Re: for herebedragons - speciation, definition first, discussion second
I don't think I ever welcomed you to EvC. So, welcome to EvC!
It's good to read true open-mindedness for a change!
First of all, I see defining a species is very subjective and difficult to nail down precisely, since there is no one "perfect" rule to apply.
On this, I agree. There is a fair amount of subjectivity involved in biological classification, no matter which system you use.
It seems to me that it is important define species accurately and with a fair amount of precision.
On this, my agreement is not so strong. As an entomologist, it irritates me to no end that many people with advanced degrees in entomology do not know how to distinguish families or even orders of insects from one another, and I am a strong proponent of requiring insect taxonomy for all aspiring entomologists.
However, as an ecologist, I also do not deal directly with taxonomy on a frequent basis, beyond identifying small arthropods under a microscope. In ecology, the only purpose in classifying organisms is the organization of biological information so that we can generate predictions that help in testing our hypotheses. In the end, classification only needs to be precise enough that we can predict which groups of organisms can serve as models for our predictions about the behavior and function of other organisms, and so we can predict which hypotheses apply to which organisms.
Within phylogenetics, the point of classification is to uncover the history and principles of the evolution of life. But, all biologists acknowledge that this is not really a means of objectively delineating the boundaries between species or other organisms. Quite the contrary, in fact: if phylogenetics has taught us anything, it is that such boundaries simply do not exist. That is why our attempts to classify are inevitably saturated with subjectivity: because the entire concept of categorization is itself subjective, and does not actually represent the reality of the situation.
A newer system of classification I found some information on is Baraminology.
“Baraminology” is actually just a new name for the oldest system of classification that exists. The concept is essentially identical to the concept used by Linnaeus: it groups things according to patterns in morphology, then groups those groups according to coarser patterns.
The only difference is that baraminology asserts that there will eventually be found a point beyond which groups cannot be combined together into larger groups, and the primary thrust of baraminology is to identify these points of distinction.
My complaint with this field of study is that valid, empirical reasons for suspecting the existence of such breaks have never been presented, and so, the entire field of baraminology can be summarily defined as the search for something that we have no reason to suspect even exists.
As a lifelong Christian, I would be very interested if such data were uncovered, but I cannot honestly characterize the basis of the field of baraminology as anything greater than wishful thinking, so I am required by my personal sense of integrity to reject it as a legitimate academic pursuit. Maybe the future will change my mind, I'm not sure, but my skepticism for that is currently very high.
Actually baraminology seeks to justify the biblical concept of kinds, and to make it sound scientific at the same time.
It is not a field of research because no conclusions can be arrived at other than those specified in scripture. It is pure religious apologetics.
You know I won't argue with any of this.
But, I'm trying to be generous for the sake of Herebedragons, who comes off to me as open-minded, intelligent and at least tentaive about the ideological aspects of creationism.
Libeling ideology runs the risk of making one's own argument appear just as ideological in nature. We dismiss baraminology because of its failure to correctly utilize empirical methodologies, not because of whatever ideological piffle it chooses to utilize instead.
We can convey the same message while entirely avoiding the emotionally-charged, polarizing topics if we simply stick to discussion of the empirical issues, which, in my appraisal, HBD seems more than willing to consider.
Creationists are constantly being asked to define what a "kind" is. I personally am not sure it is really necessary or practical or maybe even possible, but if a group of creationists are attempting to come up with a definition, maybe their work should be based on the data, not on the fact they are trying to define "kind".
But again, the entire concept of baraminology is based on the alleged existence of distinctions between baramins when there is no empirical reason to believe that such distinctions exist.
Phylogenetics and baraminology both incorporate evolution, or gradual changes over time. But, baraminology further incorporates a concept of limitations on the amount of change that can occur.
Are you familiar with the principle of parsimony? Basically, it means you don't propose a new factor in a system unless you have empirical reasons to do so.
So, what are the empirical reasons for suspecting that evolution can only go so far?
I do not really hope or expect that their work will have any real impact - partially because I think they are traveling down a dead end, or at least an end that has no hope of being resolved satisfactorily. And partially because I don't think it is actually a necessary or practical pursuit. I mean, even if they do succeed in establishing "biblical kinds", then what? They are going to jump up and declare "See I told you they could fit on the ark!" Not really a huge step forward.
I suspected that we didn't really disagree about this. Otherwise my arguments might have been more aggressive.
Anyway, it's always nice to discuss things with a Christian who's willing to think empirically.
I did comment that regardless of their findings, the results would be rejected - not based on the data, but based on the fact that their research was religiously inspired.
That's always a concern, isn't it? But, there is a sort of basic sensibility in becoming ideological about something that's extremely well supported by evidence, isn't there? It's not purely logical, per se, but it does make sense, yeah?
Nevertheless, Coyote's complaints are justified: non-empirical belief is never a good foundation on which to base a line of scientific inquiry.
I also commented that they feel they have reasons that at least in my feable, little mind are as "empirical" as persuing abiogenesis.
This is exactly what I already commented on. The available evidence suggests that life becomes simpler the further back in time we look. If all the evidence we have suggests decreasing complexity as we go further back in time, parsimony tells us that life predating the earliest, simplest life we know will be even simpler. That's the general principle we derive from a simple view of the available evidence.
But, baraminology wants to defy that general principle. Don't get me wrong: there's nothing wrong with defying general principles... but you need some evidence that nature defies the principle before you propose that it does.
I would be interested in discussing what empirical evidence you think there is that the general principle of increasing simplicity the further we go back in time is not universal, but perhaps it would be a better topic for The Grand Theory of Life or Species/Kinds (for Peg...and others). See you there?
Anyway, I look forward to your response. Merry Christmas!
So monkeys evolved from fish-like creatures? Humans evolved from fish-like creatures? Fish evolved from fish-like creatures?
Can anyone tell me what a fish-like creature is?
A "fish-like creature" is another fish.
Like Caffeine said, monkeys and humans and modern fish all evolved from ancient fish. If you were to display the evolutionary history of fish as a tree diagram, you would see amphibians, reptiles and mammals forming a single branch sprouting out of the middle of the tree somewhere.
Some fish evolved legs (and eventually arms) from fins; while others evolved more kinds of fins from fins.
By the way, how can we relate this back to the definition of species (which is what we're supposed to be discussing here)?
However, when I suggest that a fish might have evolved from a monkey you baulk at this idea.
What I am about to write is pretty much what everyone else has already written, but, the more bullets we shoot, the more chance we have of hitting the target.
I have no objections to the hypothetical possibility that fish could have hypothetically evolved from monkeys.
It is not an objection based on ideology: it is an objection based on evidence.
The evidence includes ancient fish predating monkeys, and a series of fossils that arrange chronologically in the fossil record, such that the progressively more monkey-like organisms in the sequence are found after the less monkey-like organisms in the sequence.
Therefore, I do have objections to the possibility that fish actually did evolve from monkeys.
Now if you suggested that a complex creature could evolve into a simpler creature where its very survival depended on it I might understand this. However, if I gave any example of this you would no doubt claim I was raving mad.
I’ll save you the trouble. Pentastomids (also called “tongue worms”) are most often thought of as “degenerate” crustaceans (i.e. crustaceans who have become less complex than their ancestors).
Another example is the Order Strepsiptera (also called “twisted-wing parasites”), in which the females have lost, over evolutionary time, their wings, their legs, their eyes, etc., and resemble maggots.
I would not have considered you raving mad for pointing out either of these examples. To the contrary, I would have considered you well-read and observant.
As it stands, I still don’t think you’re raving mad: but, I do suspect that you are not exercising sufficient care in constructing your arguments, and that you view yourself as more knowledgeable than you actually are.
The traditional definition of species is as a group of organisms capable of interbreeding and producing fertile offspring.
Actually, the even more traditional definition of species is as a group of organisms that possesses a given list of characteristics, which is pretty much what you're advocating here (although you are using genetic characters, whereas classical taxonomists used morphological characters). This is called “taxonomy.” The only difference is that you want species identification to require lots of expensive, fancy equipment.
Segments of the genome could be used to define existing species and assist in identifying new species.
This might be an arbitrary system but it would be far more accurate and effective amongst known living species...
... Hence this system has to be the preferred system of definition in the modern age.
So, basically, you want species definitions to just be an academic exercise of assigning names to things, and don’t really care whether it has meaning in the biological world or benefit to people who don’t have the expertise, equipment and funding to sequence genomes?
I argue that the only reason to use the methodology you espouse is because it satisfyingly parcels things into convenient packages of information that sound nice to you. But, it isn’t any more accurate or correct than any other proposed methodology, and it severely restricts the number of people who can do it.
The reason the “biological species” concept (the interbreeding criterion) was developed was to give taxonomy a reasonable grounding in reality. If we define two species based on differences in characteristics (be they molecular or morphological), then find that these differences have virtually no effect on how these organisms interact with one another, what, exactly, is the point of defining them as two species? The satisfaction of a tidy output? The solving of a little puzzle?
Classification does not exist just for the sake of classifying organisms: It exists to help scientists organize information about organisms in ways that are meaningful to the study of organisms.
Don’t get me wrong: there is some meaningful information about the process of evolution that can be gleaned from your proposed methodology (and that’s why many people subscribe to it), but that’s the extent of its usefulness, and gleaning that information doesn't ever require naming and defining species, anyway.
But we can't just make up ad hoc species and lump these fossils under that category. It couldn't be defined as a species under any of our definitions anyway.
They could be defined as a species using the Linnaean and cladistic methodologies.
Linnaean: define by specific characteristics that are regarded as diagnostic.
Cladistic: define by coding a large number of characters, and seeing which organisms cluster into distinct groups on a cladogram.
It sounds like you’re suggesting we pick one method, and stick to it. Then, when that method isn’t useful, we should not fall back on some other, less reliable method, but just leave it undefined.
This leaves us in the uncomfortable position of not being able to organize our information about things on which we can’t do genetic sequencing or breeding experiments.
I don’t see how this could be seen as helpful to science. All indications are that we accomplish more when we initially organize information poorly, and work to improve it over time, than when we refrain from organizing the information at all.
DNA works effectively for determining parentage and lineage, forensic investigation into crime and is now working very well for species identification. This isn't just words...it is happening right now.
Yes, it is happening right now, and some of us on this very thread are very aware of what we can do with DNA, because we have personally done it, and are still doing it. Please keep that in mind as you continue this discussion.
Honestly, the overtly definitive manner in which you write things that your audience knows from personal experience are total crap is extremely irritating.
DNA is not entirely arbitrary...the code for the order in which your body parts develop and the location is hard coded. Nothing arbitrary about that.
Nobody said DNA is arbitrary.
People have said that deciding on an amount of DNA similarity that distinguishes two groups is arbitrary.