Showing posts with label lemurs. Show all posts
Showing posts with label lemurs. Show all posts

Thursday, June 13, 2013

Oldest Primate Fossil Found

New Scientist has a story on the discovery of what may be the oldest definable primate, called Archicebus achilles.  Nicknamed "Archie" (naturally), the fossil dates from the Palaeocene, around 55 million years ago.  Michael Marshall, of the New Scientist writes:
According to its discoverers, Archie is a primitive tarsier – a group of primates closely related to monkeys, apes and humans. That would mean it is descended from the ancestor of all primates, but is not itself the ancestor.

That may not be the end of the story, though. Marc Godinot of the National Museum of Natural History in Paris, France, is not entirely convinced that Archie's snout is short enough to prove it is a tarsier, as its discoverers claim. "Here we have a primate which is so primitive that it could be the primitive primate," says Godinot.
In the new, genetically informed taxonomy, the two main primate branches are prosimians on one branch, which include tarsiformes and lemuriformes and anthropoids on the other branch. The lemuriformes are further subdivided into the lemurs and lorises. The anthropoids divide into New World primates, which become New World monkeys and Old World primates, which divide into monkeys, apes and humans.So, is this a direct ancestor of our line?  Maybe, maybe not. 

Tuesday, May 26, 2009

A Warning About Ida

Brian Switek writes for the Times Online that the hype surrounding Ida, the 47 million year old primate fossil only gets in the way of real research and misleads people into thinking evolution predicts that which it does not. He writes:
There is some irony in calling Ida the missing link. She was named Darwinius in honour of Charles Darwin, but the phrase “missing link” harkens back to a pre-evolutionary idea of nature. Called the Great Chain of Being, this interpreted all life as forming an immutable hierarchy, ordained by God, from “lower” to “higher”. Scholars believed that God favoured a full creation and each rank connected to the next, but “missing links” presented a problem. The link between humans and lower animals was the most elusive of all.

Our understanding of evolution could scarcely be more different. There is no evolutionary end point or fore-ordained hierarchy of beasts. Life is better understood from Darwin's perspective - as a wildly branching bush constantly being pruned and sending out new shoots through evolution. Calling Ida a missing link may grab attention, but it is incongruous with what Darwin proposed.

There has already been one ill-conceived Answers in Genesis paper because of the hype.

Sunday, May 24, 2009

Ah, the Intrigue of Palaeontology!

Here is some back story about the disovery of Ida and how it came into the hands of the scientists. It is the stuff of Nick Danger:
Hunched around a table at a vodka bar in Hamburg, Jørn Hurum, a palaeontologist, was about to make the scientific gamble of his life. Thomas Perner, a fossil dealer whom he knew well, had insisted they met; he had something very special to show him.

Looking nervously over his shoulder for prying glances, Perner put three ­photographs of a fossil on the bar table. "My heart started beating extremely fast," said Hurum. "I knew that the dealer had a world sensation in his hands. I could not sleep for two nights."

Rumours had been flying around for years in the palaeontological community about a spectacular primate fossil specimen. Now Hurum was one of the first people in the world to see it.

Read the whole thing.

Friday, May 22, 2009

AIG Takes on Ida

Answers in Genesis has decided to wade into the fray involving Ida, the 47 million year old Eocene primate skeleton, which is thought by some to show transitional characteristics between modern prosimians and modern anthropoids. That Ida is important is unquestioned. How much information she can tell us is still open to debate. Currently, it is debated as to whether higher primates derived from the tarsidae, the omomyids that currently include tarsiers or the adapids, the group that likely gave rise to lemurs and lorises. Ida suggests that the adapids were the stem group.

AIG's response is nothing short of hilarious.

They write:
The well-preserved fossil (95 percent complete, including fossilized fur and more) is about the size of a raccoon and includes a long tail. It resembles the skeleton of a lemur (a small, tailed, tree-climbing primate). The fossil does not resemble a human skeleton.
This is the worst sort of straw man. Nobody in their right mind would confuse Ida with a human skeleton and AIG knows it. Ida is 47 my old. Humans have only been around in one form or another since around 6 my. After the preliminary information, they launch into their interpretation of the find. They make six points. I will analyze them one at a time:
1. Nothing about this fossil suggests it is anything other than an extinct, lemur-like creature. Its appearance is far from chimpanzee, let alone “apeman” or human.
Once again, this is a straw man argument and reveals that the writer knows nothing about primate evolution. Humans and chimpanzees did not split until around 8-10 mya, so it is clear that no creature at 47 mya is going to have characteristics like either of them. What it does show is characteristics that presaged the Oligocene primates. It was not until the Miocene that you get things that are recognizably apes. Therefore, of course it looks like an extinct lemur-like creature.
2. A fossil can never show evolution. Fossils are unchanging records of dead organisms. Evolution is an alleged process of change in live organisms. Fossils show “evolution” only if one presupposes evolution, then uses that presupposed belief to interpret the fossil.
Evolution is observable in modern species. It has even been shown to be the mechanism by which new species arise. Even some creationists have come around to this position, in the light of the evidence. If evolution is correct, then descent with modification has been occurring since the first life forms. Further, if the concept of common ancestry is correct, and if evolution describes the palaeontological record, then it should predict that as we go back in the fossil record, fossil remains will show more primitive (in the cladistic sense) traits and that different clades can be traced back to a common ancestor for those clades. As such, then the theory will predict what will be found in the palaeontological record.

There are countless examples of evolution's predictive power, from the discovery of of the fishapod Tiktaalik, found in Devonian shallow sea deposits, to the prediction that human ancestors would be found in the same continent as modern-day higher apes to the discovery of frogamanders that show stem characteristics of both salamanders and frogs. Many other examples of this exist. Is is possible that there is another explanation for this? Absolutely. But right now we already have an explanation for these things. It is called evolution. Are these fossils dead organisms. Yup. But they show characteristics that are intermediate between those that came before and those that followed. If one presupposes progressive creation, then one is forced to consider that God created numerous, slightly different species that followed each other and then killed off 99% of them over the course of biological time. If one presupposes an antediluvian time where these animals were all part of the biosphere, then one is forced to consider that, as crowded as our earth is right now, it is nothing compared to the wall-to-wall dinosaurs, primates, elephants, tigers and other animals that occupied the earth at that time.
3. Similarities can never show evolution. If two organisms have similar structures, the only thing it proves is that the two have similar structures. One must presuppose evolution to say that the similarities are due to evolution rather than design. Furthermore, when it comes to “transitional forms,” the slightest similarities often receive great attention while major differences are ignored.
This is peculiar. One almost gets the feeling that the author wants to include the design argument here. Is it true that two animals that have similar structures show, well, similar structures. But that is where the inference of common ancestry comes in. If you find animals in the fossil record that show characteristics of two different families of modern-day animals (say a frogamander) and you can show that, as you go back into the fossil record, those two forms have successively primitive and similar characteristics, then you can make inferences about why the two animals have similar structures. This is the all-important distinction between analogy (similar function but different form) and homology (different function but similar form). Bats and butterflies, for example, have similar structures that allow them to do the same thing: fly. On closer inspection, however, the wings of butterflies and the wings of bats are composed of very different structures. The wings are analogous. The fins of the latest lobe-finned fishes in the Devonian are composed of the same elements and are similar in form to the earliest limbs of the first tetrapods. They are homologous. That is why the discovery of Tiktaalik was so important. It showed characteristics of both the lobe-finned fish and the early tetrapods.

The last statement is nonsensical since there is no evidence to back it up. The reason there is nothing to back it up is that none exists. Without an understanding of the differences between homology and analogy, it would seem that some characteristics are not seen to be as important as others. The statement, then, stems more from a lack of understanding of evolutionary theory and basic biology as anything else.
4. The remarkable preservation is a hallmark of rapid burial. Team member Jørn Hurum of the University of Oslo said, “This fossil is so complete. Everything’s there. It’s unheard of in the primate record at all. You have to get to human burial to see something that’s this complete.” Even the contents of Ida’s stomach were preserved. While the researchers believe Ida sunk to the bottom of a lake and was buried, this preservation is more consistent with a catastrophic flood.4 Yet Ida was found with “hundreds of well-preserved specimens.”5
This is one of those statements that creationists dare not take to their logical conclusions. Does Ida show rapid burial? You bet. Okay, now extrapolate that rapid burial to the rest of the planet. It cannot be done. While the geological record shows some areas of rapid burials, it also shows depositional environments that were very slow, such as varves, chalk cliffs, buried coral reefs, dessication cracks and so on. These things are simply not possible in a rapid-burial environment. So, yes Ida was rapidly buried...in the Messel Pit.
5. If evolution were true, there would be real transitional forms. Instead, the best “missing links” evolutionists can come up with are strikingly similar to organisms we see today, usually with the exception of minor, controversial, and inferred anatomical differences.
I would like to think that this statement reflects nothing more than "culpable ignorance" rather than being a flat-out lie. There are thousands of transitional fossils at every major level, from orders down to species and at all points in the fossil record. The human fossil record, alone, has hundreds of fossils that are transitional between what came before and what came after. These are not minor, controversial differences. Homo habilis has facial characteristics of Australopithecus but a massively expanded braincase. Not minor. Over the course of a million years, the brain case of Homo erectus expanded from 700 cc to 1100 cc. Again, not minor. The discovery of non-avian dinosaurs with feathers was not a minor discovery. It showed that feathers evolved because they are remarkable insulators. The transitional characters of Archaeopteryx are not minor. They show an animal with both sauropod characteristics and avian characteristics. It is not a "true" bird, and it is not a "true" dinosaur, despite what creationists might want to believe. It is a "true" transitional form. AIG has to go out of its way to ignore this evidence.
6. Evolutionists only open up about the lack of fossil missing links once a new one is found. Sky News reports, “Researchers say proof of this transitional species finally confirms Charles Darwin’s theory of evolution,” while Attenborough commented that the missing link “is no longer missing.” So are they admitting the evidence was missing until now (supposedly)?
Again, this is nonsense. Palaeoanthropologists have complained for years and years, publicly even, that they wished they had more fossil data to bolster their hypotheses about where certain forms came from. The discovery in the last fifty years of whale precursors was a boon for the study of modern and palaeocetaceans because finally, scientists could begin to draw relationships between them and that the idea that a land mammal went back to the sea suddenly wasn't so crazy after all. Palaeoanthropologists are not bashful at all about the fact that we don't have a good record of the ape-human split. We have fossilized precursors to chimpanzees and we have early bipedal hominid fossils that date to around 6 to 7 million years ago. We don't have anything before that until around 10-11 mya. That sucks but whaddya do? You wait for more fossils to come out of the ground so you can draw more relationships and you work with what you have. Nobody said the fossil record was perfect. It is far from it. But it is good enough to show relationships between species, genus, families and orders.

Ida isn't the "missing link." Practicing scientists know that there is no such thing as the "missing link." It is an idiotic notion concocted to sell newspapers that creationists have latched onto. Each fossil find is a piece of the puzzle that tells us more about how the great story of life unfolded. Over time, we can put together enough of the pieces to determine what we think happened over here in this corner or that corner of the puzzle. It is a long way from being complete, but it gets better every year. And every year, it continues to show that the theory of evolution is remarkable in its ability to explain how the puzzle came to be.

As is usual, AIG's analysis is crippled by their complete lack of understanding of how the natural world is put together and what evolutionary theory actually posits and predicts. Without that basic understanding, their analysis is facile and misguided at best.