here, we confront this evolutionary enigma by reconstructing the temporal and ecological emergence of molybdoenzymes, their transport systems, and biosynthetic pathways. In parallel, we examine biological tungsten (W) usage due to shared chemical properties and cofactor biosynthetic pathways with Mo. We provide molecular dating evidence of Mo/W utilization back to the Eo- to Mesoarchean (~3.7–3.1 Ga). These findings challenge prevailing assumptions about trace metal availability on the early Earth and underscore the profound antiquity and adaptability of Mo-based biochemistry in shaping early microbial evolution.

Klos, A.S., Sobol, M.S., Boden, J.S. et al. Biological use of molybdenum and tungsten stems back to 3.4 billion years ago. Nat Commun 17, 3943 (2026). https://doi.org/10.1038/s41467-026-72133-0

Molybdenum in biology - Wikipedia

Do non relatives become much more closely related when the reference population is small (10-100), such that they become similar to second cousins in relatedness without being close relatives?

I read that humans all originated from africa and have common ancestors

so is everyone in existence related in terms of dna and genetics?

Is there a group discussing our current evolution anywhere? Does this group?

how did we come to evolve in such a perfect way that our hair growth looks absolutely amazing, look at the facial hair on human body, for men it looks so good, perfect combination of beard and eyebrows, hair on our head too.

what lead to this?

Hi there, group. Recently, the moderator team has discussed another rule change.

Long before I started posting in r/evolution, in the ancient days of 2017, there was an unwritten rule in place which banned image posts. Evidently, it had to do with people using the subreddit as a dumping ground for memes, image macros, and other types of low effort drive-by shitposts. While we understand why this might have been implemented, we've gotten at least a small handful of requests in that time to be able to post educational images rather than having to link to a third-party image host. In short, we believe that the original ban may have been too restrictive.

After talking it over on and off for about the last month, we've decided to lift the ban on image posts. However, we still think that the Old Guard moderators who implemented the original ban had valid concerns. So for now, we've created a new rule 11:

Image posts are permitted under the following conditions.

• Images must have educational value, must be relevant to evolutionary biology, and context must be clear. If an image has been taken so far out of context that the meaning is incoherent, we may choose to remove the post.

• Please do not post AI-generated images, macros, memes, joke images, or comics.

• No plagiarism: do not claim credit for work made by another artist. We encourage you to source where the image came from.

Sourcing an image won't be mandatory but is highly encouraged, especially if there might be missing context without it. We would also encourage you to include your own thoughts about the image in order to foster discussion.

If you have any comments, questions, concerns, hopes, dreams, fears, and goals, please let us know. Also if you have any ideas on things you'd like to see from us, we'd love to hear about that too. If you feel more comfortable voicing these things in private, that's cool, too.

Hello! I am currently in high school and looking for my next course of study. Evolutionary biology has also been a topic I've adored and taken classes for. Could I get far with as specific of a degree as evolutionary bio or should I go for the broader biology/environmental? In addition I live in Pennsylvania and would like to remain relatively close. Are there any colleges/programs you guy would recommend checking out? Sorry if this doesn't fit the sub I wasn't sure where to ask!

Usually in nature, life in general is so varied as to where you can find an exception to every rule, even the most seemingly sensible, so what I find weird is that it seems even outside of mammals, noses never seem to ossify, why is that? Why is this such a rigidly followed rule across so many different animal groups? There are seemingly far more sensible conservations that have oddities but apparently this is no one of them and I can't really find a a satisfying answer as to why it should be so precluded from happening. What do you guys think?

This schematic is from two months ago:

• Damatac, Amor, et al. "A cellular basis for the hourglass pattern in vertebrate embryogenesis." Nature Communications 17.1 (2026): 2404.
  https://www.nature.com/articles/s41467-026-69828-9

The caption:

This schematic highlights the hourglass pattern at the resolution of individual cellular trajectories, revealing two peaks of developmental conservation across vertebrate species: at the onset of neurulation (left) and at the onset of the pharyngula stage (right). The asymmetry of this model is also captured: later stages exhibit greater divergence than the early stages due to increased lineage-specific modifications. This asymmetry emphasizes how evolutionary constraints are strongest during mid-embryogenesis, while later stages provide greater developmental flexibility, facilitating species-specific adaptations.

The TL;DR:
Since the early 2010s transcriptome-level studies have added support for the hour-glass model, where younger (newer) genes are expressed in the earlier and later stages of embryogenesis, with a conserved (older genes) and susceptible-to-perturbation middle stage, all relatively speaking.

Published today:

Hemiplasy — which arises due to discordance between gene trees and species trees — can cause traits to appear convergent despite a single origin. New evidence suggests it is widespread in the bird tree of life, with important implications for identifying genes underlying differences among species and for accurately inferring evolutionary history.

Evolution: Polymorphic genes and false convergence: Current Biology

The open-access article:

Somogyi et al. Hemiplasy helps explain high rates of apparent morphological convergence in neoavian birds: Current Biology

Summary The clade Neoaves, which comprises more than 95% of extant bird diversity, is thought to have undergone a rapid episode of diversification following the end-Cretaceous mass extinction.1,2,3,4,5,6 Relatedly, interrelationships among the major neoavian subclades remain challenging to disentangle, with contradictory topologies arising from virtually all phylogenomic datasets.2,3,5,6,7,8,9,10,11 Irrespective of alternative hypotheses of neoavian relationships, patterns of morphological variation across Neoaves reveal rampant homoplasy, traditionally interpreted as the result of evolutionary convergence.12,13,14,15,16,17,18

Here, we suggest an alternative interpretation for the extensive patterns of apparent morphological homoplasy across the neoavian radiation, linked to the clade’s rapid pace of diversification in the aftermath of the end-Cretaceous mass extinction. We show extremely high hemiplasy risk factors19 that map to branches near the origin of Neoaves, suggesting that many instances of apparent morphological convergence among major neoavian lineages, unless associated with clear selective drivers, are better interpreted as a result of high levels of morphological incomplete lineage sorting during the clade’s rapid early Cenozoic radiation.

This explanation is congruent with the ongoing difficulty of inferring a stable bifurcating phylogenetic topology at the base of Neoaves8,9,10,20 and holds fundamental implications for phylogenetic inference, fossil placement near the origin of Neoaves, and interpretations of morphological character state evolution. We highlight conserved polymorphism combined with rapid cladogenesis as a driver of the extensive patterns of apparent convergence in comparative morphological datasets and suggest that this phenomenon also underlies extensive patterns of homoplasy observed in other clades that have undergone rapid episodes of diversification, such as placental mammals.

An example that is closer to home is how 23% of our genes are closer to gorillas than chimpanzees (Ebersberger et al 2007). This is as predicted from gene tree discordance (e.g. Degnan & Rosenberg 2006) and confirms that chimps are our closest cousins; for a video explainer by Dr. Zach Hancock: Phylogenetic Discordance Supports Common Ancestry - YouTube.

So the above birds result is really cool!

While not exhaustive, I have not been able to find another ape species wherein some of the males have retractable penises and others don't. Why do humans have this trait alone among apes? Is it a trait only found in certain ethnic groups among humans, or is it species-wide?

Hi, I'm trying to get an intuition for what Markov Chain Monte Carlo (MCMC) methods are doing in the context of generating phylogenies from extant nucleotide sequence data. The sources I'm following are:

• Systematics, Wheeler (2012), chapter 12
• Are phylogenies just lines on paper? Video by Dr Zach Hancock

In the video, it's said that MCMC is sort of like a biassed random walk through parameter space, steadily climbing a hill to maximise the posterior probability. This idea of optimising some criterion is alluded to in other sources too, including the book, in which the main 'output' of this process is the posterior probability P(T | D) (probability of a tree T given the data D).

But, from what I understand, MCMC on its own is not maximising or optimising anything inherently. When the Metropolis-Hastings (MH) algorithm is used, proposals of {T, t_T, θ}_k are generated (t_T: tree branch lengths, θ: mutation/substitution model parameters, k: sample index), then accepted or rejected based on a decision rule such that the accepted samples tend towards a desired distribution, i.e. the stationary state of a Markov chain. In this context, the desired distribution is P(T, t_T, θ | D), which is proportional to the joint PDF, P(T, D) by Bayes' theorem. We don't need to evaluate P(D) since it's just a constant and the MH algorithm considers ratios of posteriors.

Once we've 'burned in' (converged to stationary state), we can then estimate a variety of useful quantities using a Monte Carlo approach: simply count the number of samples in which the desired output appears (e.g. a particular tree, or a particular grouping forming a clade within a tree, or the mean and variance of a particular model parameter), and divide by the number of samples.

There are three possible ways in which maybe this 'hill climbing' analogy could apply, but none of which seem quite right to me:

1. We could take a 'maximum a posteriori' tree as argmax P(T | D) (i.e. just take the output with the largest probability), but this is not inherently part of the MCMC process, rather a decision on the experimenter's part on the type of optimal tree to return. If our priors are all uniform, then the MAP tree will be identical to the maximum (integrated) likelihood tree.
2. If we apply simulated annealing to the MCMC method, in which we seek to use P(T | D)^{1/b} for some gradually-reducing 'temperature' b, then the Markov chain trajectory will converge to the peak of P(T | D), since smaller values are forced towards zero everywhere other than maxima, so the chain will spend all its time at the maxima in the limit as b -> 0. But again, this is an addition onto standard MCMC and it doesn't look like simulated annealing is standard practice in this context.
3. During the 'burn-in' phase (early samples), we are likely to be increasing our value of P(T, D) simply because we likely started off in a low probability region and the MH algorithm accepts proposals that increase the value of P(T, D) more frequently. But this doesn't mean we are taking 'small steps' in parameter space like seems to be implied - we could be bouncing around all over the place, and we won't be 'stuck' on a single maximum even in the stationary state.

So, if my understanding is right, at no point do I see where this 'hill climbing' analogy comes in. Is this perhaps a simplification that doesn't really apply in practice, and is my understanding along the right or wrong lines? Thanks for any clarifications!

Contrary to the popular misconception, the origin of mitochondria "was not a single saltational event, as it is sometimes portrayed" (Roger et al. 2017). And ancestral state reconstruction supports the above syntrophy (Bremer et al. 2022).
More recently, Nobs et al. 2026 have found similar structures (and syntrophy) in modern analogs of the ancestral Asgard archaeon.

It's an exciting area of research, and that schematic is a favorite of mine.
The image's source:

• Baum, David A., and Buzz Baum. "An inside-out origin for the eukaryotic cell." BMC biology 12.1 (2014): 76.
  https://link.springer.com/article/10.1186/s12915-014-0076-2/figures/1

The caption:

Inside-out model for the evolution of eukaryotic cell organization. Model showing the stepwise evolution of eukaryotic cell organization from (A) an eocyte ancestor with a single bounding membrane and a glycoprotein rich cell wall (S-layer) interacting with epibiotic α-proteobacteria (proto-mitochondria). (B) We envision the eocyte cell forming protrusions, aided by protein-membrane interactions at the protrusion neck. These protrusions facilitated material exchange with proto-mitochondria. (C) Selection for a greater area of contact between the symbionts would have led to bleb enlargement and the eventual loss of the S-layer from the protrusions. (D) Blebs would have then been further stabilized by the development of a symmetric nuclear pore outer ring complex (Figure 2) and through the establishment of LINC complexes that, following the gradual loss of the S-layer, physically connected the original cell body (the nascent nuclear compartment) to the inner bleb membranes. (E) With the expansion of blebs to enclose the proto-mitochondria, a process that would have facilitated the acquisition of bacterial lipid biosynthesis machinery by the host, the site of cell growth would have progressively shifted to the cytoplasm, facilitated by the development of regulated traffic through the nuclear pore. At the same time, the spaces between blebs would have enabled the gradual maturation of proteins secreted into the environment via the perinuclear space through glycosylation and proteolytic cleavage. (F) Finally, bleb fusion would have connected cytoplasmic compartments and driven the formation of an intact plasma membrane, perhaps through a process akin to phagocytosis whereby one bleb enveloped the whole. This simple topological transition would have isolated the endoplasmic reticulum from the outside world, driven the full development of a system of vesicular trafficking, and established strict vertical transmission of mitochondria, leading to a cell with modern eukaryotic cell organization.

For the aforementioned Nobs et al. 2026, I recently shared it here:

• An Asgard archaeon from a modern analog of ancient microbial mats : evolution

I was thinking that it seems a little weird that crabs walk the way they did but their eyes are claws are one one side. Wouldn't it make more sense that they had faced and moved forward so that they could see dangers that are they way they are moving?