Consider the Moa: Extinct Flightless Birds of New Zealand

An Emu parent with young in Austrlia.  Emu's look like Ostriches but are not very closely related. Image: Wikipedia

An Emu parent with young in Australia. Emu’s look like Ostriches but are not very closely related. Image: Wikipedia

I am going to wrap up my miniseries on the ostrich (see Consider the Ostrich Part I, II and III) by examining some of the questions about origins that other flightless bird raise.   The ostrich is a flightless bird that has large wings though they are inadequate for flight because they lack the bone and muscle structures and because the feathers lack the interlocking barbs that flight feathers in flighted birds have.    I mentioned before that the ostrich is only one species of several ratite birds found on other continents and islands that have similar characteristics.   These included the emu and cassowary from Australia, the kiwi from New Zealand and the rhea from South America. If we look at extinct birds we would include elephant bird from Madagascar and multiple species of moa from New Zealand.    If we include other described species of ostrich that are extinct as well as dozens  of other extinct members of the ratite family of birds that are only found in the fossil record we can see that the number of species of living ratite birds is very small compared to the number present in the past. For example, ostrich species have been identified from fossils found in multiple places in Eurasia and nearly all parts of Africa and the Middle East suggesting the range of the ostrich family was much greater than it is today.

A Cassowary is a colorful ratite bird that is most similar to the Emu and also is only found in Australia. Image: Wikipedia

A Cassowary is a colorful ratite bird that is most similar to the Emu and also is only found in Australia.  They have very small remnants of wings. Image: Wikipedia

Of these birds some of the most interesting are the nine identified species (6 genera) of moas from New Zealand.  Despite their having been extinct since the late 1700s with most of them likely being wiped out by early human settlers in the 1400s they have been well-studied.  Bones found in caves representing these birds have been found in hundreds of locations and DNA studied performed on samples that are estimated to be hundreds of 10s of thousands of years old.    What makes the moa fascinating is the very large size (over 10 feet tall) of some species and the fact that all the described species are completely lacking in wings.  In other respects they are similar to emus and ostriches in much of their anatomy.

Fig.1 from Bunce et al. (2009): Systematics, dimensions and approximate distributions of moa in the three family, six genera, nine species taxonomy advocated in this study. doi/10.1073/pnas.0906660106The data from ancient mitochondrial DNA also allowed the team to study the time-frame of moa evolution. Earlier studies have suggested that the moa radiation occurred about 15 mya, but Bunce et al.'s data indicate that the two main groups of moa (the Dinornithidae & Emeidae) happened just 5.27 mya - much more recently. (The 2009 paper discusses the reasons why their figure differs so significantly from the earlier one, which was also based on aDNA, & suggest this is related to how the data were calibrated.)

Fig.1 from Bunce et al. (2009): This shows some of the diversity of the 6 genera, 9 species in two families of Moa found on New Zeeland prior to the 1400s.  PNAS paper found at:  doi/10.1073/pnas.0906660106 

David Catchpoole has an article ““Moa’s Ark” vs. Noah’s Ark”  published on the website of Creation Ministries International (CMI) that finds it likely that the original moa was a flighted bird that flew to New Zealand after departing Noah’s ark and once there had a “mutational disorder” such that it could no longer fly but having to predators this “unfit” feature would not have been deadly and so they were able to adapt to this new land.  Evolutionary theory doesn’t disagree with this general scenario but of course has difficulty with the timelines (4-5 million years vs. less than 4000 years for young earth creationists).

A common mantra of all YEC articles like Catchpoole’s is that characteristics like loss of flight are the result of loss of information and thus are a form of downward evolution (devolution) and is to be expected as a result of a fallen world.   But are the lack of wings really a devolved characteristic?  Superficially moas might just look as if they lost wings but losing something like a wing is much more difficult than it might sound and likely requires many hundreds of mutations and many different genes.   If it were as simply as a “mutational disorder” as Catchpoole calls it why do we not see birds in captivity for thousands of years losing their wings? Furthermore, just look at the size of some of the moas.  They were taller and larger than any person is and they have dense heavy bones.  They didn’t simply lose wings they also “evolved” many new features in adapting to their environment.  When the original moa flew to New Zealand it surely was not as large and it would have had hollow bones like other flight capable birds.   The loss of wings would have to have been compensated for by a change in posture, thickening of the bones both in diameter and the filling of the center core, increased size in the beak and changes in the distribution of feather type on

A comparison of the size of four species of Moa with a human.  Image credit: Conty - Wikipedia.

A comparison of the size of four species of Moa with a human. Image credit: Conty – Wikipedia.

the body to name just a few changes.  This is not a loss of information but required changes in genes and probably new genes altogether.  Bones simply don’t become dense via a loss of information or by just a simple mutation.  This requires a network of genes working together in development.  If God created the moa with hollow bones to aid in flight then the formation of dense bones would not be a loss of information but would be the gain of a new feature.   Were it so easy to change the structure of a bone, then the many tens of flightless birds from other groups of birds such as the ducks and chicken-like birds that have become flightless in the past couple thousand years would also have dense bones but they do not.

Ultra-fast Evolution of Moas in New Zealand?

If the creationist speculation is correct that an original moa-like bird flew to New Zealand and then lost flight through mutation then a number of additional problems the foremost of which is how to explain the many species of moas on New Zealand.  All of the species lack wings including even any vestigial portion of a wing.  They all have dense bones and lack flight feathers.   In addition, there are very large species and smaller species.   If the original moa flew it must have evolved all these features very rapidly and prior to that population splitting into many sub-populations which then became the separate species and genera of moa.  There are thousands of bones of these birds and because they all share these central features (no wings and dense bones)  it strongly suggests that the moa species looked like this for a very long time.

A reconstruction of a moa based on preserved remains of feathers, tissues and bones. Note the lack of any wings.  Image credit: Wikipedia

A reconstruction of a moa based on preserved remains of feathers, tissues and bones. Note the lack of any wings. Image credit: Wikipedia

To put this into more of a genetic context, the creationist line seems to be that God created some moa-like bird with the genetic ability to morph into these large heavy boned wingless birds however in the 2000 years from the creation to the flood they didn’t experience such a change.  Then just one pair of moa were preserved on the ark, then flew to New Zealand and transformed themselves in to these dramatically different birds in potentially just a few hundred years.  How could they do this starting with such a limited gene pool of only two individuals?  The genetic divergence of moa from one another is very great and thus the millions of mutations that they have in their genome all must have happened since a global flood and before their extinction.  This is an absolutely fantastic rate of mutation and adaptive selection of those mutations.  No evolutionists would dream of such incredible rates of divergence and change in organisms as is proposed by creationists.  Young earth creationists so casually toss out hypotheses about the diversification of hundreds of species from a single founding pair of the “kind” but I have yet to see the genetic models to accompany those assertions.  The rates of change are absurd and not reflected in any known genetic mechanism.

We have only explored the moa from New Zealand but I mentioned that there are many other species of flightless ratite birds found recorded in the fossil record.   All of these fossils represent birds that young earth creationists would propose lived after the flood.  It just stuck me as I was thinking about their evolutionary model of species formation from kinds that the pattern of diversity that we see in the fossil record is exactly the opposite of what we would predict from their model.  If pairs of “kinds” stepped off the ark and from there began to populate the world and began to speciate at the same time, wouldn’t we expect that the we should find the greatest diversity of species today?   What we see with these flightless birds and I think most other groups is that we can identify far more extinct species than we have species alive today or even alive in the last thousand years.  If speciation can take place at such a rapid pace why then do we not see both continued rapid speciation today and why are is there such a tremendous amount of diversity in the fossil record?  Because of  genetic bottlenecking by Noah’s ark creationists should expect that even if there was a high rate of mutation after the flood (a completely ad hoc hypothesis BTW), that initial speciation rates would not be high and would increase over time as greater genetic diversity was obtained in large populations.  Rather, what they seem to be saying is that immediate rapid species formation occurred and then locked species into their current configurations with little change in species being observed today.   This makes no genetic sense to me.

 

Comments

  1. Excellent article, i think i might borrow some of ur knowledge :-).

    Great post btw.

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  2. Flightless birds. Did these defenseless creatures evolve? Or were these tasty things created for us? You don’t think they were? We are just super super lucky they evolved and we can taste chicken right? Why do you assume the birds flew there? I am fairly sure man brought them there. They all look like chickens and turkeys to me, basic farm fowl. The ark is reported to have many birds so of course in any interpretation it would have included some type of chicken. These are those birds. Do they seem different to you because they are more colorful? So are tuna fish and everything else when you go to the tropics. This does not indicate evolution but rather that dna is intelligently designed to adapt to different environments in different ways.

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    • Typically flightless birds are found on islands where there are no predators. So you can call them defenseless but if you don’t need defenses then it doesn’t matter so yet they can certainly evolve that way. Again, you are just making stuff hopefully and ignoring a lot of things based on very solid evidence. New Zeeland and many other small islands definitely had flightless bird on them before man arrived. It is because of mans arrival that most flightless birds are extinct. Even if they didn’t hunt them themselves, man brought snakes to islands which then ate the eggs of the flightless birds nests on the ground. So those birds were there but how did they get there then. Almost certainly by flying there. So they have lost the ability to fly. There are plenty of bird that have been kept in captivity for hundreds of years that have not lost their ability to fly so its not something that just happens overnight. You can suggest DNA that can adapt and I would agree but there is no known mechanism for organisms adapting their DNA in such short periods of time. You will have to suggest that we don’t know anything about DNA works and need to discover a whole new form of genetics in order to believe that canines, cats, whales etc all have adapted to this world in only 4000 years.

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