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Sofia Alexandra

The great Extinction and its survivors

34 posts in this topic

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. :)

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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.

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

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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 .

Edited by Rahl

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But really, only one species of dinosaur could have evolved into modern birds.

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...

And birds already existed during the dinosaur era.

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

whatever caused the dinosaurs to become extinct ..i dont see how it affected them only

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

whatever disaster befell them .. it would apply to almost all species wouldnt it ?,

No.

why would a proliferation of mammels exist after this meteor

Because they filled the ecological void left by the dinosaurs

they would have the same chances (well less really) of dinosaurs to recover from such an event .

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.

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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.

Edited by Rahl

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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.

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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...

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.

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 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 :)

Edited by Kaizen

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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)

Edited by Hehe

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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.

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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.

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

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?

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

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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.

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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).

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

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

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).

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.

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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.

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)

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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)

:rolleyes:

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.

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evolution is a slooooooooow process...

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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 :unsure2:

Scientific info nonetheless.

:rolleyes:

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.

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

Edited by Hehe

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Nice site :tu:

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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.

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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.

Edited by Hehe

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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

Edited by Rahl

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

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

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.

Edited by frogfish

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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.

:rolleyes::sleepy: 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 :w00t:

Edited by Hehe

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