As affirmed to me by several scientists, scientists use hedging words like “might have” to indicate that their conclusions are subject to further refinement. This does not mean their conclusions are unwarranted. You are misunderstanding their terminology. Astronomers who speak of the Big Bang, geologists who speak of plate tectonics, and biologists who speak of evolution are building on a strong empirical foundation.
You acknowledge the biology of opsins but seem to have missed the point that they fall into a nested hierarchy consistent with other evidence of evolution.
You do point out, correctly, that the origins of the apparatus that builds proteins from DNA are not explained scientifically.
I would go further and say that no scientist can explain why the universe even exists. What, or who, made physics? Scientists cannot say, just as they cannot explain the origin of the first single-celled organism.
Just because scientists cannot explain everything does not mean they cannot explain anything, however. The evolution of opsins is well understood.
I want to thank @paleomalacologist for the fine summary of paleontological support for the evolution of vision.
I presented it as an example of how of any theory is limited in its ability to explain the details of a stochastic process, yet it is not unreasonable to accept the explanatory power of such a theory.
I explained all that in detail. It was not analogous to biology, per se; instead, it was a way of discussing how scientific theories about a stochastic process operate, and what criteria are suitable for accepting or rejecting such theories.
I regret that I did not make this clearer in the original post. Does this post clear up the confusion, Craig?
I have not been following this conversation, but that caught my eye. Have you experienced any remarkable instances of God’s providence in your life, or do know anyone who has? Failing that, I would draw your attention to Maggie’s story, to please give that a perusal.
Was there any design involved? Were any natural laws broken?
One interesting question is how many changes would need to happen? Can you give me some specifics, along with the mutation rate and estimated number of generations between two species. That is one thing I never really see addressed though plenty of people use the “too many changes” argument.
I would challenge you, too, as I just did @cewoldt, above:
Have you experienced any remarkable instances of God’s providence in your life, or do know anyone who has? Failing that, I would draw your attention to Maggie’s story, to please give that a perusal.
Was there any design involved? Were any natural laws broken?
Let’s take the eye then. How did the octopus get eyes so similar to ours when it so far beneath us on the evolutionary ladder? How many steps does it take to get an eye from nothing? Remember it has to keep these independent steps, regardless of usefulness until the whole is present and working.
For something more useful, how many real changes would have to be made from ape to man? Things like hips, knees, vocal cords, hand and foot shape. Look up this article. I’ve been warned and don’t want to be seen as spamming the thread.
Ask John Mackay
APE-MAN? Man, apes and monkeys: what are the differences?
No one knows. What we do know is that the morphology of species is a direct result of the DNA sequence of their genome. We also know that the physical differences between species is due to the DNA sequence differences in their genomes. We also know that the observed processes that produce mutations in living populations was the cause of those differences, as shown by the evidence I presented above.
That’s just a bare assertion. You need to back it with evidence.
We have observations that match a known and observed natural process. In science, we call that evidence.
When you look at the details of the octopus eye it isn’t like ours. It is very different. For example, the retina faces forward in the octopus eye while the vertebrate retina faces backwards. The two eyes develop from different tissues. There are tons of differences and only a superficial similarity.
About 20 million. We are separated from chimps by 40 million mutations, so if half of those mutations occurred in each lineage then it is 20 million mutations. If you don’t think these mutations are responsible for the physical differences between humans and chimps then please tell us what is responsible for those physical differences.
I’m asking YOU the question based upon YOUR claim. You are the one you made the claim that they could “never happen in time.” So how many differences exist between various sorts of eyes and how many generations would you say exist to make those differences?
For anyone interested there is a good episode on the evolution of the eyes ( episode 68 ) by The Common Descent Podcast. They also have a blog on Wordpress with pictures, more info, and links. Really awesome resource.
I say they can’t be done. To build an eye, even from an existing eyespot that can only see light and shadow requires rebuilding the eye, the neural path to the brain and rewiring the brain itself to not only see, but to incorporate vision into every aspect of life.
I would agree with you if talking about an eye developing de novo in a higher animal. Those things have to be developed together, and of course that describes how evolution works, it is essentially describes what a nested hierarchy looks like at the organ level. Evolution works with what it has available.
Must mean that reaction to light is a pretty important thing for an organism to have in its skill set. That is pretty amazing and it would be interesting if it were not buried too far back in history to see if a tree could be made of eye types to see what the relationships are, if any, of one to the other.
Also given how many times it’s independently evolved, and went away such as with that 5 million year old cave that was sealed off with 33 species in it, shows how easy eye evolution is. It’s easy for them to evolve and it’s easy for them to go away.
I know it’s a bit off subject but that cave thing was really cool. 33 species evolved in a micro habitat for several million years including a plant that evolved to use the toxic air and turn it into a form of energy that fed other arthropods which was eaten by larger ones and they all basically lost the majority of their pigments and lost their eyes.
I’ve often wondered whether the development of primitive vision set in motion a kind of evolutionary arms race. After simple light/dark detection comes basic movement detection - the ability to track a dark void across a field of vision. Movement detection benefits both hunter and hunted as it allows predators to respond to prey movement more quickly but also prey to respond to predators too.
Movement detecting prey are able to move and survive out into the open, thus accessing new niches in terms of feeding and reproduction. Similarly, movement detecting predators are better able to hunt and thus out compete non-specialised predators, they in turn are granted to new opportunities to reproduce. As vision mutates, some predators are better able to hunt and so survive, whilst prey with better vision are better able to evade predators and thus survive. Either way, both pass on the benefit to the next generation, furthering the ‘arms race’. In both cases natural selection is working in response to emerging ecological opportunities and pressures.
Perhaps one example of this might be the large compound eyes of bees, wasps, flies, etc. that allow them to evade predators (among other things) and the equally large eyes of ambush predators like praying mantises that allow them to capture prey faster than the prey can respond to the visual information.
I’m not an expert so may be way off base here, either way, just a thought.
It is pretty amazing how developed the mantises eye sight is given how simple insect ‘brains’ are, both in terms of structure and number of neurons. Perhaps, complex vision does not require all the much of a complex nervous system after all…
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