Duvenoy

This may be going astray from the topic, but I couldn't resist the anglers.

Of course, various fish are the best known anglers. These are found at depths ranging from shallow reefs to deep in the abyss. Strange and wonderful creatures.

Lesser known are a few reptiles. Juvenile Copperheads, Cottonmouths, and other pit vipers of the Agkistrodon genera have sulpher-yellow tails and use them to tease lizards and frogs into striking range. Also juvenile Rock Rattlesnakes (Crotalus lepidus) use a black tail to the same purpose. These colors fade away as the animal approaches adulthood.

But the greatest angler of them all is the Alligator Snapping Turtle (Macroclemys temmincki).

These animals have a moveable, red-pink, wormish appendage on their tongues. They lie in the water, jaws agape, and wriggle this appendage. A passing fish might find it irresistable and go in to take a bite - and get bitten, torn apart, and eaten for it's trouble.

If we are to believe the Creation grift, the Deity must have been smoking some really good shit when he/she/it thought this one up.

Some years back, I read a paper (sorry, I have no addy to find it, I didn't own a computer, then) that described this animal and the loosly related Common Snapper (Chelydra serpentina) as being very old. In the paper, they were described as "living fossils", a description that I have always found ridiclous, but it makes the point.

Sorry for the digression.

d

beausoleil

I don't think likelihood of 'beneficial' mutation is relevant. Of all the planets in the universe on which life arose (an unknown number), we can only observe one on which intelligent life eventually came about. For us to be here, the Earth must look something like this.

Leaving aside evidence for the mechanism in operation, I think there is strictly no need for natural selection to explain either the fossil record or current life forms. The only planets we can observe must exhibit something like what we see, or we wouldn't be here to see them.

WalrusGumBoot

Hi gang:

I want to continue my discussion about the angler fish. I kind of digressed on my last post and didn't have the time to digest the replies (and I appreciate them all!). So here goes.

I realize there are a phenomenal amount of mutations that occur in each generation of every species. Of course, most cannot be seen by the naked eye, and for the most part they do not change the species is any way. From what I understand, the mutation "sticks" if it gains them an advantage in survival and mating opportunities.

Peez brought up the example of the mutation where it produced a knob on the fishes head. Perhaps if other fish are drawn to it like he said, I can see the advantage, but just because it catches prey more easily than the others, does that necessarily strike the death-knell for those without the knob? The fish with the knob now has the same mutations as those without the knob, so per chance one mutation entended the knob, and so on. Here is where I get totally confused. Why does it seem like the fossil record always show the "end result"? If we are talking about millions of years for the development of this "fishing pole," we should see all kinds of variations of this along the way, shouldn't we?

Another simple, almost stupid question I have is why haven't the small prey fish evolved to be larger to lessen the number of likely predators and the large, cumbersome fish evolved smaller to increase their speed and agility to be able to catch their prey more easily?

SciGirl: The Beatles song is "Come Together". Good catch!

[ May 19, 2002: Message edited by: WalrusGumBoot ]</p>

Coragyps

WGB: I'll give a short answer, and let the real biologists fill in the details.
First, the "fish with the (heritable) knob" existing doesn't necessarily doom her knobless sisters, but possibly puts the hurt on their grandchildren. If the knob makes her a better predator, she has a better chance of leaving more offspring, some of whom, at least, have knobs too. If all these knobby fishes are slightly more successful predators and reproducers than their unknobbed cousins, and if the "pond" of prey they have to work with doesn't change radically, they will gradually take over the population just by attrition of the less lucky anglers. The mathematics is just like compound interest: if you "earn" a little each year, and build on those earnings, you'll have a pile if you just keep it in the bank long enough.
As to size of fish: the little guys are specialized for feeding on little prey: all the plankton that make up most of the life in the sea. The barracudas specialize in eating middle-sized fish. If everything in the sea were suddenly the size of a barracuda tomorrow, what would they eat?
What I'm trying to get at is that say, sardines are good at what they do: they eat copepods and such and turn them into baby sardines. Perhaps if a sardine grew to 15 cm long, it would no longer be able to sustain itself on copepods, but it would still have mouthparts built for eating them. So larger size might be selected against.

The real deal is that evolution isn't going anywhere in particular: all we see today is a still out of a big, complicated movie. The ancestors of some of those big, slow fish probably were little, quick fish: an ocean sunfish comes to mind. They found a niche that let them pass on genes, mutated and unchanged, to their descendants today. And there may well be little, even quicker fish among those descendants. There's no direction to evolution, other than the luck of being in the right place, with the right traits, at the right time to be able to make babies.

Oh, welcome to II, and don't let the humidity force you into growing gills down there in Hempstead!

[ May 19, 2002: Message edited by: Coragyps ]</p>

pudsey warrior

[QUOTE]Originally posted by WalrusGumBoot: "... at this point I am still straddling the fence. I see before me three options: naturalist, Biblical creationist, or somewhere in between (a god who created the universe and laws of the universe and dispersed the seeds of life throughout to evolve). I really don't know if I like the first two options very much, the first being doomed to nothingness, and the second, well, I'm sure I deserve hell now!"

WalrushGumboot,

Would it not be more useful if your options could be better divided into just two main categories, i.e. Darwinism or Design.

Darwinians include both theists and atheists amongst its supporters. Personally, I agree with Richard Dawkins that Darwinism provides the means to become "an intellectually fulfilled atheist". Methodological Naturalism, which underpins the Darwinian position, fits more 'naturally' (and I believe, more logically) with atheism than with theism. Theistic Evolution, (i.e. the theory that believes God (or gods) initiated macro-evolution etc.), seems to me to be an oxymoron!

Those who operate within the Design camp certainly include Biblical Creationists. However many who subscribe to "Intelligent Design" (as their adherents prefer to call their movement) are not Creationists in the usual sense of the term. Creationism ultimately appeals to a text, egg. the Bible; IDists do not. Therefore Creationism is fundamentally a religious position with scientific implications, not a scientific viewpoint with religious implications. Furthermore, as I suspect has been your own experience, many Creationists hold the view that the earth was made in six (24 hour) days around 10,000 years ago.

By way of contrast, those who operate within the Intelligent design camp attempt to espouse a scientific viewpoint rather than a religious one. (N.B. In writing, "attempt to espouse a scientific viewpoint", I am neither conceding nor rejecting their claims at this point.) It seems to me that if Darwinism is to continue to hold the 'upperhand' within the scientific fraternity, the real arguments that are proposed by the leading IDists will need to be faced and answered. To label the broad IDist community as just another bunch of Biblical Creationists in disguise will risk allowing their arguments to prevail without any reasoned response.

Walrush.. perhaps it might be useful for you to 'visit' <a href="http://www.talkorigins.org" target="_blank">www.talkorigins.org</a> and see how they answer the main issues raised by wwww.arn.org and
<a href="http://www.discovery.org" target="_blank">www.discovery.org</a> etc.

All the best in your quest to unpack the issues and resolve some of the intellectual conflicts that you currently face. It isn't easy to scrutinise ideologies that are cherished by our peers and then come to a different set of conclusions.

Valentine Pontifex

"Big Fish, Little Fish" which is reprinted in Hen's Teeth and Horse's Toes.

It has an aside that is very interesting:

Quetzal

Hi, WalrusGumBoot! I'd like to make a slight digression related to your questions on angler fish. Although Peez, Coragyps, Nic and LordV have mostly covered the question pretty well, there is a bit that they alluded to in each of their posts that hasn't really been brought out explicitly, and may be causing you some confusion. This is the question that brought it to mind: I understand your confusion. There is a common misconception of evolution, primarily because of the way it is often presented to the public. Phyletic evolution (phenotypical change over time within a specific lineage) is often confused with the discredited theory of orthogenesis, or linear descent. Under orthogenesis, "daughter" species were direct lineal replacements of their "parent" species, and couldn't coexist (IOW, the death-knell you mentioned). Phyletic evolution, OTOH, represents morphological changes in a single lineage. Ultimately, these changes (whether through NS or genetic drift working on the variability within a species) may result in enough change that we typically consider the "daughter" (slowly evolved from a "parent") a new species. It isn't, really - although I can hear the taxonomists howling about that statement; bear with me. At some point in this gradual change process biologists and paleontologists more-or-less arbitrarily designate the daughter a "new" species. Hence the confusion: because of taxonomic conventions it appears that the "daughter" replaced the "parent". It didn't - the parent merely changed enough to have reached a morphological threshold and be proclaimed a new species.

If you think about it, orthogenesis and even phyletic evolution is utterly useless to explain the modern diversity of life. What really happens is something a little different. Unlike the popular view, speciation occurs most often when a subset of a population for whatever reason (and there are many) "buds" off of a particular lineage. The new "daughter" species temporally coexists quite happily with its parent. This daughter species will itself "bud" daughter species, and the original parent may ALSO bud additional species. Each "grandchild" species (is this metaphor breaking down, or what?) ALSO has the potential to bud, etc. At some point it is entirely likely that one or more parent or sibling species go extinct through the vagaries of time and natural selection, leaving its descendants and remaining siblings - all related, closely or distantly, by common descent from an original ancestor - to carry on the evolutionary dance. It is this process of speciation that creates the 200+ species of angler fish - with massively varying quality of lures, habitats, reproductive strategies, etc - rather than evolution within an "angler fish" kind. It doesn't even take that much variation per subspecies - over time, even small differences can be exaggerated as each daughter drifts further and further from the parent, each undergoing its own natural selection pressures, each with its own problems and evolutionary solutions. And each with the risk of evolutionary failure (i.e., extinction). This is what Gould was talking about in the essay that LordV quoted.

As to your follow-on statement about the fossil record only "showing the 'end result'", I'd like to point out that presentations of the fossil record (not the record itself) are often simplified. IOW, most popularizations for public consumption are unfortunately IMO lacking in the "full picture". Paleontologists often only show a single lineage - because they are trying to visually present the complicated evolutionary pathway that led up to a particular modern species.

As an example, one of the most popular "renditions" of a lineage is the evolution of the horse. Almost invariably, pictorial representations show an unbroken chain from Hyracotherium to modern Equus. The reality is LOTS more complicated. There were, for instance, eleven living species of horse - all contentedly cropping grass at the same time - until fairly "recently". Seven of these species went extinct roughly at the same time. One of the remaining species gave rise ultimately to the modern horses. (For an excellent further discussion, I highly recommend Keith Miller's excellent article <a href="http://asa.calvin.edu/ASA/resources/Miller.html" target="_blank">"Taxonomy, Transitional Forms, and the Fossil Record"</a>.)

Hope I clarified the problem a bit. If not, please ask...

Oolon Colluphid

Ref lures, another one is the (sort of) symbiotic relationship between parasitic, bioluminous copepods and Greenland sharks. As far as the copepods are concerned, it’s just parasitism: they hang on to and feed on the sharks’ eyeballs, blinding them. But there is a fringe payoff for the shark: luminous wriggly things at the head end attract other fish, which the shark can snap up.

Now, it's easy enough to see how this evolved; it is less easy to see this as part of some intelligent design -- if the shark requires a lure, an anglerfish design would surely be preferable to having its eyeballs eaten.

Cheers, Oolon

Peez

You are very welcome! My hat is off to you. I was never burdened with that mythology, so my learning was relatively unhindered (of course, I cannot claim to have had no myths of my own, but they never seemed to have the weight that creationism seems to have with those who have been initiated). To have found your way through that mindset to understand what we have learned with science took more than intelligence, it took honesty and a willingness to challenge one's own beliefs. Bravo! Of course you should not take my word for it when I state that the evidence for the common descent of living things on this planet is overwhelming, so much so that it is considered a fact. However, I hope that this will drive you to look at any position contrary to common descent with a most critical eye. By all means, subject common descent to that same critical eye, this science has nothing to fear from understanding.

I would also like to emphasize that there are many, many devout Christians (not to mention members of other faiths) who accept evolution comfortably. Many creationists do not want you to believe that, because they wish to scare you from understanding evolution the way some wish to scare you from understanding the age of the earth. It is important to understand that evolution (and science in general) has nothing to say about the spiritual nature of humans. Science, by definition, is about finding natural explanations for the natural world. Science does not deal (indeed, cannot deal) with spiritual matters. That being said, as an atheist I do not believe in a spirit as such, but I hope that you will not hold that against me. Great to have you here. Just let me know if I can help you out.

Peez

Peez

That is a reasonable summary. I am not sure if I understand you correctly. First, the fish with the knob may have an advantage, but that does not guarantee that it will even get a chance to reproduce. It might get eaten by a predator, die of a disease, etc. All we can say is that it had a greater chance of surviving and reproducing that its fellows.

Second, as the gene for the knob becomes more common in the population, more and more fish will have the knob, but that does not mean that the earlier knobless fish are leaving no descendants. It only means that their descendants are also descendants of the knobbed fish. I don't know if this is helpful. Three answers here. The first is, we often see forms that are "incomplete" in some sense, though I am unfamiliar with the angler fish fossil record in particular. Still, even if you look at living angler fish, some are "incomplete" in the sense of not having all of the possible structures (Nic Tamzek's post shows a few such forms). There are many examples in the fossil record of lineages in which changes are observed over many generations (the toes of horses, the skulls of humans, the shells of snails, etc.)

Second, "transitional" forms may not have existed for very long compared to the "end product." Imagine that the lure-less ancestral angler fish survived for 40 million years with the population of 100 million and the generation time of 2 years. Let's say that we have found 10 fossils of these fish (I have no idea how many, if any, have been found). This would represent 10 fossilized individuals out of 2,000,000,000,000,000 that lived, or 0.000000000005% (if my pathetic math skills are holding up). Now, if we go with the 4 million year model that I described in my earlier post (very slow evolution), then we might expect about 1 fossil of a "transitional" between the ancestral form and the modern form. Also remember that not all of those individuals over those 4 million years would have had the knob. In fact, if Eldridge and Gould are to be believed about punctuated equilibrium, the evolution of the new form could have occurred in a smaller sub-population, of perhaps only a few thousand individuals. In that case we would not expect to find any fossils at all. Actually, this might happen even if punctuated equilibrium is not useful.

One more answer here, but I will start with a question: what is the "end result" you speak of? This implies that evolution is working towards some end, which is not the case. Why would we consider the lure of a particular angler fish an "end product"? It should not surprise us that evolution continues, and the lure of a species of angler fish might look quite different in a couple of million years. Beware of the idea of "end products" or the "fully-formed" organisms that some creationists refer to. All organisms are "fully formed" "end products," and all organisms are also "transitional forms" as well. Each organism must survive and reproduce to pass along its genes. The angler fish with the earlier form of knob were "fully-formed" "end products" in the sense that they were the living result of past evolution, just as living angler fish are the living results of past evolution. Two answers here. First, they often have. We see many examples of so-called "arms races" in which prey evolve traits that allow them to escape predation while predators evolve ways of overcoming those traits. Second, it is much more complex than just being better because you are bigger or stronger or faster. For example, a bigger animal needs more food, takes more time to mature, is more likely to die from a fall, etc. Only if the benefits of being larger outweigh the deficits will natural selection have the potential of driving the evolution of greater body size.

Peez