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Post by Dave Evans on Jul 2, 2010 22:38:09 GMT
Dear Forum,
I had heard many comments over the years, quite often of late, that the concept of "species" is an artificial one and is not actually what is going on in the biological world.
I think this is nothing more than liberal spin. For example, seems it is obvious most humans are perfectly capable of identifying and even have an internal understanding of the concept; as do many animals. Those who advocate "species" is actually rather vague and everything is just gray, I wonder what sorts of creatures are you going to be mating with tonight?
"Species" was not something imposed on the world by scientists, the scientists are trying to understand the natural world and "species" are naturally occurring systems whether there are scientists present to identify them or not.
The way I see it; a "species" is artificial human concept when its supposed attributes and characteristics and closest related species do not actually reflect what is happening with that system and the published work was based on extremely deficient information.
The more correct information we have about a "species" the less artificial the concept becomes. For example, it might be realized the species xxx is actually a part of the larger species yyy. Changing the names around takes the taxon to a more appropriate rank of "yyy subsp. xxx" and now more resembles the actual structure of the relationship. Less artificial than before.
Comments, please.
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Post by kitkor on Jul 3, 2010 3:10:52 GMT
Interesting... While I don't agree with you on whether or not it's "liberal" spin, I think we have two camps: lumpers and splitters. Taxonomy is an informed opinion. The real unit of speciation is interbreeding populations. Sometimes population = species when there is a large, overlapping range or when there's only one population. When populations become isolated, over time they can become different species, but the trouble is when do you say they're different enough to warrant specific status?
On the other hand, my boss, a microbiologist, has a different view. She and I sparred on this very topic the other day when she asserted that the concept of a species is outdated and that most things are just bags of genes.
When it becomes an issue of semantics and how you end up defining a species, I think it's often open to interpretation, which is why we have vigorous debates about which taxa should be recognized. Often our debates are fueled by a lack of sufficient data.
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Post by Dave Evans on Jul 3, 2010 4:11:27 GMT
Hey Kitkor,
I think I read that very line somewhere recently... About everything being a bag of genes. Sounds rather like a short cut to me. Viruses are just protein envelopes with genes inside and a lock pick on the front... But other kinds of microbes are clearly much more complicated.
Speciation through isolation is probably the slowest form of evolution, unless there are more changes in the different environments the various populations end up in, causing the populations to respond in different ways. Isolation by itself probably doesn't drive evolution, but with each population coping with a different environment, it certainly can.
Heliamphora might be a little different as their isolation has been on going for dozens of millions of years. Given this large time frame, even within the same general environment speciation has taken place, might be the result of mathematical properties of genetics--simply collecting enough mutations over millions of years each population slowly drifted into different species while maintaining their fitness. Of course, the true story might be completely different than that...
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Post by BarryRice on Jul 5, 2010 1:54:47 GMT
Hey Dave,
I think that the species concept has its problems, but it still has validity and relevance.
I think the reason it is under fire, to a large degree, is that as a culture we no longer value organismal biology, and everything has become molecular. Look at the departments at major universities, and you'll see botany, zoology, mycology, are all disappearing or being consolidated in a mad dash for survival. Meanwhile, if you track down an expert in any taxonomic field, and you'll likely be talking to a grey or white haired emeritus.
I subscribe to the "biological species concept," and think it does quite well in most aspects of botany. On the other hand, my best friend is a mycologist, and she frequently laughs at the species concept as being useless in much of what she does.
In cases where hybrid swarms dominate, sure the concept of species has less relevance. But that is as important a fact than if the plants were falling neatly into line. Without a species concept, you have lost a good way to measure diversity.
B
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Post by philgreen on Jul 19, 2010 22:55:58 GMT
I think that the species concept has its problems, but it still has validity and relevance. I'd agree with that statement. The way I see it. Every organsim is primarily concerned with the survival (passing on) of its genes. This is why in some species, there is close cooperation between related individuals in raising young - a relatives offspring share some of your genes. So it there for makes most sense to breed with an individual which also has some of those same genes - hense you get species (organisms which share many of the same genes). However, when none of the same species are available, then an individual breeds with whatever is around and compatible (shares some genes, but less than the 'same species') which is why we get 'hybrids. Aditionally, the concept of a 'species' is fixed and we are seeing things at one moment in time, but evolution is ongoing. So how do you define something which is in the process of forming - things which aren't really one thing or the other. And what happens when a 'species continues to change after we have described it ? or some isolated populations do. Do we just change the deffinition ? So for me, the concept of species is the result of those selfish genes. It works well most of the time. But problems are down to the fact that we (most humans) like to put things in discrete boxes, but LIFE isn't always that simple and doesn't always play by our rules.
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Post by Dave Evans on Jul 20, 2010 1:14:13 GMT
Dear Phil,
Well, then why stick to the "idea" species are static? I'm not sure why this is then included as part of the definition if it isn't part of reality...
I really don't think everything has any interested in passing on its genes. That is what living things do, but they aren't "aware" of it.
Also, within a species, the pairs of genes match up. This isn't what happens in hybrids, unless the parent species are very, very similar. The new genetic combination/hybrid might produce individuals that are better adapted and these might go on to generate a new species. I think a hybrid swarm of Heliamphora might live for hundreds of years without changing much but that is just because they and most other species in the area are all well adapted to their environment and there is very little selective pressure one way or the other.
I think we should dispose of the idea species are static. I'd also like to see herbarium made of highly detailed digital photographs of living plants with dried materials used more as vouchers and for genetic studies. Almost all the naming problem in Nepenthes and Heliamphora can be traced back to an error in interpreting herbarium specimens and a lack of ecological data. The lumpers and splitters just try to fill in data we haven't collected or studied yet to support their prejudgemental and therefore almost certainly flawed concepts.
Do you guys have any idea how many time I've heard that 'N. northiana and N. mapuluensis are closely related and perhaps should be combined into one species'? Way too many. I suggest taking a good look at both of them before reaching for flaky conclusions...
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Post by philgreen on Jul 20, 2010 22:38:50 GMT
Dave, Personally, I don't think a solution that suits everybody and every 'species' can ever be found. As I've said, the 'idea' of species is to a certain extent a human one - or at least it is us that draw the boundarys. As kitkor has already said, there are lumpers and splitters and those two camps will never agree. Additionally we seem to have different standards when discussing the natural world and us humans. NOW PLEASE, DON'T ANYONE TAKE THIS AS A RACIST COMMENT. But with plants, birds or what ever, when they have evolved on seperate mountains / islands / continents to look different - size / colour even language (two bat species have recently been seperated because they 'speak a different language') then they are called different species or at least subspecies. But this rule is never applied to us humans. So we are already applying double standards - or is it just the old lumpers and splitters debate. And before anyone say's it - it is now known that many seperate species can interbreed and produce fertile offspring. I agree that organisms probably don't think directly about passing on their genes, but then very few actually think about breathing, they are just those inbuilt things that happen automatically, but are still a driving force. Just like it doesn't matter how ill you are feeling in that hospital bed, when that nurse comes around ..... The idea of a non static deffinition of species may sound appealing, but I can't really ever see it working in reality. A dinosaur species gradually changed into a bird and numerous birds - are they now just subspecies of a dinosaur ? If the deffinition can change, then that causes problems for naming with evolution which is ongoing. So either one species ends and other begin or with the exception of mass extinctions, most species never end, they just change beyound all recognition to the original description. So really we are stuck with what we have. It isn't perfect, but as long as we are so consumed with trying to put everything into boxes and convince ourselves that we are masters over nature, it's likely to be the best we'll get. But that will never change the fact that 'species' couldn't care less what we call them - they will continue to do whatever they want to, with who ever they want to. Neps and Heli's are ideal subjects for the lumpers and splitters. I don't really have too much problem with either camp, so long as we all know exactly what we are all talking. If that be species or subspecies or forms or even just locations - to be honest location is far more important to me.
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Post by Alexis on Aug 5, 2010 10:03:19 GMT
Yes, in theory there is no reason why the flava system shouldn't apply to homo sapiens. For political reasons I suspect we don't have H. sapiens var. atropurpurea or H. sapiens var. maxima!
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Post by Dave Evans on Oct 5, 2010 23:58:56 GMT
Dear Alexis,
Dr. Schnell's work has a serious flaw: He specifically does more work on species he personally flavors. He loves S. flava and so S. flava gets more attention in his book. He barely pays attention to S. purpurea and so doesn't understand why S. purpurea venosa var. burkei should be removed from S. purpurea venosa; despite every test one can think to give shows the result that they are not directly related.
He doesn't really pay much attention to Drosera either. And so you see a photograph of D. spatulata in the D. capillaris section...
I have been to many of the same stands of S. flava Dr. Schnell has been to and I have not noticed the differences in vegetative growth he lists in Carnivorous Plants of North America...
S. flava var. altropurpurea is a non-existent plant; it really is more of an idea than a taxon... And as Dr Schnell explains, his varieties are generally blended in most wild plants.
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Post by Dave Evans on Oct 6, 2010 0:22:25 GMT
The idea of a non static definition of species may sound appealing, but I can't really ever see it working in reality. A dinosaur species gradually changed into a bird and numerous birds - are they now just subspecies of a dinosaur ? If the definition can change, then that causes problems for naming with evolution which is ongoing. So either one species ends and other begin or with the exception of mass extinctions, most species never end, they just change beyond all recognition to the original description. Err, no. There are lines of descendants, and there are rainbows of diversity in the successful lines; before the next species evolves or emerges a lot of those colorful smears of diversity go extinct and do not contribute going forward. What is Nepenthes' closest related genus? Extinct that is what... Next closest, extinct as well. To find it closest living relative we have to go all the way back in the family tree to Triphyophylum, a part time carnivore with Drosophyllum like traps. Clearly, there a lot of other intermediate species, probably even genera with different kinds of traps, have developed since the lines split but all those 'missing links' are now extinct. Also, there isn't much evidence dinosaurs 'turned into birds', but rather a handful dinosaurs and all birds have the same dinosaur ancestor species. The dinosaurs species really did die out, a few of the ancient bird species did not. They were already long split into different lineages at 65 MYA.
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