Why do chickens lay eggs?: Philosophy Forums

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Why do chickens lay eggs?

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Why do chickens lay eggs?

unenlightened
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Posted 05/13/09 - 05:34 AM: Subject: Why do chickens lay eggs?	#1
This is probably a foolish question, but why should that stop me? (Don't answer that, that's not the question.) Given that one is a warm-blooded creature, one is obliged to sit on one's eggs, most inconveniently interrupting other activities like feeding. It would seem that there would be an evolutionary pressure towards shorter incubation times, until eggs hatched immediately upon being laid. Why do birds have the temerity to ignore this logic? Can they possibly be so stupid as not to have noticed?
...most of our actions are the result of the past, or according to a future ideal. That's not action, that is just conformity. J Krishnamurti "Philosophy, to the Philistine, is an evolutionary process, watched over by some sort of brisk dynamic Providence, and culminating in the supreme insight of modern thought." John Cowper Powys

Benkei
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Posted 05/13/09 - 05:52 AM:	#2
Reptilians, being cold-blooded, also lay eggs but that's besides the point. Since the bird was smart enough to either blend in with its surroundings or build nests away from predators, it survived without shorter incubation times. Which might be a reason natural selection did not go so far as to shorten incubation times and probably allowed for longer incubation times and therefore more complex and more specialised species of birds in the long run. And although we can understand which enviroments are conducive for or detrimental to the development of certain traits and characteristics of animals, the process of evolution as a whole is not rational or teleological. What does seem interesting to me is that evolution as a whole moves towards greater complexity. Despite sometimes simple "designs" working better. Cockroaches, viruses and bacteria seem to have a much better survival chance as a species when we aren't actively killing them.
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Cuthbert
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Posted 05/13/09 - 06:11 AM:	#3
Even better, they could 'hatch' while still inside the mother and be born 'ready-hatched'. Then mum could just lick off the afterbirth, lift up the newborn by the scruff of the neck onto its spindly little legs, and it would be ready to go and find something to eat. Hey, I just invented mammals!

unenlightened
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Posted 05/13/09 - 07:44 AM:	#4
Cuthbert wrote: Even better, they could 'hatch' while still inside the mother and be born 'ready-hatched'. Then mum could just lick off the afterbirth, lift up the newborn by the scruff of the neck onto its spindly little legs, and it would be ready to go and find something to eat. Hey, I just invented mammals! Well being, I presume, a clever mammal, you see the direction straight away, whereas these bird-brains do not get it at all. But look: in a hard summer, food is a bit scarce, birds that lay their eggs a little bit later in development will have more time to hunt or forage - an unlaid egg won't stop them flying. I assume if we are going to save the theory of evolution - which would be nice - we should come up with some speculative advantage to laying your eggs and sitting on them as opposed to keeping them within the body.
...most of our actions are the result of the past, or according to a future ideal. That's not action, that is just conformity. J Krishnamurti "Philosophy, to the Philistine, is an evolutionary process, watched over by some sort of brisk dynamic Providence, and culminating in the supreme insight of modern thought." John Cowper Powys

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Posted 05/13/09 - 08:19 AM:	#5
Perhaps by laying eggs early you can get on with generating more eggs in your body, so that when inevitably some of the previous clutch are eaten by mongooses or crows you have others ready. The earlier you lay, the more you can make and so the more successful you are at reproducing. The later you lay, the less time your eggs are at risk from predators. So there's a trade off, ending up in an optimal incubation period. Similarly with gestation period for mammals. I'm just guessing.

J. Random Hacker
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Posted 05/13/09 - 09:46 AM:	#6
unenlightened wrote: I assume if we are going to save the theory of evolution - which would be nice - we should come up with some speculative advantage to laying your eggs and sitting on them as opposed to keeping them within the body. You should read the paper "Why Are There No Viviparous Birds?" (http://www.jstor.org/pss/2461543) and I also recommend the book A Natural History of Parenting by Susan Allport. Giving birth to live young offers no net benefits for birds. There will be fewer overall births because as it is, a bird can keep producing eggs even while incubating others. There is also the increased weight to be carried around, more expended energy that could be used in producing eggs. There will also be fewer opportunities for the males of the species to help care for the unborn young. The obvious and easily researched answer is that birds are better off as they are. Evolution is not at risk by a long shot. Edited by J. Random Hacker on 05/13/09 - 09:57 AM

unenlightened
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Posted 05/13/09 - 10:25 AM:	#7
Thanks. I knew they must have a good reason, I just couldn't think what it was. I would never have dreamed it was worth writing a whole paper on though. Fortunately, not being an official academic, I don't have access to it.
...most of our actions are the result of the past, or according to a future ideal. That's not action, that is just conformity. J Krishnamurti "Philosophy, to the Philistine, is an evolutionary process, watched over by some sort of brisk dynamic Providence, and culminating in the supreme insight of modern thought." John Cowper Powys

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Posted 05/13/09 - 03:22 PM:	#8
How many mammals have beaks that are born within their parents body? Maybe the evolution was created to prevent the tearing of internal organs? What's needed for the survival of any individual? In humans we seem to ascribe to this relationship that boredom/inactivity is a requirement for survival. Then again, we did make couches.
"...There was a writer who asked why it was that when we find positive experiences we say that only the physical facts are real, but in negative experiences we believe that reality is subjective. He made an example of those who say that in birth only the pain is real, the joy a subjective point of view, but that in death it is the emotional loss that is the reality." - Tony Ballantyne, Recursion. _____________________________________________ Truth is want. - The internal state of matters. Truth is Need. - The external state of affairs.

wuliheron
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Posted 05/13/09 - 07:09 PM:	#9
When a hen lays an egg she usually leaves the roost if she can and looks for a good hiding place. The effort leaves her dazed and confused and she instinctively clucks until the rooster fetches her and brings her back to the roost where she is somewhat safer from preditors. Considering an average hen can lay roughly 200 eggs a year if a few are lost it is no big deal. In fact, chickens are canabals and often eat each other and their own eggs. Farmers carefully watch out for chickens that have acquired a taste for eggs and kill them as soon as they find them. The only form of reproduction which is virtually instantaneous is parthenogensis. Chickens lay eggs because sexual reproduction allows for faster evolution even though it requires more time and resources for the individual. Eggs contain the ingredients necessary for the chick to grow and develop enough to exist outside of the egg. Hence the idea of an egg that would hatch immediately is nonsensical. It would be a waste for a chicken to create an egg if its chicks did not need an egg. However, people have been manipulating evolution for thousands of years now. In recent decades scientists have discovered things such as fish cells that reproduce nonstop as long as they are keep in a solution of nutrients. Some day you might go to the incubator and cut off a piece to cook for dinner, cirumventing the need for fish eggs altogether.

ying
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Posted 05/13/09 - 07:10 PM:	#10
Benkei wrote: Reptilians, being cold-blooded, also lay eggs but that's besides the point. Actually, it's not. Birds evolved from dinosaurs, so it's quitte relevant, chickens being birds, and all. So the question becomes: "Why do reptilians lay eggs?" So it gets pushed back even more; ancestors of reptilians, which where some sort of fish I'd venture, also lay eggs. My guess is that the fish employing external fertilisation, then the subsequent dinosaurs evolved some sort of internal fertilisation process, then chickens happend. Or something. This gives rise to an apparent non-sequitur answer to the "chicken - egg" conundrum: Q: "What came first, the chicken or the egg?" A: "Fish". J. Random Hacker wrote: You should read the paper "Why Are There No Viviparous Birds?" (http://www.jstor.org/pss/2461543) and I also recommend the book A Natural History of Parenting by Susan Allport. Giving birth to live young offers no net benefits for birds. There will be fewer overall births because as it is, a bird can keep producing eggs even while incubating others. There is also the increased weight to be carried around, more expended energy that could be used in producing eggs. There will also be fewer opportunities for the males of the species to help care for the unborn young. The obvious and easily researched answer is that birds are better off as they are. Evolution is not at risk by a long shot. Yeah, that's an ad hoc argument or an after the facts explanation. Edited by ying on 05/13/09 - 09:55 PM
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