As Strange said, birds are left over from Dinosaurs. Even in some dinosaur finds they're beginning to find evidence of feathers. Velociraptors, the famous monsters from the book "Jurassic Park" are an example.Originally Posted by mikepotter84
Contrary to the book's description of them, they are currently believed to have looked more like this:
Velociraptor - Wikipedia, the free encyclopedia
Well, yes. I should have clarified. I meant why didn't a larger number of specie survive?Birds are (descendants of [small?]) dinosaurs.
The generalists are most likely the ones to survive and spread into other niches after the event. In many places Birds did dominate for a while, but the mammals were faster at reproducing.Well, yes. I should have clarified. I meant why didn't a larger number of specie survive?Birds are (descendants of [small?]) dinosaurs.
And no, there still isnt any evidence of notable selective pressures from egg predation
but in general we should be able to establish the effect of egg predation on the reproduction strategies of current egg-laying species ?
Is a Jurassic Park possible? It seems a bit odd that the annhilation of dinos was so complete. Something must have survived somewhere. Somewhere where we havent looked.
any particular reason why this should be so ? after all, there's loads of animal groups that once flourished and are now extinct
Where would you suggest that is unexplored enough to host a viable population of at least 500-1000 dinosaurs?
It's not odd, but I'm sure it is frightening. We could easily join them as the next totally extinct species.
Anyway, there is nowhere left to look that holds any promise. A giant dinosaur would need to live where there is lots and lots of vegetation, and humans like to live in those places as well.
It would be quite a surprise for one to exist and yet not have heard about it from any natives.
99% or more of all species that have ever existed are now extinct. Not being extinct is an oddity. (Humans are doing their best to reduce the number of oddities.)
Hi everyone,
I didn't want to open new thread(if i should tell me)so i will ask here.
How did Mary Schweitzer found soft tissue in bone of T-Rex if they are old 68 million years ago?
This is my 3th question about dinosaurs,sorry im boring.
I lack a decisive answer. Pong's hypothesis is more broadly "offspring predation" to which hard eggs are just one solution - live birth being yet another.but in general we should be able to establish the effect of egg predation on the reproduction strategies of current egg-laying species ?
"To establish the effect of egg predation on the reproduction strategies of current egg-laying species" ... I'm thinking about clownfish. One could say a resistance to anemone sting is an adaptation of the adult clownfish, simply for the survival of the adult clownfish. But in line with my hypothesis, we should say the adaptation is "mostly for" keeping eggs and young in the safety of anenomes; the adult's survival being less important. This is kinda like saying flighted dinosaurs were mostly doing it to nest in safe locations; advantages of flight to the adult being secondary. I think that is demonstrated by the majority of birds, where normal activity does not require flight, but they use flight to crucial advantage where seasonal and protected nesting is concerned.
Alternately we could go back in time and look at why reptiles happened in the first place. If I'm not mistaken the original advantage was eggs that didn't dry out, so they could be deposited in relative safety, then, on land. Later (compare wings) the opportunity to live as a dedicated terrestrial proved fruitful. This of course would lead to a resurgence in offspring predation... but that's how it goes, I think.
Why faster? I think you're saying mammals reach sexual maturity earlier, so evolve faster...? IDK... modern fowl and mammals of comparable size breed at about the same age. Besides at the smaller sizes most are constrained to breed no sooner than next summer.
Its not the breeding age you need to look at, its the gestation time of the eggs, small mammals are likely to have a shorter gestation time, and are more mobile while pregnant before birthing.I lack a decisive answer. Pong's hypothesis is more broadly "offspring predation" to which hard eggs are just one solution - live birth being yet another.but in general we should be able to establish the effect of egg predation on the reproduction strategies of current egg-laying species ?
"To establish the effect of egg predation on the reproduction strategies of current egg-laying species" ... I'm thinking about clownfish. One could say a resistance to anemone sting is an adaptation of the adult clownfish, simply for the survival of the adult clownfish. But in line with my hypothesis, we should say the adaptation is "mostly for" keeping eggs and young in the safety of anenomes; the adult's survival being less important. This is kinda like saying flighted dinosaurs were mostly doing it to nest in safe locations; advantages of flight to the adult being secondary. I think that is demonstrated by the majority of birds, where normal activity does not require flight, but they use flight to crucial advantage where seasonal and protected nesting is concerned.
Alternately we could go back in time and look at why reptiles happened in the first place. If I'm not mistaken the original advantage was eggs that didn't dry out, so they could be deposited in relative safety, then, on land. Later (compare wings) the opportunity to live as a dedicated terrestrial proved fruitful. This of course would lead to a resurgence in offspring predation... but that's how it goes, I think.
Why faster? I think you're saying mammals reach sexual maturity earlier, so evolve faster...? IDK... modern fowl and mammals of comparable size breed at about the same age. Besides at the smaller sizes most are constrained to breed no sooner than next summer.
And you have still not provided evidence of you hypothesis, rather lots of analogies to modern times, which have notable distinctions that make the comparisons tenuous.
Um, I think it boils down to the time between generations. The time from conception to sexual maturity. This tends to diminish with size in all organisms, but with terrestrial plants and animals the advantages of breeding in season (e.g. summer) generally locks them to the same rate: one generation per year. Most small birds and mammals conform to this same calendar.
Multiply by number of eggs or babies. But mammals obviously can't support more offspring than they have teats. That rules out the strategy of spawning a great number of low-odds offspring, for mammals.
Sorry, I'm not wanting to argue your statement. But neither am I convinced yet.
I do agree that generalist mammals could occupy fresh niches better than birds/dinosaurs that were specialized for ones destroyed.
It seems to me that explanations for why mammals survived, are unnecessarily indirect. Why not the simplest answer, that is primary to mammals: live birth...?
OK you won't let modern examples support my hypothesis. Could you please answer these non-rhetorical questions:
1) Would you agree that the salient trait of the first reptiles (or amniotes if you like) was having eggs that could be deposited on land?
2) When all vertebrates were aquatic, what was the most obvious advantage to putting eggs out of the water?
3) Would you agree that this paved the way for a completely terrestrial life cycle?
I believe that after answering those questions honestly, one must conclude this major step in evolution - from water to land - was initiated by an adaptation to reduce offspring predation. Then one logically supposes the same evolutionary driver could apply to other eras. My hypothesis, to repeat, is that major surviving adaptations of the mesozoic era, such as hard eggshell, flight, and live birth, initially served to reduce offspring predation. Additionally, I propose that species lacking these defenses were stressed and less likely to survive a cataclysm.
Last edited by Strange; July 24th, 2013 at 05:06 PM. Reason: inline image
parag - I'm sure...that on some far-away planet in our universe --- on some planet that supports carbon based life --- dinosaurs are living somewhere. After the asteroid impact about 65 million years ago, available plant life on sea/land took a major plunge, giving the dinosaurs with major meat/plant appetites a distinct disadvantage over the smaller mammalians. I tend to speculate that the dinosaurs came first in Earth history, because of size and meat plant eating capabilities advantages over the mammals.
Came first in comparison to what?
And Dinosaurs are unique to earth, the amount of variables needed to create them most likely can't have occurred twice.
Paleoichneum - I tend to speculate...that on typical Earth type planets in our universe --- based on evolution from Earth's history --- the odds tend to favor {barring any large cosmic collisions or catastrophes after life has gained a major foothold for bipedal and quadrupedal creatures of the dinosaur family tree; because basically --- the dinosaurs are superior to the mammals --- because they would have eaten any mammals running around with ease.
Ahhh, so in that case, dinosaurs would NOT have gained a foothold and life would have taken a Very different course of evolution on ALL the worlds as they would not have gone through the Cambrian, Silurian and Permian extinction events (all environmental and specific to this planet) that cleared the way for small reptiles to diversify into dinosaurs and mammals.
And, of course, there is no reason to assume that another planet, however Earth-like, would have anything resembling reptiles or mammals never mind anything as specific as dinosaurs. Even if you replayed evolution on Earth, under the same conditions, you could end up with something completely different.
I like to play the odds. The odds...I believe, will support the evolution of highly intelligent life --- on typical Earth type planets --- be it in the dinosaur or mammalian family tree's. Granted, any previous Earth epoch's of primitive life forms, that could have justifiably had there chance on the evolutionary life scale, but I'll still tend to hedge my bet's on the success of evolution with the dinosaur/mammal family tree; on typical Earth type planets --- such is my hope. Cheers, Erno
Strange -- I'll also speculate: That on many typical Earth-type planet's in our universe {that supports carbon based life}, with the proper nutrition --- will evolve highly intelligent life --- of the bipedal variety...be they dinosauroid or humanoid; because of bipedal dexterity and intelligence.
Care to show how you calculate these odds based, no doubt, on your in-depth knowledge of evolutionary theory, exo-biology and the geochemistry of alien worlds?
How can they be in the "dinosaur or mammalian family trees" when they are not related? The absolute best you could hope for is that they may look vaguely similar. Beyond that, not a chance.be it in the dinosaur or mammalian family tree's
It is even possible that evolution would not work in the same way on another planet.
Your speculation fails utterly after your exo-worlds pass the point in time that earth was in its "snowball earth" period. ALL life and evolution after that will diverge massively from what happened on earth. You can root for dinosaurs or mammals all you want because they are sexy to you, but they would not evolve, period.
Erno, I'm curious as to what leads you to suspect that evolution would produce such seemingly familiar forms as dinosaurs and mammals on other planets. What is the basis for this suspicion? It is an interesting one. Do you have any solid reason to support it that might persaude others to take a second look at it?
oh for the joys of fact-free certainty, for there is nothing that can budge it
if you had any feel for probability, you would put your money on a planet having no life, and if it did, the highest probability is for life to be of the prokaryotic kind
imagine : if no bacterium had discovered a way to photsynthesize, chances are that there would be no eukaryotes
no eukaryotes, no multicellular life - no multicellular life, no dinosaurs
so much for probability
The basic evolutionary physical and intelligent traits of the human body and mind, support the odds that other similar biological life on other similar habitable planets {given the time and luck}, exist as well. One of my other reasons... is my own {and other's as well}, visual sighting/sighting's of otherworlder starships, cavorting around in our atmosphere; here on Earth.
You can't conclude that from a sample size of 1.
You have not seen "otherworlder starships". (Apart from the fact there is no evidence for such things visiting Earth, your ridiculous pronouncements on this forum mean that anything you say has zero credibility.)One of my other reasons... is my own {and other's as well}, visual sighting/sighting's of otherworlder starships, cavorting around in our atmosphere here on Earth.
All you've doen here is make (another) unsubstantiated claim.
You've explained nothing.
There have been no sightings of "otherworlder starships".One of my other reasons... is my own {and other's as well}, visual sighting/sighting's of otherworlder starships, cavorting around in our atmosphere; here on Earth.
The basic evolutionary physical and intelligent traits of the human body and mind, support the odds that other similar biological life on other similar habitable planets {given the time and luck}, exist as well. One of my other reasons... is my own {and other's as well}, visual sighting/sighting's of otherworlder starships, cavorting around in our atmosphere; here on Earth.
Neither of these pronouncements are actually viable. And you have YET to acknowledge that your own initial caveat of "
Has been shown to invalidate your own speculation due to the multiple environmentally caused extinction events BEFORE the dinosaurs even evolved.
No, the theory says that:
monkeys + missing link = Human
The reason that no aliens have contacted us is because of our ghosts. The aliens arrive in their UFO's and the ghosts scare them away. Earth has tough ghosts!
No, the theory does not say that. The sequence is actually last common ancestor + genetic drift + mutation + time = humans AND monkeysNo, the theory says that:
monkeys + missing link = Human
Claiming its monkeys and a missing link is incorrect.
Oh good grief. Where do they keep coming from.
You listen only to your Pastor and never bothered to do independent research:
Fossil Hominids: the evidence for human evolution
Introduction to Human Evolution | The Smithsonian Institution's Human Origins Program
https://en.wikipedia.org/wiki/Human_evolution
There you go.
Monkeys. Do try to pay attention.
As far as I'm concerned they didn't.
women dinosaurs got educated and discovered birth control
population growth stopped, then reversed
by the time of the asteroid, they were so few that they couldn't recover
...............
alternately,
they discovered how to make fire, but never learned how to control it
and our ancestors ancestors dined on roast dinosaur
Does this mean you have read Eric Frank Russell's Next of Kin? If not, you should.
My Willy and I agree.
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