Thursday, January 7, 2010

Prehistoric Footprint Rewrites History

January 7, 2010 on ITN News:
A prehistoric footprint left by an ancestor of the dinosaurs could lead to a radical change in theories of how animals evolved.

Polish scientists have discovered footprints left by a four-legged animal called a tetrapod 397 million years ago in the Swietokrzyskie mountains in southern Poland.

The footprints, left by a creature about 2.5m long, are 18 million years older than the earliest known examples of fossilised bones of tetrapods.

According to existing fossil evidence it was thought that tetrapods diverged from the group of large fish called the elpistostegalians around 387 million years ago, but the new discovery turns this theory on its head.

At the time the footprints were made, the region was a seashore, whereas previous fossil findings of four-limbed vertebrates have been in river deltas and lakes.

The seashore could have been a tempting source of new food for ocean-dwelling animals and eventually tempted them to walk on land.


  1. Could someone please explain to me why ocean-dwelling animals aren't tempted to walk on land now? For all of the mocking of Creationists and IDers by Evolutionists, this has to be one of the dumbest assertions I have ever heard.  

  2. Gotta love the evidence that popular reporters' knowledge of basic things sucks when it comes to science reporting.  Note the phrase:  "a four-legged animal called a tetrapod", as if "tetrapod" was the name of a specific ancient animal.  The clue's in the freaking name, for crying out loud.

  3. They still are.  Evolution is very slow.  Your comment is no more sensible than the expectation of creationists that if evolution were true they'd see massive changes in body shape within their short lifetimes.

    I wonder if anyone's looked at the tides as a possible explanation of the slow ramp of evolution from sea to land animals.  In places where the slope of the shore is shallow, the tides create a huge difference.  The longer a critter can survive out of the water, the more opportunity there would be for it to forage slightly higher up the slope and survive there through the low tide without having to make a hasty retreat.  In such locations, which are common today and must have also been common back ten, there is a direct correlation between the gradient of surviving longer without water and the physical gradient up the slope toward land.  This could have provided the gentle, slow gradient toward land survival that is necessary for evolution to work.  In addition to the advantage of foraging where others cannot, there is also the advantage of predator avoidance.  Imagine a prey species in such a shallow tidally-influenced area with lots of predators trying to eat it.  Those individuals within the prey species that can make do with living higher up the slope are less tempting targets to the predators than those that live down where the predators can hunt without risking suffocation at low tide.  In such an environment, the predators would be selecting for death those prey animals that can't survive a short time out of the water and therefore can't live further up the slope toward dry land.

    I think areas of shallow sloped shoreline with drastic tide changes are an excellent environment to provide the "it doesn't have to happen overnight" slow gradient from sea animals to land animals, that evolution needs to have to work.

    For an example of such a place, think of the tides around Mont st Michel:

  4. @ Steve

    How do you know they aren't "tempted?"  I think tempted is the wrong word.  Perhaps there isn't a niche to be filled by fish walking onto land (that would take millions of years anyhow).  If a sea-creature were to evovle to walk on land now (read: over the next several million years), perhaps it would simply be eaten, due to being no available niche to fill, and the inability to protect itself outside of the water. Perhaps it is happening, but no one has found it, yet.

    There are species that live in both the water and on land.  So, I'm not sure what your point is.