5 ms·

> actual biologists don’t use this children’s definition anymore Can you link me to the definition biologists use? I googled for a minute and didn't get very

> actual biologists don’t use this children’s definition anymore Can you link me to the definition biologists use? I googled for a minute and didn't get very far. Wikipedia (https://en.wikipedia.org/wiki/Species https://en.wikipedia.org/wiki/Species): "A species is often defined as the largest group of organisms in which any two individuals of the appropriate sexes or mating types can produce fertile offspring, typically by sexual reproduction." What is the correct & concise definition?

ufo 5y ago
The whole problem is that there isn't a single correct definition. For example: https://evolution.berkeley.edu/biological-species-concept/ https://evolution.berkeley.edu/biological-species-concept/ https://evolution.berkeley.edu/other-species-concepts/ https://evolution.berkeley.edu/other-species-concepts/
- errcorrectcode 5y ago
  Yes and I think we're stuck with what's already happening: modifications to existing classifications by genetic discoveries as they occur. There's no good way to please everyone, have a trillion special cases, or throw it all away because it's imperfect.
- mcguire 5y ago
  "We know it when we see it."
hyperpape 5y ago
There isn’t a correct and concise definition, any more than than there is a correct and concise definition of good art, good code, mathematical proof, or sandwiches. https://plato.stanford.edu/entries/species/ https://plato.stanford.edu/entries/species/ Even the term planet has recently given us trouble. There we’ve adopted a definition, it’s just not fully agreed upon.
- lmilcin 5y ago
  Mathematical proof actually has very precise definition. You can take something and answer precisely whether it is or is not a mathematical proof.
- lrem 5y ago
  Wait, mathematical proof? > A mathematical proof is an inferential argument for a mathematical statement, showing that the stated assumptions logically guarantee the conclusion. Unlike all the other sciences, mathematics is abstract enough to allow for things being fundamentally simple and true.
  - mcguire 5y ago
    As a formalist, I would like to agree with you. As someone who knows most mathematicians are not formalists, I think you may have some problems.
  - hyperpape 5y ago
    As a mathematical object, a proof is a series of derivations from axioms to a conclusion. That is well defined in various systems, can be studied as a branch of mathematics. In fact, most mathematics isn't done this way (though there's interesting work in the Lean community). Mathematical proof as it is actually done is far messier. Here's the paper that first came to mind (Probabilistic Proofs and Transferability, by Kenny Easwaran), though I'm sure there is a more canonical source: https://ucfc6eb8f695030deb8332de441a.dl.dropboxusercontent.com/cd/0/inline2/BbTZopOAzf1VbSX0lAsDAl5GOKwAq1-960-jlCzC_AqYhQbFgU1Y3eicCW5UxEigaTU5t-1uWJKU7bRIOC5yXkTtM-lp6JRVwTWIAGc_iyCbSbR9lzKU4QjGrYD6h0dOtl3FstnRhM7UKfxxx91UX71ur3qxNVvR1bTH0scimARr-aKyRYQ_mmRkWKLsdSrtQ27hNrEcmJlrsyIkzE-HFAlOW_1CID5ErjA7_6qLLWlJ8mOyuNPcw1YlcEKQs10zek6qmCQ5d-02UvrsxYeJg4gBV-VijWlzOaznH9zKrJgmCPckciuTVChJBGLVjnwaAHvzDL3PVHfIr4iW-nXvOzaZyB2yftcmEttaHbsS1vh64aVFvemb1Jm8i6CzSoK-PyU/file https://ucfc6eb8f695030deb8332de441a.dl.dropboxusercontent.c... P.S. You're free to adopt a way of speaking in which you say the majority of graduate mathematics textbooks do not involve any proofs, but I think that's a revision of the term.
    - User23 5y ago
technobabbler 5y ago
> What is the correct & concise definition? IMO it's that "species" is a term coined by older, less-informed biologists who didn't yet understand all the nuances of genetics, and created a taxonomic system based, erroneously, on superficial differences in appearance. It's like how old scientists believed in "ether" to describe the mysteries of space and "humor" to describe the mysteries of the body. Species is what old scientists used to describe the mysteries of genetics.
- netizen-936824 5y ago
  This is the correct answer imo. There's a huge rift in this area of biology on how to organise things, with multiple different ideas.
- mayregretit 5y ago
  Older, less-informed biologists also gave us scientific racism. Polar bears and Asiatic black bears live in different places and have different appearances and behaviors. They called those different species. Norwegian humans and Chinese humans live in different places and have different appearances and behaviors. They called those different races.
  - technobabbler 5y ago
    If we're gonna go down that route, probably our genetics gave us racism. Many species are "racist" towards other populations that they might've otherwise bred with. Extant primates also engage in what would be called genocide if performed by humans. All just because the other group lived in some other place and might've looked/smelled/talked a bit different. Nature is cruel and unforgiving and does not give two damns about egalitarianism. Equality is a human cultural construct, a social contract that attempts to minimize in-group violence. It is itself a cultural evolution, a relatively recent one in the West, longer-lived than that in other cultures, but altogether very limited and mostly only applied to some convenient in-group du jour, not humans around the world and certainly not to hominids at large. Equality has no real evolutionary basis. Evolution depends on inequality in the face of selection pressures. May fit individuals breed, may adaptable populations persist, and may the sexiest genome win. Scientific racism failed both because of changing social norms and because taxonomy-by-appearance was doomed to fail upon closer inspection, not because humans are inherently equal... we're anything but, and those "self-evident truths" are believed by no one in particular, not even grade school kids. It's ironic that the nation who says that on one hand has, on the other hand, produced one of the most unequal societies in human history. If society is ever to actually become egalitarian, it must be because we -- by social contract or force of mythology -- place equal value on each individual, not because our genetics are the same. We're not clones and we're all better and worse at some things, and most of us are completely mediocre at everything except, maybe, being an adaptable hairless ape between ice ages in the temperate zones of a wet rock floating around a star. In other words, we can't morphologically evolve our way out of racism, but perhaps -- someday, if we survive these next few decades -- we can culturally evolve more egalitarianism. Genomes aren't the only unit of information reproduction anymore. We can only hope culture will succeed where nature failed.
colechristensen 5y ago
> What is the correct & concise definition? There isn’t one. “Species” is an abstraction, vague when you look too closely, and increasingly meaningless when you move from animals to plants to fungi to bacteria and archaea. There’s just no way to decisively say exactly when two closely related organisms transition from one species to two. You will find debate and varying methods but in the end for the professional scientist, it’s mostly an unimportant question for most because it’s obviously just vague and never possible to be perfect, and you have to ask “what’s the point?” of the really fine grained labeling which seems to only be done for the purpose of labeling.
seszett 5y ago
That Wikipedia article does cite other ways of defining species, just after your quote. The bottom line is that there is no one correct and concise definition. It's also obvious that the fertile offspring definition is not sufficient of you look at plants (pomelos, mandarins and citrons are rather obviously different species, but they are interfertile and most modern citrus species are their hybrids) or even more obviously, at bacteria or yeasts that don't even reproduce sexually.

ufo 5y ago

The whole problem is that there isn't a single correct definition. For example: https://evolution.berkeley.edu/biological-species-concept/ https://evolution.berkeley.edu/biological-species-concept/ https://evolution.berkeley.edu/other-species-concepts/ https://evolution.berkeley.edu/other-species-concepts/

errcorrectcode 5y ago
Yes and I think we're stuck with what's already happening: modifications to existing classifications by genetic discoveries as they occur. There's no good way to please everyone, have a trillion special cases, or throw it all away because it's imperfect.
mcguire 5y ago
"We know it when we see it."

hyperpape 5y ago

There isn’t a correct and concise definition, any more than than there is a correct and concise definition of good art, good code, mathematical proof, or sandwiches. https://plato.stanford.edu/entries/species/ https://plato.stanford.edu/entries/species/ Even the term planet has recently given us trouble. There we’ve adopted a definition, it’s just not fully agreed upon.

lmilcin 5y ago
Mathematical proof actually has very precise definition. You can take something and answer precisely whether it is or is not a mathematical proof.
lrem 5y ago
Wait, mathematical proof? > A mathematical proof is an inferential argument for a mathematical statement, showing that the stated assumptions logically guarantee the conclusion. Unlike all the other sciences, mathematics is abstract enough to allow for things being fundamentally simple and true.
- mcguire 5y ago
  As a formalist, I would like to agree with you. As someone who knows most mathematicians are not formalists, I think you may have some problems.
- hyperpape 5y ago
  As a mathematical object, a proof is a series of derivations from axioms to a conclusion. That is well defined in various systems, can be studied as a branch of mathematics. In fact, most mathematics isn't done this way (though there's interesting work in the Lean community). Mathematical proof as it is actually done is far messier. Here's the paper that first came to mind (Probabilistic Proofs and Transferability, by Kenny Easwaran), though I'm sure there is a more canonical source: https://ucfc6eb8f695030deb8332de441a.dl.dropboxusercontent.com/cd/0/inline2/BbTZopOAzf1VbSX0lAsDAl5GOKwAq1-960-jlCzC_AqYhQbFgU1Y3eicCW5UxEigaTU5t-1uWJKU7bRIOC5yXkTtM-lp6JRVwTWIAGc_iyCbSbR9lzKU4QjGrYD6h0dOtl3FstnRhM7UKfxxx91UX71ur3qxNVvR1bTH0scimARr-aKyRYQ_mmRkWKLsdSrtQ27hNrEcmJlrsyIkzE-HFAlOW_1CID5ErjA7_6qLLWlJ8mOyuNPcw1YlcEKQs10zek6qmCQ5d-02UvrsxYeJg4gBV-VijWlzOaznH9zKrJgmCPckciuTVChJBGLVjnwaAHvzDL3PVHfIr4iW-nXvOzaZyB2yftcmEttaHbsS1vh64aVFvemb1Jm8i6CzSoK-PyU/file https://ucfc6eb8f695030deb8332de441a.dl.dropboxusercontent.c... P.S. You're free to adopt a way of speaking in which you say the majority of graduate mathematics textbooks do not involve any proofs, but I think that's a revision of the term.
  - User23 5y ago

technobabbler 5y ago

> What is the correct & concise definition? IMO it's that "species" is a term coined by older, less-informed biologists who didn't yet understand all the nuances of genetics, and created a taxonomic system based, erroneously, on superficial differences in appearance. It's like how old scientists believed in "ether" to describe the mysteries of space and "humor" to describe the mysteries of the body. Species is what old scientists used to describe the mysteries of genetics.

netizen-936824 5y ago
This is the correct answer imo. There's a huge rift in this area of biology on how to organise things, with multiple different ideas.
mayregretit 5y ago
Older, less-informed biologists also gave us scientific racism. Polar bears and Asiatic black bears live in different places and have different appearances and behaviors. They called those different species. Norwegian humans and Chinese humans live in different places and have different appearances and behaviors. They called those different races.
- technobabbler 5y ago
  If we're gonna go down that route, probably our genetics gave us racism. Many species are "racist" towards other populations that they might've otherwise bred with. Extant primates also engage in what would be called genocide if performed by humans. All just because the other group lived in some other place and might've looked/smelled/talked a bit different. Nature is cruel and unforgiving and does not give two damns about egalitarianism. Equality is a human cultural construct, a social contract that attempts to minimize in-group violence. It is itself a cultural evolution, a relatively recent one in the West, longer-lived than that in other cultures, but altogether very limited and mostly only applied to some convenient in-group du jour, not humans around the world and certainly not to hominids at large. Equality has no real evolutionary basis. Evolution depends on inequality in the face of selection pressures. May fit individuals breed, may adaptable populations persist, and may the sexiest genome win. Scientific racism failed both because of changing social norms and because taxonomy-by-appearance was doomed to fail upon closer inspection, not because humans are inherently equal... we're anything but, and those "self-evident truths" are believed by no one in particular, not even grade school kids. It's ironic that the nation who says that on one hand has, on the other hand, produced one of the most unequal societies in human history. If society is ever to actually become egalitarian, it must be because we -- by social contract or force of mythology -- place equal value on each individual, not because our genetics are the same. We're not clones and we're all better and worse at some things, and most of us are completely mediocre at everything except, maybe, being an adaptable hairless ape between ice ages in the temperate zones of a wet rock floating around a star. In other words, we can't morphologically evolve our way out of racism, but perhaps -- someday, if we survive these next few decades -- we can culturally evolve more egalitarianism. Genomes aren't the only unit of information reproduction anymore. We can only hope culture will succeed where nature failed.

colechristensen 5y ago

> What is the correct & concise definition? There isn’t one. “Species” is an abstraction, vague when you look too closely, and increasingly meaningless when you move from animals to plants to fungi to bacteria and archaea. There’s just no way to decisively say exactly when two closely related organisms transition from one species to two. You will find debate and varying methods but in the end for the professional scientist, it’s mostly an unimportant question for most because it’s obviously just vague and never possible to be perfect, and you have to ask “what’s the point?” of the really fine grained labeling which seems to only be done for the purpose of labeling.

seszett 5y ago

That Wikipedia article does cite other ways of defining species, just after your quote. The bottom line is that there is no one correct and concise definition. It's also obvious that the fertile offspring definition is not sufficient of you look at plants (pomelos, mandarins and citrons are rather obviously different species, but they are interfertile and most modern citrus species are their hybrids) or even more obviously, at bacteria or yeasts that don't even reproduce sexually.