This is one of my favourite articles! But as someone who has recently become interested in botany, what I find really crazy about this is that there are so many different ways for plants to become trees. A listing (surely incomplete):
• Normal trees, like what you see every day, with bark and wood and so on
• Monocots like yucca and aloe and Draecena, which have no bark and become woody through ‘abnormal secondary growth’ (which I don’t properly understand but has something to do with wood development being scattered throughout the plant instead of in a ring around the edge), and tend to avoid branching except when the growing tip is disturbed
• Other monocots like palm trees and Strelitzias, where the ‘wood’ is actually the bases of dead leaves wrapped very very tightly together, firmly enough to keep the plant standing up
• Fern trees, which… I’m not at all sure about, but seem to work on the same principle where leaf bases sorta get fused together. But the Dicksonia in my front yard seems to extrude some sort of thin fiber — does that perhaps help to hold the trunk together in some way?
• And then there’s things like papaya and banana and giant horsetails, which become trees without any wood at all, and have presumably innovated other ways of holding themselves up
It’s interesting to walk around my neighbourhood and realise that many of the trees I see have evolved almost completely different methods to get to the same result!
Sure, it’s pretty common, and it never ceases to amaze me. But what I find particularly interesting about treehood is that it’s just so unexpected: I would never have expected that palm trees, aloes and gum trees (to take two random examples) not only both independently evolved from unrelated nontrees, but also evolved completely different ways of structuring themselves to do so, to end up with practically indistinguishable results. (Yes, I know they can be distinguished, but it takes some practice and still isn’t obvious.)
That's one big question I have. Instead of inheritance tree it's more like curved space tissue where anything that lives in a similar pit will evolve similar trait.
Well, I thought this was a fascinating and well-written article.
p.s. I learnt not long ago that there's no such 'thing' as an antelope:
"The term antelope is used to refer to many species of even-toed ruminant that are indigenous to various regions in Africa and Eurasia. Antelope comprise a wastebasket taxon (miscellaneous group) within the family Bovidae, encompassing all Old World ruminants that are not bovines, caprines, deer, or giraffes."
Also, you're a fish. When people talk about fish, they mean "fish that aren't tetrapods", because cladistically speaking, tetrapods (birds, reptiles, mammals) are fish too.
I don't see how the culinary definition of fish is related to cladistics.
Even if they were, I don't see what you dispute, because they agree on this point; if "vegetarian" means "avoid meat" and "meat" means "flesh of animal", then vegetarian also means to avoid fish. Come to think of it, eggs would also be included in that definition.
So from this I can tell that you're not one. Also, that you didn't get the joke.
I have been ovo-lacto-vegetarian for about 40 years now. So many self-identified "vegetarians" think that fish is vegetarian that many many restaurants etc. offer fish-based dishes as "vegetarian". I have frequently had to go totally without food because there was nothing available for me, because all the "vegetarian" options contained fish.
This is an extremely widespread issue, which you've never noticed. That's why you don't understand the relevance.
As for cladistics, again, this is very simple: look at the number of different types of animal that are called "fish".
. Shellfish (which includes crustaceans, i.e. arthropods, bivalve and gastropod molluscs)
. Hagfish (and lampreys)
. Starfish
. Jellyfish
Even going by simpler understandings: chondrichthyes and osteichthyes are both, to the general public, just "fish" with no particular distinction between these wildly different clades.
And this still overlaps with dietary restrictions. Kosher food excludes crustaceans but permits fish with fins _and_ scales, with a loose definition of both.
The public understanding of "fish" is a perfect example of the non-overlapping nature of the general understanding of groups of animals and plants, and the scientific one. The public understanding bears little more relationship to reality than Borges' classification in "The Analytical Language of John Wilkins" –
«
animals are divided into:
those that belong to the Emperor,
embalmed ones,
those that are trained,
suckling pigs,
mermaids,
fabulous ones,
stray dogs,
those included in the present classification,
those that tremble as if they were mad,
innumerable ones,
those drawn with a very fine camelhair brush,
others,
those that have just broken a flower vase,
those that from a long way off look like flies.
»
I have been. For instance, I was served trepang in a Chinese restaurant once. I asked what it was -- I wasn't veggie yet in those days, I was still just a kid. They told me it was a fish.
No Google in those days, so I had to go to the library and look through books, which told me it was a sea-slug. It's not.
It is of course an animal cell and demonstrates well the issues.
Hens lay eggs without copulation. These eggs are sterile: they cannot develop into an embryo and thus another hen. So, to some vegetarians, they are acceptable. They are non-viable.
But hens reared in the presence of a cockerel may well be fertilised, and thus viable, and thus not acceptable for very strict ovo-lacto-vegetarians.
Ducks, quails, and some other farmed birds, do not generally lay eggs unless they have copulated, and so their eggs are often not considered suitable for vegetarians.
Birds' eggs can be collected without harm or suffering to the animal; so, some vegetarians considera that fine.
But eggs of any type are quite definitely an animal product and so not edible by vegans, whether viable or not, fertilised or not.
Fish eggs are never suitable for vegetarians, because collecting them means killing the animal. This is a simple and obvious distinction but one that is not apparent to most non-vegetarians. So, no caviar, no fish roe, etc.
For the very strict, that also means not consuming a lot of beer, because it is fined with isinglass, a byproduct of killing fish. However, I know vegans who drink beer.
It is a lot more complicated than it appears to outsiders.
A good reminder that the map is not the territory. Lately I've started to see more and more "categories" in general as a very human construct, probably made to save on processing power when thinking about things. Reality is hard and very complex and you can't be thinking about all the details all the time.
"The famous pipe. How people reproached me for it! And yet, could you stuff my pipe? No, it's just a representation, is it not? So if I had written on my picture "This is a pipe", I'd have been lying!
Categories are an optimization. It is also a leaky abstraction and there are a large number of errors in our thinking due to this optimization, which is often premature.
We all work with computers all the time, and so we have a tendency to try to represent the universe in the simplest abstractions that capture the necessary detail for the project we are currently contemplating. When those abstractions fail to capture a necessary detail, it can be due to:
- a bad abstraction in the first place
- a new use for the representation that we hadn't thought about
- insufficient understanding of what we are trying to represent
I have seen all three of these situations repeatedly. They are all quite common.
That's pretty much a worse than pointless comment, isn't it, without some reason/justification supporting it. The wiki page for the term in question begins "Wastebasket taxon (also called a wastebin taxon, dustbin taxon or catch-all taxon)", so it does seem there's no one correct term.
Broadly speaking: a ruminant is a subset of ungulates. Well, technically too.
Ungulates have hooves (horses, pigs, camels, cows, etc). Ruminants are ungulates that eat grasses in a somewhat unique way, by partially fermenting it in their gut, and horking it back up for another good chew or three (cows, giraffes, deer, antelopes, etc).
And I say "broadly" and "somewhat" because, to intentionally misrepresent the article's title, there's no such thing as a tree (of ancestry/relationships). Camels also ferment food in their gut but aren't ruminants, as do (I assume) other kinds of animals. There are a lot of parallel evolutions, genetic crossovers, and general muddying with any kind of attempted high-level grouping of creatures.
Did you know ungulates include whales, for instance? You know, those hoofed, herbivorous aquatic mammals that people are so fond of. But not seahorses. https://en.wikipedia.org/wiki/Ungulate
Taxonomies are weird. And it only gets weirder as we dig into them more and more, and keep making adjustments and corrections.
And killer whales. Big, carnivorous and hooved with lots of teeth. Those are ungulates too.
Interestingly enough, Judaism uses rumination, in part, to determine whether an animal is okay to eat. It was called “chewing their cud”.
Pigs don’t do this and that’s why they’re not kosher.
I suspect this was the inspiration for pork being haram in Islam but it’s explicitly prohibited by name, rather than by property.
I’m not Jewish or by any means religious but I got curious one day and that’s how I learned what ruminants were (and even toed ungulates from the split hooves rule).
EDIT: clarity on comment regarding cetaceans as ungulates
I’ve become increasingly interested in what I think would be called “computational botany” if it were to be fleshed out. In looking at this and articles like it, and speaking with both trained and amateur botanists, a common thread is that the appearance of a plant has become increasingly detached from its scientific classification. A frequent refrain in nature hikes I’ve been a part of goes along the lines of: “this plant used to be family X, but then dna testing showed it was actually family Z” - “what? You’re kidding, that’s family Z? It has all the characteristics of an X!” - “Yep, Z. I don’t much understand it myself but apparently that’s what the dna says.”
I think this is a bit silly. It’s akin to categorizing programs by the libraries they use or the programming language they’re written in rather than the problems they solve. What’s more useful to the layperson: “VSCode, IntelliJ, and Vim are Text Editor family; Slack, Talk2Me, and mIrc are Chat family” or “VSCode and Slack are Electron family; IntelliJ and Talk2Me are Java family; and Vim and mIrc are C family”?
The idea with my proposed “Computational Botany” is that the only information used to classify a plant is that same information that would be used to generate a computer model of the plant. So if a specimen has all the markers of an X appearance wise, such that implementing its clone would take the least changes when starting from an existing X, it’s an X.
Of course, the actual implementation of these models may end up requiring an unattainable God-level intelligence, but I leave that as an exercise to future me (or you!)
The phylogenetic tree of life is organized not on the characteristics, but on the evolutionary origin of species. Species are in a specific branch of that tree if they share a common ancestor species with the whole branch. Shared characteristica were a good proxy for ancestry back when the mechanism behind inheritance of genes was not discovered yet. Of course, the concept of a species is a bit fuzzy (even the possibility of genetic compatibility for reproduction as a criteria has issues), but over long timescales the relationships should align into a tree.
A big underlying assumption of this is that genetic material is only passed from progenitors to offspring. Specifically, horizontal gene transfer (common for bacteria, viruses and possibly others, but believed to be very rare for multicelled organisms) throws a huge spanner into efforts to derive phylogenetic trees. It can still be useful though under the assumption that not all genes are eligible for being transferred horizontally.
Also organizing programming languages into a phylogenetic tree is doomed to failure because in general it's quite easy to transfer features from one language to another, and back, as languages are not picky about incorporating features from offspring languages.
> The phylogenetic tree of life is organized not on the characteristics, but on the evolutionary origin of species.
My mother's old university biology textbook presents this as one of a few "equally valid" visions for how taxonomy should be organized.
I agree with the modern view that it's the only valid vision, but it's interesting to see it presented in a "teach the controversy" way, and we can see from the comments above that other views have their defenders today.
However obvious gross physical characteristics may appear, evolutionary closeness is much more informative as to most questions. It tells you when things tend to be the same by default, as opposed to being the same due to similar environmental constraints.
> I think it's fine to think of those as equally valid.
Only for extremely limited purposes. Both approaches are about properties of the organism as it currently exists. The paraphyletic approach will let you know about similarity in maybe three dimensions of a ten-thousand-dimensional space. The monophyletic approach captures the other 9,997.
> Both approaches are about properties of the organism as it currently exists.
Not really, no. The monophyletic approach does that only indirectly.
Think of marsupial/mammal convergence. Is it really wrong to think of marsupial mice and mammalian mice as a somehow similar kind of thing?
Or consider secondary unicellularity. Losing multicellularity is as drastic a change as can be, and it makes no sense to try to understand the ecology of a unicellular organism by grouping it with its multicellular ancestors.
Living things are not the way they are just because of their evolutionary history, but also because of the ecological niche that evolution optimized them for.
When similar niches are filled by organisms that are not closely related, that often leads to similar solutions, which is interesting in its own right.
> Think of marsupial/mammal convergence. Is it really wrong to think of marsupial mice and mammalian mice as a somehow similar kind of thing?
It seems to me that most of the similarity can be explained by their shared phylogenetic history. Before the K-T extinction, that ecological niche was probably occupied by a very different small animal, and its occupation of that niche may have even been quite stable. So, occupation of a particular niche by an organism doesn't really imply optimization over the space of possible organisms, but rather over the space of relatively cheap modifications to existing body plans.
Think of it this way - say Australia had never been connected to the rest of the continents, so no organism with a common ancestor with mammals could exist there. How similar would the organisms filling the niche of marsupial mice be then? Probably some strategic similarities like burrowing etc, but probably enough to pass as a pseudo-mammal.
> Think of it this way - say Australia had never been connected to the rest of the continents, so no organism with a common ancestor with mammals could exist there.
This was more or less true of New Zealand until the 13th century. The only indigenous mammals were bats.
I understand how and why they have the naming system they do, I just am claiming that it’s become less and less helpful for amateur identification in favor of what scientists consider useful. I propose an alternative naming convention based only on the expressed characteristics as discoverable by the human eye rather than whatever DNA happens to be in the plant and how that may or may not relate to whatever DNA happens to be in other plants. Basically just demoting the value of DNA in favor of things you can actually see. This clearly wouldn’t replace the existing classifications, merely provide an alternative for folks looking for more explainable names.
Just like how a computer scientist might classify computer programs by instruction set, frameworks, libraries, etc. (things that show up clearly in the machine code but cannot be easily observed from the surface); but a layperson would just use UI and available features (things that are nearly indecipherable from the machine code but immediately obvious on cursory glance)
If your primary concern is that of the physical characteristics of the plant, then you don't need to use the classification system based on the phylogenetic tree. You can choose different classification systems based on need!
True, though I’ve explained it a bit backwards here. The true goal is to find algorithms that produce meshes which visually mimic plants. The thinking above is that doing so would result in a new visual classification phylogeny. Such a classification is not the goal, just a happy result.
Shape seems to be a very superficial trait. One need only consider an elephant's trunk. In terms of shape and size, it has more in common with my leg, but ask anyone, "What is an elephant's trunk?" and they will immediately tell you "A nose!"
When it comes to examining various lifeforms and fossil remains to determine ancestory, it seems to be more a matter of homology - the relationships between parts. Whether it's the same part over long periods of time (ex. comparing differences in the thumb) or different parts within the same individual (ex. comparing the big toe and thumb) or interspecies similarities (ex. the similarities of hands, feet, paws and flippers), evolution is a story of relationships, not size or shape.
I typed out a lot about how I've never compared my nose or leg to an elephant's trunk, but it seemed beside the point. The general idea was it's interesting to think of how we identify things, and this comment reminded me of Is The Man Who Is Tall Happy?[0][1] and the idea of psychic continuity.
Fascinating article, but I think it could benefit from some more examples. Since it mentions "a tree evolving into a dandelion (or vice-versa)" and then a paper about wood evolving independently at least 38 times in the Canary Islands, the perfect example is Sonchus Canariensis (https://www.smgrowers.com/products/plants/plantdisplay.asp?p..., better picture: https://garden.org/pics/2014-03-30/Kelli/5ef4db.jpg). I saw this plant during a hike on Tenerife a few years ago and found it so fascinating that it has stuck in my mind ever since. It's basically a colony of dandelions (ok, they're a bit larger, but still clearly dandelion-like) growing on long woody stalks. Not quite a tree yet, but definitely a shrub. I guess its peculiarity of only having leaves at the tip of its "branches" limits its growth, because the water circulation in a "tree" is made possible by the negative pressure produced by water evaporation on the leaves, so a "branch" can only get so long with leaves only at its tip?
And, since it later also mentions theoretical "insect birds"... well, there are some insects who are regularly mistaken for hummingbirds: https://en.wikipedia.org/wiki/Hummingbird_hawk-moth. In photos you can quite clearly see that it's an insect, but if you see it in real life it hovers around flowers just like a miniature hummingbird, and it's a bit large and bulky for a flying insect, so the confusion is understandable. BTW this is also an example of convergent evolution, and it's interesting that these moths don't exist on the American continent, where the actual hummingbirds have occupied this ecological niche.
I wasn't really surprised by the claim of the article but also hadnt thought about it explicitly much.
Bunchberries, for example, are really common where I am, and they're a type of dogwood (https://en.m.wikipedia.org/wiki/Cornus_canadensis). It's really obvious they're a dogwood too, once you get past the fact they're not woody.
Also, "tree" can get really fuzzy really fast with different shrubs in between.
That species of moth doesn’t exist on the American continent but other similar and related ones do, whose range does overlap with that of hummingbirds. For example:
The Common Earthball [1] f.x. is more related to a Porcino [2] than to a Meadow Puffball [3] which itself is related to the Field Mushroom [4].
Seems like genes are more like a toolbox where evolution takes from what it needs. After all we share a significant amount of common genes with totally different animals like flies.
Interesting. I couldn't understand for a moment why this should be surprising. Then I remembered English has 2 words for "grzyby" - fungi and mushrooms. Is that it?
I don't get the premise of the article. A tree is just a growth shape of a plant (plants are quite flexible regarding growth shapes, and often adapt to the environment), and a category that our minds place a plant species into. And its clearly an ancient ability common to all vascular plants to develop woody tissues. So why would we expect the tendency of a plant to become a tree to depend on its position in the phylogenetic tree? (the authors had me there for a moment. I thought they wanted to show that the phylogenetic tree is not really a tree!)
In addition to the sibling comments, I'd point out that the article is sort of an extended riff on the phrase, "There is no such thing as a fish," which was a sloppy QI paraphrase [0][1] of a principle elucidated by the 20th century paleontologist Stephen Jay Gould, and later became the title of QI's well-known podcast [2]. And of course, fish do exist, just not in the simplistic way that many of us were taught as children, that they are one of five genetically discrete, self-contained, non-overlapping taxonomic classes: Fish, Amphibians, Reptiles, Birds and Mammals.
The author is arguing that if you are going to say that about fish, you can say it about trees, fruit, and plenty of other things. That may be true, but unlike with fish, I don't ever recall being given the impression that trees and fruit were genetically discrete self-contained scientific categories. Fruit just seemed like something that some plants have, without any sense that fruity plants were necessarily more closely related than non-fruity plants. I mean, "biped" is also a category but nobody ever claimed that birds and humans are genetically discrete from the other four, six, eight, etc. legged animals. Still, it's a fun and interesting conversation, even though the author may have been forcing the fish analogy a bit.
[0] QI ("Quite Interesting") is a long-running British trivia/humor related game show
The point seems to be close to what you describe, but not entirely: "chair" is a human-made label, assigned to physical objects in the real world, but it's too abstract. Lots of objects resembling a chair or named "chair" exist, each with their own peculiarities, features, identity, but that's just humans going around, marking stuff with an invisible label maker.
Intuition and vernacular make poor guides to the formal lexicon of taxonomy, as I learned over the course of trying to answer the question "okay, so what kind of wasp am I looking at right now, anyway?" Two years, a couple shelf-feet of research material, and a great deal of dedicated study later - "dedicated" here meaning for example that I taught myself how to bind books because they're better for annotation and reference than PDFs - I find myself more or less able to give a fairly confident answer to that question in about two-thirds of cases, and even at that I'm often not very sure. And that's all just been to develop an experienced birder's sense of where a given animal fits into the broader picture! It'd be a lot more complicated if I were more than just a casual amateur.
Phylogenetically, it's likewise reasonable to say that there's no such thing as a wasp, as the category is paraphyletic in "all of Apocrita that isn't ants and bees". This doesn't render "wasp" meaningless in its vernacular sense, of course - I may know I just saw a female Auplopus architectus metallicus [1], but if you ask about her, I'll spare you the detail and just say she's a spider wasp whose babies are lucky to have a mom who's busy seeing they'll grow up big and strong like her. The point of the article isn't to discuss the vernacular, and the point of "there's no such thing as a tree" is to make a startlingly counterintuitive assertion that draws the reader into a detailed discussion of how genomic taxonomy works. Such statements constitute a fairly common rhetorical technique - one worth knowing about, so as not perhaps again to miss the forest for a single tree.
You’re right that is what makes a tree. But don’t you feel that it’s obvious that different lineages of plants could acquire, and lose, woodenness independently of each other? And therefore 100% unsurprising that “tree” is not a monophyletic group.
Definitely not obvious. I have no idea how complex "woodiness" is, evolutionarily. It's like if you asked me "don’t you feel that it’s obvious that different lineages of animals could acquire, and lose, feathers independently of each other": probability is certainly non-zero but is it negligible or is it actually likely? No idea, I'm not an evolutionary biologist, and would read an article about it with interest
Precisely. I think this has been on HN before, or if not then another “Wow you’re gonna be surprised by this — trees aren’t monophyletic!” article. Given all the surprising examples of convergent evolution, and given human tendencies to give vernacular names to paraphyletic groups, and given that it’s obviously easy for plant lineages to increase or decrease the woodiness of their stems, it is baffling that anyone would think it surprising that “trees” aren’t monophyletic.
I think you massively overestimate how much general knowledge about biology people have. For a lot (I would reckon most, but obviously I have no evidence of that) of people, terms like 'paraphyletic' are literally not in their vocabulary.
Yeah, no, fair enough. I didn't mean that people would express it in that terminology, or appreciate the distinction between paraphyly and polyphyly! What I'm trying to say is: anyone who has ever poked around in some wild vegetation (even as a kid) knows that "normal plants" vary quite a bit in their woodiness. There are little ones, and sort of stiff little ones, and then there are "shrubs". I think most people here have the nous to think at this point "wtf's a shrub?" and 'I am doubting that "shrub" is actually a real thing'. Hence, by extension, tree? They are just sort of big stiff things aren't they?
Perhaps I'm just on the low end of botanical curiosity, but I wouldn't ever have made that leap myself. If you'd asked my younger self 'what is a shrub?' I would have said 'uh, like a small bush?'. It would never have occurred to me to pursue the thought any further: my mind interfaced well with mechanical and electrical and computational things, and not at all with living things! I'd just about struggled through introductory Biology at school but was never particularly interested in it.
So - yes, if you'd asked me whether all trees had a single woody ancestor, I would probably have said yes. I'd come across the idea of convergent evolution in animals before, but at least convergently evolved animals were really obviously different. Trees were obviously all the same thing: big trunk, some branches, green bits on the end. Some of them were coniferous and some deciduous, but I would have guessed that was a far-back ancestral split.
I had no idea that tree ferns even existed!
Anyway, the conclusion of this very rambling story is that I started dating an horticulturist and rapidly learned an enormous number of mind-melting facts about plant biology. But I still remember knowing absolutely nothing.
> Why don’t more plants evolve towards the “grass” strategy?
Grasses have a trick: Grass blades grow at the base of the blade and not from elongated stem tips. This low growth point evolved in response to grazing animals and allows grasses to be grazed or mown regularly without severe damage to the plant. https://en.wikipedia.org/wiki/Poaceae#Description
This is one of the cool things about math, there are a lot of aspects of math which stem from thinking, "well what if I took a square root of negative one?" or "what if geometry worked this way?" and then someone does the thought exercise and fleshes it out into something interesting. And then there just happen to be aspects of reality that end up being very nicely described by these what if questions
> there are a lot of aspects of math which stem from thinking, "well what if I took a square root of negative one?"
I don't think that's what imaginary numbers stem from. If I recall, they came from the much more specific question of "what if I apply the formula for roots of a cubic polynomial, even when that formula produces some nonsensical intermediate values that end up canceling each other out?".
It's less about "what if we do this?" and more about "we have this method, and it seems to work even in cases where it's not obvious that it should work".
That is the reverse of this subject in botany, we have this method that we know works and is logical lets make our language more logical. The problem with that is the same reason we don't use imaginary numbers everywhere we can use them. Veritasium has a video description [1] with links to references about the history of imaginary numbers and polynomials. There are some great writing on this and understanding not the history but the problems that gave rise to imaginary numbers, this connection to taxonomy makes me want to read them again.
There must be a study of this; failed attempts of taxonomy.
Historically the square root of negative one arose more naturally than you might think; it is basically impossible to avoid it when you derive a cubic formula. Historically the work on complex numbers started as soon as cubic and quartic formulas were derived, because complex numbers emerge naturally and unavoidably from those formulas (even for polynomials that have only real roots). At first mathematicians were generally dismissive of the imaginary units and viewed them as "nonsense" terms that sometimes appear in some formulas and there was a lot of doubt about dealing with such terms (the same doubt you might have if someone divided by zero while solving some formula, even if they wind up finding the correct answer). Those doubts were completely eliminated by the proof of the fundamental theorem of algebra.
For what it's worth, you can avoid "imaginary" numbers entirely if you want -- you can do arithmetic on real polynomials modulo x^2+1, or equivalently on 2x2 real matrices of a special form.
Words for categories typically aren't defined willy-nilly. The category "tree" comprises objects that share certain traits. The article makes the point that many species that are distantly-related share those traits, while some more closely-related species don't. I find that surprising.
> ...and they all looked pretty much the same – feathers, beaks, little claw feet, the lot. You had to be a real bird expert to be able to tell an insect bird from a mammal bird
I've seen this insect in person and I was persuaded it was a hummingbird that somehow got to Poland. It's huge for an insect, feeds of flowers hovering in place just like a hummingbird does, nothing like an usual flying insect. It has texture that look like feathers and when it feeds it often looks like he has a long straight beak.
Only on photos or very up-close you can recognize some things don't match.
We argued for a few hours what it was until we found it's actually an insect.
I had a pretty rigorous and extensive course of biology in high school, we spent a lot of time poring over various details, but the word clade never even fell. (Granted, that was 1992-1996, so things might have changed.)
I only met the expression cladistics and clade much later in some popsci literature.
Most HN readers I'd wager. Regardless, "Trees are not a distinct evolutionary group" or "Trees are not all related to each other" or any number of other accurate or semi-accurate headlines are better than "There's no such thing as a tree".
I made a similar comment further up the page: I think some people massively overestimate the amount of general knowledge people have about biology. Like the article says, a lot of people are still at the 'did you know a tomato is a fruit??!' stage.
I think the first time I encountered /clade/ was in Bruce Sterling's Shaper/Mechanist stories. "Cicada Queen" was written in 1983, but I expect that I thought he made the word up for several more years.
Can we say the same about moths? I’m an avid participant on iNaturalist. I record lots of moth sightings because there really are many beautiful moths in Hong Kong.
There’s a “Hong Kong Moths” project on iNaturalist, but adding observations to that project can be very frustrating because the observation must be in one of the defined (sub)families.
But to an amateur like me, a moth is a moth is a moth. Sometimes even the machine identification is way off and I know it’s a moth because of the general body features.
And I wouldn’t want to put it in a random (sub)family just to get the observation included in the project. I’d have to @mention some moth expert (e.g. @hkmoths, Dr. Roger Kendrick) to help me ID the observation first.
This reminded me of the fascinating obversation of convergent evolution, the "independent evolution of similar features in species of different periods or epochs in time" [1].
For example, the concept of flight has evolved independently numerous of times (insects, birds, pterosaurs, and bats), so it would not be unreasonable to assume that it would evolve again, were life to start over from scratch.
This just means that our notion of a tree does not map cleanly to a genetic lineage. That does not mean the concept is useless, even in scientific fields.
Following a link in that article lead me to https://en.wikipedia.org/wiki/Welwitschia, where I found what will be probably be the best sentence that I've read today:
Plants in Angola are better protected than those in Namibia, because of the relatively high concentration of land mines in Angola, which keep collectors away.
I'm not a botanist, but I understood that trees and herbs are genetically close when I visited Madeira and saw the Dandelion tree [1] - a tree which leaves and flowers are regular dandelions.
In many parts of the US, there's poison ivy, a noxious weed that can cause severe itching, rashes, ect on contact with skin. It's common where I live, so I've become very good at identifying it.
Sometimes it's just groundcover. Sometimes it's a shrub. Sometimes it's a vine. It's surprising how its stem can take many different forms.
When I started my studies, we had a tour of the hortus of our university. A retired taxonomist gave us the tour, and was lamenting how genetic research had changed quite a bit of the taxonomy of his gardens, and that the old art of careful observation and encyclopedic knowledge of the appearance of plants was lost on his successors.
The classification we overlay on what we perceive might (or might not) relate to physical reality. One is objectively real, one is theoretical.
We can have all sorts of theories about how things have come to be, but again these might (or might not) relate to reality.
We do not and cannot achieve a theory of everything, even if we kid ourselves that we can be papering over the cracks. Physical reality just isn't that sort of thing that we can know as well as all that.
And this doesn't even mention how our data perception in only on a narrow range. Nor the fact that our theories drive the observations, rather than observations driving the theories.
We can certainly hack bits, and get them to do things, understand nature's tricks and re-implement them in a different context. But really understanding it? Not so much.
PS very interesting that the author mentions 'neoteny'. This is where a 'species' stays in a prolonged juvenile state.
I've long thought that this sounds like modern life, where people do not want to take personal responsibility for their lives, but instead look to various authorities (government, corporations, their mum) to do it for them.
There are plants that start out as parasitic vines (parasitic? Epithetic? I am not sure what words to use...) that grow, as a vine, up a tree. Kill the tree, then stand as a tree from then on.
I've seen Poison Ivy do this, at Cleburne State Park (TX), Cedar Lake.
Nestled among a beautiful bunch of cedar trees is a nice spot for a picnic. You notice that one tree stands out with broad leaves, but it doesn't look like an oak. You then notice the very distinct cedar bark. It was wild.
Epiphytic. They are freeloaders instead of parasites.
Although there is some though that for instance moss high up in some very tall trees helps them overcome their hydraulic limitations by allowing them to absorb some water from their limbs instead of just the roots.
An epiphyte is a plant that grows entirely on another plant – in other words, has no roots in the ground.
Vines and creepers are not epiphytes, because they have conventional roots in the same soil as the larger plant (or other structure) that they cling to.
I can't parse your 2nd sentence so I can't comment, but moss is not vascular and does not have roots or any mechanism to transport water internally. It just moves through the plant by capillary action.
This is the key difference between mosses and clubmosses.
Studies of temperate rain forests suggest strongly that water storage of mosses in particular allows the tree to absorb moisture directly through the bark, or in some cases form adventitious root hairs into the moss. One of the main limits to tree height is how high they can pump water through a combination of pressure and capillary action. Sequoioideae in particular have adaptations that let them push water a little higher than other trees. IIRC some of those are common to Cupressaceae (thuja plicata being the apex tree in the PNW).
We have conservationists here that have lamented the industry that has formed around harvesting moss from temperate rainforest trees. Some of these are sneaking into public lands and mass harvesting. The growth rate of these mosses barely keeps up with the rate of growth of the trees. A fully denuded tree may be dead before it's covered in mosses again.
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• Normal trees, like what you see every day, with bark and wood and so on
• Monocots like yucca and aloe and Draecena, which have no bark and become woody through ‘abnormal secondary growth’ (which I don’t properly understand but has something to do with wood development being scattered throughout the plant instead of in a ring around the edge), and tend to avoid branching except when the growing tip is disturbed
• Other monocots like palm trees and Strelitzias, where the ‘wood’ is actually the bases of dead leaves wrapped very very tightly together, firmly enough to keep the plant standing up
• Fern trees, which… I’m not at all sure about, but seem to work on the same principle where leaf bases sorta get fused together. But the Dicksonia in my front yard seems to extrude some sort of thin fiber — does that perhaps help to hold the trunk together in some way?
• And then there’s things like papaya and banana and giant horsetails, which become trees without any wood at all, and have presumably innovated other ways of holding themselves up
It’s interesting to walk around my neighbourhood and realise that many of the trees I see have evolved almost completely different methods to get to the same result!