Comment on Supreme Court Decision on Church Employment Case by Eddie.
Cavalier-Smith T. 2002. The phagotrophic origin of eukaryotes and phylogenetic classification of Protozoa. International Journal of Systematic and Evolutionary Microbiology 52(2):297-354. Abstract: Eukaryotes and archaebacteria form the clade neomura and are sisters, as shown decisively by genes fragmented only in archaebacteria and by many sequence trees. This sisterhood refutes all theories that eukaryotes originated by merging an archaebacterium and an alpha-proteobacterium, which also fail to account for numerous features shared specifically by eukaryotes and actinobacteria. I revise the phagotrophy theory of eukaryote origins by arguing that the essentially autogenous origins of most eukaryotic cell properties (phagotrophy, endomembrane system including peroxisomes, cytoskeleton, nucleus, mitosis and sex) partially overlapped and were synergistic with the symbiogenetic origin of mitochondria from an alpha-proteobacterium. These radical innovations occurred in a derivative of the neomuran common ancestor, which itself had evolved immediately prior to the divergence of eukaryotes and archaebacteria by drastic alterations to its eubacterial ancestor, an actinobacterial posibacterium able to make sterols, by replacing murein peptidoglycan by N-linked glycoproteins and a multitude of other shared neomuran novelties. The conversion of the rigid neomuran wall into a flexible surface coat and the associated origin of phagotrophy were instrumental in the evolution of the endomembrane system, cytoskeleton, nuclear organization and division and sexual life-cycles. Cilia evolved not by symbiogenesis but by autogenous specialization of the cytoskeleton. I argue that the ancestral eukaryote was uniciliate with a single centriole (unikont) and a simple centrosomal cone of microtubules, as in the aerobic amoebozoan zooflagellate Phalansterium. I infer the root of the eukaryote tree at the divergence between opisthokonts (animals, Choanozoa, fungi) with a single posterior cilium and all other eukaryotes, designated ‘anterokonts’ because of the ancestral presence of an anterior cilium. Anterokonts comprise the Amoebozoa, which may be ancestrally unikont, and a vast ancestrally biciliate clade, named ‘bikonts’. The apparently conflicting rRNA and protein trees can be reconciled with each other and this ultrastructural interpretation if long-branch distortions, some mechanistically explicable, are allowed for. Bikonts comprise two groups: corticoflagellates, with a younger anterior cilium, no centrosomal cone and ancestrally a semi-rigid cell cortex with a microtubular band on either side of the posterior mature centriole; and Rhizaria [a new infrakingdom comprising Cercozoa (now including Ascetosporea classis nov.), Retaria phylum nov., Heliozoa and Apusozoa phylum nov.], having a centrosomal cone or radiating microtubules and two microtubular roots and a soft surface, frequently with reticulopodia. Corticoflagellates comprise photokaryotes (Plantae and chromalveolates, both ancestrally with cortical alveoli) and Excavata (a new protozoan infrakingdom comprising Loukozoa, Discicristata and Archezoa, ancestrally with three microtubular roots). All basal eukaryotic radiations were of mitochondrial aerobes; hydrogenosomes evolved polyphyletically from mitochondria long afterwards, the persistence of their double envelope long after their genomes disappeared being a striking instance of membrane heredity. I discuss the relationship between the 13 protozoan phyla recognized here and revise higher protozoan classification by updating as subkingdoms Lankester’s 1878 division of Protozoa into Corticata (Excavata, Alveolata; with prominent cortical microtubules and ancestrally localized cytostome–the Parabasalia probably secondarily internalized the cytoskeleton) and Gymnomyxa [infrakingdoms Sarcomastigota (Choanozoa, Amoebozoa) and Rhizaria; both ancestrally with a non-cortical cytoskeleton of radiating singlet microtubules and a relatively soft cell surface with diffused feeding]. As the eukaryote root almost certainly lies within Gymnomyxa, probably among the Sarcomastigota, Corticata are derived. Following the single symbiogenetic origin of chloroplasts in a corticoflagellate host with cortical alveoli, this ancestral plant radiated rapidly into glaucophytes, green plants and red algae. Secondary symbiogeneses subsequently transferred plastids laterally into different hosts, making yet more complex cell chimaeras–probably only thrice: from a red alga to the corticoflagellate ancestor of chromalveolates (Chromista plus Alveolata), from green algae to a secondarily uniciliate cercozoan to form chlorarachneans and independently to a biciliate excavate to yield photosynthetic euglenoids. Tertiary symbiogenesis involving eukaryotic algal symbionts replaced peridinin-containing plastids in two or three dinoflagellate lineages, but yielded no major novel groups. The origin and well-resolved primary bifurcation of eukaryotes probably occurred in the Cryogenian Period, about 850 million years ago, much more recently than suggested by unwarranted backward extrapolations of molecular ‘clocks’ or dubious interpretations as ‘eukaryotic’ of earlier large microbial fossils or still more ancient steranes. The origin of chloroplasts and the symbiogenetic incorporation of a red alga into a corticoflagellate to create chromalveolates may both have occurred in a big bang after the Varangerian snowball Earth melted about 580 million years ago, thereby stimulating the ensuing Cambrian explosion of animals and protists in the form of simultaneous, poorly resolved opisthokont and anterokont radiations.
The abstract is super long. The author states: “I revise the phagotrophy theory of eukaryote origins by arguing that the essentially autogenous origins of most eukaryotic cell properties (phagotrophy, endomembrane system including peroxisomes, cytoskeleton, nucleus, mitosis and sex) partially overlapped and were synergistic with the symbiogenetic origin of mitochondria from an alpha-proteobacterium.” Nice hypothesis, but not much certainty.
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Eddie Also Commented
Supreme Court Decision on Church Employment Case
Interesting banter. If conservative SDAs can’t agree on the details of something as vital as how a person obtains salvation, how can all members ever be expected to agree on the details of less important matters such as how and when the creation occurred?
Supreme Court Decision on Church Employment Case
Mack Ramsy: the flood has multiple problems such as number of animals, zoological necessities, sustainable ecology, the coming and going of all the water, the mysterious olive leaf, extant archaeological evidence predating the flood, lack of geological evidence for a truly global flood, the diversity of people and animals, the time it takes to spread from Ararat to the rest of the world, etc.
Mack, I agree that the flood has multiple problems for YECs and YLCs, but geologists pretty much agree that there is substantial evidence for not one but two truly global floods, and according to their data the first nearly covered all of the continents at a time when no high mountains existed:
http://en.wikipedia.org/wiki/File:Phanerozoic_Sea_Level.png
I’m not sure how YECs and YLCs would interpret the evidence for TWO major floods, but the often-repeated assertion by SDA intellectuals that there is no evidence for a worldwide flood is simply untrue.
Supreme Court Decision on Church Employment Case
Ken: Wasn’t Jesus’s message about being humble and loving one’s fellow man rather than being self rightgeous?
Amen brother Ken!
Recent Comments by Eddie
Changing the Wording of Adventist Fundamental Belief #6 on Creation
SDA Bio Prof: The Bible makes multiple falsifiable prophecies about Nebuchadnezzar conquering Egypt, yet history never records it happening. Does this mean the Bible is effectively falsified?
Sean Pitman: Egyptians had a strong tendency not to record their losses… only their victories.
Sean, does that mean YOU personally believe Babylon conquered Egypt, just as predicted by two prophets? In the absence of any empirical evidence? If the Egyptians didn’t record their losses, why wouldn’t the Babylonians have recorded such a stunning victory?
Southern Adventist University opens Origins Exhibit
Holly Pham: One of the things that has always concerned me is that, according to what I’ve read, birds and reptiles have completely different forms of respiratory systems (flow-through vs. bellows) How is this explained by evolutionists?
Evidence from the vertebrae of non-avian theropod dinosaurs suggests that they, too, possessed unidirectional flow-through ventilation of the lungs. So, according to evolutionary theory, it evolved first in “primitive” non-avian theropods rather than in birds, and comprises one of many shared derived characters supposedly linking birds with more “advanced” theropods. However, I don’t think there is any evidence or even a hypothesis for a step-by-step process of HOW it evolved. Here is a reference:
http://www.ohio.edu/people/ridgely/OconnorClaessensairsacs.pdf
Southern Adventist University opens Origins Exhibit
@Bob Helm: Bob, if you send me an e-mail at sdabioprof2@gmail.com I will send you a pdf file of a 1991 article published by Chatterjee in Philosophical Transactions of the Royal Society B 332:277-342, titled “Cranial anatomy and relationships of a new Triassic bird from Texas.”
Curiously his description is based only on cranial anatomy. I don’t think he ever published an analysis of its postcranial anatomy.
Southern Adventist University opens Origins Exhibit
David Read: Eddie, ecological zonation will yield the same basic order that you’re pointing to: invertebrates appear before vertebrates; fish appear before amphibians; amphibians appear before reptiles; reptiles appear before mammals; reptiles appear before birds, etc.
It could, and it’s the best creationist explanation, but it doesn’t explain why flowering plants were absent from lowland forests. Or why so many land plants appeared before mangroves, which today occur strictly in the intertidal zone. Or why no pre-flood humans have been found. Or, if Sean is correct that the flood ended at the K-T boundary, why many modern groups of birds and mammals (including marine mammals) which first appear during the Tertiary were not buried by the flood.
David Read: The fact that something appears before something else in the fossil record is not proof than anything evolved into anything else.
True.
David Read: You seem to be complaining that God has not made the fossil evidence compulsory, i.e., so clear that no reasonable person can possibly doubt it. And if God hasn’t made the evidence skeptic-proof, then the skeptic is God’s fault, God is responsible for the skeptic.
I’m not complaining. I’m merely pointing out that the evidence can be interpreted in different ways by honest people. And I’m relieved to see that even you don’t think the evidence is crystal clear.
David Read: Only people of faith can be saved, that is, only people who are willing to trust God and put away doubts can be saved.
I agree.
Southern Adventist University opens Origins Exhibit
David Read: Those tracks are so obviously bird tracks that the fact that some scientists want to assign them to “birdlike theropods” is itself a very useful teaching tool as to how the model creates the data.
David Read: That the model actually creates the data is one of the hardest concepts to get across, not only to lay people but even to the scientists themselves.
How does the model affect the data? Data don’t change and they shouldn’t change. It’s the interpretation, not the data, that is affected by the model.
