Hi, in a previous post re: what came first, egg or chicken someone asked this question. It just got me thinking.
The ancestors to flying birds would have had to lay eggs correct ? IE: A pregnant bird would not be able to fly too well. Indeed, does anyone know how long before a bird lays her eggs, she is still able to fly ?
So I would have to go by the assumption that eggs predated flight ?
thanks
As far as I know, all flying birds can still fly even when they are about to lay an egg. Most flying birds have plenty of spare "carrying capacity" as the weight of the egg is small compared to the overall weight of the bird. Compare a robin's egg with an adult robin, for example, or even a chicken egg with an adult chicken.
However, you are correct that egg-laying came well before flight (At least in birds. Pterosaurs flew long before birds did, and insects were flying much earlier still. But, of course, both pterosaurs and flying insects were also egg-layers, and both were descended from non-flying egg-layers.) Birds are descended from Theropod dinosaurs, which are, in turn descended from many millions of years worth of egg-layers. The common ancestor of reptiles and mammals would have to be close to 300 million years in the past. The first birds, only about 150 million.
Of course, all these dates are based on theories that I am aware you may not accept, but I am answering from the perspective of the scientific evidence that I am aware of. If you want a Creationist perspective, I would guess that they (you) would not accept that eggs came before flight at all.
Paul
A creation story.
The space of the universe was in the shape of a hen's egg. Within the egg was a great mass called no thing. Inside no thing was something not yet born. It was not yet developed, and it was called Phan Ku.
In no time, Phan Ku burst from the egg. He was the first being. He was the Great Creator. Phan Ku was the size of a giant. He grew ten feet a day and lived for eighteen thousand years. Hair grew all over Phan Ku. Horns curved up out of his head, and tusks jutted from his jaw. In one hand he held a chisel, and with it he carved out the world.
Phan Ku separated sky from earth. The light, pure sky was yang, and the heavy, dark weight of earth was yin. The vast Phan Ku himself filled the space between earth and sky, yin and yang.
He chiseled out earth's rivers; he scooped out the valleys. It was easy for him to layer the mountains and pile them high upon high.
Then Phan Ku placed the stars and moon in the night sky and the sun into the day. He put the great seas where they are now, and he showed the people how to fashion ships, how to build bridges.
Only when Phan Ku died was the world at last complete. The dome of the sky was made from Phan Ku's skull. Soil was formed from his body. Rocks were made from his bones, rivers and seas from his blood. All of plant life came from Phan Ku's hair. Thunder and lightning are the sound of his voice. The wind and the clouds are his breath. Rain was made from his sweat. And from the fleas that lived in the hair covering him came all of humankind.
The form of Phan Ku vanished in the making of the world. After he was gone, there was room then for pain, and that is how suffering came to human beings.
http://home.earthlink.net/~jcorbally/eng203/rphanku.html
Fjord
Originally posted by prn
As far as I know, all flying birds can still fly even when they are about to lay an egg. Most flying birds have plenty of spare "carrying capacity" as the weight of the egg is small compared to the overall weight of the bird. Compare a robin's egg with an adult robin, for example, or even a chicken egg with an adult chicken.
Of course, all these dates are based on theories that I am aware you may not accept, but I am answering from the perspective of the scientific evidence that I am aware of. If you want a Creationist perspective, I would guess that they (you) would not accept that eggs came before flight at all.
Paul
Hehe, nope not at all. I am merely fascinated by some evolutionary theories. Biology was afterall one of my subjects in school.
I recall reading one of the theories that birds evolved from tree-dwelling (kinda reptiles). I can see how the chicken or the ostridge, or partridge could survive by laying eggs on the ground, however I don't understand how a small bird like creature would be able to survive by
laying eggs on the ground. I would assume that should a bird give live birth to its offspring, it would put it at a significant disadvantage throughout its gestation period (flying around with that heavy load), thus I would well imagine that to be the reason that birds lay eggs. I'm just trying to figure out at what point egg laying would have happend ? Before flight or after ?
As snakes and dinosaurs are oviporous and no birds are oviviporous or viviporous, I would have to assume (in the evolutionary model) that birds ancestors were also oviporous. However, I can't really imagine the success rate of rearing loud offspring anywhere on ground level, especially when the species is not particularly equipped to defend the offspring, and the young are entirely dependant on the parent feeding it for 6 + weeks.
Hehe, nope not at all.
Hard to keep track of the players without a program sometimes.🙂
Current information is that, yes, birds did evolve from land-dwelling dinosaurs, specifically ones in the Theropod group. Egg-laying had to come before flight as flight is more or less restricted to a sub-group of the larger group of egg-layers. Note that snakes and other modern reptiles basically lay 'em and leave 'em so you're right that they are not faced with the same level of parental care and support that birds are. There is evidence that dinos, especially the Theropods, engaged in more extended parental care than any modern reptile. I'd have to look it up to say a lot more than that, but I know that there has been discussion of the nesting behavior of dinos as evidenced by the structure and settings of the nests as well as indications that the nests were not simply hatching places, but used for extended times. Clearly it is a lot easier for hadrosaurs, for example, to defend their nests against smaller predators than for something the size of a sparrow, but then it's not so clear that the first birds were all that small, either. AFAIK, the first birds we have evidence of were more nearly the size of a chicken, if that helps. Also, remember that many modern birds nest on the ground. Quail are not all that large, for example. There is no reason to assume that small dinos and early birds made no use of cover to hide their nests. Also, remember that not all fledgeling birds are equally loud. I would speculate that ground-dwelling birds tend to be quieter simply because the quieter ones are more likely to survive.
Best regards,
Paul