5 ms·

I really like Richard Dawkins explanation of this, where he has you imagine taking a photo of yourself from your are born to you reach adulthood with 1 minute i

I really like Richard Dawkins explanation of this, where he has you imagine taking a photo of yourself from your are born to you reach adulthood with 1 minute intervals. If you stack these pictures, there is no single picture you can pull out and say: "Here I transitioned from child to adult" e.g. Likewise with animals and evolution. Changes are so minute that you can speak of a transition from one species to another happening at the point of birth. Only when you look at pictures of yourself far away from each other in the pile can you start differentiating them. Likewise with animals.

ThomPete 11y ago
Exactly, they are minute because they are constant. We are in constant flux so to speak.
sageikosa 11y ago
Also Dawkins posits a relatively good empirical definition of species boundaries (although I'm not quoting him verbatim, and I may be extending/synthesizing some of the ideas somewhat), but...a species is basically the pool of organisms available at a period of time that can generate progeny that themselves can generate progeny. That is, they have replicator compatibility... Under that definition, humans make a species. Horses make a species, donkeys make a species, but mules do not. Apparently in the world of Star Trek, Klingons and humans make a species: Worf (Klingon) had a child with a half-human/half-Klingon woman, and Tom Paris (human) had a child with a half-human/half-Klingon woman. Not sure about Vulcans and Romulans...obviously they can mate, but I'm not sure Spock himself can have children, perhaps we'll find out in a future movie. In Futurama, Kiff reproduced with Leela. As to the concept of a human as a "super-organism", the problem with bacteria being part of the equation is that they do not transmit their replicator payload through the germ-line transmission vector. They are not integrated into the next generation in whole or in part. Via the concept of the extended phenotype they may alter and extend their environment to improve their chance of success (and often mothers and children have the same bacteria flora), but it's better to think of it as symbiosis (or in the worst case, parasitism) than true "super-organism" reproduction. (Me thinks!)
- mortehu 11y ago
  > a species is basically the pool of organisms available at a period of time that can generate progeny that themselves can generate progeny That's what we learned in high-school too, but as you mentioned, it doesn't make sense for donkeys, nor does it work for ring species[1], or organisms that reproduce asexually[2]. Mules can occasionally become mothers[3]. 1. https://en.wikipedia.org/wiki/Ring_species https://en.wikipedia.org/wiki/Ring_species 2. https://en.wikipedia.org/wiki/Asexual_reproduction https://en.wikipedia.org/wiki/Asexual_reproduction 3. http://www.npr.org/templates/story/story.php?storyId=12260255 http://www.npr.org/templates/story/story.php?storyId=1226025...
  - sageikosa 11y ago
    I wasn't familiar with the term "Ring Species" (I've only gotten interested in evolutionary biology in the past few years), although I had considered that a "pool" might have a relatively fluctuating degrees of mutuality and incompatibility among candidate members. Also, I hadn't considered to qualify "sexual reproduction", as asexual reproduction might be better thought of as strains (perhaps), the classification systems for simpler organisms tends to be more structural than fecund. In my defense, I tend to refer to organisms as assemblages of organs of which simpler biota can loosely be said to possess, though I always thought of the "organs" of single-cellular creatures as organelles as they are not made up of "tissue" as they are in multi-cellular organisms.
- NoMoreNicksLeft 11y ago
  > Horses make a species, donkeys make a species, but mules do not. Rarely, sometimes mules are fertile. And as far as humans, no one's entirely sure that chimps and humans aren't inter-fertile... at least at the level of horses/donkeys.
  - sageikosa 11y ago
    Exception, not the rule, but I did warn it was a relatively good empirical formula, not a law of nature :-) I am of the mind that categories such as species are mental constructs to turn the phenomenal world into an approximate model-space so that understanding and action planning can be improved. So for me rather than concepts like "species" being meaningless, they can have meaning (or at least value), but best not to think of them as iron laws. Mostly the point I was hoping to get to in my root response before I diverted myself reading my own text while typing it. It's easier to create iron laws for categorical manipulation than it is to place observations into categories to begin with.
moron4hire 11y ago
Isn't that a bit like complaining about definitively stating in which square a chess piece currently sits because previously it had been on other squares?

ThomPete 11y ago

Exactly, they are minute because they are constant. We are in constant flux so to speak.

sageikosa 11y ago

Also Dawkins posits a relatively good empirical definition of species boundaries (although I'm not quoting him verbatim, and I may be extending/synthesizing some of the ideas somewhat), but...a species is basically the pool of organisms available at a period of time that can generate progeny that themselves can generate progeny. That is, they have replicator compatibility... Under that definition, humans make a species. Horses make a species, donkeys make a species, but mules do not. Apparently in the world of Star Trek, Klingons and humans make a species: Worf (Klingon) had a child with a half-human/half-Klingon woman, and Tom Paris (human) had a child with a half-human/half-Klingon woman. Not sure about Vulcans and Romulans...obviously they can mate, but I'm not sure Spock himself can have children, perhaps we'll find out in a future movie. In Futurama, Kiff reproduced with Leela. As to the concept of a human as a "super-organism", the problem with bacteria being part of the equation is that they do not transmit their replicator payload through the germ-line transmission vector. They are not integrated into the next generation in whole or in part. Via the concept of the extended phenotype they may alter and extend their environment to improve their chance of success (and often mothers and children have the same bacteria flora), but it's better to think of it as symbiosis (or in the worst case, parasitism) than true "super-organism" reproduction. (Me thinks!)

mortehu 11y ago
> a species is basically the pool of organisms available at a period of time that can generate progeny that themselves can generate progeny That's what we learned in high-school too, but as you mentioned, it doesn't make sense for donkeys, nor does it work for ring species[1], or organisms that reproduce asexually[2]. Mules can occasionally become mothers[3]. 1. https://en.wikipedia.org/wiki/Ring_species https://en.wikipedia.org/wiki/Ring_species 2. https://en.wikipedia.org/wiki/Asexual_reproduction https://en.wikipedia.org/wiki/Asexual_reproduction 3. http://www.npr.org/templates/story/story.php?storyId=12260255 http://www.npr.org/templates/story/story.php?storyId=1226025...
- sageikosa 11y ago
  I wasn't familiar with the term "Ring Species" (I've only gotten interested in evolutionary biology in the past few years), although I had considered that a "pool" might have a relatively fluctuating degrees of mutuality and incompatibility among candidate members. Also, I hadn't considered to qualify "sexual reproduction", as asexual reproduction might be better thought of as strains (perhaps), the classification systems for simpler organisms tends to be more structural than fecund. In my defense, I tend to refer to organisms as assemblages of organs of which simpler biota can loosely be said to possess, though I always thought of the "organs" of single-cellular creatures as organelles as they are not made up of "tissue" as they are in multi-cellular organisms.
NoMoreNicksLeft 11y ago
> Horses make a species, donkeys make a species, but mules do not. Rarely, sometimes mules are fertile. And as far as humans, no one's entirely sure that chimps and humans aren't inter-fertile... at least at the level of horses/donkeys.
- sageikosa 11y ago
  Exception, not the rule, but I did warn it was a relatively good empirical formula, not a law of nature :-) I am of the mind that categories such as species are mental constructs to turn the phenomenal world into an approximate model-space so that understanding and action planning can be improved. So for me rather than concepts like "species" being meaningless, they can have meaning (or at least value), but best not to think of them as iron laws. Mostly the point I was hoping to get to in my root response before I diverted myself reading my own text while typing it. It's easier to create iron laws for categorical manipulation than it is to place observations into categories to begin with.

moron4hire 11y ago

Isn't that a bit like complaining about definitively stating in which square a chess piece currently sits because previously it had been on other squares?