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Author Topic:   The Chicken And Egg Problem, this problem refers to all species
Nitai
Inactive Member


Message 1 of 43 (206938)
05-11-2005 4:52 AM


Hello,
As you can see from the title of the topic this is actually a very seriouas problem not only considering the chicken's origin but of insects, molluscs, arthropods etc. aswell.
So, any suggestions what was first?
PS: Please be serious.
Nitai
This message has been edited by Nitai, 05-11-2005 04:55 AM

Replies to this message:
 Message 3 by Jianyi Zhang, posted 05-11-2005 9:42 AM Nitai has not replied
 Message 4 by Yaro, posted 05-11-2005 9:46 AM Nitai has replied
 Message 9 by EZscience, posted 05-11-2005 10:50 AM Nitai has replied
 Message 41 by RAZD, posted 05-13-2005 9:07 PM Nitai has not replied

  
AdminNosy
Administrator
Posts: 4754
From: Vancouver, BC, Canada
Joined: 11-11-2003


Message 2 of 43 (207037)
05-11-2005 9:35 AM


Thread moved here from the Proposed New Topics forum.

  
Jianyi Zhang
Inactive Member


Message 3 of 43 (207041)
05-11-2005 9:42 AM
Reply to: Message 1 by Nitai
05-11-2005 4:52 AM


Please see: http://chickensfirst.net

Jianyi Zhang< !--UE-->
Edited by Adminnemooseus, : Fix link. There was a ";" where a ":" is needed. Still, it seems that no such page can be found.

This message is a reply to:
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Replies to this message:
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Yaro
Member (Idle past 6486 days)
Posts: 1797
Joined: 07-12-2003


Message 4 of 43 (207045)
05-11-2005 9:46 AM
Reply to: Message 1 by Nitai
05-11-2005 4:52 AM


Well, considering that sexual reproduction is a later adaptation, I think it would be safe to assume that "the chicken" came first.
Before the egg/chicken cycle started, the ancestor of the chicken was a simple single celled organisim that likely divided like bacteria or amoeba. As evolution progressed simple multi-cellular life which reproduced asexualy evolved. As time went on it became advantageous to have a wider variety of genes in the pool and sexual reproduction began to develop, this inevitable lead to the development of genders.
Eggs didn't come about till much later in the picture, but I think you can get the idea from here.

This message is a reply to:
 Message 1 by Nitai, posted 05-11-2005 4:52 AM Nitai has replied

Replies to this message:
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 Message 7 by Nitai, posted 05-11-2005 10:33 AM Yaro has replied

  
Wounded King
Member
Posts: 4149
From: Cincinnati, Ohio, USA
Joined: 04-09-2003


Message 5 of 43 (207063)
05-11-2005 10:17 AM
Reply to: Message 4 by Yaro
05-11-2005 9:46 AM


So you are saying that since organisms evolved before specialised sexual cells, then 'chickens' came before 'eggs'.
I've always thought about this problem at a much later stage and concluded that eggs came first since egg laying is seen in lineages much more ancient than chickens.
So I guess you pays your money and you takes your choice.
TTFN,
WK

This message is a reply to:
 Message 4 by Yaro, posted 05-11-2005 9:46 AM Yaro has replied

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Yaro
Member (Idle past 6486 days)
Posts: 1797
Joined: 07-12-2003


Message 6 of 43 (207066)
05-11-2005 10:28 AM
Reply to: Message 5 by Wounded King
05-11-2005 10:17 AM


I've always thought about this problem at a much later stage and concluded that eggs came first since egg laying is seen in lineages much more ancient than chickens.
I dunno... I would speculate that the apearance of eggs was a gradual process. I would hypothesize that there were intermediate stages to the evolution of eggs.
Furthermore, as the OT asks, what came first for all the species? It is pretty clear that genders, eggs, and reproduction in general, was a parallel evolutionary development. So the answer is not the same for all species.
Like the evolution of the eye, nature has solved the problem in a large variety of ways for all the different species. Just think about the way crabs lay eggs and compare that to frogs, or snails.
So I don't think even if there was an absolute "first", it would be the same answer for every species.
This message has been edited by Yaro, 05-11-2005 10:29 AM

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Nitai
Inactive Member


Message 7 of 43 (207067)
05-11-2005 10:33 AM
Reply to: Message 4 by Yaro
05-11-2005 9:46 AM


upside down evolution
Fern 480 White Ash 138 Carp 100
Goldfish 94 Sweet Potato 90 Turkey 82
Chicken 78 Dog 78 Duck 78
Horse 64 Cow 60 Silkworm 56
Cotton 52 Amoeba 50 Chimp 48
Tobacco 48 Human 46
This scheme shows the number of chromosomes in these species. Its unbelievable that from single celled living entity an Amoeba developed with 50 chromosomes. More then in human - only 46.
Jokingly, if I accept evolution that means humans will develop into Amoebas, sweet potatoes, a goldfish and ultimately the fern with 480 chromosomes?
And --- it seems before chickens and eggs there was a man.
This message has been edited by Nitai, 05-11-2005 10:35 AM

This message is a reply to:
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Yaro
Member (Idle past 6486 days)
Posts: 1797
Joined: 07-12-2003


Message 8 of 43 (207069)
05-11-2005 10:38 AM
Reply to: Message 7 by Nitai
05-11-2005 10:33 AM


Re: upside down evolution
Fern 480 White Ash 138 Carp 100
Goldfish 94 Sweet Potato 90 Turkey 82
Chicken 78 Dog 78 Duck 78
Horse 64 Cow 60 Silkworm 56
Cotton 52 Amoeba 50 Chimp 48
Tobacco 48 Human 46
This scheme shows the number of chromosomes in these species. Its unbelievable that from single celled living entity an Amoeba developed with 50 chromosomes. More then in human - only 46.
Huh?
What does this have to do with anything?
If I told you that modern wrist watches have less parts than older watches does that mean they didn't "evolve" from the older time pieces?
Furthermore, what do you think a chromasom is that the amount of them has to do with evolutionary descent? I have never read anything that suggests evolution predicts chromasom count to increase as aspecies change over time.

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EZscience
Member (Idle past 5144 days)
Posts: 961
From: A wheatfield in Kansas
Joined: 04-14-2005


Message 9 of 43 (207073)
05-11-2005 10:50 AM
Reply to: Message 1 by Nitai
05-11-2005 4:52 AM


Eggs before chickens if taken literally
If the problem is considered specifically w/r/t 'chickens', then
eggs were a form of reproduction in many lineages long before anything even looked like a chicken.
The first 'chicken' would have had to hatch from some 'proto-chicken' egg, and therefore the egg would have come first.
If the problem is considered more figuratively, with the chicken representing higher organisms in some general way, then the 'chicken' would have come first, simply because egg laying is a highly-evolved form of sexual reproduction (oogamy) that evolved through various intermediate stages of anisogamy (fusion of gametes of unequal size).
The ancestral state of sexuality in multicellular organisms is isogamy (gametes of equal size fuse) - there is no overt sexual differentiation in such species - only '+' and '-' mating types.
Here is a good reference on the evolution of sexuality written by one of my former advisors some years ago.

This message is a reply to:
 Message 1 by Nitai, posted 05-11-2005 4:52 AM Nitai has replied

Replies to this message:
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Nitai
Inactive Member


Message 10 of 43 (207110)
05-11-2005 1:26 PM
Reply to: Message 9 by EZscience
05-11-2005 10:50 AM


Re: Eggs before chickens if taken literally
You say: "The first 'chicken' would have had to hatch from some 'proto-chicken' egg, and therefore the egg would have come first".
Do you think here about the 'hopeful monster' theory? Chicken coming out from the crocodile egg? Or vice versa?
I cannot demonstrate that evolution implies progression towards a greater number of chromosomes but in any text book on evolution you will find the information that humans are superior because they have more chromosomes, or let's put it differently because they have more genes.
The supprising discovery I found is that human genome is comparatively small, only about 25,000 genes, compared to a rice kernel with 60,000 genes. Or look this site Sizing up genomes: Amoeba is king
This was written by serious scientists.
But OK. ALthough the evolutionary connection is not clear, let's say that the complexity of an organism doesn't depend on the number of chromosomes. At least that's obvious. Still with this, the question is not solved. And that is, how is it that so many chromosomes are there in the lower animals that are in the beginning scale of evoluton; and for what they need so much chromosomes; etc.
Finally back to the original point. If you know 100% the exact develpment of x-entity into chicken please supply here all the details of genetic transformations and demonstrate that in the laboratory. I am sure you will get a Nobel prize. But anyway, I am not interested only in dry unproved theories. I want practical proof.
Now, let me a bit speculate. If I assume that the developing x-entity (pre-chicken) was gradually evolving, the egg should have also developed gradually. But than, the problems would be:
1) laying the egg - if the shell is not strong it would be immediatelly smashed and become the feast for other animals. (Maybe some ape aeting the first egg)
2) Moreover, even if somehow the egg would not become smashed the x-entity would not lay on it to not brake the egg so the chicken or x-entity would never hatch.
So, again problems.
I look forward for your reply.
Nitai
This message has been edited by Nitai, 05-11-2005 01:29 PM
This message has been edited by Nitai, 05-11-2005 01:32 PM
This message has been edited by Nitai, 05-11-2005 01:38 PM

This message is a reply to:
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Replies to this message:
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Yaro
Member (Idle past 6486 days)
Posts: 1797
Joined: 07-12-2003


Message 11 of 43 (207115)
05-11-2005 1:34 PM
Reply to: Message 10 by Nitai
05-11-2005 1:26 PM


Re: Eggs before chickens if taken literally
1) What do you think a chromasome is?
2) What is the importance of the amount of genes in a creature versus another?
3) Why does gene quantity matter vs. Active/usefull genes?

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zephyr
Member (Idle past 4540 days)
Posts: 821
From: FOB Taji, Iraq
Joined: 04-22-2003


Message 12 of 43 (207142)
05-11-2005 2:19 PM
Reply to: Message 10 by Nitai
05-11-2005 1:26 PM


Re: Eggs before chickens if taken literally
Your attitude seems to indicate that you have already made your conclusions and are just looking for some amusing confrontation. Am I wrong?
Given that the first egg-layers lived in water, and that the first egg was laid before predators had developed egg-eating abilities and behavior (what good would it have been till then?), even a thin mucous membrane around one's developing offspring would have been an advantage. Then one can expect jaws to get sharper and shells to get thicker and harder. If you're not familiar with the concept of an evolutionary arms race, that would suggest you're not very well versed in modern biology.
quote:
in any text book on evolution you will find the information that humans are superior because they have more chromosomes, or let's put it differently because they have more genes
I'll give you two options:
A: give an example to support this claim, or;
B: retract it.
Subtle hint: you don't have a leg to stand on.
This assertion, which you claim is ubiquitous in "evolution" textbooks, would be profoundly laughable for the very reasons you describe. I learned in science class at age 12 that crawfish have several times the chromosomes I do. I also learned a bit about evolution, and it was clear that chromosome count had nothing to do with it.
You seem to have some misconceptions about evolutionary theory. You do have an interesting sample of data points... you're aware of the hopeful monster concept, but not sure how it is relevant to this issue. You seem to have just sort of flung it out there as a vague accusation, without realizing that it is simply a caricature of RM/NS and not a legitimate scientific concept. You wrongly think that chromosome count is somehow claimed by biologists as an indicator of some kind of "superiority". Unfortunately, evolutionary theory makes no claims about superiority at all. It does say that the fitness of an organism relative to its environment (which includes such things as climate, food sources, predators, and even fellow members of the species) affects its likelihood of producing viable offspring. To use emotionally loaded terms like superiority simply distracts from the issues and interferes with the ability of humans to process these ideas rationally.

This message is a reply to:
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EZscience
Member (Idle past 5144 days)
Posts: 961
From: A wheatfield in Kansas
Joined: 04-14-2005


Message 13 of 43 (207172)
05-11-2005 4:12 PM
Reply to: Message 10 by Nitai
05-11-2005 1:26 PM


Re: Eggs before chickens if taken literally
If you don't like my reasoning, you can try Zhang's.
Click here and scroll down.

This message is a reply to:
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crashfrog
Member (Idle past 1457 days)
Posts: 19762
From: Silver Spring, MD
Joined: 03-20-2003


Message 14 of 43 (207192)
05-11-2005 4:52 PM
Reply to: Message 7 by Nitai
05-11-2005 10:33 AM


Different chromosome numbers is not an issue.
quote:
Chromosome counts are poor indications of similarity; they can vary widely within a single genus or even a single species. The plant genus Clarkia, for example, has species with chromosome counts of n = 5, 6, 7, 8, 9, 12, 14, 17, 18, and 26 (Lewis 1993). Chromosome counts in the house mouse species (Mus domesticus) range from 2n = 22 to 40 (Nachman et al. 1994).
Chromosomes can split or join with little effect on the genes themselves. One human chromosome, for example, is very similar to two chimpanzee chromosomes laid end to end; it likely formed from the joining of two chromosomes (Yunis and Prakash 1982). Because the genes can still align, a change in chromosome number does not prevent reproduction. Chromosome counts can also change through polyploidy, where the entire genome is duplicated. Polyploidy, in fact, is a common mechanism of speciation in plants.
from CB141: Differing chromosome numbers
You can join or cleave chromosomes with little effect on genes or reproduction.

This message is a reply to:
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crashfrog
Member (Idle past 1457 days)
Posts: 19762
From: Silver Spring, MD
Joined: 03-20-2003


Message 15 of 43 (207194)
05-11-2005 4:59 PM
Reply to: Message 10 by Nitai
05-11-2005 1:26 PM


I cannot demonstrate that evolution implies progression towards a greater number of chromosomes but in any text book on evolution you will find the information that humans are superior because they have more chromosomes, or let's put it differently because they have more genes.
I've looked through three textbooks, and in addition, spoken to several research graduates and professors regarding this claim, and every single one of them repudiated it. I don't know where you heard this but this isn't true. (Humans generally aren't recognized to have any superior status among biologists, certainly none related to genetics.)
If I assume that the developing x-entity (pre-chicken) was gradually evolving, the egg should have also developed gradually.
Why? Chickens aren't the only organism that lays eggs. The ancestor of the chicken (probably something pigeon-like) would have been laying fully-formed eggs.
How did eggs develop, you mean? Well, they certainly wouldn't have been incubated under the bird until calciferous shells had evolved. You'll notice, I'm sure, that the eggs of reptiles are generally leathery, not hard - and the eggs of amphibians, their ancestors, are even less protected. They are laid in the water.
So, again problems.
No problems. You need to open a book, though. You need to observe the fact that plenty of organisms lay soft eggs, and somehow do just fine. You need to do a little more observation before you claim to have killed evolution with the magic bullet.

This message is a reply to:
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Replies to this message:
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