7 ms·

The black moths could still mate with the peppered variety so they're still the same species just different 'breeds', perhaps, so is this really evolution? I a

by barking 10y ago

The black moths could still mate with the peppered variety so they're still the same species just different 'breeds', perhaps, so is this really evolution? I am a layman but one criticism of the theory of evolution that seems sensible to me is the absence of intermediate forms. For example types of ape that could mate with say gorillas and chimpanzees. All the species seem very well defined when you'd expect a continuum.

danieltillett 10y ago
The most charitable thing I can think to say is you would find studying evolutionary biology very enlighting.
- barking 10y ago
  I don't think that being either helpful or charitable were motivations behind your comment.
  - danieltillett 10y ago
    Yes they were. I though of writing a snarky response, but I gave you the benefit of the doubt that your post was the result of not knowing anything about evolution and not trolling. If you really are interested in knowing the answers to your questions then you need to study evolutionary biology - it really is a very interesting topic :) Edit. If you want to know more then any of Richard Dawkins biology books are really good. The Blind Watchmaker would be my suggestion of where to start.
    - eru 10y ago
      Even Wikipedia would be a good introduction here.
      - danieltillett 10y ago
        Yes, but it can be really hard trying to make sense out of all the information without having the assumed knowledge. I would really recommend starting with a good book that assumes very little.
  - DonHopkins 10y ago
    Since you're questioning somebody else's motives yourself now, what do you think is wrong about questioning the motives of someone who parrots tired old discredited creationist propaganda, describing it as seemingly sensible? Shouldn't you be as open to criticism as the scientific theories you're criticizing?
    - barking 10y ago
      Well I wouldn't have 'parroted' it, had known that it as 'tired old discredited creationist propaganda'. Does that answer your question?
      - DonHopkins 10y ago
        Oh, so it is ok to question motives! I'm so relieved. Google and wikipedia will quickly and easily disabuse you of the idea that it's "a big flaw in the theory of evolution". What were your motives for thinking and parroting that there is a "big flaw" in evolution without bothering to look it up, when it's so easy to discover how tired and discredited the "absence of intermediate forms" argument is? Here's the first google hit with the phrase "absence of intermediate forms" you parroted, a site specifically dedicated to spreading misinformation about evolution -- Gary Bates' Creation Ministries International: http://creation.com/that-quote-about-the-missing-transitional-fossils http://creation.com/that-quote-about-the-missing-transitiona... >Gary has been speaking on the creation/evolution issue since 1990. With a background in management and marketing, in 2002, he was invited to join the ministry full-time in Brisbane and eventually became its Head of Ministry. Much in demand for his popular lay talks on creation, Gary and his family relocated to America to serve as CEO of CMI-US. He was also elected to the position of CEO of CMI-Worldwide, CMI’s international Federation of ministries. http://creationwiki.org/Gary_Bates http://creationwiki.org/Gary_Bates >Bates has a keen interest in the UFO phenomenon and wrote the Amazon.com top 50 bestseller Alien Intrusion: UFOs and the Evolution Connection. In July 2009 he was the keynote speaker at the first Christian symposium on the UFO phenomenon held in Roswell, New Mexico. And here's a more reputable source that debunks the claim you parroted -- National Center for Science Education: http://ncse.com/creationism/analysis/transitional-fossils-are-not-rare http://ncse.com/creationism/analysis/transitional-fossils-ar... >Fossils with transitional morphology are not rare. Fossils illustrating the gradual origin of humans, horses, rhinos, whales, seacows, mammals, birds, tetrapods, and various major Cambrian "phyla" have been discovered and are well-known to scientists. Explore Evolution's claims to the contrary are just a rehash of older creationist arguments on this point, relying on out-of-context quotes, confusion over terminology and classification, and ignoring inconvenient evidence.
Angostura 10y ago
> The black moths could still mate with the peppered variety so they're still the same species just different 'breeds', perhaps, so is this really evolution? It absolutely is evolution, what it isn't is 'speciation'. For speciation to occur you would have to have enough reproductive isolation and enough time to allow for sufficient change - let's say in the range of thousands/millions of years, rather than a decade or two. Biologists will tell you anyway that the concept of a biological species is a bit hard to pin down anyway. I don't quite understand your criticism regarding intermediate forms. There are many clusters of species where interbreeding is possible to some extent - Zeedonks, Ligers et all, not mention types of bluebell, dandelions etc. Moreover there are many many species where there are distinct varieties which are still similar enough to interbreed, but may be on their way to separating if given enough time and isolation.
- lanna 10y ago
  > There are many clusters of species where interbreeding is possible to some extent Do not forget that the offspring itself also has to be fertile. Most hybrids aren't.
  - deleted 10y ago
    [deleted]
- roywiggins 10y ago
  Speciation can occur more or less immediately if two species produce a successful hybrid. It's much more common in plants, but it happens in animals too. The idea is, you have two species that occasionally produce viable offspring, which are themselves reproductively isolated from their own parent species. https://en.wikipedia.org/wiki/Hybrid_speciation https://en.wikipedia.org/wiki/Hybrid_speciation
mikekchar 10y ago
When you have a continuum, species don't diverge. They interbreed. So the whole will just carry on. If a mutation occurs that stops interbreeding, then that line is likely to die out because of competition with the main line. However, imagine rabbits on an island. There are zillions of them everywhere and there is a wide variety of mutations. Mostly it doesn't matter because most of them can interbreed, and the ones that don't die out. But one day the rabbits get a terrible disease and almost all of them die. The ones that don't die have a mutation that makes them resistant to the disease. Now you have a different kind of rabbit where they are all resistant to the disease. This keeps happening. Not always disease. Sometimes their food source disappears. Sometimes a new preditor arrives. Sometimes the weather changes. Each time, they almost all die. Only the ones that could survive live. After all of that, the island rabbits are very specialised. They might not even be specialised for the current conditions. For example the disease may no longer exist. The weather may have changed back. The predators may have died out. But it doesn't matter. They are very different than the original rabbits, and also very different from the rabbits on the mainland. So much so that the two can't interbreed. There is no intermediate forms because they all died. If they had not died, the specialised form would not have developed. We can observe this both in the wild and in laboratory conditions. Especially with short lived insects (usually fruit flies) we can actually see evolution happening in this way. But with rabbits... we tried to kill all the rabbits in Australia with a disease and ended up with lots and lots of rabbits who are resistant to the disease. This is why it is important to teach evolution in school.
- barking 10y ago
  That makes sense thanks. I'm not sure how a mutation that prevents breeding would be disseminated from the animal in which it occurred?
  - tremon 10y ago
    I'm not sure I fully understand your question, but probably this: https://en.wikipedia.org/wiki/Speciation https://en.wikipedia.org/wiki/Speciation The point is that as long as two minimally diverse populations remain in close contact and can interbreed, most of their mutations will cross the population boundary and we will probably classify them as one species, even though both populations may look nothing like their ancestors of 10,000 years earlier. Mutations that prevent interbreeding usually don't occur in a single generation, they are the result of a long period of no interbreeding (and therefore divergent mutations).
dforrestwilson 10y ago
I'm scratching my head as to why you were down-voted. You may be wrong but you're not being rude or purposefully trolling.
- danieltillett 10y ago
  I think the reason for the down votes is the post is kind of trollish. The points raised by the OP are the sort of spurious arguments that are brought up by the "intelligent design" promotors. Of course the OP could have just been innocently influenced by them, but it is always hard to know.
richmarr 10y ago
> ...criticism of the theory of evolution that seems sensible to me ... Criticism of evolution isn't sensible, it's ignorant (which is fine). It's an observable phenomenon, each piece of which can be reasoned about without too much specialised knowledge. Being ignorant about evolution is fine, and you asked politely and seem to have an open mind, so I don't think you should be downvoted. I think people are just a bit tired of creationists mis-using terms, lobbying, etc, so are sensitive on this topic.
- barking 10y ago
  >Criticism of evolution isn't sensible, it's ignorant I am not criticising evolution. I'm not qualified to do that. It seems like it is the best explanation yet to explain the diversity of life on this planet. Personally, I attach no credibility whatsoever to the creationists' explanations. I do think that people, even those of us who do not know a lot about it, should be entitled to ask questions without having our motives questioned. Indeed I thought that scientific theories should always be open to criticism. To say that one theory should not be, would be to elevate it to the status of dogma. And if people are 'very sensitive' to criticism about a particular theory, there is more than one possible explanation for that. Another might be a frustrating lack of evidence. For example, in this thread 2 posters mentioned the existence of ring species and linked to the wikipedia page for that. That page has four examples but then goes on to suggest that there is doubt as to whether these are actually examples of ring species. To re-iterate, I would bet that evolution is probably correct, however a degree of humility, not always evident, from its adherents would do no harm. The sun, it turned out, didn't orbit the earth.
  - mikeash 10y ago
    You clearly are criticizing the theory. You state that there is an absence of intermediate forms, give an example of an intermediate between apes and chimpanzees, and conclude by stating that you'd expect a continuum. These aren't qualified with any of the humility you demand from others, they're just stated as bare "facts." This is typical, though. State a bunch of nonsense, then when called on it say you're just asking questions, people shouldn't be so harsh, and would it kill evolutionists to be a little more humble? It takes a lot more effort to refute bullshit than to spew it. People naturally and rightfully get frustrated when people spew it.
teekert 10y ago
I think it is a good question. But where does the definition of species go when A can produce offspring with B, B can produce offspring with C but A cannot produce offspring with C? Would you be willing to label B as an intermediate form? Moreover, recognizing that the theory of evolution does not really speak of "intermediate forms" but of common ancestors, would you be willing to label an extinct (but well preserved in the fossil record, including its DNA) species that is the common ancestor of two species as an intermediate form? In other words, what would be the evidence for evolution to convince you of the reality of the theory?
- barking 10y ago
  I am fairly convinced of its veracity as it is. I would just like to see more and more evidence as time goes by. Physicists (and I'm not one of those either) seem to have a completely different attitude to evolution scientists. Recently more evidence in support of einstein's relativity theory has been found, I believe. But they are still completely open to binning the theory if contradictory evidence appears. There just seems to be an almost religious fervour around evolution that seems a bit unhealthy
  - splawn 10y ago
    I agree that religious fervor of any kind is unhealthy... However evidence will always crowd out the possibility of "religious fervor". Biologists are just as open to changing their model as Physicists are they just need a reason to do so. All evidence points to evolution. You can find it in the geologic record as well as markers in every living organism's DNA. Speaking of DNA... evolution predicted its existence and mechanisms well before its discovery. Im not sure where your confusion stems from... religious fervor perhaps?
    - barking 10y ago
      Yes I am sure evidence will win out in the end regardless.
      - 10y ago
mikeash 10y ago
Continuous sorts of things exist: https://en.m.wikipedia.org/wiki/Ring_species https://en.m.wikipedia.org/wiki/Ring_species Living things evolve in groups which is why it's more common to have clearer lines between them, but it's not always like that.
- barking 10y ago
  There are no known examples of ring species it seems https://whyevolutionistrue.wordpress.com/2014/07/16/there-are-no-ring-species/ https://whyevolutionistrue.wordpress.com/2014/07/16/there-ar...
  - mikeash 10y ago
    Interesting. Do I understand correctly that this is more about how they're formed and exactly how continuous the variation is within them, rather than the general idea that you can end up with a population of animals with non-transitive mating viability?
  - maxerickson 10y ago
    There's not really species at all. Species are convenient labels for populations of similar organisms, but the only test for whether 2 organisms can and will reproduce is to see if proximity leads them to produce fertile offspring. Failing this test doesn't prove that they are not reproductively compatible.
    - barking 10y ago
      On that basis of that test it sounds like you could not prove that chimps and and gorillas were different species?
      - maxerickson 10y ago
        Sure, but so what, the point is that those are arbitrary human labels. I certainly wouldn't go around expecting them to make a baby based on what I've said, I just phrased things the way I did to try to emphasize the above point.
0xcde4c3db 10y ago
There is a continuum, but it's primarily over time. Everything seems separate because you're not looking at the dimension over which it connects. If you only looked at the horizontal cross-section of a tree above the trunk, you might similarly ask "how can this be one plant when none of the parts are connected?". Well, they are. You just aren't going to see the connection in that slice.
0xfeba 10y ago
> The black moths could still mate with the peppered variety so they're still the same species just different 'breeds', perhaps, so is this really evolution? Yes. Evolution is just change in phenotypes over time. Speciation is a whole other ballgame, and there's no definitive answer as to what delineates species from one another. Some different species of fish will interbreed when forced together. That is: Species are not well defined. They are only defined for human convenience, for categorization. But in reality, it's all one continuum. Interbreeding is only one factor in categorizing it. The big thing about being able to interbreed is chromosonal alignment, not necessarily whether they are differing species. The humans of today aren't the same as the humans from 500 or 1,000 years ago. Prevalence of sickle-cell disease, lactose intolerance, skin pigmentation all these little things add up. If your substantiation of evolution consists of when speciation occurs, you're limiting yourself. Take dog breeds for example. The changes we've implemented using the tool of evolution are drastic. What's to prevent this process from continuing? From eventually causing 'speciation', in the sense that two dog breeds can no longer interbreed? There are already subtle differences between dog breeds that make producing offspring difficult, and in the wild this difference would be magnified greatly.
- hayksaakian 10y ago
  I thought it was pretty clearly defined: they product offspring which can reproduce and produce viable offspring among themselves but not with the original population
  - gtremper 10y ago
    Ring species complicate that https://en.wikipedia.org/wiki/Ring_species https://en.wikipedia.org/wiki/Ring_species A can mate with B, B can mate with C, but A can't mate with C.
  - tgb 10y ago
    The question of defining "species" was one of the keystone questions used as an example in a philosophy of science course I took. See: http://plato.stanford.edu/entries/species/ http://plato.stanford.edu/entries/species/
dragonwriter 10y ago
> The black moths could still mate with the peppered variety so they're still the same species just different 'breeds', perhaps, so is this really evolution? Yes, not all evolutionary changes constitute changes of species. > I am a layman but one criticism of the theory of evolution that seems sensible to me is the absence of intermediate forms. An incomplete fossil record (and, given what is known about how the fossil record is laid down, its obviously going to be extremely incomplete even before considering how little of it we've actually been able to access) combined with evolution that is continuous (even if punctuated rather than constant-pace) is naturally going to miss lots of things between many of the things it preserves. That isn't a criticism of evolution. > All the species seem very well defined when you'd expect a continuum. There is a continuum; talking about it in any useful way, however, forces us to divide it up into discrete buckets -- taxonomic categories, whether "species" or higher- or lower-level categories -- and, where there are unclear cases, we end up arguing over which bucket they belong in, and how many buckets we should consider there to be.
Tloewald 10y ago
Species is not a well-defined term in the sense a mathematician understands well-defined. E.g. the usual "ability to breed and create fertile offspring" excludes all organisms that do not reproduce sexually, and does not account for fertile hybrids and "ring species".
quadrangle 10y ago
Actually, the world is full of high-resolution continua in species, it's just not always present. Divergence occurs due to isolation or some other factor. Horses and Zebras are different species but can interbreed. Lions and Tigers can interbreed. https://en.wikipedia.org/wiki/Hybrid_(biology) https://en.wikipedia.org/wiki/Hybrid_(biology) So the expected continuum you seek is totally there in tons of cases. It's just that there are cases where divergence gets too stark and intermediates die out. When humans choose (for conceptual and communications' sake) to identify two very similar groups as different species versus different breeds, then we call mixes "hybrids" like this. When we think it's just a little too similar and we call them "breeds" of the same species, then we don't call mixes "hybrids" as often. This is just problems with the simiplisticness of language.

by barking 10y ago

danieltillett 10y ago

The most charitable thing I can think to say is you would find studying evolutionary biology very enlighting.

barking 10y ago
I don't think that being either helpful or charitable were motivations behind your comment.
- danieltillett 10y ago
  Yes they were. I though of writing a snarky response, but I gave you the benefit of the doubt that your post was the result of not knowing anything about evolution and not trolling. If you really are interested in knowing the answers to your questions then you need to study evolutionary biology - it really is a very interesting topic :) Edit. If you want to know more then any of Richard Dawkins biology books are really good. The Blind Watchmaker would be my suggestion of where to start.
  - eru 10y ago
    Even Wikipedia would be a good introduction here.
    - danieltillett 10y ago
      Yes, but it can be really hard trying to make sense out of all the information without having the assumed knowledge. I would really recommend starting with a good book that assumes very little.
- DonHopkins 10y ago
  Since you're questioning somebody else's motives yourself now, what do you think is wrong about questioning the motives of someone who parrots tired old discredited creationist propaganda, describing it as seemingly sensible? Shouldn't you be as open to criticism as the scientific theories you're criticizing?
  - barking 10y ago
    Well I wouldn't have 'parroted' it, had known that it as 'tired old discredited creationist propaganda'. Does that answer your question?
    - DonHopkins 10y ago
      Oh, so it is ok to question motives! I'm so relieved. Google and wikipedia will quickly and easily disabuse you of the idea that it's "a big flaw in the theory of evolution". What were your motives for thinking and parroting that there is a "big flaw" in evolution without bothering to look it up, when it's so easy to discover how tired and discredited the "absence of intermediate forms" argument is? Here's the first google hit with the phrase "absence of intermediate forms" you parroted, a site specifically dedicated to spreading misinformation about evolution -- Gary Bates' Creation Ministries International: http://creation.com/that-quote-about-the-missing-transitional-fossils http://creation.com/that-quote-about-the-missing-transitiona... >Gary has been speaking on the creation/evolution issue since 1990. With a background in management and marketing, in 2002, he was invited to join the ministry full-time in Brisbane and eventually became its Head of Ministry. Much in demand for his popular lay talks on creation, Gary and his family relocated to America to serve as CEO of CMI-US. He was also elected to the position of CEO of CMI-Worldwide, CMI’s international Federation of ministries. http://creationwiki.org/Gary_Bates http://creationwiki.org/Gary_Bates >Bates has a keen interest in the UFO phenomenon and wrote the Amazon.com top 50 bestseller Alien Intrusion: UFOs and the Evolution Connection. In July 2009 he was the keynote speaker at the first Christian symposium on the UFO phenomenon held in Roswell, New Mexico. And here's a more reputable source that debunks the claim you parroted -- National Center for Science Education: http://ncse.com/creationism/analysis/transitional-fossils-are-not-rare http://ncse.com/creationism/analysis/transitional-fossils-ar... >Fossils with transitional morphology are not rare. Fossils illustrating the gradual origin of humans, horses, rhinos, whales, seacows, mammals, birds, tetrapods, and various major Cambrian "phyla" have been discovered and are well-known to scientists. Explore Evolution's claims to the contrary are just a rehash of older creationist arguments on this point, relying on out-of-context quotes, confusion over terminology and classification, and ignoring inconvenient evidence.

Angostura 10y ago

> The black moths could still mate with the peppered variety so they're still the same species just different 'breeds', perhaps, so is this really evolution? It absolutely is evolution, what it isn't is 'speciation'. For speciation to occur you would have to have enough reproductive isolation and enough time to allow for sufficient change - let's say in the range of thousands/millions of years, rather than a decade or two. Biologists will tell you anyway that the concept of a biological species is a bit hard to pin down anyway. I don't quite understand your criticism regarding intermediate forms. There are many clusters of species where interbreeding is possible to some extent - Zeedonks, Ligers et all, not mention types of bluebell, dandelions etc. Moreover there are many many species where there are distinct varieties which are still similar enough to interbreed, but may be on their way to separating if given enough time and isolation.

lanna 10y ago
> There are many clusters of species where interbreeding is possible to some extent Do not forget that the offspring itself also has to be fertile. Most hybrids aren't.
- deleted 10y ago
  [deleted]
roywiggins 10y ago
Speciation can occur more or less immediately if two species produce a successful hybrid. It's much more common in plants, but it happens in animals too. The idea is, you have two species that occasionally produce viable offspring, which are themselves reproductively isolated from their own parent species. https://en.wikipedia.org/wiki/Hybrid_speciation https://en.wikipedia.org/wiki/Hybrid_speciation

mikekchar 10y ago

When you have a continuum, species don't diverge. They interbreed. So the whole will just carry on. If a mutation occurs that stops interbreeding, then that line is likely to die out because of competition with the main line. However, imagine rabbits on an island. There are zillions of them everywhere and there is a wide variety of mutations. Mostly it doesn't matter because most of them can interbreed, and the ones that don't die out. But one day the rabbits get a terrible disease and almost all of them die. The ones that don't die have a mutation that makes them resistant to the disease. Now you have a different kind of rabbit where they are all resistant to the disease. This keeps happening. Not always disease. Sometimes their food source disappears. Sometimes a new preditor arrives. Sometimes the weather changes. Each time, they almost all die. Only the ones that could survive live. After all of that, the island rabbits are very specialised. They might not even be specialised for the current conditions. For example the disease may no longer exist. The weather may have changed back. The predators may have died out. But it doesn't matter. They are very different than the original rabbits, and also very different from the rabbits on the mainland. So much so that the two can't interbreed. There is no intermediate forms because they all died. If they had not died, the specialised form would not have developed. We can observe this both in the wild and in laboratory conditions. Especially with short lived insects (usually fruit flies) we can actually see evolution happening in this way. But with rabbits... we tried to kill all the rabbits in Australia with a disease and ended up with lots and lots of rabbits who are resistant to the disease. This is why it is important to teach evolution in school.

barking 10y ago
That makes sense thanks. I'm not sure how a mutation that prevents breeding would be disseminated from the animal in which it occurred?
- tremon 10y ago
  I'm not sure I fully understand your question, but probably this: https://en.wikipedia.org/wiki/Speciation https://en.wikipedia.org/wiki/Speciation The point is that as long as two minimally diverse populations remain in close contact and can interbreed, most of their mutations will cross the population boundary and we will probably classify them as one species, even though both populations may look nothing like their ancestors of 10,000 years earlier. Mutations that prevent interbreeding usually don't occur in a single generation, they are the result of a long period of no interbreeding (and therefore divergent mutations).

dforrestwilson 10y ago

I'm scratching my head as to why you were down-voted. You may be wrong but you're not being rude or purposefully trolling.

danieltillett 10y ago
I think the reason for the down votes is the post is kind of trollish. The points raised by the OP are the sort of spurious arguments that are brought up by the "intelligent design" promotors. Of course the OP could have just been innocently influenced by them, but it is always hard to know.

richmarr 10y ago

> ...criticism of the theory of evolution that seems sensible to me ... Criticism of evolution isn't sensible, it's ignorant (which is fine). It's an observable phenomenon, each piece of which can be reasoned about without too much specialised knowledge. Being ignorant about evolution is fine, and you asked politely and seem to have an open mind, so I don't think you should be downvoted. I think people are just a bit tired of creationists mis-using terms, lobbying, etc, so are sensitive on this topic.

barking 10y ago
>Criticism of evolution isn't sensible, it's ignorant I am not criticising evolution. I'm not qualified to do that. It seems like it is the best explanation yet to explain the diversity of life on this planet. Personally, I attach no credibility whatsoever to the creationists' explanations. I do think that people, even those of us who do not know a lot about it, should be entitled to ask questions without having our motives questioned. Indeed I thought that scientific theories should always be open to criticism. To say that one theory should not be, would be to elevate it to the status of dogma. And if people are 'very sensitive' to criticism about a particular theory, there is more than one possible explanation for that. Another might be a frustrating lack of evidence. For example, in this thread 2 posters mentioned the existence of ring species and linked to the wikipedia page for that. That page has four examples but then goes on to suggest that there is doubt as to whether these are actually examples of ring species. To re-iterate, I would bet that evolution is probably correct, however a degree of humility, not always evident, from its adherents would do no harm. The sun, it turned out, didn't orbit the earth.
- mikeash 10y ago
  You clearly are criticizing the theory. You state that there is an absence of intermediate forms, give an example of an intermediate between apes and chimpanzees, and conclude by stating that you'd expect a continuum. These aren't qualified with any of the humility you demand from others, they're just stated as bare "facts." This is typical, though. State a bunch of nonsense, then when called on it say you're just asking questions, people shouldn't be so harsh, and would it kill evolutionists to be a little more humble? It takes a lot more effort to refute bullshit than to spew it. People naturally and rightfully get frustrated when people spew it.

teekert 10y ago

I think it is a good question. But where does the definition of species go when A can produce offspring with B, B can produce offspring with C but A cannot produce offspring with C? Would you be willing to label B as an intermediate form? Moreover, recognizing that the theory of evolution does not really speak of "intermediate forms" but of common ancestors, would you be willing to label an extinct (but well preserved in the fossil record, including its DNA) species that is the common ancestor of two species as an intermediate form? In other words, what would be the evidence for evolution to convince you of the reality of the theory?

barking 10y ago
I am fairly convinced of its veracity as it is. I would just like to see more and more evidence as time goes by. Physicists (and I'm not one of those either) seem to have a completely different attitude to evolution scientists. Recently more evidence in support of einstein's relativity theory has been found, I believe. But they are still completely open to binning the theory if contradictory evidence appears. There just seems to be an almost religious fervour around evolution that seems a bit unhealthy
- splawn 10y ago
  I agree that religious fervor of any kind is unhealthy... However evidence will always crowd out the possibility of "religious fervor". Biologists are just as open to changing their model as Physicists are they just need a reason to do so. All evidence points to evolution. You can find it in the geologic record as well as markers in every living organism's DNA. Speaking of DNA... evolution predicted its existence and mechanisms well before its discovery. Im not sure where your confusion stems from... religious fervor perhaps?
  - barking 10y ago
    Yes I am sure evidence will win out in the end regardless.
    - 10y ago

mikeash 10y ago

Continuous sorts of things exist: https://en.m.wikipedia.org/wiki/Ring_species https://en.m.wikipedia.org/wiki/Ring_species Living things evolve in groups which is why it's more common to have clearer lines between them, but it's not always like that.

barking 10y ago
There are no known examples of ring species it seems https://whyevolutionistrue.wordpress.com/2014/07/16/there-are-no-ring-species/ https://whyevolutionistrue.wordpress.com/2014/07/16/there-ar...
- mikeash 10y ago
  Interesting. Do I understand correctly that this is more about how they're formed and exactly how continuous the variation is within them, rather than the general idea that you can end up with a population of animals with non-transitive mating viability?
- maxerickson 10y ago
  There's not really species at all. Species are convenient labels for populations of similar organisms, but the only test for whether 2 organisms can and will reproduce is to see if proximity leads them to produce fertile offspring. Failing this test doesn't prove that they are not reproductively compatible.
  - barking 10y ago
    On that basis of that test it sounds like you could not prove that chimps and and gorillas were different species?
    - maxerickson 10y ago
      Sure, but so what, the point is that those are arbitrary human labels. I certainly wouldn't go around expecting them to make a baby based on what I've said, I just phrased things the way I did to try to emphasize the above point.

0xcde4c3db 10y ago

There is a continuum, but it's primarily over time. Everything seems separate because you're not looking at the dimension over which it connects. If you only looked at the horizontal cross-section of a tree above the trunk, you might similarly ask "how can this be one plant when none of the parts are connected?". Well, they are. You just aren't going to see the connection in that slice.

0xfeba 10y ago

> The black moths could still mate with the peppered variety so they're still the same species just different 'breeds', perhaps, so is this really evolution? Yes. Evolution is just change in phenotypes over time. Speciation is a whole other ballgame, and there's no definitive answer as to what delineates species from one another. Some different species of fish will interbreed when forced together. That is: Species are not well defined. They are only defined for human convenience, for categorization. But in reality, it's all one continuum. Interbreeding is only one factor in categorizing it. The big thing about being able to interbreed is chromosonal alignment, not necessarily whether they are differing species. The humans of today aren't the same as the humans from 500 or 1,000 years ago. Prevalence of sickle-cell disease, lactose intolerance, skin pigmentation all these little things add up. If your substantiation of evolution consists of when speciation occurs, you're limiting yourself. Take dog breeds for example. The changes we've implemented using the tool of evolution are drastic. What's to prevent this process from continuing? From eventually causing 'speciation', in the sense that two dog breeds can no longer interbreed? There are already subtle differences between dog breeds that make producing offspring difficult, and in the wild this difference would be magnified greatly.

hayksaakian 10y ago
I thought it was pretty clearly defined: they product offspring which can reproduce and produce viable offspring among themselves but not with the original population
- gtremper 10y ago
  Ring species complicate that https://en.wikipedia.org/wiki/Ring_species https://en.wikipedia.org/wiki/Ring_species A can mate with B, B can mate with C, but A can't mate with C.
- tgb 10y ago
  The question of defining "species" was one of the keystone questions used as an example in a philosophy of science course I took. See: http://plato.stanford.edu/entries/species/ http://plato.stanford.edu/entries/species/

dragonwriter 10y ago

> The black moths could still mate with the peppered variety so they're still the same species just different 'breeds', perhaps, so is this really evolution? Yes, not all evolutionary changes constitute changes of species. > I am a layman but one criticism of the theory of evolution that seems sensible to me is the absence of intermediate forms. An incomplete fossil record (and, given what is known about how the fossil record is laid down, its obviously going to be extremely incomplete even before considering how little of it we've actually been able to access) combined with evolution that is continuous (even if punctuated rather than constant-pace) is naturally going to miss lots of things between many of the things it preserves. That isn't a criticism of evolution. > All the species seem very well defined when you'd expect a continuum. There is a continuum; talking about it in any useful way, however, forces us to divide it up into discrete buckets -- taxonomic categories, whether "species" or higher- or lower-level categories -- and, where there are unclear cases, we end up arguing over which bucket they belong in, and how many buckets we should consider there to be.

Tloewald 10y ago

Species is not a well-defined term in the sense a mathematician understands well-defined. E.g. the usual "ability to breed and create fertile offspring" excludes all organisms that do not reproduce sexually, and does not account for fertile hybrids and "ring species".

quadrangle 10y ago

Actually, the world is full of high-resolution continua in species, it's just not always present. Divergence occurs due to isolation or some other factor. Horses and Zebras are different species but can interbreed. Lions and Tigers can interbreed. https://en.wikipedia.org/wiki/Hybrid_(biology) https://en.wikipedia.org/wiki/Hybrid_(biology) So the expected continuum you seek is totally there in tons of cases. It's just that there are cases where divergence gets too stark and intermediates die out. When humans choose (for conceptual and communications' sake) to identify two very similar groups as different species versus different breeds, then we call mixes "hybrids" like this. When we think it's just a little too similar and we call them "breeds" of the same species, then we don't call mixes "hybrids" as often. This is just problems with the simiplisticness of language.