The Big Bang of Bird Evolution?

Introduction

Recently a consortium of 200 scientists from 80 institutions in 20 countries conducted genomic research attempting to find answers about the avian family tree.1 These papers were based on the recently available genomes of 48 bird species that span 32 of the 35 currently proposed orders.2

The release of genomic data from so many different birds is exciting. It allows for comparisons to be made. These comparisons can help us understand more about birds and other creatures.

Who Is Telling the Story?

One thing that is obvious from the write-ups is that there are some assumptions. The scientists have assumed that all life on Earth shares common ancestry. Based on this belief, they use the data to tell stories of how the birds may have originated or changed. And what if all birds do not share common ancestry? Then many of the stories are simply not true.

The Bible clearly tells us that God created birds and other animals according to their kinds. In other words, not all birds share common ancestry. A previous study of birds from a biblical perspective suggests that birds from a common kind may sometimes belong to more than one order, but not usually.3 So for most of the birds being compared in these studies, they are not actually related.

What Do the Comparisons Tell Us?

The comparisons can reveal similarities and differences between genomes. In an evolutionary paradigm, the more the similarity, the more closely related the two birds are believed to be. There may be times when this conclusion is correct (e.g., if both birds are finches), but it is important to realize that it is not automatically the case.

Comparisons reveal that peregrine falcons are more similar genetically to parrots and songbirds than to hawks, eagles, or owls.4 In the past, birds of prey were often assumed to be more closely related to each other. In reality, with the exception of hawks and eagles, which both belong to the family Accipitridae, the other birds are probably all from different created kinds.5

What has been surprising in recent decades is how different the family tree of birds appears to evolutionists depending on which characteristics are being compared. Comparisons based on genomic data sometimes give “trees” similar to those based on physical characteristics, but other times they give wildly different results. Even when comparing physical traits, the “trees” can be in conflict depending on which characteristics are used.6 For creationists this is not really a conundrum since universal common ancestry is not assumed.

Common Ancestry Assumed Despite the Data

Evolutionists believe that birds evolved from a reptilian ancestor. In fact, in the last decade it has become popular to consider birds a class of reptile based on evolutionary assumptions.7 Yet birds have distinctive features including wings and feathers, the ability to fly, a sturdy lightweight skeleton, a high metabolic rate, an internally regulated body temperature (endothermy), and unique respiratory and urinary/excretion systems compared to extant reptiles. Belief that they are related is not based on observation of transition, or even fossil findings exhibiting a clear transition, but rests purely on evolutionary philosophy.

One of the studies involving the bird genomes reveals important differences on the molecular level as well. There were 274 protein-coding genes that were present in humans and lizards, but absent in these bird genomes. Most of these genes are also found in fish, frogs, and crocodiles. They tend to be clustered together (on chromosome 19 and X in humans; chromosome 2 in lizards) and are associated with critical functions in a variety of organs and systems in mammals. Disruption in some of these genes is associated with death in rodents and serious genetic disorders in humans.8

So how do evolutionists believe essential protein-coding genes could just disappear in the evolution of birds? Of course, birds do have genes to carry out all essential functions. Evolutionists believe there was a transition so new genes took over the important functions and these genes were lost. How does that happen by random mutation and natural selection? It may not be difficult in the mind of an imaginative person, but there is no scientific reason to believe it could have happened in real history. It would have required a tremendous number of well-orchestrated changes that cannot plausibly be accomplished by these mechanisms.

Structures Disappear and Reappear like Magic?

In evolutionary explanations, not only are a rather startling array of things believed to have been lost, but a plethora of new structures are believed to have arisen. Since this is not supposed to be the result of any design, per se, evolutionists believed that once a particular structure is lost, it is gone forever. Not only would it be statistically unlikely for it to appear again, evolutionary changes may preclude the option altogether. This is known as Dollo’s Law, which basically postulates that evolution is not reversible.9 However, a recent paper on wrist anatomy in birds and other vertebrates claims that a structure lost in bird ancestors has reappeared.10

There are many anatomical similarities between different kinds of animals. Creationists recognize this as being from common design used by a wise Designer. Evolutionists attribute it to common ancestry, except when it shows up where it shouldn’t be. In cases where similarity is out of place, it is generally considered to be from convergent evolution (i.e. the same basic thing supposedly evolved independently two or more times). In this case, however, examination of avian embryos suggests what paleontologists had often called the ulnare in birds corresponds better to the pisiform bone.

The pisiform bone is found in the wrist of many animals, including “early” dinosaurs and adult humans. It is a sesamoid bone, meaning it is a small rounded bone embedded in a muscle or tendon, like the knee cap. This construction allows it to work as a pulley, giving the tendon a smooth surface to slide over. The problem for the evolutionary story is that this bone is not present in the skeletons of the types of dinosaurs that are believed to have developed into birds. Did it really reappear in birds after being lost in their ancestors? Again, this imaginative story rests on evolutionary assumptions.

Was There Ever a Big Bang in the History of Birds?

Grand evolutionary stories of changes involving major anatomical restructuring aside, we know from a biblical perspective that birds have changed in some ways. For example, biblically based creation research suggests all finches and sparrows come from a single created kind.11 Thus, as they reproduced and filled the earth according to the command of God (Genesis 1:21–22), they have diversified, enabling them to fill a variety of habitats and niches. The changes include such traits as size and shape (of the body and the beak), color, and song.

Probably the most famous example of documented changes in birds involve the finches of the Galápagos Islands. These birds have been the subject of scientific study for decades, and important insights have been learned in the process.12 The medium ground finch (Geospiza fortis) on one small island was studied in detail. The population had individuals with a range of beak sizes: those with larger beaks were able to crack and eat the larger and harder seeds; the ones with smaller beaks depended on the smaller and softer seeds. The average beak size of these birds shifted over time. One factor was natural selection; when a drought came which depleted small and soft seeds, only birds with larger beaks had food to survive. In a different year, the shift was in the opposite direction because the larger and harder seeds disappeared first.

A second factor affecting beak size was hybridization; a few birds bred with finches from a different species, which brought variation in beak size into the population. Further insights into changes in bird songs and speciation have been uncovered as well. Both creationists and evolutionists agree that these finches populated these islands from the mainland. In a relatively short period of time they diversified, enabling them to fill a variety of open niches. This phenomenon is called adaptive radiation.

Finches are not the only birds to have undergone adaptive radiation on islands. The vangas of Madagascar and Hawaiian honeycreepers have similarly undergone a rapid burst of speciation since colonizing their respective islands.13 Interestingly, often this is not associated with as much genetic divergence as one might expect. In fact, a recent study recognizes that epigenetic changes have been important in finch adaptation.14 Epigenetic changes involve such things as methyl tags which affect how DNA is read, but do not actually change the DNA sequence.

Adaptive Changes

While both creationists and evolutionists may agree on adaptive radiations that occurred in the past, there are some points where we disagree. The most obvious would be on the time frame. To an evolutionist, “rapid” could mean millions of years; to a creationist, it would mean thousands of years, or possibly less.

A second difference involves the mechanisms. Historically evolutionists have proposed that random mutation and natural selection are sufficient to account for these types of adaptive changes. The fact that epigenetics can be involved is at odds with classical neo-Darwinian thinking.

Epigenetics is the means by which your body controls gene expression so the right amount of product is produced at the right place and time. It is required for life because there is no “one-size-fits-all” level for gene expression. It is critical during development; different tissues have different epigenetic markings so they behave properly. It also plays a role in enabling us to adapt physiologically to changes in our environment. It is a well-designed system and clear evidence of a caring and wise Creator. With the discovery that epigenetic information could be inherited by offspring, evolutionists lost the argument that inheritance is exclusively Mendelian. Instead, it is now recognized that environment can also influence the traits of future generations.

Other factors suggest design is involved as well. For example, some genetic changes are not really random; they occur more frequently in areas known as hotspots. Some are associated with the essential process of homologous recombination, which occurs at meiosis when sex cells are formed to produce the next generation. There are specific enzymes required for the processes to take place, suggesting this may be a designed mechanism that plays a role in the adaptation we observe within created kinds.15

Additionally, factors other than natural selection can affect how common a variant becomes in a population. For example, migration and hybridization can affect alleles in a population, and the pattern could easily be mistaken for natural selection.16 Gene conversion is an event that occurs during homologous recombination; sometimes it is biased so one variant is more commonly passed on than another.17 It is possible that biased gene conversion may play a role in adaptive alleles becoming more common in a population.

Conclusion

The explosion of genomic data is certainly exciting. It allows for many different comparisons to be made. These comparisons may help answer a variety of interesting research questions. These include questions about speciation and adaptation. In some case the comparisons have already changed our way of thinking.

It is important to recognize that what we believe the data is telling us depends on our worldview. If one assumes universal common ancestry, the story will include common ancestry. This is not because of the data, but because universal common ancestry is an assumption that is not questioned—the data is simply stuffed into the paradigm.

In contrast, the data are easily explained by a biblical worldview. The fanciful changes that involve major restructuring never occurred. This is why there is no fossil evidence for such dramatic transitions. At the same time there is obvious adaptation which has taken place as created kinds reproduced and filled the earth. This innate flexibility that allows creatures to adapt to a wide variety of habitats is evidence of design by a caring and wise Creator.