In the Liaoning Province in northeast China, archaeologists recently discovered fossils of turkey-sized animals that were apparently covered with feathers. They have strong legs and stubby arms, and so the scientists proclaimed them to be feathered dinosaurs. In fact, the team of scientists who examined them, and those who wrote about them in Nature and National Geographic, have indicated that these fossils are the strongest evidence yet found to indicate that birds evolved from reptiles.
In point of fact, this only goes to show how little evidence there is to link dinosaurs to birds on some kind of evolutionary continuum. The only thing these fossils prove is that there was a group of animals that in some ways resembled dinosaurs and in some ways resembled turkeys. The scientists do not know if they were birds or dinosaurs. In fact, the fossils have been dated as being more recent than the oldest known fossils of birds. According to Alan Feduccia, evolutionary biologist at the University of Carolina, Chapel Hill, the animals preserved in these fossils could simply be birds that just happened to look like dinosaurs in some respects. Therefore, they could only be evidence of evolution to someone who already believes in evolution.
Let me explain what I mean. As I write, my wife is driving our Mercury Villager minivan to visit her cousin in Connecticut. If you have seen a Villager, you may have noticed some similarities to the Ford Taurus / Mercury Sable wagon. On the other hand, you may also have noticed some similarities to a Ford van. If an evolutionist were to find a fossil of the Villager 5,000 years from now, he would insist that it is a missing link between the van and the station wagon. However, we know that station wagons did not evolve from vans. We know that there are similarities between the different vehicles because they were all designed by human beings, for use by human beings. Likewise with the similarities between different species of animals: they were all designed by the same Creator to live on the same planet.
When we examine the question more closely, it appears that there are a number of peculiarities of birds that make it evident that they did not evolve from any other animal. Many of the biological systems of birds are so completely different from all other air-breathing vertebrates – including reptiles – that it is not conceivable that one could have evolved from the other. Let us consider the example of the bird’s lung.
When we breathe, we breathe in and out through the same passages. When we inhale, the air goes through our trachea, which divides into two tubes called bronchi, which carry the air into the lungs. The bronchi then subdivide into smaller and smaller tubes called bronchioles until they finally end in miniscule bags called alveoli. It is here, in the alveoli, that oxygen is diffused into the blood, and carbon dioxide is diffused from the blood. When we exhale, the air is forced out of the alveoli, and is carried out through the same bronchioles and bronchi. Thus, the passage of air through our lungs may be likened to the passage of cars on two-way streets that end in cul-de-sacs. Just as the cars have to turn around and go back the way they came, so does the air in our lungs. There could never be a one-way street ending in a cul-de-sac; cars would either be prohibited from entering, or they would be allowed to enter but not to leave. In similar fashion, our lungs are designed in such a manner that the bronchi must allow air to pass both in and out (i.e., they must act like two-way streets) or the lungs break down and we die. As it happens, this is true in all other air-breathing vertebrates as well – except birds.
Like mammals and reptiles, birds have bronchi. However, the birds’ bronchi do not end in alveoli. The birds’ bronchi fork or branch into smaller tubes called parabronchi. As the bird inhales, air is carried through the bronchi into the parabronchi. The bird’s body has a system of air sacs that expand and contract in such a way as to keep the air flowing continuously in the same direction through the parabronchi. (If the bird did not have this complex, interconnected system of air sacs, or if it were imperfectly developed, the bird’s lung would not function.)
The parabronchi do not end in cul-de-sacs. Rather, they come back together into bronchi that carry the air back out. Thus, the bird’s lung is a series of one-way streets. The air comes in one way, and goes out the other. This system is completely different from the respiratory system in all other vertebrates, yet it is essentially the same in every species of bird.
There are other unique aspects of the bird’s lung. For example, all other vertebrates are born with their lungs in collapsed state, because they have not yet been filled with air. Anyone who has seen a child born has witnessed this phenomenon, as the shock of that first rush of air into the lungs results in the baby’s first cry. However, this is not so with birds. Unlike all other vertebrates, the bird’s lung cannot be inflated out of a collapsed state in this manner. The design of the bird’s lung requires that it be filled with air gradually. As it happens, this process begins a few days before the bird hatches, so that it breaks out of its shell with lungs already filled with air. Otherwise it would not live, because its respiratory system does not finish developing until after it is full of air.
There is no species of bird that has a respiratory system that in some ways functions like a bird’s and in other ways functions like a reptile’s. Nor is there a species of reptile whose respiratory system functions somewhat like a bird’s. Nor, indeed, could there be. Just as a street cannot be both one-way and two-way at the same time, so also a lung cannot be both like a bird and like a reptile. There is no way that an intermediate form of lung could function. Moreover, speaking in evolutionary terms, there is no reason for such an intermediary form to develop – even if it could work. Why would natural selection cause a reptile to begin to form a different kind of respiratory system, when the system it already has is perfectly suited for it? There is no reason for such a change to take place.
We are left with the following facts: There is no physical evidence that the respiratory system of birds evolved from that of reptiles. There is no creature anywhere that has a lung that is part avian and part reptilian. In keeping with this lack of evidence, we have great difficulty imagining how such a lung could possibly work, anyway, and therefore we would not expect to find one. Besides all of that, we also have tremendous difficulty imagining why a reptile, which already has a perfectly designed lung, would ever begin to develop a completely different kind of lung in the first place. Finally, when we consider how important it is that an animal’s lungs function properly and efficiently (it would die immediately otherwise), it becomes impossible to conceive of how on earth the bird’s lung evolved from that of another vertebrate. We cannot even imagine one intermediate form of lung that would function, never mind an entire series of them! However, in order for the General Theory of Evolution to be true, this impossible transition would have to have taken place.
As noted above, there are other aspects of the biology of birds that are unique among vertebrates. The avian heart and digestive system are also unique, as well as a number of lesser systems. We must ask: when the strongest piece of “evidence” available is the fossilized remains of two turkey-sized animals with feathers and stubby arms, why on earth would anyone conclude that birds evolved from reptiles? The answer is, that the only viable option to the General Theory of Evolution is the account given in the first chapter of Genesis. There are too many people – evolutionary scientists among them – who are not willing to accept this account, or to submit to its implications.
