[_ Old Earth _] THE FROG-EATING FROG

[lordkalvan]

Well, then, neither of these eminent men must be familiar with this information:

'In nature, the fortuitous presence of structures and possibilities, evolved for other reasons, often forms the foundation for new evolutionary trends. A female R. silus swallows her fertilized eggs out of hunger. Vertebrate stomachs contain natural stretch receptors that tell an organism when to stop eating by imposing a feeling of satiety. The batch of swallowed eggs has this effect. A chance substance in the eggs halts the release of hydrochloric acid and stops the passage of eggs into the intestine. After much research, prostaglandin E2, a hormone-like substance formed throughout the body and serving many functions, was discovered in the eggs and in tadpole excretions. Prostaglandin, surely present as a biological byproduct of egg formation, turns out to suppress digestion. One female gains a reproductive edge and passes the trait onto her offspring.'

Source: http://www.brmconservancy.org/article-spring_singers.html

And:

'In southeast Queensland, Australia, there was a rare aquatic frog, Rheobatrachus silus. The female of this species swallowed her newly fertilized eggs (about 20 of them) and brooded the young in her gut. Whereas several tropical frog species had been known to brood embryos in the male vocal sac (which had already become distended to call mates), this frog actually brooded them in her stomach. The eggs develop into larvae, and the larvae undergo metamorphosis all in the stomach, and eight weeks after injection, the small frogs emerge from the female's mouth (Corben and Ingram, 1974; Tyler, 1983).

What stops the eggs from being digested or excreted? It appears that the eggs are secreting agents which stop digestion and the peristaltic contractions in the stomach. During the period of gastric brooding, the gastric musculature is altered, and the cells that are responsible for secreting acid into the stomach are inhibited. After the oral birth, stomach morphology and function returns to normal. The agent that protects the eggs and early embryos is not yet known, but the larvae secretes copious amounts of prostaglandin E2. This compound is capable of inhibiting the acid secretion by the gastric mucosa (Tyler et al., 1983).'

Source: http://9e.devbio.com/article.php?ch=4&id=68

You should note that neither 'I don't know' nor 'I don't know of any measures of prostaglandins in frogs eggs' means the same as 'prostaglandins do not exist in frogs' eggs'.

Perhaps Professor Hanken should have refreshed his memory about Michael Tyler's work?

You seem to be very quick and keen to accuse others of fraud and lying on the back of very little evidence at all.

 

[Asyncritus]

You have only confirmed what I sad: that the eggs of this species produce prostaglandin E2 which inhibits the normal production of the stomach acids.. You should have read it more carefully.

Barbarian's claim was that they all do. That's a lie, and a debating technique designed to cast doubt on this amazing phenomenon.

Unfortunately for you both, and evolution theory as far as this is concerned, both of these eminent men are in denial. Professor Denver's evidence is particularly damning since this is his field of study.

Dr. Denver is a developmental neuroendocrinologist. ...In his research he uses several model systems, including Xenopus tadpoles, wild amphibian species...

Your legalistic hair-splitting cannot conceal the fact that this was a lie - and heaven knows how many others he has perpetrated in support of this foolish theory.

Too bad for you all. RIP.

 

[lordkalvan]

You have only confirmed what I sad: that the eggs of this species produce prostaglandin E2 which inhibits the normal production of the stomach acids.. You should have read it more carefully.

I did. I see nothing in your post that acknowledges prostaglandin is common in eggs and found specifically in the 'frog-eating frog's' eggs. Indeed, your post seems directed towards throwing this fact into doubt. Perhaps you can show where you said 'that the eggs of this species produce prostaglandin E2'.

Barbarian's claim was that they all do. That's a lie, and a debating technique designed to cast doubt on this amazing phenomenon.

According to your quotation, Barbarian says no such thing, unless you think that 'normally' means 'all'. Also, your citations do nothing to support your accusation that Barbarian's use of the qualifier 'normally' constitutes part of a fraudulent lie.

Unfortunately for you both, and evolution theory as far as this is concerned, both of these eminent men are in denial. Professor Denver's evidence is particularly damning since this is his field of study.

Surprise, but Professor Denver says no such thing, according to your citation.

Your legalistic hair-splitting cannot conceal the fact that this was a lie - and heaven knows how many others he has perpetrated in support of this foolish theory.

Pointing out your errors and misrepresentations does not constitute 'legalistic hair-splitting'.

Too bad for you all. RIP.

And there you go again declaring victory over a smoking ruin.

 

[cupid dave]

As you read this account, please keep asking yourself ‘How could this possibly arise by small, naturally occurring steps?’

The frog is called Rheobatrachus silus and exhibits quite extraordinary design features.

The female frog swallows her eggs after they have been fertilised – but the PURPOSE is not to eat them, but to protect them, and incubate them.

And right here we have another defeat for evolution by natural selection and chance processes.

The frog does this SO THAT the eggs may be protected, hidden, and incubated. Why is this so? Most frogs don’t do anything like this. The eggs are laid in water, and develop there quite open to predators and the like.

This frog swallows them..

So that is how babies being delivered by storcks evolved?

The maternal instinct must be the mother of invention when we consider the Kangeroo, right?
Necessitity at some point when predators were everywhere was the reason for this weird new behavior.

 

[cupid dave]

Um, where's your attempt to answer any of the points raised? And the refutation?

I believe that these things you point to are part of the Direct Evolution which is still going on, and the "director" is the Unconscious spirit inside of life forms which we now see more clearly in man, in the form of the Collective Unconscious mind.
This "presence" which accompanies each generation fo life, in all its forms, has manifest more clearly in us.
But I believe that lower animals in particular, have also retained the experiences of their species by means of genetic memories.

What we call "instinct" is really just the over riding of conscious thinking and the explicit and overt evidence of this unconscious facility.

 

[Barbarian]

The only reason I haven't replied to your previous post is that I wanted to be sure of my facts before accusing you of being a chronic liar.

I do so accuse you now.

I see that Lord Kalvan has easily overturned your claim, but let's look at some of the specifics.

Barbarian observes:
Prostaglandin is a substance normally found in eggs. So even if these eggs had an elevated level of prostaglandin, such a change is a rather easy one. If elevated levels made survival more likely, then mothers producing eggs with higher levels of prostaglandin would leave more offspring.


From Prof. Hanken, professor of Zoology, Harvard University:
I don't know. Check with Bob Denver at U Michigan for a more informed response.

The now-extinct Australian gastric-brooding frog, Rheobatrachus silus, was suggested to produce prostaglandin while embryos were incubated in the stomach, but I don't recall if the idea was that prostaglandin was derived from maternal provisioning of the unfertilized eggs, or produced by the embryos/larvae, or by the host (female parent). Author was MIchael Tyler.

From which I gather that you are claiming to know more about the subject than a Harvard Professor of Zoology.

I do, from my undergraduate days in embryology, recall that eggs contain prostaglandin. In fact, protaglandins are substances normally found in cells of many different sorts of animals.
http://themedicalbiochemistrypage.org/eicosanoids.php

Stephen Gould, in "Here Goes Nothing" writes about this issue of prostaglandins in the stomach-brooding frogs. Fact is, the prostaglandins come from the eggs:
http://tinyurl.com/caupvwn
(page 103)

At the time the female ingested the fertilized eggs her stomach was no different from that found in any other frog species. In the jelly that surrounded each egg was a substance called prostaglandin E2 (PGE2). This substance had the ability to turn off the production of hydrochloric acid in the stomach. This source of PGE2 was enough to cease the production of acid during the embryonic stages of the developing eggs. Once the eggs had hatched the tadpoles too created PGE2. The mucus excreted from the tadpoles gills contained the PGE2 necessary to maintain the stomach in a non-functional state. These mucus excretions do not occur in tadpoles of most other species. Tadpoles that don't live entirely off a yolk supply still produce mucus cord, but the mucus along with small food particles travels down the oesophagus into the gut. With Rheobatrachus (and several other species) there is no opening to the gut and the mucus cords are excreted. During the period that the offspring were present in the stomach the frog would not eat.

He cites work done here:
http://www.sil.si.edu/smithsoniancontributions/zoology/pdf_hi/sctz-0233.pdf

Unlikely, but just to be sure, I emailed Prof. Denver at Michigan University for a more informed response as Prof. Hanken suggested.

From Prof. Bob Denver, University of Michigan:

Sorry, I don't know of any measures of prostaglandins in frog eggs. Please tell Jim I said hello.

Good luck.

Bob Denver

So neither of these eminent men know anything about frogs eggs normally producing prostaglandin E2.

Therefore your claim above is fraudulent, and a lie.

Surprise.

You're in way over your head here. Remember who you're talking to. I've spent a lifetime studying biology, and I do know what I'm talking about.

That being the case, I am forced to wonder just how many of your bombastic claims are just as fraudulent and fictional. This really casts serious doubt on all of your so-called 'refutations' of my facts. Your whole reputation on this forum is now in shreds.

And down you go, again. When are you going to learn?

Grazer and LK, you really need to take notice of this demonstration of fraud, and get on to the side of fact and truth, rather than fiction and falsehood.

Looks as though reality blindsided you once again.

 

[Barbarian]

Regarding the question of the presence of prostaglandins in other amphibian eggs:

J Endocrinol. 1995 May;145(2):235-41.
Amphibian oocyte: a model of a possible regulatory mechanism for prostaglandin E2 and prostaglandin F2 alpha synthesis.
Gobbetti A, Zerani M.
Source

Department of Molecular, Cellular and Animal Biology, University of Camerino, Italy.
Abstract

To clarify the possible mechanisms regulating prostaglandin E2 (PGE2) and prostaglandin F2 alpha (PGF2 alpha) synthesis, the effects of gonadotropin-releasing hormone (GnRH) and substance P (SP) on the release of these two prostaglandins were studied in the oocytes of the crested newt, Triturus carnifex. Full-grown oocytes of T. carnifex, freed from follicular cells, were incubated in the presence of GnRH or SP and of the inhibitors of several enzymes involved in the release of arachidonic acid (AA) and in the conversion of AA into PGE2 and PGF2 alpha. In parallel, the same experiments were performed on oocytes with membrane phospholipids labelled with [3H]AA. In addition, the PGE2-9-ketoreductase activity was evaluated through the conversion of [3H]PGE2 into [3H]PGF2 alpha. The results showed that GnRH and SP could regulate prostaglandin synthesis through the activation of phospholipase C and diacylglycerol lipase, and through the modulation of PGE2-9-ketoreductase in the oocytes of T. carnifex. In particular, GnRH enhances the activity of PGE2-9-ketoreductase with a consequent increase in PGF2 alpha, while SP inhibits the enzyme which leads to an increase in PGE2. A similar mechanism could also be hypothesized for other vertebrate species.