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Author Topic:   Egg burier animals question
arachnophilia
Member (Idle past 1427 days)
Posts: 9069
From: god's waiting room
Joined: 05-21-2004


Message 16 of 29 (438934)
12-06-2007 4:13 PM
Reply to: Message 15 by clpMINI
12-06-2007 4:08 PM


Re: Other Megapodes
that they are terrestrial (as opposed to arboreal) is probably important.
It even mentions that it is likely that temperature determines sex, making the message by Arach concerning a throwback to crocs even more meaningful.
yes. i wasn't sure if that was the case in mound-building birds, but vaguely recalled that it might have been, as in crocodiles.


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MartinV 
Suspended Member (Idle past 5911 days)
Posts: 502
From: Slovakia, Bratislava
Joined: 08-28-2006


Message 17 of 29 (438936)
12-06-2007 4:30 PM
Reply to: Message 14 by arachnophilia
12-06-2007 3:59 PM


Re: No, No Martin
you have completely misunderstood evolution. it is not survival of only the most fit, but survival of everything that except the least fit. a small survival advantage is, frankly, enough for the retention of a feature. no net effect is enough for the retention of a feature. and if there is some small advantage, that does not mean that EVERY similar animal would likewise spontaneously evolve a covergent feature or become extinct.
And perhaps it is you who do not realize into depth what you are talking about. Go to Mimicry thread we can discuss "survival advantage" and "fitness" there generally and in particular cases.
in any case, this is not what people are arguing. if you'll notice above, my argument is that it's a throwback to crocodilian practices.
That's more interesting as the reasoning of PaulK. Do you mean that genes for such behaviour were inherited from dinosurian ancestors and were somehow switched on? You know I like frontloading, epigenesis etc.. I suppose this is what you means. Otherwise if such genes has arisen de novo I wouldn't call such obviously innate and fixed behaviour as "throwback".

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Replies to this message:
 Message 19 by arachnophilia, posted 12-06-2007 4:47 PM MartinV has replied

  
reiverix
Member (Idle past 5902 days)
Posts: 80
From: Central Ohio
Joined: 10-18-2007


Message 18 of 29 (438937)
12-06-2007 4:33 PM
Reply to: Message 13 by MartinV
12-06-2007 3:35 PM


Re: No, No Martin
If somebody claims that Macrocephalon maleo bury their eggs because it gives them some survival advantage I would like to know how many Sulawesi species do the same.
But wouldn't it be a disadvantage if the other species were all doing the same? There's only so much good real estate for egg burying.

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arachnophilia
Member (Idle past 1427 days)
Posts: 9069
From: god's waiting room
Joined: 05-21-2004


Message 19 of 29 (438940)
12-06-2007 4:47 PM
Reply to: Message 17 by MartinV
12-06-2007 4:30 PM


Re: No, No Martin
That's more interesting as the reasoning of PaulK. Do you mean that genes for such behaviour were inherited from dinosurian ancestors and were somehow switched on?
crocodilians and basal archosaurs seem to have buried their eggs, and used tempurature to control gender. i'm not too clear on early dinosaurs, though the transition from cold-blooded to warm-blooded seems to have occured prior to dinosaurs' divergence, within crocodilians like postosuchus.
dinosaurs as a whole seem to have continued using egg-mounds, though in various different styles. i seem to recall that both ornithischians and saurischians tended their eggs in open nests, but that sauropods (unlike other saurischians) buried them due to the impracticality of sitting on them.
in other words, in this particular evolutionary tree, egg-burying came and went a few times (much like flight). tempurature's relation to gender might be common to the whole lineage, and egg burying may simply be a common solution for controlling temperature.
Edited by arachnophilia, : No reason given.


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nator
Member (Idle past 2253 days)
Posts: 12961
From: Ann Arbor
Joined: 12-09-2001


Message 20 of 29 (438954)
12-06-2007 6:37 PM
Reply to: Message 11 by MartinV
12-06-2007 3:20 PM


quote:
I wouldn't be surprised if next to the M. maleo holes with eggs there would be nests of another bird species which do not bury their eggs. Birds species that do not profit "small survival advantages" of burrying their eggs. I suppose there are many bird species in the area which do not bury their eggs but thrive as well as M. maleo there.
I wouldn't be surprised, either.
It's called a "niche".

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Dr Adequate
Member (Idle past 367 days)
Posts: 16113
Joined: 07-20-2006


Message 21 of 29 (438958)
12-06-2007 7:33 PM
Reply to: Message 3 by Garabato
12-06-2007 1:22 AM


Re: A suggestion first
Now since there are evolutionary advantages for deeper burial (I think). Then there is selective pressure for greater depth of burial. So after many generations of slightly increase of burial depth, the individuals who had slightly increase of physical activity to reach the surface would have a higher chance of surviving, thus having a higher chance to leave offspring.
Yes, that seems about right. As someone noted, in the early stages maybe the mother would assist.
I notice that all megapodes are born active, feathered, and even able to fly; apparently they dig their way out of the "nests" with large powerful claws. One wonders whether this precocious development is an adaptation to the egg-burying habit, or an exaption that allowed the evolution of the habit.
Interesting birds.

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MartinV 
Suspended Member (Idle past 5911 days)
Posts: 502
From: Slovakia, Bratislava
Joined: 08-28-2006


Message 22 of 29 (438998)
12-07-2007 12:57 AM
Reply to: Message 19 by arachnophilia
12-06-2007 4:47 PM


Re: No, No Martin
in other words, in this particular evolutionary tree, egg-burying came and went a few times (much like flight). tempurature's relation to gender might be common to the whole lineage, and egg burying may simply be a common solution for controlling temperature.
Do you think there was a time M.maleo ancestors nested and hatched their eggs like other birds and only their descendants (more recent M.maleo ancestors) started burrying their eggs?
In that case - because the process seems to be instinctive - do they use some inherited and switched on ancestory genes?
Scientists should also make an experiment what the birds would do having no possibilities to burrow their eggs into sand. Would they hatch them or would they leave their eggs on the ground and would not care about them?

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 Message 24 by Granny Magda, posted 12-08-2007 3:52 AM MartinV has replied

  
jar
Member
Posts: 34057
From: Texas!!
Joined: 04-20-2004
Member Rating: 4.9


Message 23 of 29 (439074)
12-07-2007 9:40 AM
Reply to: Message 22 by MartinV
12-07-2007 12:57 AM


Re: No, No Martin
Scientists should also make an experiment what the birds would do having no possibilities to burrow their eggs into sand. Would they hatch them or would they leave their eggs on the ground and would not care about them?
Other than the somewhat stupid suggestion that we increase the pressure on an already endangered species, what would that show?
I can tell you. It would show evolution in action. Those traits that successfully reproduced in that environment would gradually come to dominate the population. Those that did not would die out or move.
Plain old TOE stuff Martin.

Immigration has been a problem Since 1607!

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Granny Magda
Member (Idle past 121 days)
Posts: 2462
From: UK
Joined: 11-12-2007


Message 24 of 29 (439291)
12-08-2007 3:52 AM
Reply to: Message 22 by MartinV
12-07-2007 12:57 AM


Re: No, No Martin
Hi MartinV,
You ask;
MartinV writes:
Do you think there was a time M.maleo ancestors nested and hatched their eggs like other birds and only their descendants (more recent M.maleo ancestors) started burrying their eggs?
Well, I suppose that depends what you mean by other birds. Most birds are arboreal nesters and I cannot imagine that any megapode ever did that. They may well have nested on the ground, in a very simple nest, much like thousands of other bird species. At this remove we can only speculate (short of digging up half of Sulawesi looking for nest fossils) but there seem to be two possibilities; either the megapodes and their ancestors have always done this, right back to their Archosaur ancestors, or the behaviour re-emerged at some point, from a previously switched-off gene or a novel mutation. My bet is that the behaviour was always present. Maybe it got switched off/switched back on at some point, but I think the novel mutation sounds a bit much of a coincidence.
Fun to speculate, but it doesn't really prove anything.

Mutate and Survive

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Replies to this message:
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MartinV 
Suspended Member (Idle past 5911 days)
Posts: 502
From: Slovakia, Bratislava
Joined: 08-28-2006


Message 25 of 29 (439332)
12-08-2007 10:29 AM
Reply to: Message 24 by Granny Magda
12-08-2007 3:52 AM


Re: No, No Martin
My bet is that the behaviour was always present.
OK. It contradicts clearly other theories proposed here. What is interesting is that validity of all these theories can be supported very well by different images of natural selection. I am afraid if anyone here proposed another theory of arising of egg burrying behaviour he would backs it up by some natural selection explanation as well.
So we don't know how the behaviour has arisen. But what we know in advance is that it is "plain old TOE stuff" as jar has written it.
Edited by MartinV, : No reason given.
Edited by MartinV, : No reason given.

This message is a reply to:
 Message 24 by Granny Magda, posted 12-08-2007 3:52 AM Granny Magda has replied

Replies to this message:
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Granny Magda
Member (Idle past 121 days)
Posts: 2462
From: UK
Joined: 11-12-2007


Message 26 of 29 (439380)
12-08-2007 3:26 PM
Reply to: Message 25 by MartinV
12-08-2007 10:29 AM


Re: No, No Martin
MartinV writes:
Granny writes:
My bet is that the behaviour was always present.
OK. It contradicts clearly other theories proposed here.
I'm not sure that it does, maybe I should make myself more clear. By "always present" (an admittedly clumsy phrase) I mean that the behaviour was probably already available to the ancestors of the maleo. It may or may not have been expressed in any given intermediate species. Just speculation really, based on its similarity to the behaviour of other related critters. Croc's buried their eggs (still do), as did some dinosaurs (plenty of dinosaur nests have been found) so it seems reasonable to speculate that some birds might have inherited this behaviour, rather than the maleo displaying convergent evolution. Either way, it is not a problem for the ToE.

Mutate and Survive

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Replies to this message:
 Message 27 by molbiogirl, posted 12-08-2007 5:48 PM Granny Magda has not replied

  
molbiogirl
Member (Idle past 2724 days)
Posts: 1909
From: MO
Joined: 06-06-2007


Message 27 of 29 (439400)
12-08-2007 5:48 PM
Reply to: Message 26 by Granny Magda
12-08-2007 3:26 PM


MartinV
Granny,
Be warned.
MartinV is a notorious troll.
Take a gander at the Peppered Moth thread.
His running buddy, John A. Davison, has been banned here.
JAD also has the distinction of his own page at http://www.crank.net.
I'm just sayin'.

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 Message 26 by Granny Magda, posted 12-08-2007 3:26 PM Granny Magda has not replied

Replies to this message:
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RAZD
Member (Idle past 1488 days)
Posts: 20714
From: the other end of the sidewalk
Joined: 03-14-2004


Message 28 of 29 (439407)
12-08-2007 6:18 PM
Reply to: Message 27 by molbiogirl
12-08-2007 5:48 PM


Re: MartinV
A better intro to MartinV is Mimicry and neodarwinism (which he started and is now closed) and Mimicry: Please help me understand how. Watch for head spinning circular arguments. That repeat.
My first impression is that it is fairly normal for ground dwelling egg laying animals to cover the eggs with debris while they go to feed, as hidden eggs are less likely to be found by predators than unhidden ones.
That's all it takes to start a system of covering with selection for those that are better at hiding/burying.
I don't have any problem with this behavior being re-evolved in many different applications.
Enjoy.
Edited by RAZD, : No reason given.

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This message is a reply to:
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MartinV 
Suspended Member (Idle past 5911 days)
Posts: 502
From: Slovakia, Bratislava
Joined: 08-28-2006


Message 29 of 29 (439798)
12-10-2007 1:51 PM
Reply to: Message 28 by RAZD
12-08-2007 6:18 PM


Re: MartinV
Edited by MartinV, : misplaced post
Edited by MartinV, : moved to EvC Forum: Mimicry: Please help me understand how

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