Evolutionists aren’t yet sure if they should call it a human ancestor, but one thing they do know is that “Ardi” does away with the idea of a “missing link.”
Although first discovered in the early 1990s, the bones of Ardipithecus ramidus are only now being nominated for evolutionists’ fossil hall of fame—via a slew of papers in a special issue of the journal Science. In it, Ardi’s researchers describe the bones and make the case that Ardi is even more important in the history of human evolution than Lucy.
Despite claims of its evolutionary significance, one of the scientists who studied Ardi noted, “It’s not a chimp. It’s not a human.” That is, instead of looking like the hypothesized “missing link” (with both chimpanzee and human features), Ardi’s anatomy—as reconstructed by the scientists—shows it to have been distinct from other apes as well as from humans. The researchers have consequently shunned the notion of a missing link: “It shows that the last common ancestor [between humans and] chimps didn’t look like a chimp, or a human, or some funny thing in between,” explained Penn State University paleontologist Alan Walker (who was not part of the study).
The first question creationists have to answer is just what Ardi is. We can quickly eliminate important things that it isn’t: it’s not a human fossil, nor is it a complete fossil. In fact, even referring to “it” is deceptive, because Ardi is a badly damaged, incomplete skeleton put together with the help of a smattering of bones linked with at least 36 A. ramidus individuals. Dated at 4.4 million years old, the first bones were found in the early 1990s in Ethiopia. The delay in publishing an analysis was in part due to the poor state of the remains. “It took us many, many years to clean the bones in the National Museum of Ethiopia and then set about to restore this skeleton to its original dimensions and form; and then study it and compare it with all the other fossils that are known from Africa and elsewhere, as well as with the modern age,” said the University of California–Berkeley’s Tim White.
But the Evolution News & Views blog offered a more critical look at how the poor state of the fossils casts doubt on the scientists’ headline-grabbing claims. One telling quote comes from National Geographic News (in the same article that quoted Walker, linked above):
The first, fragmentary specimens of Ardipithecus were found at Aramis in 1992 and published in 1994. The skeleton announced today was discovered that same year and excavated with the bones of the other individuals over the next three field seasons. But it took 15 years before the research team could fully analyze and publish the skeleton, because the fossils were in such bad shape.
After Ardi died, her remains apparently were trampled down into mud by hippos and other passing herbivores. Millions of years later, erosion brought the badly crushed and distorted bones back to the surface.
They were so fragile they would turn to dust at a touch. To save the precious fragments, White and colleagues removed the fossils along with their surrounding rock. Then, in a lab in [Ethiopia], the researchers carefully tweaked out the bones from the rocky matrix using a needle under a microscope, proceeding “millimeter by submillimeter,” as the team puts it in Science. This process alone took several years.
Pieces of the crushed skull were then CT-scanned and digitally fit back together by Gen Suwa, a paleoanthropologist at the University of Tokyo.
Thus, as a starting point, creationists should remember that—as with many fossils—the state of preservation is far less perfect than what media images and “reconstructions” portray. (The “complete,” 4 feet [1.5 m] tall Ardi fossil, as reassembled, is shown on the cover of the special Science issue.)
We also know, as Walker explained (above), that Ardi actually shows many differences from both other apes and humans. Kent State University’s Owen Lovejoy described some of the features: “She has opposable great toes and she has a pelvis that allows her to negotiate tree branches rather well. So half of her life is spent in the trees; she would have nested in trees and occasionally fed in trees, but when she was on the ground she walked upright pretty close to how you and I walk.” Obviously, we would point out that the scientists haven’t actually observed Ardi walking; their assertion is based on their reconstruction of the bones. Furthermore, Ardi’s feet not only had opposable big toes, but also lacked arches, which separates Ardi from humans and means “she could not walk or run for long distances,” BBC News reports. And National Geographic News notes, “Ardi would have walked on her palms as she moved about in the trees—more like some primitive fossil apes than like chimps and gorillas.”
In fact, despite the headlines and hype, the evolutionary researchers aren’t even confident enough to say that Ardi is a human ancestor as opposed to simply an extinct ape. BBC News reports:
Even if it is not on the direct line to us, it offers new insights into how we evolved from the common ancestor we share with chimps, the team says.
Asked whether A. ramidus was our direct ancestor or not, the team said more fossils from different places and time periods were needed to answer the question.
“We will need many more fossil recoveries from the period of 3-5 million years ago to confidently answer that question in the future,” the scientists said in a briefing document that accompanied their journal papers.
“But if Ardipithecus ramidus was not actually the species directly ancestral to us, she must have been closely related to it, and would have been similar in appearance and adaptation.
Not only does that uncertainty exist; several scientists have admitted skepticism over the Ardi reports. Harvard University paleoanthropologist David Pilbeam told ScienceNOW, “I find it hard to believe that the numerous similarities of chimps and gorillas evolved convergently.” (We, too, have criticized the idea of convergent evolution in the past—albeit from the opposite angle.)
Also, anatomist William Jungers of Stony Brook University criticizes the conclusion that Ardi could walk upright: “This is a fascinating skeleton, but based on what they present, the evidence for bipedality is limited at best. Divergent big toes are associated with grasping, and this has one of the most divergent big toes you can imagine. Why would an animal fully adapted to support its weight on its forelimbs in the trees elect to walk bipedally on the ground?” he told National Geographic News.
Finally, some scientists have asked how Ardi fits into the evolutionary scheme with Australopithecines like Lucy, another supposed human ancestor said to have lived more recently than Ardi. Was there enough time, in the evolutionary timetable, for primitive Ardi to have evolved into less-primitive Lucy? The BBC quotes Chris Stringer of London’s Natural History Museum, who said, “With Australopithecus starting from four million years ago, one would have thought that things would have moved further down the line by 4.4 million years ago. OK, you can have very rapid change, perhaps; or Ardipithecus might be a residual form, a relic of a somewhat older stage of evolution that had carried on. Perhaps we will find something more like Australopithecus at 4.4 million years old somewhere else in Africa.”
We must admit that from our perspective, we’re growing desensitized to the fervor that increasingly surrounds each new fossil discovery claimed to support evolution. Surrounding Ardi’s unveiling is a spectacular media frenzy, but in many ways it’s little different than the hype over Ida less than five months ago (see Ida (Darwinius masillae): the Missing Link at Last?). That hype was quickly revealed to be unmerited at best and dishonest at worst (see Ida (Darwinius masillae): the Real Story of this “Scientific Breakthrough”). In the same way, the concerted release of so many papers on Ardi and the corresponding hubbub seems to perhaps be more about attention-seeking than about science. Could it be that the ongoing pressure for scientists to find something of evolutionary “significance” has led to a systematic incentive to make a huge deal (to use the vernacular) out of otherwise trivial fossils?
Perhaps we’re being a bit too rough, though. Evolutionists believe our own origins lie buried in such fossils as Ardi, so it’s no wonder they have a desire to interpret such finds in the light of human evolution. But in the case of Ardi (and Ida, Lucy, etc.), good science abstains from making such untestable, presupposition-driven claims.
Given the number and scope of the papers presented this week on Ardi, it will take some time before creationists are confident in our conclusions on Ardi and her kin. Based on our first look, however, the facts seem solidly behind the idea that Ardi was a quadrupedal ape with relatively little in common with humans (i.e., no more than most apes); the key basis for the alleged Ardi–human link (which even the authors are hesitant to confirm) is the idea that it walked upright—an idea that even evolutionists have criticized. And we can’t forget that all of these conclusions are inferred from digital reconstructions and fallible reconstructions of bones that were in very bad shape.
Without having a live “Ardi” to observe, scientists will only ever be able to come to probabilistic conclusions about its characteristics. As far as we’re concerned, the evolutionary “threat” to creationists from Ardi is no more than that posed by Ida: viz., none.
Evolution is a one-way street, new research confirms. So can it go only forward, or only backward?
Many readers are no doubt familiar with our frequent emphasis on the “direction” of genetic change: all observed mutations—the supposed foundation of evolution—either hold constant or reduce the amount of information in an organism’s genome. This is in direct contrast to what the grand story of evolution (i.e., from inorganic compounds to complex life in millions of years) needs: a mechanism to introduce new information in the genome. Naturally, then, news that evolution “doesn’t make U-turns” (in the words of ScienceNOW’s Michael Torrice) caught our attention.
A team led by evolutionary biologist Joseph Thornton of the University of Oregon reports new findings in Nature (“An Epistatic Ratchet Constrains the Direction of Glucocorticoid Receptor Evolution”). The team examined a protein called glucocorticoid receptor (GR), which helps control animals’ responses to the stress hormone cortisol. They hoped GR would help them answer the question of whether evolution can “go backward.” (The ScienceNOW report intriguingly notes that problems predating the study included a “lack [of] sufficient information about ancestral traits or how present-day traits evolved.”)
The researchers discovered that in its most “ancient” form, GR responded to two hormones, cortisol and aldosterone. But a more “recent” form responds only to cortisol. The team found thirty-seven amino acid differences between the two versions, but only two that were required to deactivate the aldosterone response. To answer their question (whether evolution can go backward), the scientists reverted the amino acids in the cortisol-only version of GR, hoping to “re”-enable the aldosterone response. However, the reversion not only failed to enact the aldosterone response; it destroyed GR’s ability to recognize any hormone (including cortisol)!
The problem was five of the remaining thirty-five amino acid differences: they played a part in knocking out the aldosterone-response ability as well; left unfixed, they caused the entire protein to fail after the scientists made their revisions. But because they cannot enable the aldosterone response themselves, natural selection could not act to preserve the changes in the unlikely event they “fixed themselves” (i.e., all spontaneously mutated back to the original/fully-functioning form). “They burn the bridge to return back to the ancestral function,” explained Thornton.
Thus, it seems that the GR protein has lost function over time, which affirms the creationist understanding of genetic evolution. That said, the research was partially based on “resurrecting” the ancient GR form based on the evolutionary tree of life; it may be that some organisms do not need the aldosterone response, and thus that the GR versions are each tailored designs.
If, however, some or all of the cortisol-only GR versions once had the aldosterone-response ability as well, that indeed backs up creationist teaching about the “downward” direction of mutations. The difficulty the team had repairing the protein underscores this. It is relatively easy to break the sophisticated instructions and machinery of living cells, and mutations have an excellent track record of doing just that. What scientific reason is there for believing, in spite of the evidence, that mutations could have generated the incredible biology we see all around us?
It’s the “final proof” that dinosaurs evolved into birds, say scientists.
“Exceptionally well preserved” fossils discovered in China purportedly show feathered dinosaurs from more than 150 million years ago, making them older than alleged dino-bird Archaeopteryx. A study of one fossil was published last week in the journal Nature (“A Pre-Archaeopteryx Troodontid Theropod from China with Long Feathers on the Metatarsus”), and other details were presented at the annual meeting of the Society of Vertebrate Paleontology.
The fossils, such as one named Anchiornis huxleyi, bear the imprints of what could be interpreted as feathers as well as the usual bones (see an image of the fossil slab from the Nature article). “All over the skeleton, you see feathers. . . . We realized that this was a much more important species, and definitely one of the most important species for our understanding of the origin of birds and of their flight,” said paleontologist Xing Xu of Shenyang Normal University.
University of Bristol paleontologist Michael Benton, who was not involved in the study, commented, “Drawing the tree of life, it’s fairly obvious that feathers arose before Archaeopteryx appears in the fossil record.” Of course, creationists have no bone to pick over that; if feathers “arose” on Day 5 of Creation Week (Genesis 1:20–23), and if most of the fossil record was formed almost two millennia later (Genesis 7:21–23), then feathers would indeed have arisen before Archaeopteryx remains were fossilized.
Creationists have good grounds for considering Archaeopteryx a true bird. For example, several types of birds in the fossil record have teeth. As for the “feathered dinosaur claims,” such fossils have never shown undisputed feathers, but rather vague representations that could be interpreted as something other than feathers.
In other words, there is a clear distinction between fossil dinosaurs and fossil birds, which corresponds with the fact that evolutionists cannot explain how reptilian scales could have evolved into avian feathers (which are an incredibly sophisticated design, totally different from scales). Of course, if—hypothetically—feathered dinosaurs had existed, even that would not prove dinosaur-to-bird evolution; we would merely understand that some created dinosaur kinds were feathered.
Like Archaeopteryx, A. huxleyi was probably a unique (and, obviously, now-extinct) avian creature that showed some traits that modern birds either lost over the years, or that other bird kinds never had. But their commitment to a specific interpretation of the fossil record’s dates means that evolutionists place this fossil at more than 150 million years ago—the time of dinosaurs. Hence, in their eyes, A. huxleyi can only be a dinosaur.
For all its size and strength, one mighty T. rex may have ultimately succumbed to a minuscule parasite.
In the case of the T. rex fossil nicknamed “Sue,” scientists have a new guess about what caused its death: a single-celled parasite called Trichomonas. Today, the parasite infects birds’ throats and beaks; the fossil evidence suggesting that trichomonosis affected Sue is the series of holes in the dinosaur’s jawbone.
Originally, those holes were interpreted as the legacy of bite wounds from a rival T. rex. Recently, experts have concluded that the holes appear too perfectly formed to have been caused by a bite; but if caused by trichomonosis or a similar disease, Sue may have eventually starved to death.
The authors of the PLoS ONE study (“Common Avian Infection Plagued the Tyrant Dinosaurs”) have also found other fossil evidence that they say shows the work of trichomonosis. “There’s a possibility that this disease is quite old,” said University of Wisconsin–Madison paleontologist Ewan Wolff, one of the scientists.
Wolff and his colleagues unsurprisingly link their idea to dinosaur-to-bird evolution, writing, “This finding represents the first evidence for the ancient evolutionary origin of an avian transmissible disease in non-avian theropod dinosaurs.” However, if their hypothesis is accurate, the existence of the same or a similar parasite in dinosaurs would only indicate the range of trichomonosis hosts.
Sue, whose home is Chicago’s Field Museum, is the largest and most complete T. rex fossil discovered—at 42 feet (13 m) long. The fossilized evidence of its demise (whether by attack, disease, or another cause) is another reminder that the fossil record is a record of death and imperfection—including carnivory, cancer, and thorns. Would God pronounce the earth “very good” on the sixth day of Creation Week (Genesis 1:31) if such fossils were the legacy of His creative process?
The astonishing navigational abilities of the monarch butterfly seem all the more astonishing in the light of new research.
The researchers were not studying butterfly antennae when they began their work—learning more about how the orange-and-black insects emerge and migrate from Canada and the U.S. to spend each winter in Mexico. But as it turns out, the monarch’s antennae are crucial to finding their way back home.
The new study, published in Science (“Antennal Circadian Clocks Coordinate Sun Compass Orientation in Migratory Monarch Butterflies”), discusses one the butterflies’ biological clocks—which is, unexpectedly, located in the butterflies’ antennae rather than in their brains (though other biological clocks exist in the monarch’s brain. The antennae clocks help the butterflies compensate for the movement of the sun as the day passes.
The discovery occurred after the researchers clipped some laboratory butterflies’ antennae off, then observed the monarchs’ confusion as they all “flew in random directions.” Later, they coated some of the lab butterflies’ antennae with black paint, then observed as the altered butterflies flew in the wrong direction.
ScienceNOW quotes University of Kansas insect ecologist Orley Taylor, who noted, “The deeper they dig, the more they find out about how complicated this system is.” Despite this discovery, many questions linger about how the monarchs complete their incredible journey. What we know is that the monarch is one of God’s most astonishing—and beautiful—designs.
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