Not sure I can manage all that detail, but I really like the development of the analogy! You could get a similar analysis with historical linguistics where percentages imply how long ago two dialects separated - but the data is more muddied with linguistics because of contact with other languages that might affect the data considerably. Presumably in genetics there aren’t the same issues of noise in the data?
Yes, one of the overlooked aspects of teaching is that a lesson doesn’t always go as you planned the first time around. I always presented better at the end of the day than at the beginning. Of course, the kids are more tired and paying less attention by then, so it’s never perfect.[quote=“Mazza_P, post:18, topic:36075”]
I am definitely having fun!
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The first prerequisite to good teaching. Enthusiasm for the subject can cover a lot of mistakes in delivery. 
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Hi Mary,
Yes, there’s still noise, such as a mutation + reversion being scored as no mutations instead of 2, but the noise is swamped by the amount of data.
One of the most important things is to emphasize that evolution doesn’t happen to individuals, only to populations.
One area where linguistics helps is in identifying when two dialects become two languages - it is tricky, which is why no one knows exactly how many languages there are in the world. You are looking for the point where it is hard for people to understand the other language - but how do you judge that? This could help people get the idea of the continuum from one species to another!
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And also the idea that evolution makes a tree, not a ladder.
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That is also a really good analogy. You could have participants read Old English, Middle English (Chaucer), early modern English (Shakespeare), and modern English. Old English is all but incomprehensible, but you can still find a few words that make sense. Middle English almost makes sense, but yet quite doesn’t. Early Modern English mostly makes sense.
Of course, no analogy is perfect. English had a lot of horizontal transfers of other languages, so it isn’t truly vertical like you see in most phylogenies. However, it might still work as something lay people can approach.
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A handy illustration to have:
http://evolution.berkeley.edu/evolibrary/images/evo/laddervstree.gif
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This very analogy is nicely illustrated in this Biologos essay by Dennis Venema which shows a particular bible verse in just such a transition.
The analogy is OK. But the picture is a non-living thing. It doesn’t have to continue to live and function from one version to the next version. With living things, they have to continue to function. Sure if the change is a foot gaining or loosing webbing, the creature just continues on and the slow change takes place in little steps.
But when a lower strata animal it to evolve to a higher animal, some internal parts would need to change and they can’t stop and wait. When you go from a reptile to a bird, a fish to an amphibian or a lower class to a mammal there needs to be a change to the heart (plumbing system) The two chambered heart with all the plumbing getting blood around the body ends up later as a three or four chambered heart. Each of these has different plumbing to move blood. This plumbing system has to keep functioning all thorough the evolution process. That kind of change is not covered by the series of pictures with some little changes from step to step.
I’m not sure your “spot the difference” analogy uniquely illustrates Biologos’ approach - in fact, I think it better aligns with my view as a skeptic of Darwinian evolution and sympathizer with the ID concepts:
I similarly recognize that an artist / designer would not simply start “from scratch” to make the new model in his “spot the difference” puzzle… while on the other hand, the differences introduced are distinct, clear, and sharp enough so that the observer can recognize it as a clear difference, not simply a minor or insignificant variation.
Thus I see an artist that started with whales, and said artist inserted a “spot the difference” variation by introducing integrated echolocation into one of his variants; or rodents, similarly, and introduced powered flight and echolocation into one of the “spot the difference” variants.
Point is, there are those Darwin skeptics like myself, that acknowledge God may well have worked out his variants using the very “start with the previous model” method your analogy suggests. Whether in his own mind, or in actual history, I have no problem with the idea that God started with a previous model, rather than introducing each variation from complete scratch.
Thus I don’t think the “spot the difference” analogy uniquely illustrates any uniqueness in BioLogos’ approach. I fear it illustrates even better my view as an ID-sympathizing Darwin skeptic. But thanks for the idea, it is a great metaphor - I hope you don’t mind but I think I will start using it to illustrate my view!
The problem is that we do see examples of comparable adaptations that did start from scratch. A good example is the vertebrate eye and the cephalopod eye. They are both camera style eyes with an aperture and lens up front and a retina in the back. However, the eyes differ greatly on how the retina forms. In vertebrates the retina faces backwards, with the nerves punching through the retina and passing in front of the light path. In cephalopods, the retina faces forward with the nerves going straight out the back of the retina. The two types of eyes even develop from different cell types. So why start from scratch for those eyes?
More importantly, why would God give things with backbones (e.g. fish, frogs, and people) all the same eye, and things without backbones (e.g. squid and octopus) a different type of eye? The only explanation that makes sense is evolution because those adaptations are lineage specific.
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If God were doing a variation of the aforementioned “spot the difference” method, then by definition he would be working with similar “lineages,” and the new introduced variations would by nature be the novel features. But the same principle can be found whenever someone is making changes from a previous model, whether in car design, computer code, or even textual criticism. It does not require a Darwinistic incremental variation.
My point was not that there would be no new features arising from scratch, quite the reverse. Rather, that God need not have designed the entire new animal from scratch. To follow the metaphor, when an artist adds a new feature to a “spot the difference” picture, the new feature itself is usually inserted from scratch… just not the entire artwork/organism.
Regardless, it is refreshing to see someone acknowledge that many of these biological features seem to appear as variations “starting from scratch”!
The fish eye and the human eye are not novel, they are homologous. If God used the same eye in both fish and humans, why not use the same in cephalopods?[quote=“Daniel_Fisher, post:33, topic:36075”]
But the same principle can be found whenever someone is making changes from a previous model, whether in car design, computer code, or even textual criticism. It does not require a Darwinistic incremental variation.
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Car designs and computer code does not fall into a nested hierarchy. Species do. That’s the difference.
Let’s take car design as our example. Let’s say that the designer of the Chevy Malibu finds a really good safety feature like an airbag. When that same designer is working on the new Chevy Camaro, why couldn’t the designer also use that same airbag in the design of the Camaro? Why would that designer only be allowed to use that airbag in the descendants of the Chevy Malibu? It makes no sense. [quote=“Daniel_Fisher, post:33, topic:36075”]
My point was not that there would be no new features arising from scratch, quite the reverse. Rather, that God need not have designed the entire new animal from scratch.
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This raises another interesting question. It seems that you are projecting your human qualities onto God. We reuse designs because it requires a lot of resources and time to start from scratch for each design. However, if God is all powerful, all knowing, and has no limits on time or resources then starting from scratch for each specially created kind would be just as easy as using previous designs. There is simply no reason that we would expect created kinds to share any features.[quote=“Daniel_Fisher, post:33, topic:36075”]
Regardless, it is refreshing to see someone acknowledge that many of these biological features seem to appear as variations “starting from scratch”!
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That’s what we would expect from evolution.
Feel free to use the illustration how you like! But I still think it works for my view because changes in spot the difference are usually very small - one pen stroke added or taken away.
The discussion below gets beyond my pay grade in biology, so I am not going to comment further. But thanks for the discussion! My view is that if I was God, I would do everything at once, or slowly so that each thing develops into other things - without the need for the odd infrequent adjustment or starting again. But thankfully I am not God, so I will let others in BioLogos figure out what actually happened!