Evolution for Drotar

[Drotar]

Why can't it work on marine organisms?

Actually, you are correct in that assessment. I understand the process, but was unaware of that fact.

 

[Arikay]

This is common with most radiometric dating flaws, the creationist organizations are either ignorant or they are lying to you.

I dont think I have yet to see one of the creationist "flaws" in dating that wasnt actually a flaw in their research, understanding, or reporting.

 

[Drotar]

The question I asked was why it doesn't work.

LOL- I'm QUITE aware of your opinion already ("If you really are perfectionist then one day....")

 

[troodon]

The question I asked was why it doesn't work.

Organisms take in their Carbon-14 from the atmosphere. Marine organisms are not in contact with the atmosphere. Hence, marine organisms do not have the Carbon ratio that terrestrial organisms have and that Carbon dating is calibrated to.

 

[Arikay]

Actually I was typing that while you were typing your other question, it was a comment on frums comment (just didnt know you would slip something in there. )

I would have to look it up but I believe it has to do with extra absorbtion of C-14 even after death.

Not to mention you need to be carefull of anything that talks about c-14 dating on a Live animals (although coral is a bit different, which should start sending up the red flags about whether the coral even absorbs c-14 the same as a normal tested animal).

Edit: aha, Troodon got it there too. I really need to stop using the quick reply feature, as someone always sneaks one in.

 

[Drotar]

Well, most fossils were animals that died on lake shores. Why do we carbon-date them?

Haven't people carbon-dated fossils of aquatic animals. Nautilae, ancient fish, shells, plants?

Could someone elaborate?

 

[Arikay]

They died on a lake shore, but did they live in the water?

Can you give some examples of shells being dated by C-14 and being accurate (it helps to know the circumstances).

How ancient of fish?

 

[Pete Harcoff]

Radiocarbon WEB-Info has some information under corrections to radiocarbon dates on dating aquatic organisms (specifically under the section "Reservoir effects").

 

[Drotar]

I do apologize for my ignorance on the issue of C-14 dating. I'll have to research this on both sides on my own. Thanks for the info.

 

[Arikay]

To add one bit to the C-14 info and sea creatures, some clams absorb material from around their area to build their shell. This can include C-14 from the area, which would distort their c-14.
Interestingly enough even ICR have chastized other profesional creationists for selecting things (such as these shells) that are known to give bad dates, and that was in 1989.

 

[GJG]

OOPS!

I have no idea what you knowledge filled guys are talking about here. I want to say something but I don't even know what C-14 is!

Catch you on another thread.

 

[Arikay]

Thats what questions are for.

C-14 stands for Carbon 14, its a radiometric dating method. Carbon 14 is a radioactive isotope (Carbon 12 being the normal stable carbon) in the air that is absorbed by living things, Most living things stop absorbing it when they die and so it begins to break down without being replenished. By measuring how much Carbon 14 has broken down, scientists can get a good idea of the age of the animal or plant. Currently the C-14 dating method is good for up to 50,000 years.
C-14 has a half life of around 5700 years. Other radio isotopes that have longer half lifes are used for dating things beyond what C-14 can do.

Not the best description, but it works.

Among many other things, C-14 has been used to date the Dead Sea scrolls to their expected date, Suggesting that they were authentic and not forgeries.

OOPS!

I have no idea what you knowledge filled guys are talking about here. I want to say something but I don't even know what C-14 is!

Catch you on another thread.

 

[Drotar]

But that's because the smaller age difference between now and then means a smaller margin of error. Once we get past (I heard it was 30,000) years, with that much difference in time, it becomes EXTREMELY difficult, not to tell whether it is old or not, but to tell absolutely and coordinate which age it was from.

Why does it stop absorbing c-14 with the atmosphere? Don't ions and isotopes swap? I mean, does it need to absorb C-14, or ismply come in contact with it?

How do we know what the half-life rate for C-14 in water is? Can't the consistensy change in water? Can water become polluted (but not such exactly) by introduction of other compounds that can complicate measuring? C-14 dating is a weakness of mine, I apologize.

 

[Arikay]

"But that's because the smaller age difference between now and then means a smaller margin of error. Once we get past (I heard it was 30,000) years, with that much difference in time, it becomes EXTREMELY difficult, not to tell whether it is old or not, but to tell absolutely and coordinate which age it was from."

Yep, to an extent the older the sample gets, the larger the margin of erro (the Plus or Minus X years) is. However 30,000 is an old number from the older method of C-14 testing. In the old method, 30,000 was about the upper limit of C-14 dating. However, never technology, methods and Ice core samples have allowed us to detect and calibrate C-14 back to around 50,000 years. It is thought that in the near future we may be able to consistently read back to 70,000 years.

The ratio of C-14 to C-12 has changed some during the last 50,000 years, which is why calibration is important. Tree rings have allowed us to calibrate C-14 back 10,000 years and Ice Core samples have helped us calibrate it back 50,000 years. By traping the atmosphere in them, we can use the samples to see what the ratios were as we go back through the years.

"Why does it stop absorbing c-14 with the atmosphere? Don't ions and isotopes swap? I mean, does it need to absorb C-14, or ismply come in contact with it?"

From how I understand it, C-14 is absorbed through breathing and eating. Mainly the breathing of plants. The c-14 can be part of CO2 and the plants breath it in and incorperate it into themselves when they breath. Animals then eat the plants or eat animals that have eaten the plants and the C-14 becomes part of them. Every living thing on land has about the same ratio of C-14 to C-12 in them.
Stop eating or breathing and it stops being absorbed into the animal or plant and the C-14 clock starts.

"How do we know what the half-life rate for C-14 in water is?"

Its the same in the water as in the Air. Half lifes dont change.

"Can't the consistensy change in water?"

Yep, and thats why we see a different. There is a different ratio of C-14 to C-12 in the water than in the Air.

"Can water become polluted (but not such exactly) by introduction of other compounds that can complicate measuring?"

Yep it can, and so can the Air. Which is why it has become harder to Carbon date anything that died after the Industrial revolution, because we have artificially changed the ratios in the Air.
Just like with other radiometric dating, anything after the Industrial revolution and Above ground Nuke blasts, become harder to date using radiometrics because we have screwed with the different ratios. However, we dont have to worry about that now, but future civilization would.

But that's because the smaller age difference between now and then means a smaller margin of error. Once we get past (I heard it was 30,000) years, with that much difference in time, it becomes EXTREMELY difficult, not to tell whether it is old or not, but to tell absolutely and coordinate which age it was from.

Why does it stop absorbing c-14 with the atmosphere? Don't ions and isotopes swap? I mean, does it need to absorb C-14, or ismply come in contact with it?

How do we know what the half-life rate for C-14 in water is? Can't the consistensy change in water? Can water become polluted (but not such exactly) by introduction of other compounds that can complicate measuring? C-14 dating is a weakness of mine, I apologize.

 

[lucaspa]

I wouldn't quite say that about my teacher. If someone else had taught me, I NEVER would have learned that much in class. Any errors or flaws in my posts should be traced back to me alone.

BTW, did you help grade the AP exams for biology? I just received word that I got a 4, which is good news for me, but not something that's going to impress a scholar of your caliber. Just curious if you helped out with that.

No. My daughter also got a 4, however.

Not again! Equations! Drat!

Well, that looks like some aspect of the Hardy-Weinberg theorum.

It's not Hardy-Weinberg but simply elementary mathematics. Applies to proportions of ANYTHING. For instance, if you get a pizza half cheese and half pepperoni, you have N=2. Since C =1 and P =1, you have C/2 + P/2 = 1.

Hardy-Weinbery LAW is simply an extension of Mendelian genetics. If you have a trait P and p and mate the two, the offspring will be PP, 2Pp, pp witht the ratio of 1:2:1.

Now, if you have a population in which the frequency of allele P is "p" and the frequency of allele p is "q", then Hardy Weinberg says that, in the next generation, IN THE ABSENCE OF ANY OUTSIDE INFLUENCE, that p and q will not change.

Agreed, however you left out a vital assumption. That resources are so limited that animals are literally starving to death- BEFORE the reproductive age.

That's not an assumption, but a simplification.

[/QUOTE] Animals aren't the only ones reproducing. Plants are too. [/QUOTE]

But plants are up against a set if FINITE resources: space, nutrients, sunlight. Plants can't go on expanding their population forever. So there is a finite number of plants for herbivores to eat and therefore a finite number of herbivores for predators to eat.

The food chain, without man's interference, is relatively stable. At the rate which animals consume, the naturally dense forests reproduced to accomodate the life it held.

But that's NOT the amount of animals there COULD be if EVERY individual grew to adulthood. Each salmon, for instance, lays over 10,000 eggs, but of those only 2 survive to come back and reproduce. If all 10,000 salmon from all million salmon lived to reproduce, in one generation that would be 10 BILLION salmon. And the next generation there would be 10 TRILLION salmon and the next generation there would be 10 QUATRILLION salmon, and so on. So most are not surviving to adulthood.

Usually, if you really think about it, you really don't see animals lying on the floor or in trees starving to death.

Drotar, here you are not looking at the examples for what they are there for: to look at your "death rate has to be more than the birth rate for proportions to change" but have shifted the argument to "starving to death". I'll take it as accepted that your argument has been answered.

Fact: I never doubted the possibility for adaptation to function on a relatively small scale, WITHIN a species due to alleles. I did doubt speciation. And even if you DID prove it was possible, you can't prove that THAT was what actually happened. What, are you going to use carbon-dating?

That's the second time you have tried to divert the discussion to carbon dating. Tell you what, read these websites (all the pages) and then we can discuss it if you still have questions:
1. http://www.c14dating.com/
2. http://www.howstuffworks.com/carbon-14.htm
3. http://www.don-lindsay-archive.org/creation/carbon.html

However, we have SEEN speciation happen before our eyes in both the lab and the wild and the fossil record. Also, looking at such things as biogeography, morphology, physiology, embryology, and genetics, the ONLY hypothesis to explain those that has not been falsified is speciation from a common ancestor. Special creation is falsified by data in those fields.

Didn't you just make the claim that atmospheric conditions are extremely unstable? (And I"m not just talking about the climate now- you gotta give me a little credit.)

No. I said climate could change.

That's where we differ. The claim that N is constant. If given time, the population expands. Now here's the issue: Is the difference between the death rates before the reproductive age of L-I GREATER than the expansion rate of the steadily growing population, which is N.

In most situations, N is constant. Documented. Populations do not expand, and they can't. There simply is not enough room on the planet for the population of every species to expand. Darwin calculated that, if left unchecked, in 10,000 years elephants could overrun the planet if the population was left unchecked.

Human populations in the last 300 years or so are an exception because we keep expanding our food source. But even here there are limits. There are finite resources, and the population can't expand forever.

To answer your question, YES! (But N is NOT the expansion rate. That would be N2-N1 were N2 is the number of individuals in generation 2 and N1 = the number of individuals in generation 1). I've given salmon as an example. Try your maple tree in your yard. How many seeds produced each year. How big an expansion of the number of maple trees in your neighborhood?

It's too simple- there are billions of factors in teh enviornment and diseases and genetics and whatever that can alter the results in a HEARTBEAT.

And those factors are all selection pressures, right? Drotar, we are trying to SIMPLIFY natural selection for you. Yes, there are at least hundreds and perhaps more selection pressures on each population. That is immensely complex. So we do what science does in ALL areas: we study situations that are representative of the system but are not as complex. If the hypothesis is right, then we can detect the action of the process -- natural selection in this case -- in the simple system. If natural selection is not operating, then we couldn't detect it in the simple system, could we?

I think it does. If we're still talking about the contribution of old alleles increasing, DESPITE the fact that they have the proper number of toes on each foot (hoof, sorry), then I maintain my old position. Change or not, the extra toe isn't going to be so substantial so as to wipe out group A. Forests, plains, swamp, whatever. It's a stinking toe man.

I have shown that the contribution of the old alleles in the population DECREASES. That is, the the number of individuals with alleles that make a small middle toe DECREASE with time, and the number of individuals with alleles for a larger middle toe INCREASE. Eventually, the alleles for a small toe disappear entirely and the population contains ONLY the alleles for a larger toe.

It doesn't matter that is is just a toe. As long as it gives some advantage in the competition, it will eventually replace the older trait.

Let's give you more equations. Sorry, but that's the way it is.
Remember that, in the absence of any outside influence, such as natural selection, the frequency of an allele does not change from generation to generation. That is, if you have a population and 100 and 10 individuals have allele A and 90 have allele a, the next generation will be exactly the same: 10 A and 90 a. This is called the Hardy-Weinberg Law. Frequencies are symbolized mathematically by p and q. W is the relative fitness value. So we have W(A), W(B), and W(AB). The last is the fitness of the heterozygote in a sexually reproducting population.

So, for the first generation the frequency p of A in the population is: p^2 +2pq + q^2. Straight Mendelian genetics.

The frequency of p in the next generation after selection is: p' = p^2W(A) + pq W(AB)/p^2W(A) + 2pq W(AB) + q^2 (WB).

Now, if W(A) and W(AB) are higher than W(B), it can be seen that p' will increase. Not chance, but pure determinism.

You can see all this and a lot more in Chapters 4 and 13 in Futuyma's Evolutionary Biology, 1999.

Remember Hardy-Weinberg. The frequency of an allele remains unchanged from generation to generation in the absence of outside influence. Therefore, the fitness of a new mutation is defined as the ratio of the number of progeny actually produced divided by the number of progeny expected by Mendelian genetics. This is going to be greater than one in the case of favorable mutations. From that we get a selection coefficient such that fitness = 1 - s.

Now, doing the math we find that the advantageous allele A increases in frequency, per generation, by the amount delta p = (1/2)spq/(1-q).

If you look at the equation, you see that delta p is positive as long as s is greater than 0, even if it is very small. Eventually p will equal 1, which means that every member of the population will have the allele. Thus, a characteristic with even a miniscule advantage will be fixed by natural selection. "Fixed" means every individual will have the allele.

So, as long as a trait is at all, even by the smallest degree, beneficial, then the odds that it will spread to become all the population is 100%.

 

[lucaspa]

How do we know what the half-life rate for C-14 in water is? Can't the consistensy change in water? Can water become polluted (but not such exactly) by introduction of other compounds that can complicate measuring? C-14 dating is a weakness of mine, I apologize.

The rate of radioactive decay does not significantly change for anything. It is dependent on hte content of the NUCLEUS. Therefore polluted water, high temperature, etc. has no effect on the half-life.

Yes, IF the organism is getting some of its carbon from a NON-ORGANIC source, then the measuring technique is no good. FOR THAT ORGANISM.

For instance, clams and other mollusks use inorganic carbonate in the water to make their shells. Since that carbonate has been around a long time the C14 in it has had time to decay BEFORE the clam used it for its shell. Therefore, dating a clam by C14 will give you wrong results and have the clam appear older than it is.

This is well-documented (a study in Science) and was published as a limitation of the methodology.

 

[lucaspa]

lucaspa: Remember, the appendix may be functional but the small appendix is JUST AS FUNCTIONAL. BUT, the large appendix is going to have a metabolic cost and a cost of higher disease. Let's do some simple numbers with simple assumptions.

Whoa, wait a sec. So you're saying that our appendix is just as functional? It is my assumption that evolutionists claim the appendix to be a vestigial organ. I am right, right? I always thought that the appendix served little known purpose as of now. Are you going against these medical claims?

I'm sorry, I confused you. Listen carefully: IF the appendix is no longer needed, then a non-functional appendix is just as functional as the orginal. Right? NEITHER are doing a needed job. So, the original large appendix is still doing what it always did, but it is not serving any useful function. So, a new variation in the population making the appendix smaller is going to be just as functional as the original, since the original isn't doing anything needed anyway.

OK? All cleared up?

The purpose of the appendix was to buff the immunity against foreign pathogens in the digestive tract, particularly with uncooked food. Now, that sure as day says to me that that would PREVENT disease. Thus, though a higher metabolic cost, a LOWER rate of disease and a HIGHER rate of survival. Something doesn't add up. I stink at math, but I know there's a problem here.

Yes, the original appendix would (if the proposed original function is correct) protect against disease, but there was always the price that it would get infected itself. So, you balance two evils: getting infected from uncooked food or having an inflamed and burst appendix. On balance, the good outweighed the bad.

UNTIL humans started cooking their food. THEN there were no pathogens due to uncooked food, BUT the appendix could STILL get inflamed and kill you. Thus, the good was gone and only the bad was left. SO, people born with smaller appendices less likely to get inflamed would, on average, do better than those with the original large appendix. They would get fewer inflammations of the appendix and fewer would die, meaning that they would have more offspring. Natural selection.

[/QUOTE] Charge that. I understand natural selection (better than some classmates anyways- if that's of any consolation). I've got little discrepancy with the theory itself. Simply in the fact that it's not applicable in practice. IMHO, the shoe DOESN'T fit.

Please don't get upset that I cut your quote short here, but I undrstand what you're saying. It's the part where there's only food for 100 individuals. Go outside. Take a photograh of an owl leaned against the trunk of a tree starving to death, or a mouse cuddled in the fetal position because it can't find any food in the forest. I know I'm sounding silly. There's not just enough food for 100 individuals. It's not that simple-there are millions of factors. Evolution works only if you give overly-simplified examples. My point is that you very, VERY rarely see animals starve to death in the wild. Resources aren't THAT limited.[/QUOTE]

It's easier to DEMONSTRATE it if you give simplified examples. But it works in the complicated situations, too. Have you had physics yet? Did they get into Relativity? If so, I bet they gave you simplified examples so you could understand it. In fact, Newtonian mechanics are simplified Relativity equations. They are easier to understand than the more complicated equations but the more complicated equations are true, too.

Now, how many owls and mice do you NORMALLY see out in broad daylight? The starving ones are there, but they hide away when they don't have enough energy to forage for food anymore. There are islands off Vancouver where deer have colonized. No predators since wolves haven't made it to the islands. And there the researchers did document starved deer when the population got too large for the plants on the islands to support them.

Even if they WERE, who's to say a toe did that. Are we going to blame an animal dying on THAT? Or on some other factors? Who's to say the MORE evolved didn't make it this time? I understand the lines of what you're going to say next, but please understand that my point in asking is merely to emphasize that we cannot successfully predict that stuff, and blame it consistently on a toe.

For the fossil record, a lot of deciding what had a survival advantage comes from reverse engineering. We look at the design, figure out what it did that the old design didn't, and then look to see why the new design would do better in the new environment.

We are not "blaming" anything on a toe. We are showing how a larger toe would do better in the new environment than a smaller toe. Therefore saying that the larger toe had a selective advantage in the new environment, therefore selection would make sure that all the individuals in the population would have a larger toe -- and thus evolve to a new species different from the old.

Now, there have been some studies where results were predicted in advance because we understood the environment well enough that we could predict which designs natural selection would favor. Here are two of them:

1. Case, TJ, Natural selection out on a limb. Nature, 387: 15-16,May 1, 1997. Original paper in the same issue, pp. 70-73 (below). Discusses natural selection in the wild where lizards were introduced tovarious islands in the Bahamas. Length of limbs varied according to theplant life present on the islands.

2. Evaluation of the rate of evolution in natural populations of guppies (Poecilia reticulata). Reznick, DN, Shaw, FH, Rodd, FH, and Shaw, RG. 275:1934-1937, 1997. The lay article is Predatory-free guppies take an evolutionary leap forward, pg 1880.

This is an excellent study of natural selection at work. Guppies are preyed upon by species that specialize in eating either the small, young guppies, or older, mature guppies. Eleven years ago the research team moved guppies from pools below some waterfalls that contained both types of predators to pools above the falls where only the predators that ate the small, young guppies live. Thus the selection pressure was changed. Eleven years later the guppies above the falls were larger, matured earlier, and had fewer young than the ones below the falls. The group then used standard quantitative morphology to quantify the rate of evolution.

So we have a study in the wild, not the lab, of natural selection and its results. In this study natural selection was measured quantitatvely, and even predicted since it was predicted that, in the absence of predators that fed on large guppies but in the presence of ones that fed on young guppies, the guppies would grow larger and mature earlier to avoid the predators. That is exactly what happened.

In a metaphysical sense, there's no such thing as chance. Everything happens through a result of causes leading to an effect. Having a functional appendix vs. a non would in theory make a difference, in theory, but in actuality there are millions of contingencies and causes. In practice, we cannot calculate all that causes it. Since the natural population would slowly rise, and since the change is QUITE insubstantial, I would say that also given the biollions of factors, the rate of evolution is way, WAY overexaggerated, if worthy to be considered evolution at all.

And natural selection is not chance or without cause. What you are saying is that 1) you deny chance but invoke contingency, which is the same thing and 2) that we cannot calculate all that causes it because there are many selection pressures. And that is true in most cases. We can demonstrate in the equations, however, that if there IS a selection pressure, then the INEVITABLE effect will be that populations will change and that the favorable allele will replace the original allele.

However, you assertion that natural populations would slowly rise is simply wrong. That only happens where a population is using new resources and hasn't yet reached the limits of those resources. Once the limits have been reached, population MUST remain steady. There is no choice.

Now, as to rate, the guppy study found that natural selection can work at a rate of 1,000 to 10,000 times FASTER than seen in the fossil record. The rate of natural selection is measured by the darwin. A darwin = rate of change of the character/natural logarithm of time. Therefore on a log e (natural logarithm) scale 1 darwin = unit of change (mm or whatever) per million years.

The fish evolved at 3700 to 45,000 darwins, depending on the trait measured. In contrast, rates in the fossil record are typically 0.1 to 1.0 darwin. So natural selection can move MUCH, MUCH faster than previously thought. The rate has been undermeasured, not overexaggerated like you claim.

 

[lucaspa]

Here's another factor: you claim that those with small appendixes require a smaller metabolic input.

During development, yes.

First, the difference of a toe isn't gonna make that much a difference. The MUCH bigger factor lies in the fact that animals, just like humans, each VARY in metabolic rates.

Go back to the equations. ANY difference, no matter how small, that results in a selective advantage will result in the trait being fixed. Sometimes it takes quite a while if the selection pressure is very small. Which is why we have vestigial organs. You are aware that the modern horse still has two small toe bones adjacent to the main toe bones, right? Remnants of the former toes. The metabolic price of these small slivers of bone is simply too small to make a large difference in selection in modern horses. s = a very small number. So those bones are still in the process of being removed and probably will be becasue delta p per generation is SO small.

We're assuming that there's one absolute rate and that those with smaller appendices or toes or whatever will survive since there's less energy expenditure. But the assumption is that "If X population remains constant" or "if X (metabolic rate) is an absolute". The theory of evolution must be overly-simplified. A toe isn't the issue, it would still be this here.

We're not assuming an absolute rate at all. We are "assuming" a bell-shaped curve. Or rather, two bell shaped curves. One for 5 toed and one for 4 toed with the means separated by very little and a huge overlap of the curves.

The constant population is not an assumption, but an OBSERVATION. A fact. See http://pages.britishlibrary.net/charles.darwin/texts/origin_6th/origin6th_03.html

Question: And what of a trait being dominant or recessive? It must be one or the other.

If a trait that encourages survival is recessive, and thus overpowered by the allele for the proper number of toes (this is ridiculous), then shall we say that this SERIUOUSLY complicates the issue?

It complicates the issue, but not seriously. Go back to the equations and see that selection values apply to each homozygote and the heterozygote. If W(B) (the recessive) is higher than W(A) or W(AB) (the dominant), the result is still the same.

Let me introduce new questions: how does mutualism evolve?

http://www.eseb.org/index.html?http://www.eseb.org/anstett.htm

Leigh, E. G. Jr. and T. E. Rowell. 1999. The evolution of mutualism and other forms of harmony at various levels of biological organization. Écologie 26: 131-158

http://westgroup.icapb.ed.ac.uk/meetings/Ferdy et al. 2002.pdf

Sheep can't fly, hide, camouflage, jump, or even RUN- their knees buckle. If they fall over, they cannot right themselves. If you don't lead them to grass or water every day, they die because they are incapable to survive without a shepherd. Perhaps I don't understand the theory as I thought, but where does the natural selection therein lie?

You forget that domestic sheep are a product of ARTIFICIAL selection. Human selection for traits like wool and mutton. So those detrimental traits were also selected artificially because the humans involved didn't care about them.

Now, can you find such species in the wild? Then perhaps you could make a case for artificial selection by God that He would make such a helpless species that He had to miraculously take care of. Do you have any?

 

[lucaspa]

And for what its worth, the bottleneck effect is even less common than the founder. The real-life examples used for the BN effect are a reslt of man's interference.

Any Founder Effect is also a bottleneck effect.

Part of my problem lies also with taxonomy. Different species? Or variation of the same?

The biological species concept requires watching whether the populations naturally interbreed. For comparing past populations and present ones that isn't possible. Nor is it possible for fossil species. In those cases what is compared is the morphological and physiological traits with the understanding that, past a point of difference, interbreeding is not possible. This is the morphological species concept

The morphological species concept is always going to UNDERESTIMATE the speciation, especially in the fossil record. Changes in soft tissue and behavior that would result in two species will not always show up in the bones and shells. For instance, there are two species of wren in England that look identical in their general morphology, feathers, and bones, but are two separate species. Biochemical differences. There are two species of snails with identical shells, but one species is hermaphroditic and the other has two distinct sexes.

So, in the case of insects before DDT and after, the morphological shape is the same but the biochemistry is significantly different, with new enzymes to handle the pesticide.

Laziness? Or a proper understanding of alleles, traits, and variation to species. I think we are a little too trigger-happy at labeling things as speciation.

And you, for obvious biased reasons, want them to be the same.

True, but will that result in speciation, or naturally selected variation within the species?

New species. The new population does not interbreed with the old or, if it does in the "hybrid" zone, the hybrids are not viable.

Forgive me if I respectfully disagree. If they wind up in place that they have trouble surviving in, they go back home. They don't tough it out and evolve. For all they know they're dying.

How would they know where "home" is? It's not like they packed up the family sedan and kept a roadmap. Where they are is home. Also, HOW do they know "they're dying"? This involves a lot of abstract thought that most species don't demonstrate. Even humans don't demonstrate it. After all, 1) how long did it take to become apparent that the death rates in Love Canal were higher than they "should" be? and 2) how many people moved out of Love Canal even when they knew? Most stayed because that was "home".

Show me an animal that, when posed with a difference in environment, doesn't move to where it is best-suited?

The original finches on the Galapagos. The original Drosophila in Hawaii. The apple maggot fly. Leopard frogs.

If it's cold, they'll find themselves south. They don't stay and grow thicker fur. They go where it's warm.

This is ONE example of a larger mammal that migrated. However, the evidence is that at least one species of mammoth -- the wooly mammoth -- did indeed stay where it was during the Ice Age and evolved thicker fur.

[QUOTE ]I wasn't talking about climate. I understand that there are things called seasons and that sometimes weather changes. You gotta give me a little credit.

I'm talking about conditions in the atsmosphere. There's MUCH more oxygen gas than at the beginning of the world. Let's say, also, a change pertaining to the Van Allen radiation belt. You're a clever guy- you know where I'm going with this.[/QUOTE]

I can guess where you are going, but it is irrelevant to the discussion of natural selection. I'm not talking about changes in the atmosphere here, but changes in the environment.

Yes, when photosynthesis increased the oxygen content of the atmosphere past a certain level, then variations that required higher oxygen levels became selectively advantageous. Just like the mutation for the enzyme that degrades nylon may have happened dozens of times in 4.5 billion years, but the individuals unlucky enough to have it couldn't use it because there was no nylon. Now there is, and the lucky bacterium with that mutation now has a brand new food source that gives it a huge selection advantage.

If you want to go there, then do so.

 

[lucaspa]

You must be careful which lab results you read. There was a case where students nad a piece of LIVE coral. The scientists didn't know what they were testing on, but they estimated it to be 14,000 years old!

And the results weren't published in a peer-reviewed journal, were they? Why not? Because BEFORE this trick was played, a paper had come out where the researchers had shown that using C-14 to date organisms that make shells -- and corals do -- is invalid because the C-14 doesn't come from organic sources but INORGANIC ones that have been around long enough for the C-14 to decay. Doing exactly what was done here: make the animals appear older than they are.

I didn't see what you were talking about. I do better without examples or illustrations becasue they usually skew my understanding of what we're talking about.

I do better WITH them because they anchor the abstract comments in the real world. I can then picture them. So you are going to keep getting the examples to anchor YOU in the real world and get you in the habit of testing your ideas against the real world.

Just give me the classic textbook definitions of the two types of speciation. I take it this isn't gradualism vs. punctuated equilibria.

This is somewhat gradualism vs PE. Gradualism is phyletic gradualism or the transformation of the whole large population to another. PE is allopatric speciation.

Again: "Allopatric speciation is the evolution of genetic reproduction barriers between populations that are geographically separated." The definition from Futuyma.

Sympatric speciation occurs when a biological barrier to gene exchange arises within the confines of a randomly mating population in the same geographic area.