The sea slug seems to fit that bill perfectly: slug has acquired plant genes and photosynthesizes. If creationism is true “Goddidit”. If evolution is true “Evolutiondidit”. Either way it’s outside the usual nest.
But George’s point, if I take him right, is that morphological taxonomy has always been based on nested hierarchies, yet is often now overturned by cladistic analysis. Forget the cars, it’s easy, and common, to make artificial categories for natural entities, and the issue is to sort the one from the other. The only decent thing I ever read by a post-modern author (Foucault, The Order of Things) deals with that in (typically opaque) depth.
I fully agree that the abiotic synthesis of RNA, DNA, and protein molecules is a very big and important question, especially when it comes to chirality. However, these questions can be answered independently of one another. What some scientists are doing is seeing if the RNA World hypothesis can even lead to life if there are RNA molecules present. It doesn’t make much sense to do all the work of figuring out how RNA molecules can be produced through abiotic processes if they can’t lead to life. Scientists are still finding new and interesting lines of research, so I don’t see the harm in letting them pursue these questions. The only way of finding out if science can answer these questions is by doing the science.
So just the sea slug was created by God?[quote=“Jon_Garvey, post:356, topic:36790”]
But George’s point, if I take him right, is that morphological taxonomy has always been based on nested hierarchies, yet is often now overturned by cladistic analysis.
How so?[quote=“Jon_Garvey, post:356, topic:36790”]
Forget the cars, it’s easy, and common, to make artificial categories for natural entities, and the issue is to sort the one from the other.
I am not forgetting cars. When you group them by shared derived features they do not produce a statistically significant phylogenetic signal. Eukaryotes do. The act of using cladistics does not guarantee that you will produce a statistically significant phylogeny for any group of objects. Human designs consistently violate a nested hierarchy, and that includes organisms that humans have designed. Therefore, there is no expectation that life should fall into a nested hierarchy unless they descended from common ancestors through the process of evolution.
This example shows precisely the opposite of “outside the usual nest,” because it can be explained* by mundane processes of gene transfer. It’s cool, no doubt, but it shows nothing more or less than this: nested hierarchies result from descent with modification, no matter what you’re talking about. Genes lie in nested hierarchies, and organisms do too, but because genes and organisms are not identical, the hierarchies can be uncoupled. That’s the whole story of sea slugs and photosynthesis.
*Note that the actual capturing of genes by sea slugs is disputed, and the evidence in favor of it is thin. But the phenomenon of lateral gene transfer is not disputed, and so the point remains that a difference between a gene tree and an organism tree is not an example of “outside the usual nest.”
BTW, the paper on why sea slug gene capture is probably wrong is a great summary of the whole sea slug saga, and it’s a fun read:
I bumped into an article about a carnivorous one celled organism that couldn’t digest a specific algae cell it swallowed … and the symbiotic of the two life forms (one inside the other) made it more resilient to food shortages.
Was I imagining that article, or are you familiar with the case?
It is a fact that entire generations of thinkers didn’t see a problem with nonexistent species. It is not a fact that a creationist principle of plenitude in some cases entails nested hierarchies. Or at least it is not a fact that has been established in this exchange, and it’s the only fact that matters for whether nested hierarchies are evidence for creationism.
I have no doubt that Linnaeus expected nested hierarchies; anyone who’s spent much time observing living things will unconsciously absorb the general pattern they fall into. But that does not tell us whether nested hierarchies follow logically from the premises of creationism or not.[quote=“Jon_Garvey, post:355, topic:36790”]
The question of non-existent species being astronomical seems par for both courses still to me: there are maybe 150K fossil species and 10m living ones. If we follow the “99% extinct” guesstimate, non-represented species in the evolutionary past would be 6.6K to 1.
I don’t know what point you’re making here. There is no expectation under evolutionary models that all possible species should ever have existed.
The existence of multiple consistent nested hierarchies, determined from different traits (genetic and morphological, or multiple independently determined genetic phylogenies) in living things greatly strengthens the case for common descent, no doubt. But I’m still objecting to the claim that even the existence of a single nested hierarchy can be considered evidence for creationism.
One example I have run across is the inverted retina found in vertebrates. Everything with a backbone, including fish, have a retina that faces backwards. However, we find forward facing retinas in groups of invertebrates, specifically in octopi, squid, and cuttlefish.
I described this arrangement to one creationist, and his response was to claim that the inverted retina was due to The Fall (i.e. expulsion from Eden). When I pointed out that this would require the sudden evolution of forward facing retinas to backwards facing retinas in every species with a backbone but none of the species without a backbone, the creationist grew silent.
I guess one could argue that God would or wouldn’t use imperfect designs, or that they were once perfect and are no longer perfect. It is also strange that God would start a nerve up in the neck, loop it through the chest and under the aorta, and then have it move back up and enervate the larynx. I guess God could have been in a jovial mood that day, so maybe not the best argument.
In the end, it really is just the distribution of shared derived characteristics which evidences evolution, regardless of how we judge the worth of those characteristics.
I don’t know what you mean by “this step-wise process,” but the GBE article I linked previously mentions that true LGT has been very rare in eukaryotic history. But the symbioses that I thought we were discussing are common. It would help if you asked a question that was a little more specific.
I dunno. In cell culture, interspecies fusions have happened zillions of times, I suspect. But we’re discussing symbiotic “fusions” that involve engulfment. Again, I really can’t tell what you’re asking. Maybe read and digest the articles I’ve posted so far.