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How Dinosaurs Shrank and Became Birds
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.
You can't fit dinosaur legs in the fryer, so of course they had to get smaller. Defective by (intelligent) design.
Birds are dinosaurs with a genetic condition stunting their development. Yes, this will end well.
How can I believe you when you tell me what I don't want to hear?
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.
excitingthingstodo.blogspot.com
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.
I used to own an African Grey parrot who definitely had the disposition and attitude of a T-rex.
SJW's don't eliminate discrimination. They just expropriate it for themselves.
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.
SJW n. One who posts facts.
Go not to /. for intelligent discussion of evolutionary biology.
Some mornings it's hardly worth chewing through the restraints to get out of bed.
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.
"Who the **** put an emergency exit in the interrogation room?!" -- Police chief, "Jesus Christ Supercop"
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. A T-Rex likely tasted more like beef than chicken.
Even that is a misnomer. It's more of a blend, not distinct steps.
“He’s not deformed, he’s just drunk!”
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.
Lost at C:>. Found at C.
"adapted a number of pre-existing features to a new use" = Exaptation also referred to as a Co-option, this is a shift in the function a biological feature serves in the organism. The trait may have been non-adaptive (i.e. without function) before the functional shift, for example it may have been a Spandrel.
"adoption of a more babylike skull shape into adulthood" = Neoteny, 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.
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, and represent a school of thought that critiqued the so called Panglossian Adaptationism which Dawkins, Dennett and (formerly) Williams explound/ed.
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 are more closely related to humans than they are to any extant reptiles.
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?).
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?
"Growing old is inevitable; growing up is optional."
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.
Jeremy
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.
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.
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.
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!
The Quirkz Handbook of Self-Improvement for People Who Are Already Pretty Okay
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.
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.