It is the overall model that biologists use to describe how organisms changed over time and continue to change. It is made up of hundreds of thousands of papers, and even includes the mechanisms described by the Extended Evolutionary Synthesis group. It is a lot like Quantum Theory or the Germ Theory of Disease (and those are not called Plankism or Kochism, by the way). Another good parallel is geology, where there are tons of different mechanisms that have had different effects on how the Earth has changed over time (and no one calls it Lyellism, by the way).
Can you describe the model?
No more so than I can explain the geologic model in an online forum. Entire books have been written on the subject, and they still didn’t include everything. The big hitters are random mutations, selection, neutral drift, and speciation. Just within speciation we could write pages about the relative contributions of phyletic gradualism and cladogenesis, as well as the importance of different modes of speciation like sympatric or allopatric speciation.
I assume you would include common descent here or is that included in speciation?
I will assume random mutation means all type of possible changes that are not deterministic ie gene duplication SNPS frame shifts HGT etc.
Is speciation these mechanisms working independently on separate populations?
To be clearer, I would break it down into vertical and horizontal inheritance. Universal Common Descent is a bit vague for my liking since there could have been some weird lines of inheritance for different aspects of biology.
Mutations refers to heritable changes in DNA sequence, and random refers to the consensus finding that there is no detectable connection between what the organism needs in a specific environment and the mutations it gets.
Speciation is more about population dynamics and gene flow. If there is a barrier to gene flow between two sexually reproducing populations then you can have different mutations accumulating in each population which causes divergence of genomes over time. There can also be effects from hybridization after the species have begun to diverge. We can also include processes like incomplete lineage sorting within speciation and in combination with population dynamics.
Can you briefly explain this term?
It is unlikely that all alleles that exist in a population will make it into both lineages during a speciation (splitting) event.
I don’t know what that means.
You accused me, mistakenly, of quote mining. You suggested, mistakenly, that I had merely done a Google query. So from my perspective, you said far too much. Far more than you had warrant to say. I request that you attempt to do better in the future.
Yet it appears all humans share the same gene set.
Which has nothing to do with Rumraken’s point about each group of a splitting population (i.e undergoing speciation) not retaining all the alleles of the entire population.
Can you expand on this. What is the level of variation?
Humans Have Different Sets of Genes
Im missing the point of this. Just because the theory of evolution that had the names “darwinian” then “neo darwinian” and now “evolution science” that all relate to how the theory has evolved over the years does not warrant reasoning that the naturalistic methodology embedded in all three is true. What you are explaining is circular and illogical. In fact, the failures of previous models could point to the failure of the very foundation of the theories.
Just bc we see evidence of species evolving in some degree does not warrant that naturalism is true which science is 100% dependent upon.
So what if the theory evolves a million more times bc of failures of previous models where the backbone of naturalism is still clung to? I believe that it is a real possibility, knowing human nature, that a million failures of the natural explaining life may not alter the human mind towards design if design is not permitted due to the philosophical bend. If the evidence all points to design, the scientist bent on naturalism due to tendency towards atheism and not theism may choose to close his mind to this. Why Christians give such license to take such pathway is strange. I as a Christian stand with exactly what Ro 1 says: we see creation that insinuates a purposeful plan and design was followed to create, so we KNOW a Creator exists, therefore man is without excuse. Both the philosophy embedded in theistic evolution and evolutionary creationism inject mind numbing alternative philosophies sadly blind people from the reality of a living God (or potential reality to those seeking) who is the best explanation of the existence of mass energy and living things.
If scientific, empirical, evidence starts pointing towards design (how are you going to prove design when it comes to biological constructs anyway?) then I’m sure scientists are gonna say ‘it’s designed’.
You and I have mutant versions, as in alleles, of our genes we don’t share.
When gene sets are compared like in Venn diagrams gene sets within species appear to be the same. How true is that? If we did a comparison between humans what would the Venn diagram look like?
That is true but not really directly relevant to what we have been discussing.
The method used to infer incomplete lineages sorting can’t be directly compared to the one used to make the Venn diagram you like so much.
Incomplete lineage sorting is about the branching orders of phylogenetic trees that can be inferred from different shared orthologous genes. So if species H, G, C share say ten genes, and seven of these ten genes imply a relationship ((H, C)G), as in H and C are more closely related according to this gene. But then if the remaining three genes yield a phylogenetic tree that implies the relationship ((H, G)C), then incomplete lineage sorting is an explanation for how you could end up having some conflicting gene trees in this fashion.
The Venn diagram is constructed by searching for orthologous genes between species. Here the variations in branching orders from different genes is not considered at all. Only the method of detecting orthologous genes is. So it is the presence or absence of orthologous genes that matters in the Venn diagram, not the individual branching orders of phylogenetic trees inferred from those genes.
If we did a comparison between humans what would the Venn diagram look like?
We would still find that some times genes aren’t shared between different individuals. Some humans are born with significant deletions in their chromosomes, many of which which can lead to all sorts of congenital anomalies, metabolic diseases and so on.
Thanks Rum. What is your explanation of why this pattern occurs. Is it gene loss?
The explanation for incomplete lineage sorting is deep coalescence–i.e., the orthologous gene copies coalesce (trace their ancestry back to a single lineage) prior to when the species split. If population sizes are large and/or there is not a lot of time between successive speciation events, shared genetic variants may persist even after speciation, and when an allele eventually does get fixed in each species the gene genealogy will not necessarily be the same as the species tree.
It’s easier to understand visually. Just Google incomplete lineage sorting or deep coalescence and take a look at some of the diagrams.