11-27-2019, 07:55 PM
CLASSIFICATION & NAMING OF SPECIES
Levels of Classification
Biologists’ definitions for the term “species” has changed over the years, and every version has faced problems when applied in some situations. The most common definition used nowadays can basically be given as “A group of organisms that share common ancestry with each other more recently than with the members of any other group, and within which — if they practice sexual reproduction — any sexually-mature adult that produces male gametes is theoretically capable of producing viable & fertile offspring with any sexually mature adult that produces female gametes.” Its main problems involve organisms that use asexual reproduction instead, defining “viable” adequately when there is actually a continuum of possibilities (particularly for certain groups, e.g. the genus Canis…) rather than just a simple ‘yes/no’ question, setting the cut-off point between two species where one is descended from the other and so there has probably always been reproductive compatibility among the members existing at any one time, and types of organism that have relatively wide ranges within which the varieties at either end are no longer compatible with each other but can still be linked through one or more other mutually compatible populations living in between them. Despite these potential problems, this is still a good enough definition to use in most cases when considering living types of organisms that reproduce sexually — which includes most of the types that I will consider in these articles — and consequently is the one that I will use.
Every species must be placed within a nested sequence of ‘higher’ groups: The “obligatory” ones are the genus (plural = genera), family, order, class, division (botanical) or phylum (zoological; plural = phyla), kingdom, and —added to this list quite recently — domain. Other levels may also be inserted between these where it seems advisable for clarity, but this is generally atthe classifier’s discretion.
The relevant ‘domain’ for most if not all organisms that I am likely to discuss is the Eukaryota, which contains every living thing except for the ‘Archaea’ (formerly included among the Bacteria, now counted as a full domain in their own right), ‘Bacteria’ (formerly included for a while among the Plants, and then treated as a separate kingdom, but also counted as a full domain; less what is now the Archaea, but plus the ‘Cyanobacteria’ which were also formerly include among the Plants under the name of “Blue-green Algae”), and — if one actually count them as “living” — Viruses.
The two kingdoms whose members I am most likely to mention here are the ‘Animalia’ (all of the multi-cellular animals, from Sponges “upwards” in complexity) and the ‘Chlorophyta’ (all of the “land plants” plus the Green Algae, Red Algae, and a smaller group of algae called the Glaucophyta),and in those cases this detail should usually be obvious enough that I don’t need to specify it very often. All fungi, and the slime-moulds, form the kingdom ‘Fungae’. Brown Algae, and most if not all of the other groups traditionally grouped together as “Algae” comprise (along with a group called the ‘water moulds’) the kingdom Chromatophyta. All of the other kingdoms currently recognised contain only single-celled organisms.
Mammals, birds, reptiles, amphibian, and “true” fish (i.e. not ‘starfish’, or “shellfish”…) are all in the phylum ‘Chordata’, collectively forming the subphylum ‘Vertebata’.
I might add some details here about further phyla, and about ‘divisions’ of plants as well, later on.
The Giving of Names
Every genus must be given a single-word name in ‘taxonomical Latin’, which must be unique [and not just in spelling, it can’t be homonymous with another one either] except that any particular name can be used once each in Zoology and in either Botany, Mycology, or Bacteriology.
Every species must be given a two-word name (a “binomial”) in which the first part is the name of its genus and the second part is its individual identifier: The second part only has to be unique within that actual genus, so the same one can be used for other species too as long as they are in different genera. The name of the genus is always begun with an upper-case letter, and the species’ individual identifier with a lower-case one. In some cases names may be expanded to three or even four parts, thus: Genus (Subgenus) species subspecies, in which case all elements after the first must match the first in gender. These names are normally written in italics, or sometimes underlined, to set them apart from the surrounding text. In some situations the surname of the person who named them and the year in which this happened are added afterwards, but this is not something that I’m going to bother with here so I won’t bother to explain the rules involved either. When the same name is used repeatedly before the first occurrence of another one that shares the same initial letter all of its terms except for the last one may be abbreviated to their initial letters followed by full stops, for example when listing the species one could say “Genus speciesone, G. speciestwo, G. speciesthree, G. speciesfour, “Anothergenusspeciesone, A. speciestwo, A. speciesthree,” and on.
International committees lay down the rules about how these names are to be announced & recognised, which nowadays normally requires their use with an adequate definition (including a good enough description of a chosen ‘type specimen’ for others to use when identifying organisms found, and details of where it lives or lived) in a suitable peer-reviewed publication: They also set the rules under which names that have been officially recognised can, if certain limited conditions apply, be changed.
The name of any group above the level of Genus should always be written with an upper-case first letter but should not be set aside like that of a species or a genus by using italics or underlining. Each must be a single word, although possibly a newly-formed compound one, in ‘taxonomical Latin’. There are only a few rules about the forms for names to be used at these levels, for example a family’s name is formed from the name of one of its constituent genera, although from its ‘genitive’ case rather than its usual spelling, with the ending “-idae” in Zoology or “-aceae” in Botany, Mycology, or Bacteriology. The names of order follow fixed patterns for birds and for fish, both of which alter the name of one of the constituent families by replacing the “-idae” with “-iformes”, but not for other types of animals; and for orders in Botany (etc.) the families’ ending “-acaea” is replaced by “-ales”.
There are also specified endings for some of the optionally-used levels below that of order, but not for all of them: The ones that I’m most likely to use here are for Zoology, in which a superfamily of two or more families replaces one family’s “-idea” with “-oidea” (although this ending is also sometimes used at higher levels as well…), an epifamily (between superfamily & family in rank) uses “-oidae” instead, a subfamily (next level downfrom the family) uses the genitive form of an included genus — that from which the entire family is named, if present here — but with “-inae” rather than “-idae”, an infrafamily does likewise but with “-itae”, a parvfamily with “-irae” (Wiki says that in RL the correct from is actually “-od”, but both the Bears IC and I myself OOC don’t like that idea… and this level isn’t used much in RL anyway… ^_^), and a tribe (a rank that can also be used directly between family and genus) with “-ini.When I name a group whose rank can’t be determined by these rules I will explain its rank at the time.
For these purposes the term ‘clade’ can be used as meaning “a group of organisms that contains a single ancestral species and all of its descendants but no species that are not descended from that ancestor.” Some taxonomist today prefer to define species’ relationships using sets of nested clades, ideally based on a series of two-way splits, without necessarily giving those clades particular ‘ranks’ as in the traditional system: In some cases they may even just identify clades as something like “the lineage consisting of X, Y, and Z” without actually giving them real names.Both the Bears IC and I myself OOC prefer the more traditional system, however, and will generally still use that method where possible.
Taxonomical Latin
The rules for “taxonomical Latin” are rather different from those for Latin in general. The most relevant ones here are:
1.) You can use elements not only from Latin itself (whether ‘classical’ or ‘late’), but also from Classical Greek as well and can even form compound names that combine elements from both of those sources. The only elements normally allowed from English or other modern “civilized” languages are the names of people or places, and even then only if either combined with other elements of more ‘classical’ origins for the names of genera, or with Latinised endings for the individual species’ designations. However, you can use the relevant “everyday” names from the native languages of less “civilized” modern peoples, even if those have also been adopted as the ‘English names’ as well! Thus, the existence of such RL scientific names as Puma concolor, Equus zebra,Llama llama, and Okapi johnsoni.
2.) Although reversing the spelling of one genus’s name to use for another related (or, at least, similar) genus gives you results that probably don’t make sense in “proper” Latin, there is accepted precedent for doing this in taxonomy. For example the famous Argentine palaeontologist FlorentinoAmeghino, who discovered many species of fossils in South America during the late 19th& early 20th centuries, named quite a few new genera for those and used this method to come up with the names in a number of those cases. I have used it for some genera here, partly because of not having enough access to the relevant native languages to find out what names they use for the types of organism concerned.
_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _
Latin is not a subject that I’ve actually studied much, but I have picked up the meanings for quite a few terms used in RL organisms’ scientific names, and how they work, over the years; have at least some access to various Latin/English dictionaries (in my local library) and to “dictionaries of science”, to find other terms; and have sought t& received some help in NS’s forums as well.
If you know this subject better than me, and spot any errors here, then please let me know so that I can fix them. Also, if you think that I am using any particular element too much, feel free to suggest synonyms with which I could replace it in some of those names.
Levels of Classification
Biologists’ definitions for the term “species” has changed over the years, and every version has faced problems when applied in some situations. The most common definition used nowadays can basically be given as “A group of organisms that share common ancestry with each other more recently than with the members of any other group, and within which — if they practice sexual reproduction — any sexually-mature adult that produces male gametes is theoretically capable of producing viable & fertile offspring with any sexually mature adult that produces female gametes.” Its main problems involve organisms that use asexual reproduction instead, defining “viable” adequately when there is actually a continuum of possibilities (particularly for certain groups, e.g. the genus Canis…) rather than just a simple ‘yes/no’ question, setting the cut-off point between two species where one is descended from the other and so there has probably always been reproductive compatibility among the members existing at any one time, and types of organism that have relatively wide ranges within which the varieties at either end are no longer compatible with each other but can still be linked through one or more other mutually compatible populations living in between them. Despite these potential problems, this is still a good enough definition to use in most cases when considering living types of organisms that reproduce sexually — which includes most of the types that I will consider in these articles — and consequently is the one that I will use.
Every species must be placed within a nested sequence of ‘higher’ groups: The “obligatory” ones are the genus (plural = genera), family, order, class, division (botanical) or phylum (zoological; plural = phyla), kingdom, and —added to this list quite recently — domain. Other levels may also be inserted between these where it seems advisable for clarity, but this is generally atthe classifier’s discretion.
The relevant ‘domain’ for most if not all organisms that I am likely to discuss is the Eukaryota, which contains every living thing except for the ‘Archaea’ (formerly included among the Bacteria, now counted as a full domain in their own right), ‘Bacteria’ (formerly included for a while among the Plants, and then treated as a separate kingdom, but also counted as a full domain; less what is now the Archaea, but plus the ‘Cyanobacteria’ which were also formerly include among the Plants under the name of “Blue-green Algae”), and — if one actually count them as “living” — Viruses.
The two kingdoms whose members I am most likely to mention here are the ‘Animalia’ (all of the multi-cellular animals, from Sponges “upwards” in complexity) and the ‘Chlorophyta’ (all of the “land plants” plus the Green Algae, Red Algae, and a smaller group of algae called the Glaucophyta),and in those cases this detail should usually be obvious enough that I don’t need to specify it very often. All fungi, and the slime-moulds, form the kingdom ‘Fungae’. Brown Algae, and most if not all of the other groups traditionally grouped together as “Algae” comprise (along with a group called the ‘water moulds’) the kingdom Chromatophyta. All of the other kingdoms currently recognised contain only single-celled organisms.
Mammals, birds, reptiles, amphibian, and “true” fish (i.e. not ‘starfish’, or “shellfish”…) are all in the phylum ‘Chordata’, collectively forming the subphylum ‘Vertebata’.
I might add some details here about further phyla, and about ‘divisions’ of plants as well, later on.
The Giving of Names
Every genus must be given a single-word name in ‘taxonomical Latin’, which must be unique [and not just in spelling, it can’t be homonymous with another one either] except that any particular name can be used once each in Zoology and in either Botany, Mycology, or Bacteriology.
Every species must be given a two-word name (a “binomial”) in which the first part is the name of its genus and the second part is its individual identifier: The second part only has to be unique within that actual genus, so the same one can be used for other species too as long as they are in different genera. The name of the genus is always begun with an upper-case letter, and the species’ individual identifier with a lower-case one. In some cases names may be expanded to three or even four parts, thus: Genus (Subgenus) species subspecies, in which case all elements after the first must match the first in gender. These names are normally written in italics, or sometimes underlined, to set them apart from the surrounding text. In some situations the surname of the person who named them and the year in which this happened are added afterwards, but this is not something that I’m going to bother with here so I won’t bother to explain the rules involved either. When the same name is used repeatedly before the first occurrence of another one that shares the same initial letter all of its terms except for the last one may be abbreviated to their initial letters followed by full stops, for example when listing the species one could say “Genus speciesone, G. speciestwo, G. speciesthree, G. speciesfour, “Anothergenusspeciesone, A. speciestwo, A. speciesthree,” and on.
International committees lay down the rules about how these names are to be announced & recognised, which nowadays normally requires their use with an adequate definition (including a good enough description of a chosen ‘type specimen’ for others to use when identifying organisms found, and details of where it lives or lived) in a suitable peer-reviewed publication: They also set the rules under which names that have been officially recognised can, if certain limited conditions apply, be changed.
The name of any group above the level of Genus should always be written with an upper-case first letter but should not be set aside like that of a species or a genus by using italics or underlining. Each must be a single word, although possibly a newly-formed compound one, in ‘taxonomical Latin’. There are only a few rules about the forms for names to be used at these levels, for example a family’s name is formed from the name of one of its constituent genera, although from its ‘genitive’ case rather than its usual spelling, with the ending “-idae” in Zoology or “-aceae” in Botany, Mycology, or Bacteriology. The names of order follow fixed patterns for birds and for fish, both of which alter the name of one of the constituent families by replacing the “-idae” with “-iformes”, but not for other types of animals; and for orders in Botany (etc.) the families’ ending “-acaea” is replaced by “-ales”.
There are also specified endings for some of the optionally-used levels below that of order, but not for all of them: The ones that I’m most likely to use here are for Zoology, in which a superfamily of two or more families replaces one family’s “-idea” with “-oidea” (although this ending is also sometimes used at higher levels as well…), an epifamily (between superfamily & family in rank) uses “-oidae” instead, a subfamily (next level downfrom the family) uses the genitive form of an included genus — that from which the entire family is named, if present here — but with “-inae” rather than “-idae”, an infrafamily does likewise but with “-itae”, a parvfamily with “-irae” (Wiki says that in RL the correct from is actually “-od”, but both the Bears IC and I myself OOC don’t like that idea… and this level isn’t used much in RL anyway… ^_^), and a tribe (a rank that can also be used directly between family and genus) with “-ini.When I name a group whose rank can’t be determined by these rules I will explain its rank at the time.
For these purposes the term ‘clade’ can be used as meaning “a group of organisms that contains a single ancestral species and all of its descendants but no species that are not descended from that ancestor.” Some taxonomist today prefer to define species’ relationships using sets of nested clades, ideally based on a series of two-way splits, without necessarily giving those clades particular ‘ranks’ as in the traditional system: In some cases they may even just identify clades as something like “the lineage consisting of X, Y, and Z” without actually giving them real names.Both the Bears IC and I myself OOC prefer the more traditional system, however, and will generally still use that method where possible.
Taxonomical Latin
The rules for “taxonomical Latin” are rather different from those for Latin in general. The most relevant ones here are:
1.) You can use elements not only from Latin itself (whether ‘classical’ or ‘late’), but also from Classical Greek as well and can even form compound names that combine elements from both of those sources. The only elements normally allowed from English or other modern “civilized” languages are the names of people or places, and even then only if either combined with other elements of more ‘classical’ origins for the names of genera, or with Latinised endings for the individual species’ designations. However, you can use the relevant “everyday” names from the native languages of less “civilized” modern peoples, even if those have also been adopted as the ‘English names’ as well! Thus, the existence of such RL scientific names as Puma concolor, Equus zebra,Llama llama, and Okapi johnsoni.
2.) Although reversing the spelling of one genus’s name to use for another related (or, at least, similar) genus gives you results that probably don’t make sense in “proper” Latin, there is accepted precedent for doing this in taxonomy. For example the famous Argentine palaeontologist FlorentinoAmeghino, who discovered many species of fossils in South America during the late 19th& early 20th centuries, named quite a few new genera for those and used this method to come up with the names in a number of those cases. I have used it for some genera here, partly because of not having enough access to the relevant native languages to find out what names they use for the types of organism concerned.
_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _
Latin is not a subject that I’ve actually studied much, but I have picked up the meanings for quite a few terms used in RL organisms’ scientific names, and how they work, over the years; have at least some access to various Latin/English dictionaries (in my local library) and to “dictionaries of science”, to find other terms; and have sought t& received some help in NS’s forums as well.
If you know this subject better than me, and spot any errors here, then please let me know so that I can fix them. Also, if you think that I am using any particular element too much, feel free to suggest synonyms with which I could replace it in some of those names.