Author Topic: Discrepancy between episodes 36 and 37?  (Read 2772 times)

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Offline Larry Coon

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Discrepancy between episodes 36 and 37?
« on: November 26, 2006, 12:34:26 AM »
Sorry to drag up old episodes, but I'm just getting to them.

In episode 36's Science or Fiction, the fictional item was: "Fossil evidence confirms that the arctic polar region was once home to lush tropical forests."  In the ensuing discussion, Steve confirmed that the region was never tropical nor even subtropical.  The info section includes the following article (excerpted):

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From the March 21, 1936, issue of Science News
ARCTIC NEVER TROPICAL
Forests that grew ages ago in the lands around the North Pole were never tropical, as old-time natural history books used to say. For theoretical reasons, they couldn't have been. And when the theory is checked up by examining fossils from the Far North, the fossils give strong evidence that the theory is right. Thus another favorite notion of our younger days is outlawed to the limbo of facts that have been turned into fictions.

Not that there never were any forests around the North Pole. There were; great and luxuriant ones, if the wealth of fossil leaves and other plant parts is any indication. Where the tallest trees are now little willows 6 inches high, in such places as the islands north of Canada and Siberia, there were once woods as pleasant as any to be found in Ohio or Oregon. But the point is, they were such woods as can be found now in Ohio or Oregon, or perhaps Georgia and Arkansas, and not such jungles as those of Brazil or Burma, as was once imagined.


In the next podcast they spent a lot of time on the recent discovery of Tiktaalik.  The info section includes the following article (also excerpted):

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The near-pristine fossil was found on Ellesmere Island, Canada, which is 600 miles from the north pole in the Arctic Circle.

Scientists from the Academy of Natural Sciences in Philadelphia, the University of Chicago, and Harvard University led several expeditions into the inhospitable icy desert to search for the fossils.

The find is the first complete evidence of an animal that was on the verge of the transition from water to land. "The find is a dream come true," said Ted Daeschler of the Academy of Natural Sciences.

"We knew that the rocks on Ellesmere Island offered a glimpse into the right time period and were formed in the right kinds of environments to provide the potential for finding fossils documenting this important evolutionary transition."

When Tiktaalik lived, the Canadian Arctic region was part of a land mass which straddled the equator. Like the Amazon basin today, it had a subtropical climate and the animal lived in small streams. The skeleton indicates that it could support its body under the force of gravity.

Was this discrepancy ever explored?  Or am I just missing something?

Offline pholt

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Discrepancy between episodes 36 and 37?
« Reply #1 on: November 26, 2006, 03:44:08 AM »
Yes, you are missing something.  It's called continental drift.  The area around the poles has never been tropical, however the land that is there now hasn't always been there.

Your highlighted section from episode 37 expressed it quite clearly.  The land that is now the Canadian Arctic wasn't always arctic, at one time it was tropical, straddling the equator.  As that land mass drifted north, it's climate would have changed.  That's a quite different idea from the polar regions themselves being tropical.

Offline Larry Coon

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Discrepancy between episodes 36 and 37?
« Reply #2 on: November 26, 2006, 12:05:42 PM »
Quote from: "pholt"
Yes, you are missing something.  It's called continental drift.  The area around the poles has never been tropical, however the land that is there now hasn't always been there.

Plate tectonics, actually, not continental drift, and yes, I'm well aware that the land that is currently above the arctic circle was once part of Pangea and located near the equator.

Quote
Your highlighted section from episode 37 expressed it quite clearly.  The land that is now the Canadian Arctic wasn't always arctic, at one time it was tropical, straddling the equator.  As that land mass drifted north, it's climate would have changed.  That's a quite different idea from the polar regions themselves being tropical.

The highlighted sentence might be the issue.  Is 36 actually talking about the arctic regions themselves, or about the land currently in the arctic regions?  My interpretation is that 36 was talking about the land.  First of all, it's tautological to say that the arctics were never tropical, since both arctic and tropic are defined on the basis of latitude, and there is no overlap.  Second, not only was the current arctic land not above the arctic circle, I don't think any land was, so it'd be hard to describe the conditions for land that wasn't there (or if I'm wrong, and it really is describing land, where is that land today?).  Third, if you listen to the podcast, the discussion seemed (to me) to be consistent with describing the land that's now in the arctic, and not the arctic regions themselves.  Steve even acknowledged another panel member's (don't remember which one) assertion that because of plate tectonics the land was once at a lower latitude.