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submitted 4 weeks ago by [email protected] to c/[email protected]

Did they determine this by comparing what DNA fragments they've managed to recover, or by physical skeletal structure similarities, or what?

I'm no expert in the field, but I just don't see it.

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[-] [email protected] 7 points 3 weeks ago

Not exactly ancestors, as others have said.

DNA doesn't last nearly long enough. Scientists have made great strides in analyzing ancient DNA (aDNA), They have decoded the genomes of Neanderthals and other extinct human species. But that aDNA is only tens of thousands of years old. IIRC the theoretical maximum is something like 1 million years. No chance on dinosaur DNA.

As to how what evidence there is, I think that's already sufficiently answered, and better than I could.

[-] [email protected] 8 points 3 weeks ago

That's a mental shortcut, the birds came from dinosaurs, the birds cladistically ARE dinosaurs; birds, dinosaurs and crocodilians are archosaurs, but birds are closest dinosaurs relatives

[-] [email protected] 3 points 3 weeks ago* (last edited 3 weeks ago)

Okay, gotcha.

Still, maybe I'm a dumdum, but aren't alligators and crocodiles and similar species mighty close to the ancient dinosaurs?

Edit: Are those closer or further away from dinosaur relatives than birds? Either way, what makes one group of creatures closer to dinosaurs than the other?

[-] [email protected] 2 points 3 weeks ago

As for what makes some clades closer to ones than others, we know when they appeared in fossil records relative to each other

[-] [email protected] 5 points 3 weeks ago

Yup, that's what I said, crocodilians and birds

[-] [email protected] 4 points 3 weeks ago* (last edited 3 weeks ago)

Oh shit, my bad. I just woke up like 30 minutes ago, my eyes are still adjusting back to my glasses LMFAO!

[-] [email protected] 4 points 4 weeks ago

Half science half click bait, completely awesome

[-] [email protected] 2 points 4 weeks ago

They put a plunger-looking appendage on a chicken's ass and discovered that after this was done it walked more like a T-Rex does...seriously.

[-] [email protected] 2 points 4 weeks ago

Is this gonna be on the next Obscurist Vinyl album?

[-] [email protected] 15 points 4 weeks ago* (last edited 4 weeks ago)

Over the last 15 years, scientists have updated the theorized appearance of thousands of species of dinosaurs to have feathers. Most of these species are in the theropod family. You’ll be seeing updates in natural history museums as time goes on.

https://www.amnh.org/exhibitions/dinosaurs-among-us/feathers

There’s also the chicken’s talons to consider. Birds with similar claws are called raptors due to their similarity in appearance to the dinosaur. This does not mean they are direct descendants, however, but that they have a genealogically shared ancestor.

[-] [email protected] 4 points 3 weeks ago

According to Merriam Webster, raptor described birds first. And we don't call certain birds raptors strictly for their appearance or lineage; raptor means bird of prey. Lots of birds have gnarly claws but aren't raptors, like emus, who use their claws for self defense.

[-] [email protected] 2 points 3 weeks ago

I had it reversed. Good to know. Thanks!

[-] [email protected] 7 points 4 weeks ago

https://terriblelizards.libsyn.com/tls02e07_bird_origins

Terrible Lizards Podcast episode on bird origins. (Dinosaur means Terrible Lizard)

[-] [email protected] 42 points 4 weeks ago* (last edited 3 weeks ago)

The common ancestor thing is hard to wrap my brain around. Dawkins gives a cool thought experiment where he says imagine a card catalog with photos of you and your ancestors in chronological order. If you look back 10 generations, you'll find a human. If you go back 100 generations, you'll find a human. If you go back 5,000 generations, you'll still see a human! However, they probably won't look exactly like a moden human. If you go back 15,000 generations, you'll find something human-like, but not really a modern homo sapiens. All of those cards along the way have miniscule,imperceptible differences. If you go back far enough, you'll find something like a rodent. But the number of cards you need to flip through to find that rodent is extremely large. Something like 200 million generations. Keep in mind the more ancient animals had shorter life spans.

So t-rex and chickens may have come from the same branch, but there are millions of "cards" between them.

[-] [email protected] 3 points 3 weeks ago

It’s “Homo sapiens”, not “homo sapien”.

[-] [email protected] 3 points 3 weeks ago

Keep in mind the more ancient animals had shorter life spans.

What? Why?

[-] [email protected] 3 points 3 weeks ago

Rodents don't live as long as hominids.

[-] [email protected] 2 points 3 weeks ago

Especially if the hominids happen to own a pet felid.

[-] [email protected] 4 points 4 weeks ago

The best evidence for their common ancestry is from 2008, but it doesn’t look like there have been any new developments since then.

Molecular analysis of a shred of 68-million-year-old Tyrannosaurus rex protein — along with that of 21 modern species — confirms that dinosaurs share common ancestry with chickens, ostriches, and to a lesser extent, alligators.

Source Harvard Gazette

[-] [email protected] 6 points 4 weeks ago
[-] [email protected] 29 points 4 weeks ago

i think a better way to look at it is; the chicken and the t-rex share a common ancestor

an animal existed that branched into 2 different paths, one towards birds and the other big ol lizard things (conjecture, am stupid)

[-] [email protected] 26 points 4 weeks ago* (last edited 4 weeks ago)

This is exactly right. T-Rex is a Therapod. Another line of Therapods turned into birds. That line of Therapods is called Dromeasaurs.

https://en.m.wikipedia.org/wiki/Dromaeosauridae

Also (maybe more accurately) https://en.m.wikipedia.org/wiki/Paraves

[-] [email protected] 5 points 4 weeks ago

Sounds about right LOL!

(also am stupid)

[-] [email protected] 12 points 4 weeks ago

we have an obscene amount of fossils sittin around in drawers collecting dust. i cant wait til we can feed all that crap into 3-d scanners, feed it into some detection LLM and vastly expand our knowledge at a rate we are not currently capable.

i read a lot of 'random scientist finds some random fossil in a drawer proving the opposite of some accepted fact'

[-] [email protected] 5 points 3 weeks ago

Yes, better tools to analyze data will yield great results. Even a good push to scan all those finds and make all the data available would probably allow amazing new discoveries. The catch is that people like to hoard that data and milk it for their own careers and fame.

That said... LLM is Large Language Model. By definition, LLMs are unlikely to analyze 3-dimensional shapes. The newer AIs, like Gemini or GPT-4o, also use vision and audio but they are often still called (multimodal) LLMs. It's justifiable as they still seem to have language at the core, but it's getting increasingly dubious.

[-] [email protected] 8 points 4 weeks ago* (last edited 4 weeks ago)

This exact scenario scares me, because what we know about current LLMs is not that they are good discovers of things, but that they are very convincing liars.

[-] [email protected] 3 points 3 weeks ago

That's because most of what we hear about "AI" is revolving around content "creation" controversies, but these are successfully used in analyzing wide data sets for scientific purposes, like finding new foldings of proteins, diagnosing cancer, reading ancient burned scrolls via etcxrays

[-] [email protected] 2 points 3 weeks ago

And all of those things are then analyzed and verified before anything is done with them. No reputable scientist is taking those results and dumping it straight into a paper; the deep learning engines are pointing scientists in the right direction; they're taking the haystack and making it a handful. Protein folding is a little different because the results can be directly verified programmatically (I think; I'm not an organic chemist, or biologist, or whoever is doing this research).

The output of LLMs can be great outlines. They can also be wildly, and confidently, wrong.

[-] [email protected] 1 points 4 weeks ago

the tech is in its infancy. dont discount what its capable of based on its current iteration. science is a progression

[-] [email protected] 3 points 3 weeks ago

Oh, believe me, I don't. At all. I've been working in the software engineering sector since the mid 90's; I'm quite aware of the rapid pace of change in this sector. I was briefly considering a focus on AI when getting my degree, back in the early 90's.

But this specifically mentions LLMs, and the fundamental way LLMs function is not going to lead to self-aware AI, or any sort of system that is going to be able to self-evaluate for accuracy or "truthiness." It's going to take an advance in neural net science; maybe in combination with LLM - but LLMs by themselves will only ever be dumb machines that generate predictive text based on - I don't know, Bayesian probabilities, or whatever.

[-] [email protected] 4 points 3 weeks ago* (last edited 3 weeks ago)

ha, i never meant full-on GAI, singularity. i just meant a visual model good enough to classify what it sees in a very specific context. i never mentioned or meant to refer to 'ai'

[-] [email protected] 4 points 4 weeks ago* (last edited 4 weeks ago)

Yeah, about that..

Different AI models are developing in different ways. Some are learning from legit, curated sources from reputable scholars and professors and such.

But other AI models are learning from less than reputable sites, such as Reddit...

Google is learning from Reddit. This tech journey is gonna be fun...

this post was submitted on 25 May 2024
51 points (90.5% liked)

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