[karajorma]

Originally posted by mikhael
Bacteria is a hard one to claim as evolution. Its one of the rare cases where organisms use each other's DNA, regardless of species. One bacteria can toss some DNA that another bacteria--unrelated--can then use.

Nonetheless evolution of bacteria can be observed under laboratory conditions where care is taken to ensure that no foreign DNA is available to cause contamination.

Originally posted by mikhael
As for micro vs macro evolution: WTF? I could no more make a distinction there than I could state, with honesty and integrity, that Creationism is a valid theory.  

I knew you couldn't. Omni was trying to say the two things were different but the point I was making is that if I can point out any incidence of evolution you wouldn't care whether it was macro or micro. Both would be equally

Originally posted by mikhael
Kara, my point was that evolution is a process that is not fractal. You can't point to a bit of evolution and say "that's evolution". You can only point at a bit and say "that contributed to the overall evolution of the species as we know it".  Kind of like when you have an accelleration curve, you differentiate it and get a speed at a given moment in time. The speed of the car doesn't really tell you anything about its accelleration, but the accelleration can tell you about its speed.

I disagree. Punctuationism states that there are actual steps in evolution and that it's not a continuous process like a curve. There are long periods when nothing happens and short ones where a lot of change occurs.

If you catch the right species at the right time you can actually find a time when a change is occuring and then you can say look evolution without needing to wait a million years for it.

That was the point I was making about the ants. The ones which make the gardens are obviously very different from those which don't yet since they are the same species they must have accumulated that change since speciation.

[mikhael]

I don't buy into punctuationism, mainly because it seems to assume a time scale small enough that statistically irrelevant variances are signifigant. Again I must reference the accelleration curve problem: while indeed my individual speed at any given point may or may not fit the proposed curve precisely, my overall accelleration does fit it reasonably well. In other words, on long enough time scales, evolution will be smooth. I'd say 4.5 billion years, plus or minus 20 million is a long enough time scale to smooth things out. Hell, even 3.5by is enough (if we go with the earliest stromatolites as the first life).

As for the bacteria study, can you show me where this has led to distinct speciation? If it doesn't result in speciation, is it really, in the end, evolution?

[karajorma]

Originally posted by mikhael
I don't buy into punctuationism, mainly because it seems to assume a time scale small enough that statistically irrelevant variances are signifigant.  

The fact is that there isn't a single evolutionary biologist who doesn't buy into some form of punctuationism. The only difference between the theories is how large the plateaus are and how short the periods of change are.

Originally posted by mikhael
As for the bacteria study, can you show me where this has led to distinct speciation?  

Yep I can. Not a bacterium in this case but I'm sure that speciation in an alga is good enough for you.

Coloniality in Chlorella vulgaris

Boraas (1983) reported the induction of multicellularity in a strain of Chlorella pyrenoidosa (since reclassified as C. vulgaris) by predation. He was growing the unicellular green alga in the first stage of a two stage continuous culture system as for food for a flagellate predator, Ochromonas sp., that was growing in the second stage. Due to the failure of a pump, flagellates washed back into the first stage. Within five days a colonial form of the Chlorella appeared. It rapidly came to dominate the culture. The colony size ranged from 4 cells to 32 cells. Eventually it stabilized at 8 cells. This colonial form has persisted in culture for about a decade. The new form has been keyed out using a number of algal taxonomic keys. They key out now as being in the genus Coelosphaerium, which is in a different family from Chlorella.


Boraas, M. E. 1983. Predator induced evolution in chemostat culture. EOS. Transactions of the American Geophysical Union. 64:1102.

If you want more than that I suspect I'm going to need to ask Fragaria to look up the paper for us.

[Bobboau]

has anyone tryed the specisation experiment I sugested with something that has a very short maturation? you say it's been done with dogs and hoarses, but they take sevral years to reach maturity, if some insect with a very fast reproduction rate was used then I think it might have a posibility of working within a human life, assumeing they were given sufficent stress.

I'm thinking doing a full environmental stress test would work, get a collony of fruit flies, sence they have a life cycle of 2 weeks, you can get thousands of generations within a single human life.

you take population A and saturate its food with sevral acidic chemicals, not enough to kill them, but enough to make them unhealthy, keep the atmosphere very dry and the food not overly moist.

population B's food gets saturated with sevral alcaline chemicals a super humid atmosphere and the food is almost desolved completely in water saturateing the botom of the enclosure.

you could also have populations with other varialbes, maybe haveing heavy exposure to petrolium chemicals, but the general idea is just to streas diferent populations diferently in hopes that it will cause cellular level evolution that causes the diferent populations to diferentiate, every year you could take a few males and females from the diferent populations and see if they are able to mate with members of the other population.

unfortunately the 2 week life cycle would ultimately be long, my estimate based mostly on fosil record secisation and life cycle lengths of the exsisting decendendts is that it takes somewere between 50,000 and 200,000 generations for a speciese to diferentiate, even assumeing the diferent hostile environments accelerated the proces by an order of magnatude (meaning it would take 5,000 generations) it would take about 350 years for the experiment to work useing fuit flys that have 14 generations per year.
in order to get a diferent species within a decade you'd need an organism capable of a new generation 10-40 times a day. and it'd need to be complex enough to reproduce via some form of sex.

[Black Wolf]

Originally posted by mikhael

As for micro vs macro evolution: WTF? I could no more make a distinction there than I could state, with honesty and integrity, that Creationism is a valid theory.

Macroevolution is somewhat different, but only in the fact that it takes specific mutations to trigger it. You need to manipulate Hox genes or alter embryonic developmennt, or some other relatively major change. At it's core though, it's all still the same stuff.

[StratComm]

Why do we have two of these threads active at once?

As I posted in the other evolution:no evolution thread, bacterial evolution is different from that of more complex organisms.  There's no denying that.  Of course, bacterial reproduction is also quite different from higher-order reproduction.  Sexual reproduction should have a fairly stabilizing and slowing effect on evolution, if just because the whole population, or at least a significant subset of it, must share genes and thus will have to be on the same evolutionary path.  (Never mind the longer life cycles and slower reproductive rates that the more complex organisms require).  Bacteria can share their DNA with other species, which means it only takes one strain of one species to develop a new trait and then every bacteria exposed to it could potentially pick it up.  But what really drives the speed of "micro-evolution" is that it really only takes one bacterial cell to undergo a mutation and all of the bacteria that arise from it will have the same mutation.  Plus, other bacteria can pick up the mutation and thus become the same strain while they are still alive (very much a difference between bacteria and multicellulars).  If that leads to a novel benefit over other bacteria of the same species, then the new strain will out-compete (and/or assimilate) the old in VERY short order.  The difference in the method of genetic transfer alone accounts for the ability to observe differentiation in human years (well, defining differentiation on bacteria is dicy anyway, since the "can it mate with subspecies x" test doesn't exactly work).  And of course there's the fact that most cells in a sexually reproducing organism don't get passed on to offspring; reproductive cells specifically (or an embrio, but only very early in development) must be the ones on the recieving end of a mutation in order to be passed on to children.  Because of the stabalizing effect of the means of reproduction (and of course the complexity of the organism) it takes millions of years to accomplish what a bacterial colony could in months, there is absolutely no reason that the same guiding forces acting on bacteria do not also apply to multicellular organisms.  A hypothesis stating otherwise carries the burden of proof, not the other way around.

[Black Wolf]

Originally posted by StratComm
Why do we have two of these threads active at once?

We don't - this one is about evolutionists disagreeing with evolutioists on points of detail within the theory. The other is more or less your bo standard HLP evolution/creation thread.

[StratComm]

Ah, I saw Omni's post, which on reading back, really doesn't fit the rest of the thread well.  My bad.  My rant can actually be transferred to the standard HLP debate thread as it's really more a matter of common sense than anything else.

[mikhael]

Originally posted by karajorma


The fact is that there isn't a single evolutionary biologist who doesn't buy into some form of punctuationism. The only difference between the theories is how large the plateaus are and how short the periods of change are.

Which ignores the fact that in the 3.5by curve, it all will tend to even out (which would be a short plateau, short period of change, for those keeping score).

Yep I can. Not a bacterium in this case but I'm sure that speciation in an alga is good enough for you.

If you want more than that I suspect I'm going to need to ask
Fragaria to look up the paper for us.

That works. Good stuff that. What about more complex organisms? Bob's insects would work (though I'm pretty sure the whole fruitfly experiment cycle, which has been repeated by every college biology student since the seventies rules out simple breeding leading to speciation).

[karajorma]

Originally posted by Bobboau
has anyone tryed the specisation experiment I sugested with something that has a very short maturation?

Yep. And it resulted in speciation too.

In a series of papers (Rice 1985, Rice and Salt 1988 and Rice and Salt 1990) Rice and Salt presented experimental evidence for the possibility of sympatric speciation. They started from the premise that whenever organisms sort themselves into the environment first and then mate locally, individuals with the same habitat preferences will necessarily mate assortatively. They established a stock population of D. melanogaster with flies collected in an orchard near Davis, California. Pupae from the culture were placed into a habitat maze. Newly emerged flies had to negotiate the maze to find food. The maze simulated several environmental gradients simultaneously. The flies had to make three choices of which way to go. The first was between light and dark (phototaxis). The second was between up and down (geotaxis). The last was between the scent of acetaldehyde and the scent of ethanol (chemotaxis). This divided the flies among eight habitats. The flies were further divided by the time of day of emergence. In total the flies were divided among 24 spatio-temporal habitats.

They next cultured two strains of flies that had chosen opposite habitats. One strain emerged early, flew upward and was attracted to dark and acetaldehyde. The other emerged late, flew downward and was attracted to light and ethanol. Pupae from these two strains were placed together in the maze. They were allowed to mate at the food site and were collected. Eye color differences between the strains allowed Rice and Salt to distinguish between the two strains. A selective penalty was imposed on flies that switched habitats. Females that switched habitats were destroyed. None of their gametes passed into the next generation. Males that switched habitats received no penalty. After 25 generations of this mating tests showed reproductive isolation between the two strains. Habitat specialization was also produced.

They next repeated the experiment without the penalty against habitat switching. The result was the same -- reproductive isolation was produced. They argued that a switching penalty is not necessary to produce reproductive isolation. Their results, they stated, show the possibility of sympatric speciation.

Rice, W. R. 1985. Disruptive selection on habitat preference and the evolution of reproductive isolation: an exploratory experiment. Evolution. 39:645-646.

Rice, W. R. and G. W. Salt. 1988. Speciation via disruptive selection on habitat preference: experimental evidence. The American Naturalist. 131:911-917.

Rice, W. R. and G. W. Salt. 1990. The evolution of reproductive isolation as a correlated character under sympatric conditions: experimental evidence. Evolution. 44:1140-1152.

There are some more examples of speciation etc here Most of those are due to artificial selection pressures but in this case the pressure is closer to that seen in nature.

Originally posted by mikhael
Which ignores the fact that in the 3.5by curve, it all will tend to even out (which would be a short plateau, short period of change, for those keeping score).

But we're not talking about the evolution of every single creature that has ever existed so I really don't know why you're going for such an absurdly large timescale.

[Bobboau]

Originally posted by mikhael
I'm pretty sure the whole fruitfly experiment cycle, which has been repeated by every college biology student since the seventies rules out simple breeding leading to speciation

collage students don't keep two isolated populations alive for fifty years in systematicly diferent environments.

[mikhael]

Originally posted by karajorma

But we're not talking about the evolution of every single creature that has ever existed so I really don't know why you're going for such an absurdly large timescale.

Because I was making a distinction between the overall (Evolution) and the immediate (natural selection, mutation, artificial selection, etc). Given that the first fossiles, so far, are 3.5by old, I use that as a good first milestone on the evolutionary curve. There is, of course, some evidence of prior organisms that may go back as much as 250-500my more, however.


Now, for these flies, in the study you mentioned: what criteria are used to determine speciation between the environmentally unique groups? That wasn't really addressed in the abstract.

Bob: college students may not, college biology professors and their labs DO.

[Flipside]

So what is being said here is that Evolution has been a smooth progression on average despite the fact that individual creatures within the sphere may evolve in fits and starts?

I suppose that makes sense, since not all environments change simultaneously, an increase in salinity of the sea would eventually lead, most likely, to an increase of precipitation (assuming that increase is by a reduction in water and not an increase in salts), but I suspect seaborne creatures would feel, and be start to evolve around, the effects of that long before land-based ones do etc.

[mikhael]

That's my view, yes, Flipside.

I can't make any claim as to what function that smooth curve approximates. It could have inflection points. It might be logarithmic. It might be exponential. I'm pretty sure its not factorial though.

[karajorma]

Originally posted by mikhael
Because I was making a distinction between the overall (Evolution) and the immediate (natural selection, mutation, artificial selection, etc). Given that the first fossiles, so far, are 3.5by old, I use that as a good first milestone on the evolutionary curve. There is, of course, some evidence of prior organisms that may go back as much as 250-500my more, however.

This whole debate is based around whether or not you can point to something and say See! Evolution! Not whether you could see the whole of evolution. If speciation has occured you can definately say that.

*Points at the alga* See! Evolution!

Originally posted by mikhael
Now, for these flies, in the study you mentioned: what criteria are used to determine speciation between the environmentally unique groups? That wasn't really addressed in the abstract.

Unfortunately that abstract is all I've got since I don't have access to the journals.
 In the case of the alga the fact that it's now in a different family let alone species should be sufficient to say that it has evolved though.

[mikhael]

The second part of that is critical to the first part of that, Kara.

Trees and ants are not algae.

[karajorma]

Who said they were? But if you can observe evolution in fruit flies (and the link I posted has several examples of that) then ants are not too large a stretch, especially if we're not talking about speciation but much quicker behavioural changes.