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I was discussing a known rapid one-gen "macro" evolution as a possible response to the creationist claim that we NEVER see "macro" changes in species, and the implications for the specimen's chances for successfully passing on that mutation.
(December 19, 2016 at 7:17 am)Gawdzilla Sama Wrote: I was discussing a known rapid one-gen "macro" evolution as a possible response to the creationist claim that we NEVER see "macro" changes in species, and the implications for the specimen's chances for successfully passing on that mutation.
Unfortunately, that's not highly likely. Your 2-headed cow example is a good one as gross mutations can & do occur. In the main though, they're likely to confer little/no advantage but that doesn't mean that they can't; it all depends on environmental & social selection pressures and if they're favourable, the mutation is passed and the allele frequency increases. However if you think of things the other way round, you get a better argument. I assume you've heard of recidivisms? Sometimes humans are born with tails because we still have the genes within us and sometimes random mutations will result in expression of such genes when normally they wouldn't. That's a perfect demonstration of 'macro' evolution.
(December 19, 2016 at 7:17 am)Gawdzilla Sama Wrote: I was discussing a known rapid one-gen "macro" evolution as a possible response to the creationist claim that we NEVER see "macro" changes in species, and the implications for the specimen's chances for successfully passing on that mutation.
You want Hyla Versicolor then, the Gray Tree Frog. It's an American frog that's largely identical to the Cope's Gray Tree Frog, except that the latter is diploid, and the former is tetraploid. Over the course of one or two generations, Hyla Versicolor evolved a double chromosome set that classifies is as an entirely new species. If literally doubling your chromosome count doesn't qualify as a macro change, I don't know what does.
Unless, of course, "macro" changes are supposed to be obvious, outward appearance changes, which only really bespeaks a superficial understanding of biology. If you're being asked for a crocoduck, then you're being asked for evidence of chimera-ism, not evolution. If immense, baseline genetic changes that fundamentally alter the species you're in don't count, then it's possible, just saying, that creationists are just looking for reasons not to be pleased and nothing would satisfy their conditions.
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(December 19, 2016 at 7:17 am)Gawdzilla Sama Wrote: I was discussing a known rapid one-gen "macro" evolution as a possible response to the creationist claim that we NEVER see "macro" changes in species, and the implications for the specimen's chances for successfully passing on that mutation.
Unfortunately, that's not highly likely. Your 2-headed cow example is a good one as gross mutations can & do occur. In the main though, they're likely to confer little/no advantage but that doesn't mean that they can't; it all depends on environmental & social selection pressures and if they're favourable, the mutation is passed and the allele frequency increases. However if you think of things the other way round, you get a better argument. I assume you've heard of recidivisms? Sometimes humans are born with tails because we still have the genes within us and sometimes random mutations will result in expression of such genes when normally they wouldn't. That's a perfect demonstration of 'macro' evolution.
I don't expect to convert creationists, of course, but I never hoped for that. I wanted to have a handy counter to their claim for the fence sitters.
(December 19, 2016 at 4:27 am)downbeatplumb Wrote:
(December 19, 2016 at 1:12 am)RoadRunner79 Wrote: How did you come to that conclusion? I don't see the multiplication and addition of micro + time resulting in macro... what is your evidence or reasoning for this claim?
Also, in most of the fossil record we see either very small differences, over very large periods of time, and fairly large changes over relatively short periods of time. How do you account for this as you have defined things here?
That would be down to the evolutionary pressures, if the environment favours the current body it does not change much.
But at other times the environment changes or another creature starts to invade the territory or lady squid start liking men squid with extra large tentacles.
Quote:Developmental research in 2004 found that bone morphogenetic protein 4 (BMP4), and its differential expression during development, resulted in variation of beak size and shape among finches. BMP4 acts in the developing embryo to lay down skeletal features, including the beak.[28] The same group showed that the development of the different beak shapes in Darwin's finches are also influenced by slightly different timing and spatial expressions of a gene called calmodulin (CaM).[29]Calmodulin acts in a similar way to BMP4, affecting some of the features of beak growth. The authors suggest that changes in the temporal and spatial expression of these two factors are possible developmental controls of beak morphology. In a recent study genome sequencing revealed a 240 kilobase haplotype encompassing the ALX1 gene that encodes a transcription factor affecting craniofacial development is strongly associated with beak shape diversity
So sometimes subtle tweeks can exert large influences on body or in this case beak shape and will of course be due to evolution proceses.
Quote:During the survey voyage ofHMS Beagle, Darwin was unaware of the significance of the birds of the Galápagos. He had learned how to preserve bird specimens while at the University of Edinburgh and had been keen on shooting, but he had no expertise in ornithology and by this stage of the voyage concentrated mainly on geology.[8] In Galápagos he mostly left bird shooting to his servant Syms Covington.[9] Nonetheless, these birds were to play an important part in the inception of Darwin's theory of evolution by natural selection.
On the Galápagos Islands and afterward, Darwin thought in terms of "centres of creation" and rejected ideas concerning the transmutation of species.[10] From Henslow's teaching, he was interested in the geographical distribution of species, particularly links between species on oceanic islands and on nearby continents. On Chatham Island, he recorded that a mockingbird was similar to those he had seen in Chile, and after finding a different one on Charles Island he carefully noted where mockingbirds had been caught.[8] In contrast, he paid little attention to the finches. When examining his specimens on the way to Tahiti, Darwin noted that all of the mockingbirds on Charles Island were of one species, those from Albemarle of another, and those from James and Chatham Islands of a third. As they sailed home about nine months later, this, together with other facts, including what he had heard about Galápagos tortoises, made him wonder about the stability of species.[11][12]
Following his return from the voyage, Darwin presented the finches to the Zoological Society of London on 4 January 1837, along with other mammal and bird specimens that he had collected. The bird specimens, including the finches, were given to John Gould, the famous English ornithologist, for identification. Gould set aside his paying work and at the next meeting, on 10 January, reported that the birds from the Galápagos Islands that Darwin had thought were blackbirds, "gross-beaks" and finches were actually "a series of ground Finches which are so peculiar [as to form] an entirely new group, containing 12 species". This story made the newspapers.[13][14]
Darwin had been in Cambridge at that time. In early March, he met Gould again and for the first time got a full report on the findings, including the point that his Galápagos "wren" was another closely allied species of finch. The mockingbirds that Darwin had labelled by island were separate species rather than just varieties. Gould found more species than Darwin had expected,[15] and concluded that 25 of the 26 land birds were new and distinct forms, found nowhere else in the world but closely allied to those found on the South American continent.[14] Darwin now saw that, if the finch species were confined to individual islands, like the mockingbirds, this would help to account for the number of species on the islands, and he sought information from others on the expedition. Specimens had also been collected by Captain Robert FitzRoy, FitzRoy’s steward Harry Fuller and Darwin's servant Covington, who had labelled them by island.[16] From these, Darwin tried to reconstruct the locations from where he had collected his own specimens. The conclusions supported his idea of the transmutation of species.[14]
I agree with pretty much all of that. I would also consider it to be microevolution or natural variation. I don't believe that it explains large changes in body plan or morphology. What is the mechanism or theory, by which these types of changes occur? Or if understanding is lacking, what is the evidence, that these did occur as the story is told? We do are best to connect the dots, as evolution tells us, but what tells us, that we should be drawing these lines at all?
This highly regarded chemist says that he doesn't understand it, and seems to say that there is a distinction.
Let me tell you what goes on in the back rooms of science – with National Academy members, with Nobel Prize winners. I have sat with them, and when I get them alone, not in public – because it’s a scary thing, if you say what I just said – I say, “Do you understand all of this, where all of this came from, and how this happens?” Every time that I have sat with people who are synthetic chemists, who understand this, they go “Uh-uh. Nope.” These people are just so far off, on how to believe this stuff came together. I’ve sat with National Academy members, with Nobel Prize winners. Sometimes I will say, “Do you understand this?”And if they’re afraid to say “Yes,” they say nothing. They just stare at me, because they can’t sincerely do it.
...But about seven or eight years ago I posted on my Web site that I don’t understand. And I said, “I will buy lunch for anyone that will sit with me and explain to me evolution, and I won’t argue with you until I don’t understand something – I will ask you to clarify. But you can’t wave by and say, “This enzyme does that.” You’ve got to get down in the details of where molecules are built, for me. Nobody has come forward.
...Now, I understand microevolution, I really do. We do this all the time in the lab. I understand this. But when you have speciation changes, when you have organs changing, when you have to have concerted lines of evolution, all happening in the same place and time – not just one line – concerted lines, all at the same place, all in the same environment … this is very hard to fathom.
December 19, 2016 at 9:19 am (This post was last modified: December 19, 2016 at 9:53 am by downbeatplumb.)
Down my way we have a well respected chemist who actually runs the creationist museum in Portsmouth.
I was at an open meeting where creatoinism was discussed and it became clear that he knew a lot about chemistry but sod all about anything else.
He was quite, quite mad.
Mr Fibble mad.
(December 19, 2016 at 9:07 am)RoadRunner79 Wrote: I agree with pretty much all of that. I would also consider it to be microevolution or natural variation. I don't believe that it explains large changes in body plan or morphology. What is the mechanism or theory, by which these types of changes occur? Or if understanding is lacking, what is the evidence, that these did occur as the story is told? We do are best to connect the dots, as evolution tells us, but what tells us, that we should be drawing these lines at all?
This highly regarded chemist says that he doesn't understand it, and seems to say that there is a distinction.
Microevolution over time leads to bigger changes. Its the difference between taking one step down a road and taking many. So an accumulation of small changes leads to big cjanges eventually.
I shall explain this as though to a simple child. If everyday you put a pebble in one spot on the ground over enough time you will have a mountain of stones. Little things accumulate and there has been billions of years of evolution, which sped up exponentially when sex started.
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