Some 65 million years ago something happened that made the dinosaurs die out. Most evidence points to a disaster caused by a meteorite, but as we don't know 100% for sure I won't say more about it. It is not the topic of discussion in this thread anyway, only a somewhat important sidenote.

Anyway, something happened that wiped out the dinosaurs, but there's still life on this planet and birds evolved from dinosaurs. How did that happen? The answer is, not all life died out.
At the end of the dinosaur era there were small mammals running around, and when the big dinosaurs died the mammals survived by feeding on the carcasses. Same thing goes for the small dinosaurs/birds/inbetweens that were already around. And, when they suddenly found themself able to move about without the risk of being stepped on or eaten, the mammals could start to evolve, get bigger, and take over the planet. The birds took to the skies, which were now cleared of pterosaurs (and don't bring up the thunderbird legend here, it's neither the right forum nor the right thread).
Various amphibians, fish (including sharks), reptiles and insects survived the Extinction as well. It was the big creatures that didn't make it.

So why am I posting this? Well I've seen people asking how birds can be the descendants of dinosaurs when the dinosaurs died out, as well as wondering how and why great big dinosaurs evolved into small twittering birds. It's strange how easy it seems to be to forget that there were small dinosaurs as well; some people seem to think that chickens are the direct decendants of Tyrannosaurus Rex...

Just my two cents.

Yes, the smaller animals filled the voids left by larger animals that died out...their niches were empty. Its highly doubtful that T-rex evolved into a bird, but more like a small dromaeosaur, compsognathus, and other small dinos.

But really, only one species of dinosaur could have evolved into modern birds. And birds already existed during the dinosaur era.

whatever caused the dinosaurs to become extinct ..i dont see how it affected them only , whatever disaster befell them .. it would apply to almost all species wouldnt it ?, why would a proliferation of mammels exist after this meteor .. they would have the same chances (well less really) of dinosaurs to recover from such an event .

No, more than one species of dino could evolved into birds...at some poin, they indeed shared a common ancestor, but that is most likely at the archosaurs...


So??? What does that have to do with it? They still evolved from dinosaurs/archosaurs...we evolved from primates, and they are still around...


I didn't, it killed of all Euryapsids ( marine reptiles) and all pterosaurs


No.


Because they filled the ecological void left by the dinosaurs


Why less? They would have a much better chance...They are smaller, they were more "mammalian" then dinosaurs...DInosaurs des ou because the "extinction event" wouldn't allow the ecosystem to harbor such large animals...after they died, the smaller animals (mammals, birds, snakes, other reptiles) took the place of the dinosaurs and other large reptiles.

ah ok, and there was i believing that our concept of dinosaurs all being 'big' was untrue. I was under the totally false impression that dinosaurs could be as small as chickens.

Ahh, you fail to see my point... I hope you see the space that dinosaurs take in a ecosystem, even ones a small as compsognathus, are much bigger than the space taken by mammals like Megazostrodon. Its not about physical size, but about how they fit into an ecosystem.

Next time, I advise you to learn about the subject you discuss, and not remark on topics/posts you clearly don't understand.

How? Modern birds are all too similar with each other. By your theory: one species of dino evolved into perching birds. Another species of dino evolved into ducks. And another species of dino evolved into birds of prey. That would require an insane amount of convergent evolution! I think all modern birds decended from a single species of small theropod.



I was just pointing out that small dinosaurs DID NOT survive the the mass extintion. They had already evolved into birds long before. You always act as though I'm arguing with you. Relax

Can someone please explain (with detail) how the process of evolution caused a dumbass (or smartass) Therapod (or whatever other dinosaur you might think) to take on flight. In other words, try to describe to me how a therapod figured out flight was "meant" for it and how the process of evolution provided the necesary parts (eg. wings, light bone structure, feathers, aerodynamicly shaped body etc.0

On the subject of flightless birds in todays world (chickens, ostriches, penguins etc.): did they "loose" their ability to fly or are they evolving to take on flight sometime in the future.
Can anyone think of an animal in todays world that is evolving in the direction to take on flight in the future? Maybe the flyingfish (family:Exocoetidae). Any other?

Do we know whether birds evolved before the great extinction (if so how did they survive) or after the great extinction (if so, from what?)

Thanx (Frogfish i know you are aking to answer it, as i think it is your niche to answer these little questions)

If a huge ass meteor big enough to whipe out all large dinosours hit the Earth, how did even the small dinos survive? THAT is a mystery. Even if you dug deap into the ground, I doubt that'd help. Talk about some major Earth Shattering going on.

All of today's flightless birds evolved from birds that could fly.



The flyingfish? Maybe. But they have yet to evolve ways of surviving ouside water for extended periods of time.

No, no, you took misunderstood me...I meant that there were a couple species of dinos thet evolved inot birds...some might not of survived though...Sorry there, I misunderstood you.

Possibly the simplest explanation as for why dinosaurs completely disappeared after the end of the Mesozoic was that the large creatures (large being relative) died out in the mass ecosystem collapses, and the smaller creatures were either outcompeted by the new mammalian rivals, or were simply unlucky (it happens).

That what I have been saying in a nutshell...

Ah, they evolved into evolutionary dead ends. Ok, I see what you meant Frogfhish.



Yeah probably. I think there was alot more to the dinosaur extinction than just a meteor impact. There are alot of other theories out there and I think more than one of them could be right.

Ok.. so from what i gather, the general trend is that more animals tend to loose the ability of flight, than animals evolve to gain flight, in the last say... 60 million years? Why is that?
Is there a rational explanation with good proof to describe it?

Insects: Anything evolving to gain flight. The stick insect "Phasma gigas" lost its ability and "appears" to be "re-evolving" its wings (Contrary to Dollo's Law).
As far as i know i only know of insects that somewhere along the line lost their ability of flight. Eg. Lice, fleas, some beetles (All belong to Pterygotes)

Can't scientists design an experiment to accelarate the "re-evolving" of wings of the Phasma gigas stick insect. (http://www.astrobio.net/news/modules.php?op=modload&name=News&file=article&sid=358)

We must be living in a dull era of evolution as nothing constructive seem to evolve. (Oh wait, they think we might be getting smarter)

Evolution happens continually, but it takes a long time and it's nothing you notice in just one lifetime. And if you don't think there's anything interesting happening right now, check back in some 10000 years.

evolution is a slooooooooow process...

I knoooooww.
Cant you see the trend though (loosing and not gaining)? Or is it sooo slooowww that you cant?

According to this guy evolution is even slower,
Primate evolution: http://www.evolutionfairytale.com/forum/in...p?showtopic=596
It adresses the human/primate genome similarities and looks at what makes us human on a genetic level.
Quite interesting even though the website adress sounds a bit... fundamental
Scientific info nonetheless.


Im guessing that you're implying that 10000 years ago we were stupid cavemen and now we are intelligent. Im sure you're not implying that 10000 years ago there were less biodiversity than today, although it would seem logical how evolution tend create new families of species.

According to this site, 10000 (500 generations) years is too little for humans to evolve much in the line of intelligence.
http://www.anth.ucsb.edu/projects/human/epfaq/holocene.html

Nice site

HeHe, one thing that needs to cleared up is your idea of devolution and evolution. You can't think of natural selection as causing species to evolve towards some goal of perfection. Perfection as defined by natural selection is being suited to survive long enough to pass on genes. It's entirely random. Take Crocodylia for example, while its untrue to say they haven't changed (i.e. haven't faced selection) their general morphology is amazingly consistent for millions of years. They have dominated the shoreline niche they exist in, are very successful, and thus haven't needed vast adaptions. Just bear in mind these adaptations come about from constantly ongoing minute genetic variations (its actually quite a bit more complex than that but that's a whole other post). These variations are passed on if they benefit the animal's survival in its environment (i.e. if it lives long enough to reproduce). If there isn't a vast change in environment an animal can stay morphologically similar for millions of years. Anyhow this is very protracted. I'd suggest going to library for the for more complete picture of genetics. You'd be better served there than here.

Please dont insult my intelligence, but thanks for the rudementary lesson in genetics and evolution. I must admit genetics is not my strong point as i am more interested in human physiology and biochemistry, but i did complete 3rd year genetics and and i understand the main theories. Bear in mind that you are the first one to mention "devolution" here. Was i not clear enough for you? What i said was that the forces of natural selection (be it mutatonal change or environmental change) tend to favour the change of "flight-abled" to flightless animals in recent history.
The reason i am asking this is that for the life in me i cant imagine how eons ago the first animals took to the air. Guess that is why no-one can give me a scientific article on how the mechanism of flight evolved (It is a hot topic of of debate for scientists).
All i get is everyones opinions and ideas (speculation), and no-one seems to agree on a common mechanism. Although Richard Dawkins did try valiantly in one of his books (think Ancestor's tale).
Cursorial and arboreal are the only two mechanisms to explain how flight evolved but evidence for either are.... well circumstantial and purely speculative.

I do not look for frogfish to provide any answers, because he has none with his schoolboy knowledge he knows very little but is full of opinions and attitude. . He is a narcissistic arrogant little person who thinks that insulting people impresses people into thinking he knows anything. I am pleased to never hear from this fool again . /ignore list frogfish

With your inability to understand evoluion and biology, Rahl, you should be welcome to corrections.



If you choose to ignore the facts, fine...But do not come back if you can't handle corrections. Its science - It's called peer review.

Ugh childish banter. How about staying on topic. Someone should create a topic named "The Cockpit" so that these cockfights can be settled. Betting should be allowed

Me like it

i have an idea, and i'm not sure if i heard it somewhere or just in my own little head:

there was definitely some kind of world-changing event, probably an impact, as evidenced by the KT boundary. i think perhaps it reduced the amount of oxygen in the atmosphere, and killed off anything that could not quite handle the reduced oxygen intake. perhaps the dino/bird connection did not begin with flight, but with the smaller size and better respiratory system. with smaller size, and perhaps lighter bones for oxygen storage, they may have taken to the trees for safety, and later, the air.

let me know if you guys have heard it somewhere, or just what you think about that.

also, that extinction was actually pretty small, it only killed off 1 or 2% of life forms. but the big stuff definitely went, so we give it more thought than the permian extinction, which killed off 98% of life.

Chill HeHe,
I mistook your losing and gaining idea. Also, I wasn't insulting your intelligence but you weren't using concepts of evolution correctly, or at least not clearly enough to me that I gathered you understood them. Just trying to help.

As for where birds came from:

http://news.bbc.co.uk/2/hi/science/nature/2684927.stm

http://www.china.org.cn/english/culture/118778.htm

http://palaeo.gly.bris.ac.uk/dinobase/feat...saurs_final.pdf

http://english.people.com.cn/200210/21/eng...21_105389.shtml

http://www.findarticles.com/p/articles/mi_...010/ai_n8915231

http://news.nationalgeographic.com/news/20...ird_fossil.html

As you see China is a hotbed of feathered dinos and there may now be sufficient evidence coming to light that suggests birds probably existed during the time of dinosaurs in great abundance and simply outlasted them.

As for flightless birds. They can only evolve where there are minimal land predators (the exception being larger and more ancient forms such as the emu and ostrich) and these are very isolated locals. I'm no expert on them but flightless bird evolution should be able to happen rather quickly as a population spends more time on the forest floor. The naturally smaller winged birds would quickly be selected for their ability to move and forage better. These types morphological changes can happen quickly as is evidenced by studies of sparrow populations that where seperated fairly recently (13,00 years):

http://elibrary.unm.edu/sora/Auk/v110n04/p0844-p0856.pdf

I don't know of any evidence that would point to more birds becoming flightless in recent millenia than in the past but either way, if there's a niche, something will fill it.

Sorry Frothy, but bones don't store oxygen...only calcium. PTH releases it. The KT event wiped out all the larger lifeforms that could not sustain, he dinos, the pterosaurs, and the marine behemoths. They took up to much 'space', and could not survive on the damaged ecosystem. The voids left by these animals were filled by their evolutionary ancestors, the birds, and the mammals. The mammals grew larger to become the dominant species. Flightless birds are just a branch of birds that evolved without the need for flight, due to their environment or size.

If a disaster was to happen today, all the large lifeforms (as in space) would die out aka. the mammals...

Clearer?

I think what Frothy was trying to say was that: Because the big dinosaurs had such small nostrils (minimal air intake) there had to be more oxygen (higher pressure). I donno frogfishy, do you want to insult him by pointing out that bones dont store oxygen, sure is juvenile (but i see that you attend biology, at least you know what PTH is, oh yeah, ever heard of Calcitonin and Vit D). Why would the the KT event only kill the bigger animals? Was it less... food, air or water? Specifics here now, and facts... not speculations FACTS!! Now the standard answer will be that the KT event killed off the majority of plant life so that only the small herbivores and carnivores survived.... ok why did the small ones survive... ok they survived off the dead big ones, how long did this last? Again FACTS are always better than speculation, otherwise i can speculate all day.



What part of the environment or their size drove the first animals to take on flight? Facts would be nice and since this seems to be your niche, im sure you will point them out.

Capeo... thanks for those links. I will have a look, im sure i will find those speculations and facts interesting.

If I were frogfish I'd tell you to look it up yourself. Why is someone going to answer you when you jump all over them when they do? The links I posted note most current theories. Go read them.

New Zealand- No natural predators, so birds did not need to evolve for flight. I.E. Moa, Cassowarie, Kiwi, and Kakapo. I have been pointing out facts Hehe, not my fault you choose to ignore them.


That what they had mouths for! I even don't think she was trying to say that. Nostril size does not impede your ability to breathe Get your facts straight.


Do I have to repeat this again? Look at post #29. They died out as they didn't have enough food/ physiological items to meet their needs after the disaster. Smaller animals, therefore could survive. I suggext you read posts before you post yourself.


So instead of pointing out HER mistake, I should let her go without knowing the truth? Should I let a blind man walk over a cliff? Sure seems juvenile of YOURSELF to tell people to stop correcting others. Actually, I know that because I'm studying for MCAT (yes, at this early age...already studied for SAT and ACT) Yes I do know what Calcitonin and Vitamin D is. You can stop trying to find fault with me and making yourself look smarter.


Not my fault you choose to ignore the facts. Go ahead and speculate! If you ever change your mind, and actually CHOOSE to read posts, you can come back.

thanks for fixing that, frogfish. i heard somewhere that birds' bones are a more active part of the circulatory system, and i never fully checked up on it. whoops. i also never checked post-KT geologic data to confirm a low oxygen environment. double whoops. i'll be more careful to check up on my facts before i post ideas.

frogfish, you are awesome.

Sorry, but is that sarcasm..I can't detect it
If not, no, feel free to post any ideas...people here can help.