Warm-blooded, cold-blooded, or none-of-the-above?
How do you take a dinosaur’s temperature? Ask nicely? What if it’s dead? Paleontologists have long debated whether dinosaurs were cold-blooded or not. An analysis of sauropod tooth enamel may shed light on the subject, but the debate remains far from settled.
Historically, scientists have assumed that dinosaurs, like living reptiles, were cold-blooded. That is, until the 1960s. As secular paleontologists tried to explain how cold-blooded creatures could survive in polar climates, grow so big, develop the sort of bone structure they have, become fast and active, and evolve into warm-blooded birds, many began to suggest dinosaurs were warm-blooded. (Notice many of the “facts” the scientists were trying to explain are unprovable assumptions. Others are generalizations for which there are living exceptions.)1 Nevertheless, whether a scientist subscribes to evolutionary ideas or not, without live dinosaurs around, the question can only be approached indirectly.
This indirect approach involves isotope ratios. (We recently learned about the diet of “Nutcracker man” from carbon isotopes in tooth enamel.2) Scientists have observed that chemical reactions taking place at lower temperatures tend to incorporate more of the heavier, rarer isotopes.
Caltech scientists have therefore been using “clumped-isotope thermometry”3 to make guesses about the climate at the time rocks were formed. John Eiler and Robert Eagle decided to try the method on dinosaur tooth enamel. Tooth enamel is thought to remain stable over time. No radioactive decay is involved. They calibrated their system using “teeth of living animals.”4
Then they measured isotope ratios in fossil teeth “from three large dinosaur species. . . . The team concludes they can safely peg the temperature range of the sauropods at roughly 96 to 101 [degrees Fahrenheit].” These temperatures match those common to mammals and birds.
So why isn’t the body temperature question settled? For one thing, as paleontologist Kevin Padian notes, “We don't have an independent test of how far off the results could be.”
Furthermore, an animal may be warm because it really is endothermic—that is, able to regulate its own body temperature—or because it is an ectotherm which lives in a hot tropical climate, has a fairly high metabolic rate (like some sea turtles), or is so big it has difficulty cooling off. Thus results may be different when smaller dinosaurs are examined. The authors note, “Our data, taken in isolation, are not unambiguous indicators of endothermy (warm-bloodedness) vs. ectothermy (cold-bloodedness).”
From a creationist perspective, the endothermic/ectothermic question for the dinosaurs has no particular ramifications. While evolutionists insist that endotherms evolved from ectotherms, however, we maintain that God created both endotherms and ectotherms during the creation week. And warm-blooded birds were created the day before land animals, including dinosaurs, whatever their metabolism was like.
Selecting for snowflakes or evolution of multicellularity?
The Society for the Study of Evolution was all abuzz with the news: a multicellular organism has evolved from a single-celled ancestor right before our eyes. William Ratcliff, presenting the paper, reported, “The evolution of multicellularity was one of the most significant innovations in the history of life. Its initial evolution, however, remains poorly understood largely because all known transitions are ancient. Using experimental evolution, we demonstrate that key steps in the transition to multicellularity evolve far more easily than previously thought.”5
Ratcliff’s group coaxed brewer’s yeast to do what evolutionists speculate may have happened to make multicellular life possible. They “subjected the unicellular yeast Saccharomyces cerevisiae”5 to a daily centrifuge ride, drawing the largest organisms to the bottom. They saved this sludge and pitched the rest. Brewer’s yeast reproduces by budding. Yeast which had not yet pinched off their buds were thus repeatedly selected to survive. These multicellular forms eventually resembled snowflakes.
Ratcliff “expected multicellularity to be adaptive”5 in his centrifuge, and it was. Only bigger clusters were allowed to survive and reproduce. “The key step in the evolution of multicellularity is a shift in the level of selection from unicells to groups,” says Ratcliff. “Once that occurs, you can consider the clumps to be primitive multicellular organisms.”6
But the excitement didn’t stop there. Eventually, these yeast snowflakes developed what the researchers called “division of labor,”5 a necessary leap toward being a bona fide multicellular organism. “We observed the evolution of programmed cell death (apoptosis) among cells within multicellular clusters,” they wrote. “Cellular suicide, while costly to the cells that express this behavior, is nevertheless adaptive, benefiting viable cells within the multicellular cluster by regulating propagule size.”5 They believe they have observed that “key aspects of multicellular complexity . . . readily evolve from unicellular eukaryotes.”5
So what about it? Have we witnessed an evolutionary steppingstone like that which supposedly happened millions of years ago? The writers admit this evolutionary step is “poorly understood” because there are no transitional forms for us to look at. But if evolution has been observed under their guiding hand, who can say it didn’t happen randomly and repeatedly millions of years ago?
But let’s take a closer look. Like many fungi, brewer’s yeast is known to engage in “dimorphic switching.” Programmed into its genome is the ability to change forms depending on conditions. Brewer’s yeast is considered unicellular because it usually is. However, under certain conditions—nitrogen starvation, for instance—it becomes a multicellular filament. A study7 in 1993 identified three genes responsible for this branching growth. Thus, genetic information to become multicellular did not evolve in Ratcliff’s laboratory; the information was in the genome all along.
Due to this dimorphic nature, some evolutionists are skeptical about Ratcliff’s interpretation. They believe this yeast has a multicellular evolutionary history with “a vestigial ability to become multicelllular, rather than evolving into something entirely new.”
Thus, brewer’s yeast already had the genetic ability to stay hooked together after budding. Repeated culling allowed only yeast with the tightest grip to survive and reproduce. In botany and animal husbandry, this process is called selective breeding. And not only were these yeast still yeast, the cells in each snowflake were “genetically identical,”8 “clonally related cells.”5 They had not evolved anything new genetically. They had been selected for abilities they already had.
Finally, what about Ratcliff’s claim that he saw “reproductive division of labor” evolve? When rows of cells died, the clusters reproduced by fracturing. Did those cells acquire the genetic ability to die as a group? Brewer’s yeast has a known genetic mechanism for programmed cellular death.9 The capacity of single-celled organisms to coordinate group suicide and other activities is commonly seen in biofilms, cooperative communities of microorganisms like dental plaque and slime mold. So if unicellular organisms that are not clonally related can communicate to coordinate cellular suicide, why should such behavior in connected clones signify evolution to a new kind of multicellular organism?
Ratcliff plans to try his experiment on “Chlamydomonas, [a] single-celled organism with no multicellular ancestry.” Though he is optimistic about gaining insight into “one of the most crucial phases in our evolutionary history,” we maintain that multicellular behavior in Chlamydomonas, if it occurs, will be a manifestation of that organism’s underlying genetic ability. Phenotypic switching is quite common among both prokaryotic and eukaryotic microorganisms. (This ability allows many to become pathogenic10 and escape host immune systems.) Evolution of a new kind of organism will not be observed, but with enough selective pressure and culling, perhaps the reawakening of a dormant ability will be.
Selective breeding is selective breeding, not evolution.
Genesis captures solar wind and blows a hole in the nebular hypothesis.
NASA’s Genesis spacecraft traveled about a million miles from earth to collect solar wind particles. The samples sent home were “the first material collected beyond the moon.” Unfortunately, the cargo capsule crashed in Utah in 2004. Researchers have spent seven years decontaminating and analyzing the samples. Their results, published in Science, have surprised many.
According to the Jet Propulsion Laboratory, “The data revealed slight differences in the types of oxygen and nitrogen present on the sun and planets. . . . The implications could help determine how our solar system evolved.”
The “nebular hypothesis” is believed by most secular scientists to explain the origin of the solar system. They maintain that our solar system formed 4.6 billion years ago from a cloud of dust and gas. Since everything formed from the same raw materials, they expected the chemistry to be the same throughout. But the isotope ratios found in these solar wind particles do not match those on earth.
Oxygen and nitrogen, like all elements, exist in more than one isotopic form. The isotopes of a given element behave the same way chemically but differ in the number of neutrons per atom. Most oxygen is oxygen-16, but some is oxygen-17 or oxygen-18. Likewise, most nitrogen is nitrogen-14, but some is nitrogen-15 or nitrogen-16.
Compared to the earth, the moon, and meteorites, the sun is high in oxygen-16. The differences in nitrogen isotopes are even greater: “when compared to Earth's atmosphere, nitrogen in the sun and Jupiter has slightly more N-14, but 40 percent less N-15. Both the sun and Jupiter appear to have the same nitrogen composition.”
“The implication is that we did not form out of the same solar nebula materials that created the sun—just how and why remains to be discovered,” said Kevin McKeegan, author of one of the reports in Science.
“These findings show that all solar system objects, including the terrestrial planets, meteorites and comets, are anomalous compared to the initial composition of the nebula from which the solar system formed,” according to Bernard Marty, author of the other report. “Understanding the cause of such a heterogeneity will impact our view on the formation of the solar system.”
Creationists have long pointed to problems with the nebular hypothesis, yet most secular scientists have clung to the nebula from which they knew we sprang despite the aberrant physics it demands. Perhaps these new discoveries from Genesis will lead at least a few to take another look at the eyewitness account of our origins in Genesis.
Why fly when you can flap-run up the evolutionary tree?
If you were a bird, wouldn’t you rather fly up a steep hill than run? Well, some birds don’t. A study published in the Journal of Experimental Biology reveals the advantage of Wing Assisted Incline Running (WAIR)11 and suggests this behavior explains how dinosaurs evolved the ability to fly.
In an effort to explain why pigeons habitually choose to flap-run uphill despite good flight capabilities, Dr. Brandon Jackson and colleagues implanted electrodes in the flight muscles of a group of pigeons. They measured muscle activity as the birds flew or flap-ran up various inclines.
Once the incline reached 65 degrees, the electrodes revealed that the energy expenditure for flap-running was only about ten percent of the energy required to ascend in flight. “The birds seemed to be using hardly any power to flap their wings as they ran up the slopes,” said Jackson.
WAIR is a crucial step in the flight training of baby birds. “Flap running... lets young birds that cannot yet fly - because of small muscles, small wings, weak feathers, etc - get off the ground and away from some predators,” Dr. Jackson said.
“And if baby birds can perform these behaviours, benefit from them, and transition gradually to flight in their life-time,” he added, “we think it's probable that dinosaurs with (similarly small wings) could have performed these behaviours, benefited from them, and transitioned towards flight over evolutionary time.”
“Very small wings powered by small muscles had aerodynamic function and survival benefits when they were flapped,” he concluded. “No more major steps were required after that, just gradual but beneficial steps. And we can actually observe [those steps] in developing birds today.”
Thus, because birds can conserve energy using WAIR and because baby birds train for flight this way, evolutionists believe WAIR to be “the extant biomechanical analogs for incremental adaptive stages in the evolutionary origin of flight.”11
The anatomical changes required for bird flight, however, go way beyond getting a good upper body work-out. An aerodynamic wing design, feathers, lightweight bones, and a respiratory system unique to the demands of bird flight are in no way acquired by running around and flapping. Furthermore, the author blithely refers to “very small wings” as if there were any evidence that dinosaurs had them. Without the wings, the show is over before it gets off the ground.
The study does a great job of revealing the design advantage of certain behaviors available to adult birds, fledglings, and even flightless birds. WAIR enables them to climb with less effort, exercise flight muscles before learning to fly, and negotiate obstacles. God created birds on the fifth day of creation week, and He designed them well. But these results do not show how flight evolved or how a reptilian creature could obtain the genetic information to become a bird.
Speciation’s secrets are multiple-choice.
What do phlox flowers, stickleback fish, monkeyflowers, and Bogota fruit flies have in common? They all suggest genetic mechanisms for speciation.
ScienceNews collected information to illustrate those genetic secrets. Naturally the article refers to evolutionary changes, but in every instance the organism is only moving toward a split into non-interbreeding species.
Species is a slippery word. The author writes, “Deciding what makes a species distinct from its evolutionary neighbors can get fuzzy, and there are about as many different definitions as there are biological disciplines. An old and often cited explanation comes down to sex. . . . Members of separate species don’t mate, at least not successfully.”
Creationists acknowledge that organisms often change over time, within the limits of created kinds. Furthermore, when similar organisms are isolated from one another, differences may accumulate until the populations become incapable of interbreeding. Speciation has then occurred.
Two varieties of purple phlox share their Texas habitat. The annual phlox, light purple elsewhere, are bright scarlet where they come in contact with the purple pointed phlox in the southeast near Austin. Butterflies distinguish them, and cross-breeding is decreased by about two-thirds. Since their hybridization rarely produces mature seeds, prevention of cross-breeding helps both populations. Duke University researchers discovered that enzymes controlled by two genes cause this color switch. “As far as speciation genes go, few examples put their stamp so directly on mating.”
The puzzle for evolutionary scientists, however, is to figure out some evolutionary advantage to a system which causes two phlox populations competing for the same resources to thrive in the same habitat. “Successful reproduction is a very important thing for organisms, so why evolution would tolerate two populations of would-be parents that can’t interbreed has been hotly debated among biologists.”
The stickleback fish provides an example of a species that may be on its way to speciation. Freshwater and saltwater sticklebacks are able to interbreed in the laboratory. The ocean version is armored for life in the sea, whereas the smooth freshwater variety would have difficulty coping with ocean predators, discouraging interbreeding in the wild. The ectodysplasin gene is responsible for this armor plating. Isolation may eventually allow sufficient differences to accumulate to make interbreeding impossible.
Yellow monkeyflowers may be en route to speciation through another genetic avenue. The Pacific and inland varieties prefer different environments. Genomic analysis has shown that one has an inversion. In other words, part of a chromosome is flipped. Such an arrangement discourages much shuffling of nearby genes. So while the varieties can interbreed, the association of genes for certain environmental tolerances tend to stay boxed in by the inversion. Since the hardiest genetic combinations for each environment survive, these varieties are discouraged from successful interbreeding in the wild.
Finally, the Bogota fruit fly possesses an overdrive gene which causes near-sterility if cross-bred into U.S. fruit flies. The overdrive gene does not cause sterility in the Bogota population because the Bogota flies also possess several genes which prevent expression of the birth control effect. These flies are the same species, but in the wild speciation would be expected. The Bogota fruit fly illustrates how certain combinations of genes can be advantageous.
As creationists we marvel at the ways God has designed for organisms to develop variety within their kinds. Notice that none of these examples showed any evidence of acquiring new information but only of reshuffling old information and losing information within certain populations. Isolation and natural selection can then lead to speciation.
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