|
Register | Sign In |
|
QuickSearch
EvC Forum active members: 65 (9162 total) |
| |
popoi | |
Total: 915,806 Year: 3,063/9,624 Month: 908/1,588 Week: 91/223 Day: 2/17 Hour: 0/0 |
Thread ▼ Details |
|
Thread Info
|
|
|
Author | Topic: Should the term species be used? | |||||||||||||||||||||||||||||||
wolfwing Junior Member (Idle past 4817 days) Posts: 9 Joined: |
This was a topic I had started on another forum, and just curious about in general.
The term species works, but in reality looking at long time, it doesn't exist. We've found many fossils of various animals, and call some species like T-rex, triceratops and so on, but in reality what were seeing is a snapshot of a continual line of animals. We have species today, but what were seeing is a snapshot of the animal lines that exist today. If we had a picture of every single animal from early bacteria bush at the base of the evolutionary tree, all the way up to every single living animal now along with every single extinct animal along the way, what we would find is snapshots of groups that we could call a species. Or even a line, say mine all the way back to the common ancestor of chimps and us, taking a section of the timeline you could say this was say aferensis, and this section past it is the next species. Of course the problem would be that the line is arbitrary, since if you took the section between the two you could call that a species just as easily. Reason I say this is that as we keep finding with animals alive now, there really isn't any easily defined definition of species even using animals alive, what many would consider a species, like lions/leopards/tigers can still interbreed and ocasionally produce reproductive capable offspring. Plus it gets hung up on the creationists term Kind and get into semantic arguments. Is there a better word that could be used other then species, or some way to make species fit more what we actually see? It's just a weird thought I had :> SOmething I had been wondering about for a bit.
|
|||||||||||||||||||||||||||||||
AdminModulous Administrator Posts: 897 Joined: |
Thread copied here from the Should the term species be used? thread in the Proposed New Topics forum.
|
|||||||||||||||||||||||||||||||
RAZD Member (Idle past 1404 days) Posts: 20714 From: the other end of the sidewalk Joined: |
Hi wolfwing
The term species works, but in reality looking at long time, it doesn't exist. We've found many fossils of various animals, and call some species like T-rex, triceratops and so on, but in reality what were seeing is a snapshot of a continual line of animals. We have species today, but what were seeing is a snapshot of the animal lines that exist today. One of the things to consider is the difference between species identified by speciation events - where a parent population divides into two or more daughter populations that have become reporductively isolated - and species identified by arbitrary comparison of traits - as in the gradual change of species along a lineage.
Or even a line, say mine all the way back to the common ancestor of chimps ... That would be a speciation event that divide the populations between chimp ancestors and human ancestors.
... and us, taking a section of the timeline you could say this was say aferensis, and this section past it is the next species. That would be the arbitrary speciation designations along a lineage. A good visual example of this difference is found in Pelycodus evolution:A Smooth Fossil Transition: Pelycodus quote: The division shown is a speciation event, and as you look at the lineage you will see several arbitrary speciation designations to differentiate the morphological changes (including size) as they trend from the bottom to the top. You will also see that the overall trend from Pelycodus ralstoni at the bottom to Notharctus venticolus at the top right has a gradual "trendency" of increasing size with time, but that the divergence of Notharctus nunienus from that trendency occurs at a greater rate of change. This likely occurs for two reasons: (1) the original ecological niche of Pelycodus ralstoni still exists, providing an open opportunity for a smaller species, and (2) the separation in habitat\ecology is necessary to reduce competition between the daughter species (without it one species will likely drive the other to extinction or being reabsorbed - as you can see occurred between Pelycodus trigonodus and Pelycodus jarrovii when an earlier shift to the left shows up, then dissappears).
Reason I say this is that as we keep finding with animals alive now, there really isn't any easily defined definition of species even using animals alive, what many would consider a species, like lions/leopards/tigers can still interbreed and ocasionally produce reproductive capable offspring. There is a difference between animals that can be made to interbreed in captivity, and what animals chose to do in the wild. If the mating signals are all wrong between daughter populations, they will not chose to mate whether they are capable of doing so or not. A good example of this is the ring species, the Asian Greenish Warbler:Greenish warblers quote: The mating songs and the plumage are sufficiently different at the overlap that the two populations remain reproductively isolated, yet the hybrid zones between each of the pairs of varieties as you go around the ring from one end to the other show that in these zones the mating songs and the plumage do not prevent or inhibit interbreeding, because they are still recognized as being potential mate material. Also see Definition of Species Plus it gets hung up on the creationists term Kind and get into semantic arguments. In my humble (or not so much) opinion, the best comparison with the creationist "kind" is with clade, from cladistics, as all descendants are members of the same clade\kind. Species is useful in clarifying what we are talking about, but should also be taken with a grain of salt. Enjoy. by our ability to understand Rebel American Zen Deist ... to learn ... to think ... to live ... to laugh ... to share. Join the effort to solve medical problems, AIDS/HIV, Cancer and more with Team EvC! (click)
|
|||||||||||||||||||||||||||||||
Larni Member (Idle past 163 days) Posts: 4000 From: Liverpool Joined: |
All taxonomy is categorical.
As such you have to accept that there are going to be categorical errors. A useful short hand.
|
|||||||||||||||||||||||||||||||
nwr Member Posts: 6408 From: Geneva, Illinois Joined: Member Rating: 5.1 |
We classify into species, in order to better organize biological data. It doesn't matter that the division points are somewhat arbitrary. What's important, is that they are useful.
Should we give up our concept of length, because the division points on the ruler are arbitrary? Jesus was a liberal hippie
|
|||||||||||||||||||||||||||||||
wolfwing Junior Member (Idle past 4817 days) Posts: 9 Joined: |
This was more of a thought experiment is it worth doing it. Just something I was thinking of, sort of what I was talking about is.
Lets say there is a species of hermaphoditic animals on some planet that evolve rapidly, something simular to almost like pokemon, they have a high rate of mutations and their nature allows them to change alot, so each generation is only able to mate with those before and afterwards the mother or the daughter. So you get something like. A - B - C - D - E - F with only those to the left or right able to mate. Is each individual one a species? Is every two a species? Is every 3 a species? This is sort of a extreme example, but it's what we see with populations and such in RL and in the fossil record. While there are speciation events that make C descendants unable to mate with each other, thre is no clear definition backwards along those lines. I'm not talking about species on the same point of time but along the timeline of that species. indviduals from A1's third generation can't mate, but C can mate with B and D. Not sure if I'm explaining what I mean right. Lions and tigers are on the same time line and as a snapshot due to various reasons can be considered a species. but along the timeline from tigers to the common ancestor to lions and tigers while if we found fossils we would consider the ancestor a seperate species, the line that divides it between tiger and itself in the time line still interbreed and if you took that you could consider that section it's own species. I'm just thinking if maybe a better way to divide the line, like instead of thinking of species, think of them as being more of a series. Mehh....sorry if not making sense :> Might be completly stupid and pointless, but it was a thought I had wanted to hear peoples thoughts, or ideas of how this could be useful. heh I think too much some times :>
|
|||||||||||||||||||||||||||||||
Omnivorous Member Posts: 3977 From: Adirondackia Joined: Member Rating: 7.3 |
wolfwing writes: Reason I say this is that as we keep finding with animals alive now, there really isn't any easily defined definition of species even using animals alive, what many would consider a species, like lions/leopards/tigers can still interbreed and ocasionally produce reproductive capable offspring. It's worth noting that these events occur in captivity, under artificial conditions and pressures.
Plus it gets hung up on the creationists term Kind and get into semantic arguments. I'd recommend against semantic arguments with creationists. There's neither profit nor joy in it.
Is there a better word that could be used other then species, or some way to make species fit more what we actually see? No. The world we see is complicated, and any one word is simple. How light does it get before it isn't dark? Creationists think the simple shorthand of "species" is problematic because they don't know or care to know or understand the qualifications and exceptions familiar to scientists (or informed laypersons). Our language maps the world, but (as a wise orangutan was once fond of saying), the map is not the terrain. Like Grace Slick sang, "The human name doesn't mean shit to a tree." Tell them that humans could almost certainly breed with chimps. Ask them, would a humanzee mean we are not different species? Would it mean we are the same "kind"? I know there's a balance, I see it when I swing past. -J. Mellencamp Real things always push back.-William James
|
|||||||||||||||||||||||||||||||
Blue Jay Member (Idle past 2697 days) Posts: 2843 From: You couldn't pronounce it with your mouthparts Joined: |
Taxonomy is the source of much disagreement in biology. Many ecologists and physiologists don't even think it's important to know or be able to identify species, while taxonomists and systematists regularly insist that proper identification is the basis of all biological information.
I tend to side with the taxonomists on this one. Taxonomy itself (the basic classification of life forms into categories such as "family," "species" and "kingdom") is a rather invalid way of viewing biodiversity, but it is a necessary convention in order to enable better communication of information between researchers. When speaking of the names of biological species, there are a number of conventions that biologists use. For instance, each species is referred to by a binomial name consisting of a "generic name" and a "specific epithet" (example: Tyrannosaurus rex). "Tyrannosaurus" is the generic name (name of the genus) and "rex" is the specific epithet (name of the species). Binomial names are always supposed to be written in italics (or underlined when written by hand). Generic names are always capitalized. Specific epithets are not. Binomials are often abbreviated by using only the first letter of the generic name and the full specific epithet. The proper format is T. rex, not T-Rex or T-rex as is often written by the lay public. A species epithet is never to be used in isolation, without the generic name either in full or abbreviated (although this rule is frequently violated). Example: afarensis should be written: Australopithecus afarensis or A. afarensis. Also of interest is that the common names of dinosaurs usually derive from their generic names (e.g., "Triceratops" is both the generic name and the common name for Triceratops horridus, and also for another species, "T. prorsus," which may or may not be valid). One exception is Tyrannosaurus rex, which, for whatever reason, lay sources insist on referring to by the full binomial, without realizing that they are violating basic requirements of parallelism in writing and presentation by not also calling "Triceratops" by its full binomial. This is, of course, relatively harmless when it's just used for kids' books and toys, because the non-systematic approach for kids' products is sufficient to fill the kids' needs to choose their favorite dinosaur and play games with their friends. But, for scientists, more rigor is generally needed (particularly for living organisms), and I must insist that the concept of species (whatever definition you feel is most valid) is absolutely critical for the sake of communication among scientists, despite the inherent kinks, hitches and constant revisions that the system must undergo. Sorry for the rambling, but I felt like it was important to at least make sure people were aware of conventions, even if you don't care and don't intend to follow them: just so long as you know they are there and that they do have a purpose in science. Edited by Bluejay, : superfluous quote -Bluejay (a.k.a. Mantis, Thylacosmilus) Darwin loves you.
|
|||||||||||||||||||||||||||||||
wolfwing Junior Member (Idle past 4817 days) Posts: 9 Joined: |
hmmm lets look at my example here again this is sort of what I mean.
These is the line of my hypothetical species, but can consider it snapshots in the RW of species, just this is a example to simplify it down. we could if all we saw was find the fossils of B and D consider them their own unique species and someone would say, show B evolving into D. And you might get this (ABC)(DEF) of the actual organisms being defined as a species as they can interbreed. BUT it could also be shown that (BCD) where you end up with 3 species, ABC, DEF, and BCD, where BCD is actually overlapping the other two species. This is sort of my point when we look at fossils and species now, all were seeing is ABC DEF as unique species, or in RL case were seeing is C with B extinct and D yet to evolve from C. It works as snapshots, but it doesn't work when trying to describe evolution, the creationists want and many people get confused by expecting to see B evolve into D or even E not realizing that at the borders between what we call species B and E they could just as easily be considered their own unique species if thats the only snapshot we had. If that makes any sense. I just think that species works, but when put into evolutionary terms it just confuses and muddies the water giving the picture of snapshots when it's a smooth gradual line. Take Dawkins example *I think it was him* of a paper with the left side black, and the right side white and shading it so that it gradually becomes more white. You could take the colour at every inch and show that colour and say this is X colour, but when you compare them on the paper and say, when does X colour become Y colour you can't because the border line between them is bluired. This is how it is in evolution/modern day terms for species, your taking a thin slice of the line and giving it a name and saying species, but if you had a entire line from ancestor of chimps and humans, and showed every female up to humans, at any given point there be no difference to the left and right it's when you take snapshot of every 100 or 1000 you see enough change to call this a species. Edited by wolfwing, : No reason given. Edited by wolfwing, : No reason given.
|
|||||||||||||||||||||||||||||||
New Cat's Eye Inactive Member |
Welcome to EvC, wolfwing.
Take Dawkins example *I think it was him* of a paper with the left side black, and the right side white and shading it so that it gradually becomes more white. You could take the colour at every inch and show that colour and say this is X colour, but when you compare them on the paper and say, when does X colour become Y colour you can't because the border line between them is bluired. Like this:
<!--B<!--B<!--B:o--><img src="Images/Smilies/redface.gif" border=0><!--E-->--><img src="http://www.evcforum.net/Images/Smilies/redface.gif" border=0><!--E-->aDDxDGVunvoiM:http://jtrujillo.net/digital-[/img]-->
Click the Peek button at the bottom right to see the text I entered where you can find the image tags I used to link to pictures. The pictures do have to already be hosted somewhere in the internets to link to them. Too, there a link to the left of the reply you type into that says "dBCodes On (help)". THe help link takes you to a list of codes for making your posts sweet <-- waiting.
This is how it is in evolution/modern day terms for species, your taking a thin slice of the line and giving it a name and saying species, but if you had a entire line from ancestor of chimps and humans, and showed every female up to humans, at any given point there be no difference to the left and right it's when you take snapshot of every 100 or 1000 you see enough change to call this a species.
I think most people here realize this. In fact, when using the word species in that way, I think people are actually referring to just that: an arbitrary line in an otherwise continuum of organisms. BUT... As RAZD shows in Message 3, there is another usage of the term "species" which is when taking about speciation events. For that, the meaning is less ambiguous.
|
|||||||||||||||||||||||||||||||
Omnivorous Member Posts: 3977 From: Adirondackia Joined: Member Rating: 7.3 |
Wolfwing, you've received a number of thoughtful replies from different members; those replies took effort.
But you just keep restating your case as though you are the only one in the room, without responding to the explanations and arguments from others. Use the Reply button on the lower right of the message to which you are replying, next to the Peek button. You can also see how folks produce boxed quotes and other formatting by clicking the Peek button. Stop using the Gen Reply button on the left. You should reply to people who take the time and trouble to reply to you: It's the only civilized thing to do. You are supposed to be having conversations, not tossing leaflets around the site. Dost thou think, because thou art virtuous, there shall be no more cakes and ale? -Shakespeare Real things always push back.-William James
|
|||||||||||||||||||||||||||||||
New Cat's Eye Inactive Member |
You will also see that the overall trend from Pelycodus ralstoni at the bottom to Notharctus venticolus at the top right has a gradual "trendency" of increasing size with time, but that the divergence of Notharctus nunienus from that trendency occurs at a greater rate of change. This likely occurs for two reasons: (1) the original ecological niche of Pelycodus ralstoni still exists, providing an open opportunity for a smaller species, and (2) the separation in habitat\ecology is necessary to reduce competition between the daughter species (without it one species will likely drive the other to extinction or being reabsorbed - as you can see occurred between Pelycodus trigonodus and Pelycodus jarrovii when an earlier shift to the left shows up, then dissappears). To me, it looks like the smaller version was "trying" to split off a few times over and over again and then finally found a niche where it worked. Any ideas on what could be driving that? Doesn't look very random...
|
|||||||||||||||||||||||||||||||
Blue Jay Member (Idle past 2697 days) Posts: 2843 From: You couldn't pronounce it with your mouthparts Joined: |
Hi, Wolfwing.
We're talking past each other. Let me make something clear. Everybody who has replied on this thread knows how evolution works and knows what it means for the definition of the term "species." We all know that evolution is messy and makes "species" indistinct and the lines between them blurry. We are arguing that, despite this, the species concept is still useful and important for a number of reasons, such as its utility in communication among scientists, and its accuracy in describing a number of real-world cases in which populations are distinct enough to be considered isolated species. -Bluejay (a.k.a. Mantis, Thylacosmilus) Darwin loves you.
|
|||||||||||||||||||||||||||||||
wolfwing Junior Member (Idle past 4817 days) Posts: 9 Joined: |
heh sorry on the not using replies, I did it partly because when there is 3-4 people replying rather then make 3-4 seperate posts and spaming the topic I tend to try to consolidate then into a single post that makes it less spammy.
If it's prfered I can do it to individual :> Just trying to keep the topic cleaned up heh. as for restating, I wasn't sure if I was making it completly clear enough I have a hard time putting into words what I visualize in my head, if I had a blackboard I could explain it, why I went with the more specific example in the last time.
|
|||||||||||||||||||||||||||||||
wolfwing Junior Member (Idle past 4817 days) Posts: 9 Joined: |
I agree it's useful and handy, and most here hopefully know what it means. I'm not exactly posting these ideas strictly to fix problems with creationist missunderstanding, but that the term species feels inadequate a term for long time. For all I know species is the best word to use, I'm just wondering if it couldn't be done in a better way that fits more the DATA in long time. Were always changing words, or using new words or old words in new ways to fit our understanding.
Einsteins theories replaced newtonian physics because they worked better in describing what was seen. Yes Newtonian was adequate, but for larger scales it doesn't work. Thats sorta what I feel here with the current definition or idea of species, that it's adequate in short time or snapshots, but doesn't erally work for long time in my mind. Maybe ring species is the best example in snapshot of what I'm refering too. And I'm not sure were talking past, I understand what you guys are saying, I'm just not sure species is adequate a word for what we see, it fits, and is useful, but might there not be a better way to describe what we do see.
|
|
|
Do Nothing Button
Copyright 2001-2023 by EvC Forum, All Rights Reserved
Version 4.2
Innovative software from Qwixotic © 2024