|Based on the structure of Arboroharamiya's lower jaw,|
palaeontologists believe that the animal had a mammalian-like ear.
This article by Sid Perkins in Nature a couple of days ago illustrates how new information in science often opens up more questions than it answers and challenges previous ideas. It also illustrates how science responds to such challenges and so moves continually closer to the truth.
Creationists hold two diametrically opposite views of science simultaneously - never a problem for creationists who don't do joined-up thinking or bother too much about having inconsistent and contradictory views. They traditionally trot out whichever one they think will fool most people when the opportunity arises. They believe:
- Science is like a religion and has unchallengeable fixed dogmas which all scientists have to subscribe to.
- Science is always changing its mind and saying that what they thought was the case yesterday is now wrong and should be disregarded.
The article reports the discovery of two fossils which seem to tell two different stories about the early evolution of mammals around 250 million years ago; or was that 180 million years ago?.
The fossils represent previously unknown species, described today in Nature 1, 2. Both are members of the haramiyids, a group of animals that first appeared around 212 million years ago and that researchers first recognized in the late 1840s. Until now, the creatures have been known only from isolated examples of their distinctive teeth — which have some rodent-like features — and a single fragmentary jawbone. But both fossils described today include not only the distinctive teeth, but also vertebrae and bones from the limbs, feet and tails.The controversy comes about because one fossil, placed in the genus Arboroharamiya, has characteristics typical of mammals, including a mammal-like lower jaw where some bones present in reptilian jaws have evolved into the small bones of the middle ear. This seems to have lived in trees. Placing this species in the mammal evolutionary tree suggests mammals had evolved somewhere between 282 ands 201 million years ago.
The other specimen, placed in the genus Megaconus, lived between 164 million and 165 million years ago and had characteristics closer to the pre-mammalian reptiles, suggesting that the common ancestor of all living mammals evolved about 180 million years ago and that Megaconus branched away from that tree some 40 million years before true mammals evolved.
These sorts of controversies are of course characteristic of science and are to be expected when looking at fossils from a point close to the divergence into new branches when species would not have diversified that far from ancestral species. We would expect it to be difficult to place these species accurately.
What is really interesting here is how disagreement and conflicting evidence is actually welcomed by science because it raises new questions and causes us to re-examine and re-evaluate evidence and rebuild our understanding. No one minds at all if older ideas are overthrown because that is precisely what good science should seek to do.
But how does science resolve these differences and difficulties?
With more evidence.
Cifelli [a vertebrate palaeontologist at the Oklahoma Museum of Natural History] says that the confusion can be cleared up only with more fossils — preferably ones that include all or a significant part of a skull, whose anatomical features are particularly instructive in working out evolutionary relationships. “To break this tie, we really need more information,” he says.So, creationists may be right in one respect. If there is a dogma in science it is that nothing is certain and the only way to know what is right and what isn't is with evidence.
Contrast that with religion, particularly with Creationism, where everything is certain and the last thing wanted is evidence especially the sort of evidence that would shake their unshakeable certainties. Science is reasonable uncertainty; religion is unreasonable certainty.
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