How Dinosaurs Shrank and Became Birds 90
An anonymous reader writes: Discoveries have shown that bird-specific features like feathers began to emerge long before the evolution of birds, indicating that birds simply adapted a number of pre-existing features to a new use. And recent research suggests that a few simple changes — among them the adoption of a more babylike skull shape into adulthood — likely played essential roles in the final push to bird-hood. Not only are birds much smaller than their dinosaur ancestors, they closely resemble dinosaur embryos. Adaptations such as these may have paved the way for modern birds' distinguishing features, namely their ability to fly and their remarkably agile beaks. The work demonstrates how huge evolutionary changes can result from a series of small evolutionary steps.
First dino-post! (Score:2, Funny)
You can't fit dinosaur legs in the fryer, so of course they had to get smaller. Defective by (intelligent) design.
Re: First dino-post! (Score:1)
You always wondered what dinosaurs taste like ... (Score:3)
Now you know once and for all, dinosaurs taste like .... Chicken!
What would be really interesting is to know how the family tree shakes out and what our domestic chicken used to be. It could have been a T-Rex, Triceratops, or a raptor. Of course, it could have been something else all together. Either way, it would be fun to think about each time you visit KFC.
Re: (Score:3)
Now you know once and for all, dinosaurs taste like .... Chicken!
Unlikely. Small animals taste like chicken, including rabbits, squirrels, lizards, snakes, even frog legs. Big animals taste more like beef, even if they are birds, such as an ostrich [wikipedia.org]. A T-Rex likely tasted more like beef than chicken.
Re: (Score:3)
Well, a T-rex was a large meat eater ... so I'm thinking bear or wolf might be better guesses.
And I gather as a rule large meat eaters don't make for good eating.
Re: (Score:2)
Well, a T-rex was a large meat eater ... so I'm thinking bear or wolf might be better guesses.
And I gather as a rule large meat eaters don't make for good eating.
Predators aren't bad "eatin" but they're terrible for farming.
I've eaten crocodile, wolf and dingo. They're not bad, much like Kangaroo they tend to have a very rich flavour. The problem with sourcing this meat is that it needs to be hunted as farming it is prohibitively expensive and its also dangerous to hunt so it tends to be rare and relatively expensive. That being said, I regularly eat shark as it's the cheapest fillet for Fish and Chips in Australia (often called Flake in Oz) although I occasional
Re: (Score:3)
Have you ever actually eaten rabbits, squirrels, lizards, snakes or frog legs? They taste nothing like chicken. Why do people always say this? Or people's pallets really so fucked up they can't distinguish between different types of meats?
Re: (Score:2)
I think it's because everyone overcooks the hell out of everything in fear of bacteria, and add tons of additives to restore "flavor" that they don't ever taste chicken.
"Chicken" Top Ramen sure doesn't taste like chicken.
Re: (Score:2)
They don't taste like chicken... but some things taste more like chicken than other foods we are used to. For instance, alligator tastes nothing like chicken, but relatively speaking, it tastes WAY more like white meat chicken than beef. Frogs legs are in the same category for me. Squirrel I have only had once, and I didn't like it... but maybe it was similar to dark meat chicken, which I am not a huge fan of. Never tried the others on this short list.
Re: (Score:3)
Or people's pallets really so fucked up they can't distinguish between different types of meats?
My palate may be screwed up, but my homonym detector is in prime form!
Re: (Score:2)
Nice. Totally missed that in my post. Yet another Doh! moment.
Re: (Score:3)
Have you ever actually eaten rabbits, squirrels, lizards, snakes or frog legs?
All of the above, and then some. For the best selection, go to the West Virginia Roadkill Cookoff [pccocwv.com].
They taste nothing like chicken. Why do people always say this?
We say that because it is the closest point of reference when talking to normal people. If I am talking to a nerd co-worker, I will say that possum tastes like chicken. If I am talking to one of my hillbilly relatives, I will say it tastes like racoon.
Re:You always wondered what dinosaurs taste like . (Score:5, Interesting)
Well, dinosaurs were divided into two main groups, the lizard-hipped and the bird-hipped dinosaurs. Birds evolved from the lizard-hipped dinosaurs, and the bird-hipped dinosaurs died out.
Reptile is a catch-all term that doesn't really mean anything. Crocodiles are much more closely related to birds and dinosaurs than they are to any other reptiles (so should probably be grouped with birds rather than lizards and snakes), and extinct "reptiles" like dimetrodon [wikipedia.org] are more closely related to humans than they are to any extant reptiles.
Re: (Score:3)
Reptile is a catch-all term that doesn't really mean anything. Crocodiles are much more closely related to birds and dinosaurs than they are to any other reptiles (so should probably be grouped with birds rather than lizards and snakes), and extinct "reptiles" like dimetrodon [wikipedia.org] are more closely related to humans than they are to any extant reptiles.
Birds are warm-blooded, while crocodiles, lizards, and snakes are all cold-blooded, thus the distinction and groupings.
Re: (Score:3)
Birds are warm-blooded, while crocodiles, lizards, and snakes are all cold-blooded, thus the distinction and groupings.
And actually this distinction is why today we consider dinosaurs to be more closely related to the modern bird than to the modern reptile.
Re: (Score:2)
That's arbitrary. It'd make just as much sense grouping animals by what colour they are. Crocodiles used to be warm blooded, too, so when did they switch from being dinosaurs to reptiles?
Re: (Score:2)
Re: (Score:2)
Modern thinking is that crocodiles descended directly from a warm blooded ancestor, and reverted to being cold blooded, because there's no reason for the warm blooded characteristics they have now without having had a warm blooded ancestor, and there's not been enough time to evolve new things rather than revert.
Re: (Score:2)
We would just make bigger fryers, duh!
:(
What a delicious alternate reality that must be
Re: (Score:2)
You can't fit dinosaur legs in the fryer, so of course they had to get smaller. Defective by (intelligent) design.
Fred Flintstone didn't seem to have that problem.
Ah...hmm. (Score:4, Funny)
Birds are dinosaurs with a genetic condition stunting their development. Yes, this will end well.
Re:Ah...hmm. (Score:5, Interesting)
The more I read, the more it looks like it should be possible to "backport" birds to a surprising degree even without any unobtanium "dinosaur DNA". Even without studying what specific genes do, we can already start by comparing different lineages to see what genetic shifts in birds occurred between their theropod ancestors and modern descendents (for example, if most other groups of animals, including alligators, have a certain gene but birds don't, then that change occurred at some point on the bird side of the branching point between birds and alligators). Looking at modern descendents won't give us an exact picture of their common ancestors, but it'll certainly let us role back a lot of the changes. Combining that with reasoning out and experimenting with what morphological changes in birds that differ from dinosaurs are the result of what genes... we should be able to come up with something rather close to their ancestors at different stages.
It's amazing how much detail they're starting to be able to determine about ancient species - even to the point of being able to determine the number of wing quill feathers in velociraptors. We're certainly constraining the reversal problem more and more.
Re: (Score:2)
Some success has already been achieved in chickens. Fiddling with gene expression has allowed scientists to produce chicken embryos with teeth and chicken embryos that retained their dino-tails - though in neither case was a chicken successfully hatched.
Hen's Teeth were successfully produced by transplanting the tooth buds from chicken embryos to frog's mouths. Apparently, although both species are toothless, the mechanisms which suppress tooth maturation are different enough between the two species that they do not interfere with the other species' suppression mechanism.
Re: (Score:2)
The more I read, the more it looks like it should be possible to "backport" birds to a surprising degree even without any unobtanium "dinosaur DNA"
You're in good company [wikipedia.org].
Re: (Score:2)
Re: (Score:1)
Don't worry, huge carnivorous flightless birds couldn't thrive unless the Earth got much warmer like it was in dinosaur times.
Top secret Dinosaur government project (Score:3, Funny)
They saw their own extinction coming - it wasn't that hard to detect the meteor - and began a secret government project to breed themselves into small, flying creatures.
Only way they could think of to survive.
Re: (Score:2)
Phase 2 of their program remains little known to this day. It involves them splicing in their old DNA into their bird DNA and growing large and menacing in the jungles of South America...and then spreading out in force and with speed to reclaim their planet.
"and their remarkably agile beaks." (Score:2)
Beaks have *one* joint. How the hell they be agile?
Re: "and their remarkably agile beaks." (Score:1)
TLDR for "intelligent design": God in an EXtreme programmer. The whole world is agile!
Re:"and their remarkably agile beaks." (Score:4, Insightful)
Beaks have *one* joint. How the hell they be agile?
Go and watch a dextrous bird (such as a smart parrot) manipulating things with its beak. You won't be incredulous that such a thing is possible when you've seen it in action.
Re: (Score:3)
My parrot can take the backs off my earrings and take my earrings out without eating the backs or damaging my ears. He can open clasps on my clothes. No question that their beaks are dexterous.
However, I think the author was actually referring more to "adaptable". Bird beaks come in all sorts of shapes, apparently achieved by relatively simple genetic tweaks that allows them to adapt quickly (in evolutionary terms) to changing food sources.
Re: (Score:2)
manipulating things with its beak.
How much of the dexterity comes from the tongue?
Re: (Score:2)
How much of the dexterity comes from the tongue?
Lots. It's a combination of beak and tounge. The beak is very mobile, not just a simple open and closing hinge like the OP is thinking of.
Re: (Score:1)
Re: (Score:2)
Re: (Score:2)
I agree - it makes no sense. I can feel my agility dropping off after even half a joint.
Re: (Score:2)
Ever tried using chopsticks?
Re: (Score:2)
It's *not* the chopsticks that are agile; it's the joints *behind* the chopsticks.
Likewise, beaks *can't* be agile. But their tongues and necks can.
I beleive it (Score:5, Funny)
I used to own an African Grey parrot who definitely had the disposition and attitude of a T-rex.
Re: (Score:2)
Oh god, I just had a terrifying thought... A T-Rex with the threat gestures of an Amazon. For those who don't own Amazon parrots, when they get overexcited or aggressive, they not only do this fantail display, but they have this creepy thing that they do with their eyes where they make their pupils expand and contract. Picture this [google.is], but with the pupil repeatedly changing in size 3x while it stares at you. It basically means "This is my Crazy Time. Go on, try coming close to me, see what happens!" They rea
Re:I beleive it (Score:4, Interesting)
Other things too, from thinking about modern birds: can we assume that theropods had a syrinx rather than a larynx? Then they would be able to have very tonally-complex sounds, including vocalizing multiple different frequencies at the same time.
I assume they had a similar lung layout? Birds have a really brilliant respiratory system. The lungs are rigid and more like tubes for the passage of air rather than storing it. On inhalation, half the air goes directly into one air sac and the other straight through the lung into a different air sac; then on exhalation the sacs reverse so that the "used" air goes straight out and the "unused" air goes through the lung on the way out. So they get fresh air moving through their lungs both on inhalation and exhalation, and they never mix fresh air with used air. This means that the oxygen content of air in their lungs is much higher, which means that the oxygen levels in their blood can be much higher. It helps sustain them during high metabolic activity such as flight; I'm sure their giant predatory ancestors made good use of that oxygen as well.
I wonder if their ancestors had a similar sort of relatively inefficient fast-through digestive system, or whether that's an adaptation their descendents have made for flight? It's known for a fact at the very least that some dinosaurs consumed rocks to aid in digestion (gizzard stones) in the same way birds consume grit. Hmm, so theropods would likely have some sort of a crop then? I mean, there is evidence [livescience.com] that at least some theropods [wikipedia.org] cared for their young. Picture a bunch of baby velociraptors reaching their heads into a parent's jaw to get a meal!
It takes no imagination to picture correspondence between the legs / feet, bird legs and feet already look positively dinosaurian.
Even the evidence of fossilized prints of rough scaly skin from some tyrranosaurids (in addition to evidence of feathers, and some completely feathered) shouldn't be a real shock because we see that in modern bird species. For example, look at the head of a bald ibis or turkey vulture.
Re: (Score:3)
Re: (Score:2)
They are a very quiet sort. Not so good at learning words and phrases, though.
Re: (Score:2)
But what a beautiful plumage!
Delicate Fabric: (Score:2)
"How Dinosaurs Shrank and Became Birds"
Lemme guess. You didn't read the label and washed them in hot water?
Re: (Score:2)
". . . caused by a really hot meteor"
That's one hell of a spin cycle.
Sigh... (Score:3, Insightful)
Re: (Score:2)
Re: (Score:2)
But where else could you find cleverly insightful "tastes like chicken" jokes about dinosaurs?
They shrank? (Score:2)
Okay, maybe the dinos shrank, but those droppings on my car look like they came from a damn brontosaurus!
"small evolutionary steps" (Score:2)
Even that is a misnomer. It's more of a blend, not distinct steps.
Question: Fossil Expansion? (Score:1)
I'm hoping to be educated here by someone with better (any?) knowledge of the fossil record. :)
My general sense is that pretty much old everything is big. But what if fossils expanded with time?
One possible mechanic for this might be the metric expansion of space, which supposedly isn't discerned at small scales. But perhaps, over a long period of time, with molecules uncohesive enough to be replaced by minerals through diffusion in fossilization, perhaps metric expansion would provide just enough space h
Re: (Score:2)
Mega fauna seem to be very vulnerable. They are quite easy to wipe out. They take a long time to grow and do not reproduce fast. There are other reasons.
Re:Question: Fossil Expansion? (Score:5, Interesting)
My general sense is that pretty much old everything is big. But what if fossils expanded with time?
Not really true. The number of different species that have lived on the earth, it would be astonishing if the largest species to ever have lived had evolved recently... but this is exactly what has happened.
Also, there are some things (I hesitate to call them species) like the Coelacanth which have stayed very similar in form over hundreds of millions of years.
Large animals get more press. I'd guess they also fossilise better and are easier to find.
Regarding large insects and arachnids.... no one is completely certain, apart from the fact that there was a much higher oxygen content in the atmosphere during the Cambrian, allowing larger sizes. This does not explain everything though (but what does?).
Re: Question: Fossil Expansion? (Score:1)
Yes it does seem that coelacanths have kept much the same size range. If anything, I've found more pictures of live coelacanths that were larger than the fossils I found. Interesting. Thank you.
Re: (Score:3)
Your post made me curious about expansion, so i read the wikipedia article.
It sounds like expansion is only occurring on a very large scale, where matter isn't gravitationally bound. So things outside the milky way, andromeda and virgo cluster are expanding away, but there is no expansion within.
So your hypothesis is wrong. I've often wondered though if there is some fosilization phenomena that could cause them to grow over time.
Re: (Score:2)
I've often wondered though if there is some fosilization phenomena that could cause them to grow over time.
There isn't. A story ran on /. several months (years?) ago about an experiment where someone leeched all the minerals out of a fossil dinosaur bone. The result behaves just like a modern bone when you leech all the calcium out of it. It was the same length and width after the procedure. Just floppier. They really were that big. (Except for the little ones, which weren't.)
Re: Question: Fossil Expansion? (Score:1)
No, it's not. I'm aware of that theory and don't believe it holds water.
If I understand correctly, small scale expansion isn't absent at small scales, just overwhelmed by other forces. Say the earth did expand outward in all directions by a few microns. Gravity has plenty of opportunities to squish the Earth back to its original density. If my cells were found slightly apart from each other, there's electrical forces between the atoms in my body, air pressure from the outside, that keep things from dri
And again with more jargon (Score:3)
"adoption of a more babylike skull shape into adulthood" = Neoteny [wikipedia.org], or the distortion of the developmental timeline as to extend the duration of what was previously a juvenile stage into adulthood. Developmental pathways - which are regulated in part by specific biomolecular pathways - provide evolution with a set of channels through which it can naturally and easily evolve; easy to reach and viable variations morphology a few mutations away! Famously, this is how humans developed their marvellous cabbage heads.
"huge evolutionary changes can result from a series of small evolutionary steps" not equal, but at least highly related to the concept of Punctuated Equilibrium [wikipedia.org].
This is a type of explanation draws on the very important concept of Historical Contingency, i.e. the idea that the particulars of a (natural) history processes are largely determined by the coincidence of circumstances which are effectively random, and therefore on a larger scale seem not to be completely deterministic or teleological processes (at least not completely, although I cannot deny there may be some features of the process which are). Whether completely true or false or anything in between, I like this approach to explanation in historical processes of complex systems. It seems to imply use of a type of simplifying assumption which might call a principle of Epistemic Parsimony in complex system; you assume that most types of events are the result of processes to complex to comprehend and therefore - for you as observer - are effectively random. Of course a collection of random events can yield a perfectly tractable and even almost deterministic cohort, just as conversely a collection of deterministic events can yield a delightfully random swarm.
Most of the above concepts were - if not explicitly (co)developed and conceived - championed and expounded by Stephen Jay Gould [wikipedia.org], and represent a school of thought that critiqued the so called Panglossian Adaptationism [wikipedia.org] which Dawkins, Dennett and (formerly) Williams explound/ed.
Re: (Score:2)
This, mod parent up. It's weird to have a solid concept wandered around in the summary when it has a name. Neoteny is in play not only with humans (we're neotenic monkeys), but also with dogs, which is why they don't just eat us up as wolfs would do.
Re: (Score:3)
And at which point did they become warm-blooded animals? How does that happen?
Dinosaurs were always warm-blooded, at least the larger ones were. Analysis of the T-Rex heart cavity indicates structures implying such.
But most damning, cold-blooded creatures don't scale well in size. The larger a creature grows, the more difficult it is for them to regulate temperature through external means (like sunning themselves). When you get to Apatasaur/Brachiosaur size, it seems fairly implausible that they could have been cold-blooded.