“Species”

On the thread entitled “Species Kinds”, commenter phoodoo asks:

What’s the definition of a species?

A simple question but hard to answer. Talking of populations of interbreeding individuals immediately creates problems when looking at asexual organisms, especially the prokaryotes: bacteria and archaea. How to delineate a species temporally is also problematic. Allan Miller links to an excellent basic resource on defining a species and the Wikipedia entry does not shy away from the difficulties.

In case phoodoo thought his question was being ignored, I thought I’d open this thread to allow discussion without derailing the thread on “kinds”.

1,427 thoughts on ““Species”

  1. John Harshman: All you care about is that those dang evolutionists are messing things up.

    once again
    Intelligent design is not anti-evolution.

    It’s not “evolutionists” that are messing things up it is blind adherence to an untenable definition.

    peace

  2. fifthmonarchyman: If I was in charge taxonomy would be based solely on phenotypic considerations. I would remove phylogentic speculations from the equation entirely.

    There’s a reason I put “phylogenetic” in quotes in “‘phylogenetic’ species concept”. In fact it relies on phenotypic traits, mostly, and has little to do with phylogeny. Anyway I think you had stated at one point that molecular traits were phenotypic. Certainly they’re observable and they provide clear differences between groups. What’s not to like?

    So, yeah, you favor the phylogenetic species concept, despite the name. Now one problem with that concept (and of course yours) is it doesn’t tell you which phenotypic differences ought to count. There are features unique to individuals, features of local populations, features of biological species, features of genera, features of families, and so on. How do you know what’s a species and what is more properly a subspecies, genus, etc.? You have no guide.

  3. John Harshman: There’s a reason I put “phylogenetic” in quotes in “‘phylogenetic’ species concept”. In fact it relies on phenotypic traits, mostly,

    Not sure why you say that.

    The “Taxonomic vandals” the article describes rely on phylogenetic trees and geographic isolation and look at “phenotypic traits” only superficially (i.e. red verses green) when they “discover” species.

    Are you saying that the article is incorrect?

    John Harshman: I think you had stated at one point that molecular traits were phenotypic.

    Could be, just because a trait is small does not mean it’s insignificant.

    Phenotype classification is still the preferred method of classification when looking at single celled organisms for example.

    John Harshman: How do you know what’s a species and what is more properly a subspecies, genus, etc.?

    There are eight major taxonomic ranks. When you classify you generally start with the general and move to the more specific.

    You seem to think I’m advocating more than I am, Taxonomy worked just fine before Mayr came along. I’m not talking about blowing up the entire system

    The world would not explode if we modified the modern definition of species a little bit.

    peace

  4. CharlieM:

    How about the use of power? Can you use your power in a way that dictates everything that others do and still give them unconditional love?

    You think that if God took the loving step of warning you about a hurricane that was going to destroy your house in two weeks, he would be “dictating everything that you do”?

    In order to give someone the freedom to go against your wishes can you still say that you have total power over them?

    Yes. Think it through, Charlie. The fact that you allow someone to do something doesn’t imply that you’ve lost the power to prevent it if you so choose.

    What you are saying is that a person can choose to hand power over to another person while still retaining total power. It does not make sense.

    Suppose a dictator allows someone to publish a book critical of the government. Does that mean he has relinquished, now and forever, the power to prevent other critical books from being published? Of course not.

  5. John Harshman: There’s a reason I put “phylogenetic” in quotes in “‘phylogenetic’ species concept”. In fact it relies on phenotypic traits, mostly, and has little to do with phylogeny. Anyway I think you had stated at one point that molecular traits were phenotypic. Certainly they’re observable and they provide clear differences between groups. What’s not to like?

    So, yeah, you favor the phylogenetic species concept, despite the name. Now one problem with that concept (and of course yours) is it doesn’t tell you which phenotypic differences ought to count. There are features unique to individuals, features of local populations, features of biological species, features of genera, features of families, and so on. How do you know what’s a species and what is more properly a subspecies, genus, etc.? You have no guide.

    I don’t know how you can write that paragraph, and then say there are features of biological species?

    Its difficult to define species because some features are unique to species?

  6. If only those annoying scientists would stop changing how they use words every time they discover something new about the world!

  7. Kantian Naturalist: If only those annoying scientists would stop changing how they use words every time they discover something new about the world!

    There’s nothing preventing them from creating new words. They already do it all the time when they name a new species.

  8. newton: Since there are no actual mechanisms associated with ID we can’t know whether or not it is anti-evolution or not.

    This is simply nonsense. Evolution is a mechanistic theory. In order for ID to be a challenge to evolution it would have to offer an alternative mechanism.

  9. Mung: This is simply nonsense. Evolution is a mechanistic theory. In order for ID to be a challenge to evolution it would have to offer an alternative mechanism.

    That seems right. But to do that ID would have to specify the mechanisms that underlie the process of intelligent design and propose a test whereby those mechanisms can be detected with regard to the origins of novel phenotyoes. I don’t see anyone working in ID trying to develop a mechanistic explanation along those lines.

  10. KN,

    I don’t see anyone working in ID trying to develop a mechanistic explanation along those lines.

    Nor do they want to, since there is no evidence for such a thesis.

    Their eggs are in the “evolution is false, so ID must be true by default” basket.

  11. Kantian Naturalist: I don’t see anyone working in ID trying to develop a mechanistic explanation along those lines.

    Kind of hard to do when they can neither contradict YECism nor some sort of multi-billion year tinkering “evolutionary” process.

    Two reasons: 1. It’s a political/apologetic stance trying to save God as designer/creator, and 2. because they simply have no scientific ideas about the design of life at all.

    Glen Davidson

  12. Mung: This is simply nonsense.

    No, it’s entirely correct. There ARE no actual mechanisms associated with ID.

    Evolution is a mechanistic theory. In order for ID to be a challenge to evolution it would have to offer an alternative mechanism.

    This is, I think, not so correct. ID has without question been challenging evolution since it was invented, and in some quarters the challenge has been effective and ID is indeed regarded as a superior explanation for the design of life. The mechanism of “that’s the way the Christian god (some versions) chose to do it” is quite sufficient for some people.

    The fact that this “mechanism” is supernatural, a matter of faith, and not subject to any sort of empirical test is regarded as a strength of ID “theory”, not a weakness.

  13. keiths:

    Their eggs are in the “evolution is false, so ID must be true by default” basket.

    That particular false dichotomy is all they have.

  14. Pedant: That particular false dichotomy is all they have.

    That’s right. Evolution could be guided. Evolution could take place and ID could be true as well.

  15. Mung: This is simply nonsense. Evolution is a mechanistic theory. In order for ID to be a challenge to evolution it would have to offer an alternative mechanism.

    That question was not about a challenge , it was whether ID is anti-evolution, all I am saying until a mechanism is proposed we don’t know. What might be true is ID is not necessarily anti-evolutionary theory though the acceptance of random mutations causing variations seems to be a problem per local discussions.

    But a cursory glance at ID apologists the focus is only on one mechanism and its faults.

  16. Mung: The part that infers design based on patterns, just like evolution!

    I was unclear, which part is Intelligent design and which part is evolution? Take the eye, for instance.

    Rereading I see the guiding part is ID, thanks.

  17. Mung: That’s right. Evolution could be guided. Evolution could take place and ID could be true as well.

    Coulda woulda shoulda.

  18. Mung,

    Evolution could take place and ID could be true as well.

    No. The same evidence that overwhelmingly confirms common descent also confirms that evolution is not guided, as I’ve explained many times, both here and at UD.

  19. keiths:
    Mung,

    No.The same evidence that overwhelmingly confirms common descent also confirms that evolution is not guided, as I’ve explained many times, both here and at UD.

    Sorry, but I don’t understand your explanation. I think we can safely say that IF AND ONLY IF we make a certain set of presumptions about the means, motivations, and goals of the guide, and make sure this set is other than what we observe, we can then say evolution is unguided by THIS guide, according to THESE assumptions.

    We can also safely say that IF evolution is guided, the guide seems to act indistinguishably from we’d expect if there is no guide.

    But (I guess unlike Mung), I don’t see the utility of presupposing a guide whose actions are identical to the no-guide condition.

  20. Flint,

    Sorry, but I don’t understand your explanation. I think we can safely say that IF AND ONLY IF we make a certain set of presumptions about the means, motivations, and goals of the guide, and make sure this set is other than what we observe, we can then say evolution is unguided by THIS guide, according to THESE assumptions.

    It’s the other way around. The only way to rescue ID is to assume that the Designer, by choice or constraint, acts in a way that mimics unguided evolution. However, that assumption is so ad hoc and unjustified that it renders ridiculous the very hypothesis it is intended to support. IDers have no reason to make that assumption, and therefore no reason to favor ID over unguided evolution, a theory that matches the evidence without requiring ridiculous, ad hoc, unjustified assumptions.

    My go-to analogy for this is the Rain Fairy. Here’s a parallel version of the above paragraph, but in terms of the RF:

    It’s the other way around. The only way to rescue the Rain Fairy hypothesis is to assume that the Rain Fairy, by choice or by constraint, acts in a way that mimics unguided meteorology. However, that assumption is so ad hoc and unjustified that it renders ridiculous the very hypothesis it is intended to support. Rain Fairyers have no reason to make that assumption, and therefore no reason to favor the Rain Fairy hypothesis over unguided meteorology, a theory that matches the evidence without requiring ridiculous, ad hoc, unjustified assumptions.

    The nice thing about this analogy is that IDers instantly recognize the absurdity of the Rain Fairy hypothesis. They’re taken aback when it’s pointed out that ID uses the same bad logic.

  21. Surprisingly, and in spite of literally thousands of scientific papers relevant to the subject, there are more species concepts in popular usage today than at any point in the past century, and the consensus in zoology about the Biological Species Concept has begun to unravel. An aggressive search for a species concept that is consistent with phylogenetic theory has begun.

    Species Concepts and Phylogenetic Theory (2000)

  22. I never cease to be amazed at how intelligent folks can hold to wildly contradictory understandings at the same time and not even realize that there is a discrepancy.

    How in the world is a second generation hybrid finch considered a species and the red wolf is not??

    https://www.sciencedaily.com/releases/2017/11/171124084320.htm

    What is it going to take for Darwinists to finally abandon the “biological species” concept that is the foundation of the New synthesis ?

    Apparently an “instant” species is not going to do it

    Move along nothing to see here,

    Individual species boundaries are just a little fuzzy and ill-defined due to the extraordinarily long periods of time necessary for speciation to occur via rm/ns. but we know that the idea is fundamentally sound…….it must be

    LOL 😉

    peace

  23. I know I sound like a broken record but when unexamined whacked out ideology results in real world harm it gets my dander up.

    Here is some sage advise that will probably be ignored,

    quote:

    Lead author Rutledge proposes another way for conservationists to approach this: focus on the ecosystem not the species.

    “Conservation focuses on a very species-specific model,” she says. “Agencies often want to know first whether a species is taxonomically valid, but that may not be an efficient way to approach conservation in general. Our research shows that what species are can be very difficult to pin down.”

    “But we know that ecosystems need top predators,” she continues. “That is so clear in the case of over-abundant white-tailed deer in eastern forests. The eastern wolf could play that role, if it could disperse.”

    In other words: Let’s quit trying to make wolves fit into our neat little taxonomic boxes. Let’s focus instead on how to protect and restore their critical role as top predators.

    end quote:

    https://blog.nature.org/science/2015/08/03/wolf-coyote-coywolf-understanding-wolf-hybrids-just-got-a-bit-easier/

    peace

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