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> What this article is saying is that trees form a polyphyletic group. This example seems reasonable in that way because there isn't some parallel definition o
by repsilat 5y ago
> What this article is saying is that trees form a polyphyletic group.
This example seems reasonable in that way because there isn't some parallel definition of "tree".
A layman, on hearing that (according to evolutionary biologists) "birds are dinosaurs" might reasonably assume that evolutionary biologists will also say that dolphins are fish. Alas, no -- "dinosuar" has a parallel phylogenetic definition that differs from the lay one, but "fish" doesn't.
Botany is a source of this sort of confusion a lot. Raspberries and strawberries and blackberries are culinary berries, but not botanical berries. (A tomato is a botanical berry, though. -EDIT, said culinary originally.)
I'm of two minds about it. If you need a word, maybe it's best to use an existing one when there's a large overlap. But then again, the closeness of many legal terms ("murder", say) to their lay definitions arguably causes more confusion when those definitions differ. With biologists "just assume their meaning is totally different to yours" is a good heuristic, and with lawyers (or mathematicians talking about "knots" and "sets") the similarity causes perhaps more difficulty.
- jessaustin 5y agoWhat sort of berry is a tomato? I would have thought culinarily it would be a vegetable.
- intuitionist 5y agoIt’s a botanical berry but a culinary vegetable (as are the other fruit we eat from the Solanaceae)
- repsilat 5y agoWhoops, corrected, thanks.
- jameshart 5y agoI mean, dolphins are fish, in the sense that the most recent common ancestor of all modern fish is also the common ancestor of all modern dolphins. Very few animals aren’t fish in this sense though. Birds are also fish. What’s surprising is that you can exclude sharks and rays from your definition of ‘fish’ and this statement will still be true - you are more closely related to a salmon than a salmon is to a shark.
- goldenkey 5y agoIt's not just a rooted tree, it has crossovers and cycles. Trying to draw boundary boxes is a fools hardy.
- jameshart 5y agoThis is true, when you zoom in closely, but when you zoom out, it is quite treelike. phylogeny isn't useless just because the process of speciation isn't instantaneous.
- User23 5y agoIt’s very helpful to learn to recognize lumper versus splitter arguments. Pointing out that lumping things together or splitting things apart is arbitrary just isn’t very interesting. What is interesting is why some things are lumped and some are split. For example why are polar bears and grizzly bears considered different species? They can breed just fine after all.
- jameshart 5y agoRight, and when you notice that a bunch of organisms share a trait, the fact that they share that trait in spite of their common ancestor not sharing it is inherently interesting, right? We know that traits are heritable, so when you have a bunch of different organisms that exhibit the same characteristic, if you can trace back and determine they are all specialized descendants of some ancestor which first developed that characteristic, that’s the complete story right there. But when we see the same behavior appear in different organisms without them sharing a common root for that characteristic that’s interesting precisely because we need another means to explain it. I mean, if grizzlies and polar bears could interbreed even though their nearest common ancestor was, say, some kind of small Cretaceous rodent, then weld have some explaining to do, right?
- User23 5y agoAbsolutely. I find the cladistics approach appealing. On a bit of a tangent I did some searching and found this[1]. Nightjars are cool! [1] https://scienceblogs.com/gregladen/2010/09/09/one-could-say-that-bats-evolve https://scienceblogs.com/gregladen/2010/09/09/one-could-say-...