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How Birds Evolved From Dinosaurs (2015)
- titzer 6y agoThe article is actually really interesting and has a lot more up-to-date information than the title would suggest. For example, one new idea I gleaned from this is that the evolution towards smaller body size happened long before the extinction event 65 million years ago. Miniaturization stretches back at least 200 million years. Other neat fact: early birds looked very much like infantile or even embryonic raptors, suggesting that instead of evolving a whole new set of traits, small modifications to embryonic development were more likely. It seems this idea is also picking up in other areas of studying evolution as well.
- hyperpallium 6y ago> early birds looked very much like infantile or even embryonic raptors Sounds like neoteny, the retention of juvenile characteristics in adulthood. See: domesticated foxes, dogs (esp toy breeds), people. Seems like a particularly easy evolutionary path, perhaps take a step back, then forward.
- traes 6y agoI think the original title, "How Dinosaurs Shrank and Became Birds," would do this article more justice. The title makes it seem like the article is just discussing a well known fact, but it actually goes quite in-depth.
- dang 6y agoI've re-howed it.
- sopooneo 6y agoDoes this mean that distinct, non-flying species of dinosaur independently evolved to be able to fly? Or does it mean that one species of dinosaur evolved to have the ability to fly, and then further branched into all know species of birds?
- loosescrews 6y agoAccording the the Wikipedia page on animal flight, dinosaurs and birds are believed to have evolved flight independently. https://en.wikipedia.org/wiki/Flying_and_gliding_animals https://en.wikipedia.org/wiki/Flying_and_gliding_animals
- tsimionescu 6y agoActually, according to that article pterosaurs, that are explicitly not dinosaurs, evolved flight separately from the dinosaurs/birds (with two other separate times flight evolved mentioned, in insects and in bats).
- ajuc 6y agoAnother time it evolved independently was in homo sapiens.
- gnulinux 6y agoI think you meant to say pterosaurs and dinosaurs (in particular, avian dinosaurs, including birds) evolved flight independently.
- thaumasiotes 6y ago> “Archaeopteryx seemed to emerge fully fledged with the characteristics of modern birds,” said Michael Benton Pun intended?
- philoye 6y agoI suspect so, another one: > Yet once those avian features were in place, birds took off.
- andrewflnr 6y agoIt's almost not even a pun, just a literal statement. "Fledge" just means "to become feathered". https://www.etymonline.com/word/fledge https://www.etymonline.com/word/fledge
- ianmcgowan 6y agoInsert Simpson's <"That's the joke"> meme here...
- mrfusion 6y agoIs there a picture anywhere of the chick embryos with the dinosaur like face they mention?
- Jtsummers 6y agohttps://www.smithsonianmag.com/smart-news/chicken-embryos-get-dino-snouts-thanks-biological-tinkering-180955250/ https://www.smithsonianmag.com/smart-news/chicken-embryos-ge... That one has an image.
- mrfusion 6y agoI never understood why bipedal locomotion would evolve in dinosaurs. Especially since the article says it happened well before any kind of flight or even gliding.
- danieltillett 6y agoBipedal locomotion is more efficient in that it takes less energy to cover a certain distance on two legs than four.
- mrfusion 6y agoI never thought about that. I wonder why it hasn’t evolved more often then? Basically limited to humans and birds. (I guess kangaroos too?)
- emmelaich 6y ago"Paedomorphosis" doesn't sound that different to the "Ontogeny recapitulates phylogeny" observation. Adds an interesting perspective on the controversy. Link: https://en.wikipedia.org/wiki/Recapitulation_theory https://en.wikipedia.org/wiki/Recapitulation_theory
- chewxy 6y agoThis sentence strikes me as interesting: > (For ethical reasons, they did not allow the chickens to hatch.) What exactly is the ethical reason? Do they suspect that the dino-faced chickens will not have a good quality of life? How do they know that? Also, who doesn't want to see a dinosaur-faced chicken?
- nn3 6y agoI bet it was something like - Do we do the experiment now (or in the next quarter at least), or do we spend a lot of time getting through ethics boards with new unique proposals that would likely take forever to get approved.
- DC-3 6y agoIt's not a dino-faced chicken. It's a deformed-chicken-face chicken. You're not going to get something cohesive by flipping a couple genes, you're going to get something malformed. Edit: a bit of googling suggests that, at least according to the scientist leading the project, I am wrong here: For now Bhullar has no plans, or ethical approval, to hatch the snouted chickens. But he believes they would have been able to survive "just fine". "These weren't drastic modifications," says Bhullar. "They are far less weird than many breeds of chicken developed by chicken hobbyists and breeders." "The rest of the animal looked OK, but one needs to think about this carefully from an ethical point of view."
- emmelaich 6y agoJust found this ... https://en.wikipedia.org/wiki/Hoatzin https://en.wikipedia.org/wiki/Hoatzin > notable for having chicks that have claws on two of their wing digits. > In 2015, genetic research[5] indicated that the hoatzin is the last surviving member of a bird line that branched off in its own direction 64 million years ago, shortly after the extinction event that killed the non-avian dinosaurs.[6]
- Scarblac 6y agoGiven how much that looks like a bird, that strongly suggests we would also recognize avian dinosaurs as birds, right?
- TomMarius 6y agoIt hasn't remained the same for all that time.
- hansbo 6y agoFor any feature this bird and other birds have in common to have come later, they would have to have evolved twice. This could be the case for some features, but is highly unlikely to be responsible for large part of the similarities.
- gpderetta 6y agoMy understanding is that non avian dinosaurs are the birds.
- nn3 6y ago"Former senior writer" One idly wonders what must be going on at Quanta that she ended up with such a title.
- romanhn 6y agoThe article is from 2015. From the profile, it sounds like she no longer works there and the profile was updated to reflect that.
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- kbk 6y agoevolutionist on HN! no critical thinking, keep it for IT!
- kbk 6y agoexpect down vote ... no free speech right! evolutionist: believe or I kill you(r voice)!
- coldcode 6y agoBirds did not evolve from dinosaurs, they are dinosaurs. Just read "Some Assembly Required: Decoding Four Billion Years of Life, from Ancient Fossils to DNA" by Neil Shubin. The pathway how a current species became what it is is quite surprising. Most features you see today came about as copies of other features that were repurposed over time, like feathers did not evolve to support flight, but for other reasons, and then lead to flight later. This idea of repurposing started with a Darwin comment in his last update to The Origin Of Species.
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- throwaway894345 6y agoI hear this a lot, but I don't understand in what capacity it is true. Why can we say "Birds did not evolve from dinosaurs they are dinosaurs" but not "Humans did not evolve from fish they are fish"?
- jonchang 6y agoHumans can be classified as lobe-finned fish, so it wouldn't be wrong to say that humans are fish.
- throwaway894345 6y agoMy question was more along the lines of "is it wrong to say 'Humans didn't evolve from fish because humans are fish'"? This is by all appearances the same argument the GP and others make when they say "Birds didn't evolve from dinosaurs; they are dinosaurs".
- crazydoggers 6y agoBirds are part of what’s called the Dinosauria clade. Clades are monophyletic meaning they encompass all the descendants of a common ancestor and all share common traits. Humans and fish on the other hand can’t be grouped into a clade. That’s because it you trace back the common ancestor you’ll find other monophyletic groups descending from those ancestors. Think of a clade as the end of a branch and all its leaves... whereas if you go far enough down you’ll find other branches that shoot off in other directions far off, even though they’re in the same main trunk. https://en.m.wikipedia.org/wiki/Clade https://en.m.wikipedia.org/wiki/Clade
- jdmichal 6y ago> New research suggests that bird ancestors shrank fast, indicating that the diminutive size was an important and advantageous trait, quite possibly an essential component in bird evolution. This is making the common mistake regarding evolution. Evolution doesn't select for advantageous things, but against disadvantageous things. It's not survival of the fittest, but death of the inadequate. It seems nitpicky, but it's very important for diversity. If getting larger or smaller doesn't drastically hinder your survivability, then one ends up with a large range of sizes.
- woodandsteel 6y agoDo evolutionary biologists generally agree with what you are saying? Is it what I would be taught if I took a course in evolutionary biology?