EvC Forum: Wombat Pouch

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Topic: Wombat Pouch

Straggler

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Message 11 of 85 (615563)
05-14-2011 11:03 AM

Reply to: Message 9 by Percy
05-14-2011 9:55 AM

Percy writes:

Here's an interesting fact - the koala bear's pouch is also inverted. So much for the connection
with burrowing.

An animal that climbs trees with it's belly dragging across the surface of the tree arguably has much the same reasons for an inverted pouch as a burrowing animal.

Or koalas are descended from burrowing animals and evolution was incapable of inverting a fully formed pouch?

The inverted pouch question is more interesting than it first appears.........

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Straggler

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Message 12 of 85 (615566)
05-14-2011 11:24 AM

Koala Pouches

Apparently koala pouches are not upside down as such:

Link writes:

"Female koalas have been described as having a ‘backward-opening’ pouch, in common with wombats and in contrast to an upward-opening pouch like kangaroos. However, that's not strictly true. When a female koala first gives birth to young her pouch opening faces neither up nor down, although it is located towards the bottom of the pouch rather than at the top. It faces straight outwards rather than 'backwards'. It sometimes appears to be ‘backward-facing’ because when the joey is older and leans out of the pouch, this pulls the pouch downwards or 'backwards'."

Koalas

Straggler

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Message 14 of 85 (615570)
05-14-2011 11:53 AM

Reply to: Message 13 by jar
05-14-2011 11:44 AM

Re: passing the plate

jar writes:

Would infants killed because they were smothered in dirt while in their mothers pouch pass on their genes?

Obviously not. Which explains why the wombat pouch isn't the same as that of a kangaroo. But how this difference in pouch orientation occurred remains a valid question.

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	Message 13 by jar, posted 05-14-2011 11:44 AM		jar has replied

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Straggler

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Posts: 10333

From: London England

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Message 16 of 85 (615574)
05-14-2011 12:07 PM

Reply to: Message 15 by jar
05-14-2011 11:59 AM

Re: passing the plate

jar writes:

So would the genes from the mothers who just happened to have a pouch opening that protected the infant more get passed on?

Of course. But how does that get translated into graduated change in orientation?

That is the (possibly flawed) question.

We know why wombat pouches face the other way. the question is how did this come about via gradual evolutionary change given that all marsupials are reckoned to be derived from a common ancestor.

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	Message 15 by jar, posted 05-14-2011 11:59 AM		jar has replied

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Straggler

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Message 18 of 85 (615578)
05-14-2011 12:17 PM

Reply to: Message 17 by jar
05-14-2011 12:13 PM

Re: passing the plate

So your answer to the question is that the pouch opening gradually moved downwards?

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Straggler

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Message 51 of 85 (705480)
08-27-2013 6:15 PM

Reply to: Message 45 by Big_Al35
08-23-2013 6:39 AM

BA writes:

Even better would be a pouch that rotates at the flick of a switch. A gentle spin speed would be natures very own merry go round.

Good idea. The fact this doesn't exist suggests that if there is an inteligent designer he/she is not even as clever as you are.....

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	Message 45 by Big_Al35, posted 08-23-2013 6:39 AM		Big_Al35 has not replied

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