This is an interesting idea. Do you have any recommended references on this subject. I agree common descent has occurred the question is how much. The study of flightless birds (paleognaths) is also interesting and relevant to Australia (kiwi’s). How did these birds get placed all over the globe?
Land animals got all over the globe. Why would paleognaths find it more difficult?
So how is it that I can raise the issue of Marsupial and Placental mammals, with no comment from you, while you raise the issue of the Kiwi bird?
FIRST: I think you will find that the Kiwi bird is a denizen of New Zealand, rather than Australia.
SECOND: Kiwi’s are not found all over the globe.
THIRD: Part of the question of their distribution and evolution includes the part of their history when the ancestral population of Kiwi could fly.
So . . . are you ready to discuss flightless mammals in Australia?
Advent blessings to you
The interesting issue is the age of the species sharing a common ancestor. If they are old enough then being dispersed all over the world is easier to explain based on continents land masses being connected. The paleognaths are believed to share a common ancestor and are too young have found homes globally without having to travel over large stretches of ocean. The current theory is multiple losses of flight. In my mind this raises all kinds of questions. If you are interested I can supply a paper that takes this into detail.
I am ready and look forward to your argument.
The paragraph below comes from another thread. It focuses on the oddities of Australia’s mammals.
4) Then we have the Australian populations of mammals which until relatively recently, were all marsupials (the placental mammals that once lived there went extinct long ago). Apparently the marsupials in Australia, being isolated from placental evolution going on in the rest of the world, was protected from competition from the more robust placental mammals. And in the rest of the planet, only a handful of marsupials were able to compete against the other mammals (like the possum).
5) The YEC explanation for this pattern (Australian Marsupials vs. Placentals beyond Australia) does not exist. YEC’s would essentially have to propose the following sequence:
a) The Great Flood kills all animals in Australia and elsewhere.
b) When the animals are released from the Ark, the marsupial mammals (even the slow ones) manage to travel directly to Australia before it separates from the main continent…
c) … while the placental mammals completely ignore Australia for generations.
This, of course, is an impossible scenario.
ORIGINALLY PART OF THIS THREAD:
Sure, post a link, I’d find it interesting.
Here it is.
Current Issue > vol. 105 no. 36 > John Harshman, 13462–13467, doi: 10.1073/pnas.0803242105
Phylogenomic evidence for multiple losses of flight in ratite birds
So based on this story I would assume it is backed up by global marsupial fossil records that back up this claim
The young earth story is also certainly problematic.
Do you believe this is evidence of special creation?
I want to do some more reading on this subject. Thanks so much.
I think you have misunderstood the biology here. Prior to the evidence of continental drift, ornithologists were indeed puzzled by the appearance of paleognaths on multiple continents:
Most recent studies have also strongly supported ratite monophyly (9–12, 14), suggesting a single loss of flight in their common ancestor. This puzzled biogeographers for more than a century, because ratites would be unable to achieve their current distribution on southern land masses if their common ancestor was flightless.
However, the puzzlement ended when continental drift became understood:
Continental drift provided a compelling solution. No longer was it necessary to imagine giant flightless birds crossing vast oceans; they could have rafted to their current distributions on fragments of the Earth’s crust (15). Although the proposed phyletic branching patterns for ratites do not correspond perfectly to the order of separation of land masses during the breakup of Gondwana, the convenient serendipity of continental drift as a mechanistic explanation for ratite distribution proved irresistible (10, 11, 14, 16), and it stands today as a textbook example of vicariance biogeography (17, 18).
So ornithologists weren’t scratching their heads, flapping their arms, muttering “We just can’t figure this out, how did those emus and ostriches and rheas scatter to the four winds? Oh, it must have been convergent evolution!” No, they had a highly plausible solution (continental drift) that did not require convergent evolution.
Very recently, the paper you cited announced that, based on analysis of 20 genes, there are three phyla among the paleognaths. It was only the DNA evidence that suggested that convergent evolution explained the distribution of flightlessness among paleognaths.
Convergent evolution is a concept that has been around for almost a century and a half. I do not see anything unscientific about the idea that similar natural selection pressures would favor similar adaptations. It almost seems trivial.
Warm Advent wishes,
I am trying to understand your argument. There are two solutions you mentioned which are convergent evolution and continental drift. Are you saying these are two strong reasons for paleognath global distribution we observe and should support a common ancestor claim among paleognaths?
Do you consider universal common descent as an a priori assumption in your analysis?
How do you account for the divergence of the ostrich DNA in the Harshman et al paper?
The story of Australia is inconsistent with Every scenario… except an Old Earth and Descent from a Common Ancestor.
It doesn’t jibe with YEC and makes for pretty poor corroboration with Special Creation in an Old Earth context.
Most Marsupials outside of Australia were ruined by the greater survivability of placental mammals.
Marsupials enjoyed success in New Zealand and Australia because… for reasons inexplicable to YEC’s… did not become swamped by Placental Mammals.
Natural Selection is not random, but Variation is random.
While I agree that Natural Selection is not random, but determinative. If Natural Selection is determinative, then Evolution is determinative. If evolution is determinative, then it should be evident which direction it is moving.
MS evolutionary science has failed to identify this direction. Has EC?
It is hard to say that evolution is not random, if there Is no evidence of evolutionary direction.
Do you believe this process of descent from a common ancestor is solely from isolated populations and reproduction?
Hardly. My use of Australia is not as a model, but as convincing evidence that millions of years and isolation can demonstrate many a prediction of Evolution … without excluding the possibility that God was involved.
Australia does show YEC as not credible, and Old Earth Special Creation as a most strange “beast” indeed.
According to ornithologists, the paleognaths are about 100M years old, and their dispersion is readily explainable by vicariance as Gondwana split apart. The problem is that this easy explanation is not consistent with genomic evidence. It was the genomic evidence, not the “youth” of the paleognaths, which compelled Hashman’s team to favor three loss of flight events within the ratites. I agree with Harshman’s decision to trust the genomic evidence. Not that my vote counts for much.
Absolutely not! Here are two very strong reasons to ascribe common ancestry to the ratites:
(1) The shared 8 base pair deletion in ALDOB (see Figure 3)
(2) The machine learning hierarchical clustering analysis, which yields a cladogram in which ratites have common ancestry.
I would like to take a moment to point out something very important: every day of the week, courts all across the globe uses the analysis of genetic similarities and differences to make inferences about common ancestry. That’s how paternity lawsuits get settled. That’s how distant nephews of great-grandsons lay successful claim to a share of an intestate bilionaire’s estate. It’s how executors of estates refute the false claims of purported distant nephews of great-grandsons. It’s how we know that Thomas Jefferson was the father of the children of a Jefferson slave, Sally Heming. You measure the genomic differences and similarities, apply the mutation/inheritance model, and infer (or disprove) common ancestry.
My sister-in-law’s 23andme analysis turned up a big surprise: she (and my wife, we all presume) had about 1% Middle Eastern ancestry and 8% Berber. The whole family was initially stunned; my mother-in-law’s family had claimed Castilian roots, but not Middle Eastern and North African! Then we remembered: the Arabs conquered Berber North Africa. Then the Moors conquered most of Spain (Andalusia) and ruled it for centuries. That’s how significant amounts of Middle Eastern and Berber ancestry turned up in the genetic analysis.
Harshman’s analysis of paleognaths, volant tinamous, neognaths and crocodilians is based on the same principles and techniques that 23andme uses for human genetic analysis.
Harshman offers 2 possible explanations:
(1) Vicariance: “Africa was the first piece of Gondwana to separate, and the African ostriches are the first clade to diverge.”
(2) Incomplete lineage sorting.
Given the paucity of fossil evidence related to the ratites, it is not possible to make a determination with 100% confidence. Harshman seems to favor ILS, however.
I would welcome any feedback from real biologists if I have misunderstood anything or explained anything poorly. I’m pretty good with statistics and building ML clustering models, but I could be a little fuzzy on their application to evolutionary biology.
Good questions, Bill. Warm Advent wishes!
 Some of Jefferson’s modern-day descendants point out that the genomic analysis would also be consistent with Thomas’ brother being the father of Heming’s kids. However, the initial case for Thomas Jefferson’s role was based on the fact that each of Sally’s children were born about 9 months after one of Thomas’ visits to the estate.
Hi @Billcole -
A recent article in the Science section of the NY Times provides further evidence of the power of machine learning genomic clustering analysis. Munshi-South, et al., trying to understand the origins of NYC’s rat population, analyzed DNA samples from 314 rats from 31 cities. Read about their conclusions here. (Browse in privacy/incognito mode if you have trouble accessing the article.)
@gbrooks9 you were replying to a comment about natural selection as though the commenter were talking about mutation. Yes mutation is unguided and so can do damage to functional systems. But natural selection counteracts that by discarding the changes that are harmful and promoting those changes that are useful.
This is what is meant by “Natural selection isn’t random.”
Natural selection favours the “noise” that increases fitness and filters out the “noise” that decreases fitness.
I love it when conversations here begin to revolve around actual scientific findings.
Actually, all I was pointing out is that humans frequently refer to something as “random” that is 100% lawful…
or in reference to things that look random to them, but which are not random to God.
I recommend being very careful trying to prove something just because you want to call something random or non-random.