Those who believe God created the rich variety of life on earth, entity by entity, would be inclined to say, look how it all fits together, balanced and sustainable! Those same considerations apply in naturalistic ecology. Land varies by climate, altitude, seasonality, water flow, geological features, and degrees of isolation which will drive adaptation in various directions. Likewise the oceans feature blackened depths, sunlight surface waters, mega-currents, estuaries, and tidal zones. The exploitation of the rich variety of niches favors finer and finer degrees of specialization, both of vegetation and animals. Adding predation and symbiotic relationships amplifies specialization and you arrive at the tapestry of the history of life on earth.
The is a difference, however, in that commonality of structure found in nature, is inherent in common descent. An ecological niche may provide an opportunity, but with common descent, you can only adapt what you already have, so you would expect to find nested hierarchies, kludgy compromises, and vestigial anatomies, as existing features are adapted. If God created each entity individually, common design becomes a arbitrary constraint on creation which looks less and less like creation of platonic ideal creatures, and more and more like built in age from DNA through to flesh and bones.
swamidass
(S. Joshua Swamidass)
Split this topic
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Ok, I give up, what is a YLC? Its not a term we use in New Zealand.I looked on wikipedia and the most relevant seemed to be Young Liberals of Canada? YLC - Wikipedia
Young Life Creationist. @r_speir sometimes thinks that the earth and universe are old but life is young. It’s a self-contradictory belief, but that doesn’t stop him. @stcordova has sometimes taken this position too. It’s impossible to get either of them to support that claim.
It’s not just a backbone. It’s a host of other morphological and molecular characteristics that fit together into a single nested hierarchy. Just one wouldn’t show anything. Consider the dorsal, hollow nerve cord, notochord, pharyngeal slits, iodine-binding cells in the floor of the pharynx, two sets of paired fins, hemoglobin, etc., all arranged in that nested hierarchy.
Aren’t those all characteristics above the vertebrate line? I am asking about the vertebrate line. Your hierarchies get broader and broader causing you to conclude relatedness and common ancestry. How do you know for sure that they should be that broad at the bottom?
Above and below, regardless of what you mean by “above”. That’s how nested hierarchies work: lots of characters at various levels. I could go on listing characters.
I do not understand the question. Could you rephrase?
The picture is not complete, and probably never will be. If you go back to the Cambrian, the gaps do get larger and so some proposed descents are more suggestive than definitive. It helps that new early Cambian discoveries near the Burgess and China are revealing troves of new specimens.
That’s science journalism/university press release hype. No scientist takes it seriously. And in fact you should discount any claims of direct ancestry in the fossil record, since there’s absolutely no way to tell. What we can actually determine are cladistic relationships, i.e. that nested hierarchy we’ve been talking about.
I will address gaps later…maybe. My point was your broad base. I can construct a pictograph of any and all animals such that if I make the base broad enough, they all appear to be related.
I can blur a picture to the point where you can’t tell what is in the image. This isn’t a valid reason for throwing out all photographs as evidence. Resolution matters for pictures, and it matters for phylogenies.
I find the evidence, say for whales being descended from land mammals, pretty convincing; even if all you had to go on was the anatomy of living cetaceans alone. I do not find the basis there to overly broad at all, you may see it differently. But the idea of whale descent also has very solid support from the fossil record, as well as the dating of geology which embeds those fossils. The consilience of evidence supports the outline of the tree of life.
Don’t forget the molecular evidence, which was the first to place whales within artiodactyls. The fossil evidence for that didn’t come along until a few years later.