Saturday, April 17, 2010

Tiktaalik: Real extinct animal & evidence of evolution. No hoax. Not "discredited"

File:Tiktaalik BW.jpg

Based on the dismal consensus reality score it is getting on Xeno's "What's Real?" Quiz, I've decided I absolutely must stand up for the Tiktaalik.  The Tik has something which should put him way above "Dragons" and the "Loch Ness Monster": real physical evidence.


Tiktaalik lived approximately 375 million years ago. ... [It] is representative of the transition between fish such as Panderichthys, known from fossils 380 million years old, and early tetrapods such as Acanthostega and Ichthyostega, known from fossils about 365 million years old. - wiki

Tiktaalik is one of many fossil transitional species, and is clear evidence of evolution because it not only had features of both fish and tetrapods, but it existed during the transition from fish to tetrapods.

Thus, as you might expect, the poor Tiktaalik has been heartily attacked by Creationists.

Evolution deniers usually fail to understand one or more of these three important things:

1) The conditions to make a fossil are very rare. Most species that ever lived had all traces wiped out.

2) Evolution did not happen along ONE line. Evolution is a tree with many failed attempts. Most of the branches didn't make it.

3) The 3.8 billion years during which life evolved is such long time that the human mind can't begin to grasp it.

Here are some of the attacks on Tiktaalik:



  • http://www.darwinistsdefeated.com/"this creature is obviously a "mosaic" combining a great many features. ...The platypus found in modern-day Australia is also a mosaic creature that shares mammalian, reptilian and bird characteristics at one and the same time. Yet nothing about it can be depicted as proof of evolution."


Tiktaalik was a real transitional form in a branching cloud of species that emerged out of the Devonian period.


Tiktaalik is not a "missing link" because evolution is not a simple chain.  Evolution is a tree with many different branches.


a reconstruction of Tiktaalik and a cast of its fossil





The platypus is one more modern example that evolution took many different paths during those 3.8 billion years.  The oldest fossil of a modern Platypus dates to about 100,000 years ago. As evolution would predict, there are earlier fossil ancestors of the Platypus. For example,  Monotrematum sudamericanum, lived 167 million years ago.  Since there is evidence of platypus evolution, you can't use a platypus to disprove Tiktaalik as an example of evolution.

tree showing the relationship between Tiktaalik, other fish, and four-legged vertebrates


The evidence for evolution is clear. We have witnessed the formation of new species, but there is even better evidence:

All over the planet, layers of earth can be dated. The deeper you dig, the farther back in time you reach. (Still with me?) As you dig down you find simpler and simpler animals. Always. There were no elephants 475 million years ago! No reptiles, no mammals, no birds, no flowers! But there were fish and proto-amphibians.

How do you explain the fact that we find fossils of ancient fish, but no mammals, birds or reptiles at 475 million years ago?

Go back further, and one billion years ago, there were no fish! No proto-amphibians, no arthopods ... as well as no elephants, reptiles, birds, flowers and so on. But there was multicellular life a billion years ago.   There was photosynthesis.

How do you explain that fish did not exist on earth until 1.5 billion years after we find the first complex cells?

Somehow, and this baffles me, somehow, creationists are able to put these mountains of evidence aside and say, well, what about the Coelacanth, believed to have been extinct since the end of the Cretaceous period, but which was captured off the east coast of South Africa, near the Chalumna River in 1938?

A fair question. This is not a Darwinian embarrassment. Natural selection can also cause a species to remain relatively unchanged over 100 million years ... as long as the strategy for survival and reproduction remains effective.  (Even today, no one is going to eat a Coelacanth because they emit disgusting oils.) Squids, sharks, and sea turtles are also similar in appearance to their Cretaceous period ancestors.

But, yes, the coelacanth did evolve. It isn't a "living fossil" after all.
The modern coelacanths, Latimeria spp., are members of the relict taxon of Sarcopterygian fishes, but are distinguishable from species known from the fossil record. This is important. A species that is distinguishable on its morphological characters can be told from related species. The last known fossil species in the clade that includes Latimeria spp. is placed in a different genus [1]. Genus-level differences in morphology indicate that it would be difficult to mistake specimens of each species for the other.  - antievolution.org

"In fact, living coelacanths are adapted for deep-water habitats off the Indian Ocean coasts of Africa and Indonesia, where they use a specialized organ in their noses to detect weak electrical signals from prey hidden in the mud along the seafloor. Unlike fins on living coelacanths and lungfishes, the fossil fin has an asymmetrical pattern in which there are more bones on the front of the central shaft than the back. It has more in common with the anatomy of four-limbed vertebrates, called tetrapods, and even humans than it does with the anatomy of living coelacanths. The discovery of the new fossil means scientists can no longer make inferences about the evolution of limbs based on living coelacanths and lungfishes." - Foxnews: 'Living Fossil' Not So Primitive After All

So, there you have it. And now, for something completely goofy:





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