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”.
fifthmonarchyman,
No, endless repetition without comprehension.
We all point put the difficulty of defining species, precisely because the ‘materialist framework’ renders them fuzzy. If evolution were true, species would be expected to be fuzzy at the boundaries. They are, by complete coincidence.
Your ‘framework’, so-called, is the unknowable mind of God, in which you assume that your personal (and your appealed-to 5-year old observer’s) recognition of discrete categories represents something akin to his.
I have been involved in two threads with you on this, and your answers devolved into repeating the same mantra. You claimed that God’s categories can be discrete because he is ‘timeless’. I pointed out the unavoidable continuum of individuals during anagenesis rendering discreteness impossible in a framework of descent, even for a ‘timeless God’. You just blinked.
Correct yet we don’t experience species to be fuzzy at the edges. We experience species as discrete entities. Wolves are Coyotes are not the same
Who said the “mind of God” is unknowable?
We all know what a circle is despite there being nothing in the physical would that corresponds precisely to the form
you are going to have to unpack this for me. Just claiming something does not make it so
peace
fifthmonarchyman,
I would concur with this, but add, that we end up calling ‘everything” a species, so they can be fuzzy or not fuzzy, or the same thing perhaps, or something totally different, we have no idea what we are talking about when we say a species. is Neanderthal a different “species” from humans? Why so? If that is the case, then why aren’t Samoans and Swedes different species? Deers, reindeer, elk, moose, antelope, big horn sheep, bison, giraffes, hippopotami, pigs, donkeys, impalas, wildebeests, rhebok, okapi, cows, camels, rhinoceros, lambs …..which are different species and which are different animals?
fifthmonarchyman,
Yes, we do. Or are you now saying there is no such thing as ‘the species problem’? Species are the things we experience to be discrete, and not-species are the things we experience to be not-discrete. That’s massively helpful, in a not-at-all-helpful kind of way. Ta.
I did. You claim to know it, but you are just making stuff up and claiming it as revelation.
So bleeding what?
Like you say , “Just claiming something does not make it so”. Your claim that God recognises transition between discrete categories in a line of descent being one such claim.
If you didn’t understand the point the first time, or the second, you aren’t going to understand it the third.
phoodoo,
So you are saying that there is a species problem? Well done you.
I’m saying that you only have a species problem when you use reproductive compatibility to define and bound a species. Then you have a big problem.
No I’m not. I’m claiming that we all know things like the difference between a circle and an oval and can determine which of those shapes a stone we happen to find is .
That is all that we are doing when we differentiate between a wolf and a coyote
This is not me making stuff up. This is the common knowledge and practice of humanity. It’s called categorization and we do it all the time. It only becomes difficult when you try to shoehorn reproductive compatibility into the definition
Let me see if I can help you.
Suppose you are reading a book. In that case you have a perspective that is outside the temporal universe of the characters in the book. Are you with me so far?
Now suppose you want to categorize the characters as hero or villain.
You would have no trouble doing so even if the characteristics of the dramatis personae formed a continuous normal distribution from good to evil.
You could do this even if individual characters changed through the course of the book.
Why could God not have this same ability.
A being outside of time could take all the individual organisms in our universe and place them in what ever category buckets he chose to.
If not why not?
peace
The concept of genus and species would work in each of those examples
Neanderthal and Homo sapien are two “species” in the genus Hominid. At the same time Samoans and Swedes are “species” in the genus homo sapien.
It all depends on the resolution of your categorization effort. This principle works all the way down to the individual.
check it out.
http://www.philosophy-dictionary.org/GENUS_AND_SPECIES
peace
This discussion is not just academic it’s likely two rare canines will loose protection because of the insistence on linking our understanding of species with mere reproductive compatibility
It’s sad
check it out
peace
Ive been doing some studying on the implications of the discovery that red wolfs can not be considered a separate species according to the usual definition.
quote:
If biologists focused solely on species status as the guide for
determining whether an endangered group should be protected, such findings could be the death knell for the red wolf. Yet there are compelling reasons protection should continue. Captive breeding of the red wolf may have preserved unique physical characteristics or behaviors not revealed in the studies done so far. More important, such qualities may not be easily regenerated through the mating of modern gray wolves
and coyotes.
and
Additionally, ecological concerns need to be considered. Red wolves, even if they are hybrids of coyotes and gray wolves, are once again important predators of many wild animals,including rodents, rabbits and deer, in the south central U.S. The red
wolf may also play a role in some habitats that its smaller kin, the coyote, cannot entirely fill.
end quote:
from here
http://redwolves.com/wp/wp-content/uploads/2016/01/23-Wayne-and-Gittleman-1995.pdf
like I said it’s just sad
peace
Still more
quote:
The case of the red wolf suggests to us
that in deciding which animals to protect most assiduously, biologists must look beyond the taxonomic classification of an endangered hybrid or subspecies; they should also take into account its unique function in an ecosystem or possession of special traits that cannot be reproduced by crossbreeding of contemporary representatives from the parental species
end quote:
That is why this is an important topic.
Continuing to Limit ourselves to a definition of species that is dependent on reproductive compatibility results in losses of ecological diversity and can adversely effect entire ecosystems.
It does not have to be that way
peace
I would like to offer a compromise tri-perspectival definition of biological species that I believe would solve the species problem and be workable and intuitive at the same time.
Suggestions for improvement and critiques are welcome
Two organisms are members of the same species if
1) They share a relatively recent common ancestor
and
2) The are relatively similar genetically
and
3) They are have a relatively similar phenotype and occupy the same ecological niche
*relative means as compared with organisms not of the same species.
This definition would save the red wolf and also things like the remnant native bears in the Ozarks that are being threatened by bears introduced from Canada under the mistaken belief that one bear is as good as another.
What do you think
peace
Which in turn would be defined as “relatively dissimilar” as compared with organisms of the same species. See the problem here when this similarity decreases gradually?
It’s always a problem when the definition of a word has to include the word itself, even in a footnote. What you have defined is a cluster of similar individuals. But there are clusters within clusters. How do we decide which cluster is a species, rather than a genus or subspecies, or a family, or a local population? Evolution, unfortunately, doesn’t tie everything up neatly for us.
For conservation it might be good to just go with preserving local populations. It’s already a goal to preserve subspecies, so the species definition doesn’t matter as much as one might think. Now, the problem with the red wolf is that it’s apparently a hybrid swarm and isn’t distinct even under your definition.
No,
In my work I convert continuous data into discrete all the time. It’s as simple a picking a number an declaring everything to the left 1 and everything to the right 0.
That is simple and how we do it in the real world. We choose how circular an object must be before we classify it as a circle.
I don’t see any problem at all.
perhaps you can explain what you mean.
peace
You choose. Then you defend your choice if need be. That is how we do it in everyday life for every other categorization we do.
That is why I suggest leaving evolution out of it all together. There is no reason to include that I can see.
I don’t think my definition does that let me spell it out explicitly
species- a group of organisms that are relatively similar genetically and phenotypically share a relatively recent ancestor and occupy the same ecological niche.
how does that sound?
peace
except that is the very reason that critics are giving to cancel the red wolf program
If it is the case that red wolf are a hybrid swarm then you would be correct.
However my understanding is that the wolf ancestor of two typical red wolfs is closer than the wolf ancestor of one red wolf and a typical grey wolf.
Regardless if this turns out to be true it puts the question of whether red wolfs are a separate species on objective empirical grounds. That is much better than the situation today
peace
But on what criteria will you defend your choice? You definition contains no such criteria, so where will you find them?
Most species definitions don’t mention evolution. What are you suggesting we leave evolution out of, exactly?
I think it suffers from the ambiguity of “relatively”, and your attempt to fix that problem is what led you to use the word “species” in its own definition. If your definition doesn’t include that asterisked note, you’re back to the problem of ambiguity. It also seems to import evolution (“ancestor”), which you wanted to leave out. Finally, it includes four criteria (genetic similarity, phenotypic similarity, recent ancestry, and shared niche), each of which might conflict with the others; what do you do in cases of conflict?
Now, I like the so-called biological species concept, because it’s both unitary and is capable of being applied and defended empirically. Its main drawback is that it covers only obligately outcrossing populations, but I don’t see that as a problem if we agree to limit its scope.
I also don’t see why we have to use species as a basis for conservation biology decisions.
That depends on whether you think hybrid swarms ought to qualify as species. Based on your definition I can’t tell, which is another problem with it.
You certainly can’t ‘leave evolution out of it’ if you are considering fossils, common ancestry or lines of descent. This is where the problem arises.
The argument seems to go thus:
1 – I can see that living species are discrete, when examined cursorily.
2 – This leads me to suppose that species really are discrete categories, and things that don’t fit neatly into such categories can be made to do so, because (see 1). I do it all the time.
But it breaks down both in time, and at moments occurring within the process of speciation. One could simply accept the continuum, but that way appears to lie madness to many Creationists. So, one puts the square pegs into their square holes and the round pegs into their round holes. And the pegs that are a bit o’both get rammed in as best they can.
The difficulty to me is that, at some point in a line of descent, one must declare a parent and offspring to be different species – different ‘essences’. One wouldn’t if presented with both together, or even if presented with every single parent-offspring pair throughout the line, but one must (if one is an essentialist). But there seems no reason to do so other than that one has exported one’s casually-observed notions of discreteness at the present moment to the line of succession, and is determined not to yield this intuition.
It’s not just a question of lopping off a few decimal points to generate discreteness from a continuum, or rounding.
I think you are mistaken here is my definition of species yet again. The word species is not in it
———-
a group of organisms that are relatively similar genetically and phenotypically share a relatively recent ancestor and occupy the same ecological niche.
——–
There is no circular reference AFAICT. What am I missing?
Since it does include the asterisk we are just fine right?
You are assuming evolution. Even the most ardent YEC believes that organisms have ancestors
I see it as a weighting scale in which the weight of each criteria is averaged with the others. For example two organisms might have
.8 genetic similarity
.9 phenotypic similarity
.7 recent ancestry
and
.4 shared niche
The resulting calculation is (.8+.9+.7+.4)/4=.7
If we determine that our threshold is anything above a .65 then the two organisms are members of the same species
It all seems pretty unambiguous to me.
peace
My definition does not factor in reproductive compatibility at all. That is not a bug it’s a feature
peace
Why is that a difficulty? Parents and their offspring are different individuals there is no particular reason to expect them to have the same essence is there?
Are you assuming some sort of great chain of being In which new essences can’t arise de novo ? Why?
Here is where I think you are dead wrong.
Often we decide that a parent is different than it’s offspring sometimes radically different.
An introvert can give birth to a social butterfly and no one bats an eye. Two jocks can be the parents of a couch potato. From time to time albinos are born to parents with normal pigment.
It happens all the time.
I think you are tied to the idea of “the great continuum” of life for some reason.
That’s fine but it is a philosophical position and not one based on evidence.
The evidence is that organisms are individual separate entities that we can subjectively decide to group how ever we wish.
What we want to do is try and have our subjective grouping match the objective one.
peace
A core presupposition of science is that the present is like the past.
If the past was radically different than today we could know nothing about it.
We must assume that the discreteness we see at present extends to the past unless we have evidence that it does not. That seems like a nobrainer
peace
You are self-contradictory. If your definition includes the asterisked note, it includes the word “species”. Let me remind you that your note was “*relative means as compared with organisms not of the same species.”
Can one species be related to another species by descent or not? If so, that’s evolution. If not, why bother with “relatively recent ancestor” rather than just “ancestor” (in which case a species is a kind)? I don’t think you’ve thought this through.
Then I suggest you are fooling yourself. You have an arbitrary threshold to judge an arbitrary combination of four arbitrary numbers. It’s both complicated and unjustified, and we’re no closer to being able to diagnose species than we started.
Yes, temporal limits to species are fuzzy and lead to the kind of problems that bedevil species classification of hominid fossils. But, especially for an allopatric speciation event like an island stranding where there is immediate and irrevocable separation of gene pools, that is what happens.
fifthmonarchyman,
A core presupposition of science is not, however, that sideways is the same as up/down. That’s what you are doing. You are looking between mountain tops poking out of a sea of cloud and declaring that there is no connection, down there in the mist. Because all you can see are tops, you think that’s all there is.
And of course we have scads of evidence that it does not, so we pretty much have that one covered.
Alan Fox,
At no point is a parent a different species from its child, though?
Is French the same as Latin?
Yes, it’s a no-brainer, basic processes are the same as in the past (it’s why common descent mechanisms are sensibly taken to be the same today as in the past, in languages and in organisms), while results differ.
It takes thinking, not your reactionary defense of anything and everything that you’ve always believed.
Glen Daivdson
fifthmonarchyman,
Well, yes there is. Unless you have some of that good old evidence that Creationists are always demanding of evolutionists, I would say that every individual is the same ‘essence’ as its parent, down any lineage you care to name.
Hardly a ‘great chain’, but by routine observation, parents and offspring are not different ‘essences’. Apart from a few instances of polyploidy, which can’t lead to speciation in obligate outcrossers, offspring form part of the gene pool of, and share almost all the characteristics of, their relatives. They are not materially different.
These counterexamples are just plain stupid.
I recognise that offspring and parents are not radically different types of organism, if that’s what you mean.
HAHAHAHA. So says Mr Essences.
The subjective grouping (informed by your ‘look-around-you’ analysis) loses traction in lines of descent. That is the problem you pretend does not exist, by just insisting that lateral disconnection MUST imply temporal disconnection, absent evidence to the contrary. It doesn’t at all, as examination of any handy tree would confirm.
I guess that depends on whether one considers the isolation of gene pools as the beginning of the speciation process. If one sibling is a pregnant female tortoise that washes up on the Galapagos when another remains on the mainland, the accumulation of different slight variation may take many generations to achieve breeding incompatibility in the two siblings’ descendants. It seems only a problem if one insists on sharp edges.
Alan Fox,
I think it depends more on how fine-scale one wishes to go. Speciation starts even before separation, simply because any population has polymorphism which can affect a subsequent founder effect. Divergence is always in train, and gene flow (or potential flow where separation has occurred) generally attenuates only gradually. And the potential can exist for 20 million years or more, if non-geographical reproductive barriers are the criterion.
But still, I’d say with very few exceptions every individual is the same species as parents, wherever they live. You wouldn’t call two closely related individuals different species just because one lived on a rock!
Allan:
Alan:
No, because as Allan explained, the speciation event is itself fuzzy.
Allan Miller,
I’m sorry I have to violently agree. It’s not a problem for living species or anyone studying them. Being short-sighted, all lines look blurry to me! I was going to say something about human evolution and deciding where to draw the line between modern Homo and early Homo and just thought I’d check my facts. Distracted by shiny things. Homo sapiens idaltu is described as having “certain cranial traits [that] are outside the range of modern human variation”. But presumably there is a direct line of descent from parent to child across that 100,000 years or so.
Thanks for pointing that out!
ETA:
AF wrote in the OP
“How to delineate a species temporally is also problematic.”
Alan,
You’re welcome.
Now let’s see if you got the message.
Do you understand that there is no point at which parent and offspring are of different species, contrary to your claim?
Wasn’t aware I’d claimed that other than to say if you insist on sharp delineation to be drawn across lines of descent, the reductio ad absudiam insists you draw it somewhere. Or you can take the opposite tack and say its all one species. Pragmatically, one takes the fuzzy view.
Alan,
You claimed it here:
Allan:
Alan:
You made the same essentialist mistake as fifth. That’s why Allan objected.
I can see it being read that way, but I read it as saying that an essentialist must draw a sharp line, not that Alan does.
As I was told, for practical purposes two populations that rarely if ever interbreed can be regarded as different species, regardless of the reason they don’t interbreed. This can happen gradually, as the rate of interbreeding (in nature) diminishes to near zero, or immediately when some organism washes up on an island.
In the first case, there are almost certainly some physical differences driving the split (pheromone variations, for example), and in the second case there are no immediate biological differences at all. The “separate species” determinations here are a matter of operational convenience.
petrushka,
Why? There’s nothing in Alan’s statement to indicate that he is speaking for anyone other than himself.
Well, exactly. One can quite happily work with the fuzziness. As in the example of humans, adaptation over time can make a temporal categorisation convenient, without ever needing to qualify the obvious fact that breeding isolation can never be tested with dead organisms. (Though molecular phylogenetics – where DNA survives – is an additional tool to apply to the issue.)
Indeed. Just the niche has changed.
I should point out that my poorly expressed ideas are not original. I’m pretty sure Dawkins said something more eloquent in one or other of his books.
You have no interest in or willingness to figure out what other people are saying, and no interest at all in why someone might say something. So when someone who obviously understands evolution says something that doesn’t seem right, your first instinct is to jump into the fray with guns blazing, rather than ask for clarification.
It’s a character trait you share with some of our creationist friends.
petrushka,
I judge comments by their content. Alan’s comment was wrong, and Allan corrected him.
That should have been the end of it, but Alan is childishly refusing, as usual, to admit his mistake.
Alan,
You claimed that an island stranding was an instance where a parent and offspring had to be of different species:
Allan:
Alan:
That isn’t what happens. As Allan pointed out, speciation is a fuzzy process. and it makes no sense to point to a particular parent/offspring pair and claim that they are of different species.
Here’s the rest of Allan’s comment:
Keith’s I think you should know that people will remember my one comment on your behavior long after they have forgotten a thousand of your posts.
Being right all the time gets you nothing, except contempt.
petrushka,
There is nothing wrong with being right, and I won’t apologize for it. There is no wrongness quota that I am required to fulfill, though you might wish otherwise.
If you’re uncomfortable with skepticism, perhaps The Skeptical Zone isn’t the right place for you. In any case, your irrational annoyance will not dissuade me from continuing to be skeptical.
Being an asshole is not the same thing as being a skeptic.
It’s not the content of your ideas but the way you interact with people.
petrushka,
I agree with people when I think they’re right, and I disagree with them when I think they’re wrong. I give my reasons, and I consider theirs in return.
What I don’t do is to tiptoe around fragile egos, including yours, and I won’t be bullied out of pointing out errors when I see them.
Alan made a mistake, and Allan Miller pointed it out. Alan’s childish refusal to acknowledge it is no reason for the rest of us to play along. As I’ve said before, this is The Skeptical Zone, not Alan’s Safe Space.