Really existing living objects in nature, studied by all biologists - individuals (individuals, organisms), populations, races (species and subspecies) - are classified by taxonomists, starting with objects of the population-species level of organization of living things, from the level of race.
Races as a collection of individuals connected by a “tribal community” (V. L. Komarov), i.e., by the reproduction of similar individuals, related and compatible in genotype with all the organisms that make up the race (species or subspecies) are, first of all, holistic systems of individuals from the point of view of genetics (their genotype is common, and this commonality is ensured by panmixia). But the commonality of the genotype is also ensured by isolation from individuals of other (in plants, primarily the closest) races. Reproductive isolation (inability to produce viable, fully competitive offspring during crossing) is ensured different ways- biologically, ecologically and geographically (figuratively, S. I. Korzhinsky called the totality of these characteristics of a race a biont and an area, and V. L. Komarov defined it as “the place of a species in the economy of nature”). Let me emphasize once again that in plants it is between distant races (and not the closest ones) that there can be quite fruitful crossing, and only ecological, and, to an even greater extent, geographic isolation ensures their independent existence. The totality of all these signs of a race (species, subspecies) tells us that this is a very real natural object.
There are a lot of natural races - species and subspecies of plants (only plant species without fungi - at least 450,000, of which vascular plants - at least 320,000-350,000). Such diversity cannot be perceived otherwise than in a certain system. The most easily perceived (and giving full visibility) system in this case is a hierarchical system. In a hierarchical system, species are united in a certain order into larger unities (by similarity or kinship), these groups, in turn, into even larger ones (if possible, also natural and, therefore, related by kinship). An ascending series of subordinate groups is created, the highest of which unites all plants on Earth. Such a hierarchical system is very convenient for memorization, and, most importantly, for viewing the entire set of objects (in this case, plants).
The groups that make up this hierarchically organized order according to a specific system (which may be very different in detail) are called taxa (taxon, plural - taxa). As a collection of any real races (or even a separate race or part of it), a taxon is, of course, an objective reality, but, as a collection limited completely subjectively, any taxon is a concept, an idea, an image. The method of delimiting taxa in a hierarchical system is ranking, and an integral part of any taxon is its rank (position in the hierarchical chain of subordination).
The set of laws of botanical nomenclature to which all work of taxonomists is subject - the (International) International Code of Botanical Nomenclature - already in its second article states: “Each individual plant is considered as belonging to a number of taxa of successively subordinate ranks.” That is, the specimen of Pelargonium zonale that I have on the window, at least belongs to the species P. zonale, genus Pelargonium, family Geraniaceae, order Geraniales, class Dicotyledonae, division (or phylum) Angiospermae and, of course, to the plant kingdom - Regnum vegetabile. The Code specifically stipulates that the basic concept in the hierarchy of taxa is the rank of species.
A species as a taxon is obligatory and refers in an ascending series to a genus, family, order, class, division (or type). In Latin nomenclature, this is a series of taxa: species - genus - familia - ordo - classis - divisio. But the code allows the use of other taxa (taxa of other ranks) for taxonomy purposes. Species within the same genus can be combined in an ascending series into series (series) - series, subsections, sections - sectio, subgenera; genera within one family - into subtribes, tribes (tribes) - tribus, subfamilies; families within one class - into suborders, orders, superorders, subclasses. It is also possible to use a taxon of rank II - subdivision (subtype). The main thing that the Code of Nomenclature requires is to observe a single series of main taxa, the order of which cannot be changed (species, genus, family, order, class, department) and the order of additional taxa between the main ones (if they are necessary). Any division of a system that follows this series (and is correctly described) is a taxon. But the Code allows (if taxonomy desires) the identification of taxa at a rank below species. Their descending series is a subspecies, variety, form (its complication is possible - a subvariety and even a subform). It is natural to believe that intraspecific and supraspecific taxa are essentially something different, although in the Code they are equivalent. Intraspecific taxa as collections of individuals in the genetic sense are a single whole (they have a common genotype, ensured by common panmixia, free crossing in different directions within this collection). Supraspecific taxa, as collections of individuals of two or more species, as a rule, are not united in free crossing systems into a unity supported by panmixia, and, therefore, they do not have a common genotype. But both taxa, significantly different in rank from the point of view of the Code, can completely coincide with each other in volume from the point of view of taxonomists who use these taxa for classification.
Enough simple operation constructing a system of any content as a hierarchy of subordinate taxa arranged in accordance with their rank does not, however, relieve (for a good taxonomist) the obligation to discuss the question of whether the taxa he accepts are natural as collections of individuals (living organisms), whether they are also related by kinship, and, if so, which taxa and to what extent are natural. And to this day there are many biologists (including taxonomists) who believe that all taxa are natural objects. At the same time, they bear with a light heart the inevitable facts in our practice, when a species (previously known to them) is transferred to another genus, a genus to another family, and a family wanders from order to order. They believe that all this represents the course of development of science, when we are subjectively gradually approaching the truth, the natural order of things. But, perhaps, the majority of taxonomists treat taxa as convenient in form and useful, but completely subjective concepts, which, if they have objective content, then only in time series of development, which we can restore, but, of course, also quite subjectively (and incompletely) ). All this, however, applies only to supraspecific taxa, since the main taxon—species (race)—is a natural phenomenon that is accessible to knowledge in its contemporary context, and partly in time, and even in experiment. Another thing is that we can also express this objective nature of a species, a race, within the framework of the system of taxa below the species allowed for use by the Code, and express it quite subjectively (and in different ways for different researchers). This is usually associated, first of all, with how different researchers understand the species itself, whether they allow its interpretation as a system of relatively independently existing populations in nature, having different evolutionary histories and
Fate, and, consequently, different (at least in particular) genotypes, consider a species to be the smallest natural unit that has a single genotype. But this may also be due to the fact that to interpret the same evolutionary phenomena at the population and species levels, different researchers can arbitrarily select taxa of different ranks (forms, varieties).
But the interpretation of the same groups (as collections of individuals and species) in different systems supraspecific taxa can be extremely sharply different, and the whole point is that the choice of the rank of a taxon is a purely subjective act, and for any theoretical justifications. The genus Ixiolirion, consisting of 2-3 good species (and possibly 2-3 more subspecies), is eastern Mediterranean and even extends into the territory of Russia - in old systems it belonged to the family. Amaryllidaceae, usually forming a special tribe there. In the system of A.L. Takhtadzhyan (1965), he is not even mentioned, apparently due to the traditional placement of him there. In the system of Takhtadzhyan (1980), it is recognized as a special subfamily within Amaryllidaceae. In R. Dahlgren’s system, it is initially interpreted in the same way (but in the 1983 system, it is separated into a special family Ixioliriaceae, standing near Hypoxidaceae in the order Asparagales, which also includes Amaryllidaceae, but all the Liliaceae kinship constitute a special order Liliales). In A. Cronquist’s system, it is part of the family. Liliaceae (together with Amaryllidaceae) and is not isolated here in any way. In the system of R. Thorne (1983), it is also included in Liliaceae, but as a special subfamily, and in the most recent version (90s), apparently, it is also distinguished as a special family. And in Takhtadzhyan’s system (1987) this is a special family, but in the order Amaryllidales, already separated from Asparagales. Finally, in another system by Takhtadzhyan (1997), Ixioliriaceae is already included in the order Tecophilaeales, separate from the order Amaryllidales, and even very distant from it, since Tecophilaeales is close to Iridales. In none of these cases did the volume of the taxon - the genus Ixiolirion - change, just as the volume of this group as a special taxon did not change in all variants of the system, except for the systems of Takhtadzhyan (1965) and A. Cronquist (1981-1988), where the scope of the group including Ixiolirion was not specifically specified. But his rank changed several times, as did his position in the system. And these are all different taxa... As for the characteristics of the genus, they have not changed one iota over the last 30 years! What is this connected with and does it have a basis in the theory of systematics? Oddly enough, this question should be answered positively.
Genus in taxonomy has always been a typological concept that generalizes some features of the species belonging to it. Moreover, at some stage in the development of taxonomy, genus as a typological concept clearly seemed to be a more important concept than species (and recurrences of these judgments have survived to this day, especially among zoologists and paleobiologists). The genera were described for the first time, and the first received trivial names (mononominals). Then, more and more numerous species began to differ in the composition of genera. Moreover, genera became the first taxa to have natural content, and the similarity of characteristics of species within the same genera was often interpreted as evidence of kinship. And such is the natural and typological (figurative) nature of genera that even realizing that the origin of any modern species included in any genus from other modern species of the same genus is almost incredible, taxonomists still believe that genera, they unite obviously closely related species, closer than the species they group within other genera. How dubious this thesis is is easy to see in modern systems, say, the tribe Triticeae (Gramineae), for most of the genera i and species of which have already been established quite a long time ago the most important features genome structure. It turns out that the same individual genome is characteristic (in various combinations with other genomes) of a number of genera containing a different number of species.
We can look into this in more detail using very interesting article our outstanding taxonomist (and, above all, a world-famous agrostologist), N. N. Tsvelev, “On the genomic criterion of genera in higher plants” (Botanical Journal, Vol. 76, No. 5, 1991). In general, it has never been seriously discussed in the literature (although there are references to it), and yet its main idea is this: “The study of genomes is the key to the natural division of plant genera.” This idea, however, is not from Nikolai Nikolaevich, but from the author of the concept of childbirth that he examines in the article - Askell Leve.
A. Leve is one of the largest karyotaxonomists of the late 20th century (he considers himself a “cytogeneticist”), a supporter of extreme narrow understanding genera in plants. The concept that N. N. Tsvelev discusses in his article concerns the system of genera in the two most genetically studied tribes of cereals - Triticeae and Hordeeae. Lewe himself worked with this group as a geneticist, but took advantage of the genetic developments of W. Dewey, the owner of a large collection of wheat and their relatives and a major Canadian-American geneticist of wheat (and less so of barley). Below we will examine in more detail the basis of this concept in more detail, but for now it is necessary to say a few words about N.N. Tsvelev’s article itself, which, as always, is interesting because of what is the position of Tsvelev himself on more general theoretical issues in general (and N.N. never hides them, expresses them directly, he is a man very enthusiastic and enthusiastic, and loves botany like life itself).
The article begins with N.N.’s own credo: “All taxa actually exist in nature, and the task of the taxonomist is to identify them and give them a certain taxonomic rank.” Further, N.N. stipulates that this does not apply to erroneously established taxa. In general, it is difficult to speak more definitely. But a taxonomist like N.N. Tsvelev thinks so, and our other venerable taxonomist, A.K. Skvortsov, also spoke so, and it seems to me that many, many young taxonomists cannot help but flock to such statements of such outstanding taxonomists. True, N.N., unlike A.K., is not a cautious person, but extremely open, absolutely courageous! And he immediately gives an example to confirm his thought. Schouten and Feldkamp (Y. Schouten, I. Veldkamp) are now genetically proving that the genera Anthoxanthum and Hierocloe are one genus! N.N. himself does not like this, and he emphasizes that they still have different basic numbers of chromosomes (Anthoxanthum - x = 5, and Hierochloe - x = 7). On this basis, he believes that Anthoxanthum cannot be connected with Hierochloe, but, in general, Anthoxanthum is now, of course, understood differently than in Linnaeus. You can understand it even more narrowly, and in this case you must see them (these series) as a reality given by nature.
But here's the problem. Both Anthoxanthum L., and Anthoxanthum in the sense of Tsvelev, and Anthoxanthum in the sense of Schouten and Feldkamp are taxa (and not natural genera, since they all have different contents). So which one is reality? Visible absurdity!
The fact is that a taxon is never identical to a phylum (let alone its section). A taxon (above a species) is always an abstraction (and in a number of cases it is an abstraction even when it is equal to only one now actually existing (and cognizable by us) species! We will see this further.,.). A phylum is a segment of phylogeny, represented either by a trunk or a hybridization network; of course, a reality, but a reality that we have not fully observed (without preceding modern species). But only this part of this reality, not observed by us, defines a taxon above a species.
A taxon seems real to taxonomists when the system options are practically exhausted, there is an established tradition, there is a stable image of the taxon (but in this case the choice of rank is always arbitrary!).
This is the philosophy (or epistemology) of taxa, but, alas, it is necessary because our points of view on them are different.
Actually, N.N. turns to Leve’s concept in order to strengthen precisely his opinion that taxa (at least genera!) are real if they are correctly identified... And he finds that Leve’s work finally confirms this with genomic analysis. After all, wheat has already been studied so well...
Therefore, we should now turn to Leve’s concept.
According to Leva, a genus is a group of closely related species that have either a completely specific (primary, considered unique in this group) genome, or a unique combination of primary genomes (multiple or in different combinations of multiples). It is this abundance of possible options (and there are 4 of them in the definition, but in reality there are more) immediately promises enormous difficulties for taxonomists who believe in the reality of the genus. Yes, we are promised the uniqueness of the genome, but what are the limits of this uniqueness, and, therefore, how many combinations are possible? How high should the accuracy of isolating primary (simple) genomes be? And although all this has been studied in wheat and their relatives for a very long time, and their genetics is extremely detailed, deciphering the genomes, generally speaking, is still very far away.
What does Lewe offer us in the system of wheat relatives? It is also important to know that it actually shows haplomes (parts that make up either one pair in the general genome, or a certain number of pairs (for polyploids - from two to six, but there can be several times - 3.5 pairs)) ... This is an additional complexity for taxonomists (and for Lewe, as a karyosystematist, it partially dictates the distribution of these taxa accepted by him).
Four taxa, according to Leve, have unique genomes that are not involved in combinations with other genera of this group. (It must be said that the genus Amblyopyrum was among those that, in some schemes of the relationship of wheat, were considered to participate, at least introgressively, in the creation of genomes of cultivated wheat). (Do we even know that Triticale still exist and, therefore, some parts of the Triticum and Secale genomes are quite compatible?!).
But let’s turn to the main part of the table, where, in fact, there remain different wheats and, in a broad sense, different parts of the large genus Aegilops (but not all), which, as we have long known, played a huge role in the genesis of cultivated tetraploid and hexaploid wheats. Back in the 20s, this was clear, and several scientists, including P. M. Zhukovsky, were engaged in the hybridization of wheat and Aegilops.
What is Leve showing us? He shows us that in the genera he allocates in the system, they have simple (unique) genomes (which do not sound like haplomes A, B, but in reality - AA, BB, etc.), but, at the same time, 8 genera he allocates - these are genera with combined genomes, which, by the way, can represent not just ABAB, but also AAB AAB [and ABD ABD/ABD ABD/ABD ABD/, because real wheats are hexaploids].
And this is where the question arises - why, in fact, should we make a decision only to Leva? And should these 18 (or 14) births be considered real? We have a number of other solutions here! Only for the first 4 genera there are two more solutions: either they are a single genus! (Triticum s. I. + Sitopsis, and so it was traditionally!), or A, B, AB, AAB are one genus, and ABD is a cultivated genus. We have different solutions and by combining all the types which I have colored blue and green, i.e. Aegilops s. sir. and all that do not have these colors, i.e. wheat and a significant part of Aegilops, and not just Sitopsis. There are many options here, and they are no worse, since in Leve’s system taxa that are combinative in genome are allowed, along with simple ones. And there have been many such decisions before. Option included in wheat sect. Sitopsis of the genus Aegilops was proposed by P. M. Zhukovsky! In the 50s, the prominent Canadian botanist-agrostologist and geneticist W. Bowden proposed combining wheat and all annual Aegilops in general.
The reality of all such constructions is no less than that of Leve’s scheme, but not greater either!!
The point, firstly, is that we do not know what the genome combinations were in previously existing wheat and, especially, Aegilops! (And there must have been quite a few of them (Aegilops) even earlier, at least since the Pliocene!).
Secondly, people who are not at all familiar with the genetics of wheat can, of course, be deceived by the subtlety of the analysis of Dewey and Leve, but anyone who knows at least something about this (and whether he knows about this, say, Tsvelev is silent) can remember one story. Triticum timopheevii Zhuk, in this scheme is considered as a spelled type with an AB combination, but a number of good wheat geneticists believe in this case that this is only a slightly modified BB genome, i.e., the Sitopsis genome. In general, a number of works discuss the possibility of the emergence of the Sitopsis (SS) genome by structural rearrangement of the SS genome (these are parts of the genomes of perennial Triticeae).
Thirdly, for the sake of any reliable interpretation of the scheme that Leve gave, we can ask geneticists for evidence that the evolution of triticoid cereals proceeded precisely (and only) through the recombination growth of genomes, and not through, say, post-hybridization splitting of simple genomes from more complex primary ones. And they won’t give us this evidence. And Leve has all the loose ends hidden. He does not consider either Agropyrum, Elytrigia, or Elymusl in this connection. Meanwhile, back in 1955, E.N.S. and a certain person proposed a hypothesis (rather controversial, but not refuted!) that wheat comes from unknown ancestral wheatgrass, a side branch of whose development (with hybrid influences) was the group Elytrigia jurtcea – E. elongate. The genomes of E. juncea and E. elongata turned out to be elementary, simple (they were identified with parts of the genomes of wheat (composite - in emmer and, in fact, wheat), but the genomes of most of Elytrigia (and the groups Trichopyrum, Psammopyrum), as well as Elymus ( Roegneria) - complex.
What if it was precisely the hybridization of complex genomes that led to the splitting of simple ones? And, in part, we could find evidence of this if we carefully consider the genetics of the perennial types of Triticeae (it was Dewey who worked with them the most!! And Leve, I repeat, is not a geneticist, but a cytosystematicist).
Now, based on the above (and much more), I cannot, alas, like N.N. Tsvelev, joyfully exclaim that, finally, there is a natural criterion for the genus, even only in Triticeae, which illuminated us, as at the exit from tunnel, which is already 1/2 step away. I think that upon leaving, we will immediately come to our senses and realize that everything is more complicated, and the light is everywhere (and not just at the exit from the tunnel). And then we will be convinced once again that, alas, taxa are not reality (but our creation).
But a completely different fact is even more indicative. Both among the genera in most large families, and among the genera generally known at the present time, monotypic genera (containing one modern species) sharply predominate. It is absolutely clear that for such species it is impossible to strictly select a modern species from any other genera that could be considered as the ancestor for such a modern monotypic genus. Hence, we must imagine that any of these genera descends only from some now extinct ancestor, separated from modern look of a monotypic genus precisely in time (and how far distant it is is not at all clear).
It is this idea of a genus as a fragment of a specific phylum that developed over a fairly long time, but clearly longer than the existence of only one modern species, now constituting a monotypic genus, and supports the idea that the genus is just as natural natural unity, like the modern appearance we now observe. Moreover, as already mentioned, there are significantly more such genera than multi-species genera, although they unite a significantly smaller proportion of species than multi-species genera.
But at the same time, we must still be clear that this fragment of the phylum can be restored in very different ways. We can restore this phylum as a series of successively replacing each other species of the same genus, only one of which has survived to our time (two options are possible here, depending on the type of speciation we accept and two options reflecting the connection with some nearby genus) .
All of these are only variants of virtually equivalent taxa—monotypic genera.
Another option is associated with the idea of a sharp (saltation) origin the only kind modern kind from species of another modern genus, no matter how far back in time.
It is quite obvious that any of these options is extremely difficult to prove, and usually only some morphological features are used for evidence, which can only give us some idea of the scale of divergence modern races(and in the first two options - this is also unclear). But this is clearly not enough.
In the case of polytypic genera containing big number species, to clarify their relationship we can use some other characteristics (not only morphological, but also ecological and geographical). In the case of monotypic genera, any construction of the phylum is essentially arbitrary. At the same time, the presence of scattered fossil types can help us to a very small extent, which we can also interpret, in essence, only according to some incomplete scattered morphological characters, which give a certain trend of changes, and there is also added a trend of changes in the general ecological situation (and sometimes evidence of some changes in the geography of a species we presume to be ancestral). We usually cannot create any image of a fossil species that is equivalent to the image of a modern species.
What then can we say about such polytypic taxa as, say, the Umbrella family together with the Araliaceae family. Or about the cruciferous family with its strange relationships with Caperaceae (especially Cleomeaceae) or Moringaceae. Naturally, even these natural families can be revised more than once both in volume and in the composition of taxa. And in the case of families such as Flacourtiaceae or, say, Rosaceae, there is nothing to say.
Thus, the theory, or rather the incompleteness of the theory of systematics, gives us grounds for numerous changes in the rank and volume of taxa, although in no case here can we objectively achieve a reflection of the true nature of things. After all, again and again we have to remember both the incompleteness of the geological record and the fact that the pace of evolution, alas, is very individual in different phyla.
It is the latter circumstance (known as “Simpson’s law”) that allows us to completely categorically reject all attempts to equalize the rank and volume of taxa in systems. In every business (and in every section of science) there are always people who want to formalize any phenomenon and any process. Taxonomy is no exception, and voices are constantly heard in it calling either to evenly divide all large (still extant) genera, or to evenly enlarge some taxa. Moreover, some of these calls are based on the false idea that basically divergent evolution according to Darwin leads to a strict dichotomy. This is completely incorrect, since divergence (evasion) most often leads to the death of the original species, and with geographical replacement according to the classical type (the formation of subspecies that can further separate into a species) - to a bunch of races, as a rule, apparently existing for a shorter time and than subspecies structures, and than the original species. All the more unlikely is the dichotomy usually drawn on diagrams in large phyla. Nature, of course, is much more diverse, and it cannot allow any leveling.
At the first stage of classification, experts divide organisms into separate groups, which are characterized by a certain set of characteristics, and then place them in correct sequence. Each of these groups in taxonomy is called a taxon (from the Greek taxon - (location, order). A taxon is the main object of taxonomy research, representing a group of zoological objects that actually exist in nature, which are sufficiently isolated, they can be identified and assigned a certain rank. Examples of taxa include such groups as “vertebrates”, “mammals”, “artiodactyls”, “red deer” and others.
Taxon (Latin taxon, plural taxa; from taxare- “to feel, determine the price by feeling, evaluate”) is a group in the classification, consisting of discrete objects, united on the basis of common properties and characteristics.
In the International Code of Botanical Literature (Vienna Codex, 2006), the term “taxon” is understood to mean a taxonomic group of any rank, and it is understood that each plant is considered to belong to an indefinite number of taxa of successively subordinate rank, among which the species rank is considered the main one. Taxon is defined similarly in zoology.
In modern biological classifications taxa form a hierarchical system: each taxon, on the one hand, consists of one or more taxa of a lower level of generality, at the same time, each taxon is part of another taxon - a group of a higher level of generality. Such a hierarchical system is called a taxonomic hierarchy, and its various levels are called taxonomic ranks
The three most significant characteristics of a taxon in modern biological systematics are volume, diagnosis and rank.
In the classification of the “father of taxonomy” Carl Linnaeus, taxa were arranged in the following hierarchical structure
Kingdom (lat. regnum) Animalia (animals)
Class (lat. classis) Mammalia (mammals)
Order (Squad) (lat. ordo) Primates (primates)
Genus (lat. genus) Homo (human)
Species (lat. species) Homo sapiens (reasonable man)
Variety (lat. varietas)
The levels of this hierarchy are called ranks. Ranks (universal levels of hierarchy that have their own names) were reflected in the classification at the end of the 17th century and since then, despite criticism from theoretical positions, have formed an integral part of taxonomic practice. In connection with the significantly more detailed understanding of taxonomists about the structure biological diversity the number of ranks has increased significantly since the time of Linnaeus.
Taxon volume can be objectively specified by listing organisms (or taxa of lower rank). Often, the volume of a taxon in the course of the historical development of ideas about the system of a particular group turns out to be much more stable than its rank. Thus, liver mosses in different plant systems were considered either as a family, or as a division or class (in this case, only the rank of the group changed, but not its volume). Such taxa, for which there are established ideas about volume, but not about rank, are often simply called “major groups”.
Monophyly(ancient Greek μόνος - one and φυλή - family clan) - the origin of the taxon from one common ancestor. According to modern concepts, monophyletic in biological systematics is a group that includes all known descendants of a hypothetical closest ancestor, common only to members of this group and to no one else. In some groups of organisms, phylogenetic relationships have not been definitively established.
It is now generally accepted that taxa must include descendants and all or some ancestors, although the validity of this latter requirement is increasingly subject to debate. A natural taxon is one such group that is generated through the process of evolution. Such groups are monophyletic. An artificial taxon is the result of an old way of classification (for example, by apparent similarity resulting from the evolution of dissimilar organisms), that is, such taxa are polyphyletic or paraphyletic.
One of the principles of systematics is the principle of hierarchy, or subordination. It is implemented as follows: closely related species are united into genera, genera are united into families, families into orders, orders into classes, classes into types, and types into a kingdom. The higher the rank of a taxonomic category, the fewer taxa at that level. For example, if there is only one kingdom, then there are already more than 20 types. The principle of hierarchy allows one to very accurately determine the position of a zoological object in the system of living organisms. An example is the systematic position of the white hare:
Kingdom Animalia (Animalia) Phylum Chordata (Chordata)
Class Mammals (Mammalia)
Order Lagomorpha Family Leporidae Genus Lepus
In addition to the main taxonomic categories, additional taxonomic categories are used in zoological systematics, which are formed by adding the corresponding prefixes to the main taxonomic categories (supra-, sub-, infra- and others) or auxiliary taxa (cohort, section).
The systematic position of the mountain hare using additional taxonomic categories will have next view:
Animal Kingdom (Animalia)
Subkingdom True metazoans (Eumetazoa) Phylum Chordata (Chordata)
Subphylum Vertebrates (Invertebrata)
Superclass Tetrapoda
Class Mammals (Mammalia)
Subclass Viviparous (Theria)
Infraclass Placental (Eetheria)
Order Lagomorpha (Lagomorpha)
Family Leporidae
Genus Hares (Lepus)
Species Mountain hare (Lepus timidus)
Knowing the position of the animal in the system, one can characterize its external and internal structure, features of biology. So, from the above systematic position For the white hare, you can obtain the following information about this species: it has a four-chambered heart, a diaphragm and fur (characters of the class Mammals); in the upper jaw there are two pairs of incisors, there are no sweat glands in the skin of the body (signs of the order Lagomorpha), the ears are long, hind limbs longer than the front ones (characteristics of the Leporidae family), etc. This is an example of one of the main functions of classification - prognostic (forecast, prediction function). In addition, the classification performs a heuristic (cognitive) function - it provides material for reconstructing the evolutionary paths of animals and an explanatory one - it demonstrates the results of studying animal taxa. To unify the work of taxonomists, there are rules that regulate the process of describing new animal taxa and assigning scientific names to them. These rules are compiled in the International Code of Zoological Nomenclature, which is published by International Commission on zoological nomenclature, the latest 4th edition of the code came into force on January 1, 2000.
The history of the development of zoology is closely connected with the history of the formation of the basic principles of animal taxonomy. It would be impossible to understand all the diversity of the Earth's fauna without an apparatus that allows us to record the position of the organisms being studied on the phylogenetic tree of the animal kingdom. Such an apparatus is modern taxonomy, which arose as a result of the painstaking work of many zoologists throughout the history of the development of science.
– assignment scientific name or concepts.
- description.
– highlighting similarities and differences with related concepts.
– classification.
- similarity of species.
The science of the diversity of plants, animals, fungi, microorganisms and their combination into groups (classifications) based on kinship is called taxonomy. Within the framework of this science, organisms are given names and grouped into groups, or taxa, based on certain relationships between them.
Higher taxon- this is a super-kingdom (domain). Next comes the taxon, called the kingdom, followed by phylum, class, order, family, genus and species for animals. When classifying plants, the same taxa are distinguished as those of animals, but with slight differences. A taxon of the same rank as a phylum in animals is called a division, and to an order there corresponds a taxon called an order. Different researchers identify from 4 to 26 different kingdoms, types - from 33 to 132, classes - from 100 to 200.
Plants Animals
Angiosperms Chordata
Dicotyledonous Mammals
Legumes Carnivorous
Bean Bears
Clover Bear
Red clover Brown bear
Biological nomenclature based on the binomial system proposed in the 16th century. K. Linnaeus (the name of each organism consists of two words, the first denotes the genus, the second - the species). Generic the name is written with a capital letter, specific- with small: Betula alba - birch (genus name) white (species name); Viola tricolor - tricolor violet; Homo sapiens is a reasonable person.
Human:
phylum chordata,
subphylum vertebrates,
class mammals,
subclass placental,
primate squad,
suborder great apes,
family apes,
kind of people.
Evolution of the organic world:
Modern system of the organic world:
Empire Empire
Noncellular Cellular
overkingdom overkingdom
Prokaryotes Eukaryotes
kingdom kingdom kingdom kingdom kingdom kingdom
Viruses Bacteria Archaea Animals Fungi Plants
Thematic assignments
A1. The main struggle for existence occurs between
1) classes
2) departments
3) families
A2. Habitat is the area of distribution
3) kingdoms
AZ. Indicate the correct classification order
1) class – phylum – family – order – species – genus
2) type – class – order – family – genus – species
3) order – family – genus – species – department
4) species – genus – type – class – order – kingdom
A4. Indicate the characteristic on the basis of which two finches can be classified as different species
1) live on different islands
2) vary in size
3) bring fertile offspring
4) differ in chromosome sets
A5. Which plant taxonomic group is incorrect?
1) class dicotyledons
2) department angiosperms
3) coniferous type
4) cruciferous family
A6. Lancelet belongs to
1) class chordates
2) subclass of fish
3) type of animal
4) subtype of skullless
A7. Cabbage and radish belong to the same family based on
1) structure of the root system
2) leaf venation
3) stem structure
4) structure of the flower and fruit
A8. In which case are the “kingdoms” of the organic world listed?
1) bacteria, plants, fungi, animals
2) trees, predators, protozoa, algae
3) invertebrates, vertebrates, chlorophylls
4) spores, seeds, reptiles, amphibians
IN 1. Choose three titles families plants
1) dicotyledons
2) bryophytes
5) moths
6) Rosaceae
AT 2. Choose three names of animal orders
2) reptiles
3) cartilaginous fish
5) tailless (amphibians)
6) crocodiles
VZ. Establish the sequence of subordination of systematic groups of plants, starting with the largest
A) department Angiosperms
B) family Cereals
B) type awnless wheat
D) genus Wheat
D) class Monocots
In any classification there are larger and smaller groups of plants that are interconnected. Large groups are divided into smaller ones; and small ones, on the contrary, can be combined into larger groups. These systematic groups, or units, are called taxa.
The main taxonomic (systematic) unit is the species – Species. Species arose as a result of the long evolution of plants, and each species has a specific area of natural distribution on earth - a range. Individuals of the same species have common morphophysiological and biochemical characteristics and are capable of mutual crossing, producing fertile offspring in a number of generations (i.e., genetically compatible).
Each species belongs to a genus. Genus - Genus - a larger taxonomic unit, includes a group of closely related species that have many common features, for example, in the structure and arrangement of flowers, fruits and seeds. But there are also distinctive features: pubescence of leaves, color of the corolla, shape or division of the leaf blade, etc.
The next larger taxonomic unit is the family - Familia, which unites close and related genera. Their affinity lies both in the structure of generative organs (flowers, fruits) and in the structure of vegetative organs (leaves, stems, etc.). The suffix “aceae” is added to the end of the family. For example, the buttercup family is Ranunculaceae, and the Rosaceae family is Rosaceae.
Similar families are combined into a larger group - order - Ordo. Orders are combined into classes - Classis, and classes are combined into divisions - Divisio or types. The departments make up the kingdom - Regnum.
If necessary, intermediate taxonomic units can be used, for example, subspecies (subspeaes), subgenus (subgenus), subfamily (subfamilia), superorder (superordo), superkingdom (superreginum).
Taxonomic characteristics of the plant using the example of chamomile
Medicinal.
Systematics of lower and higher plants
Lower plants
All vegetable world divided into two large groups: lower plants and higher plants.
Lower plants– layered, or thallaceous, have a body called thallus or thallus. These include prenuclear and nuclear organisms, the body of which is not divided into vegetative organs (root, stem, leaf), and does not have differentiated tissues. Among lower plants there are unicellular, colonial and multicellular forms.
Prenuclear forms - Procaryota - do not have a membrane-bounded nucleus, chloroplasts, mitochondria, Golgi complex and centrioles. Ribosomes are small, many have flagella, and the cell wall of many prokaryotes contains the glycopeptide murein. Mitosis and meiosis, as well as sexual reproduction are absent, reproduction is carried out by dividing cells in two. Sometimes budding (yeast) occurs. For many, oxidative processes are represented by fermentations of various types (alcoholic, acetic acid, etc.). Photosynthesis, if it exists, is associated with cell membranes. Many prokaryotes are capable of fixing atmospheric nitrogen; among them there are aerobes and anaerobes. Some prokaryotes form endospores that facilitate the transfer unfavorable conditions external environment.
Prokaryotes are apparently the first organisms to appear on Earth. Prokaryotes belong to one kingdom of Drobyanok - Mychota, and it is divided into three subkingdoms: archaebacteria, true bacteria, oxyphotobacteria. The role of prokaryotes is enormous: they participate in the accumulation of carbonates, iron ores, sulfides, silicon, phosphorites, and bauxites. They process organic residues and participate in the production of many food products (kefir, cheese, koumiss), enzymes, alcohols, and organic acids. With the help of biotechnology, antibiotics produced by bacteria, interferon, insulin, enzymes, etc. are obtained. This is a positive role of prokaryotes.
Lower plants include nuclear organisms - Eucaryota, whose cells have nuclei bounded by a membrane. Nuclear organisms include Fungi - Mycota (Fungi) and plants - Plantae (Vegetabilia).
Mushrooms – Mycota
Mushrooms are varied in appearance, habitats, physiological functions, sizes. The vegetative body - mycelium, consists of thin branching threads - hyphae. Fungi have a cell wall containing chitin, their storage nutrient is glycogen, and their feeding method is heterotrophic. Mushrooms are immobile in the vegetative state and have unlimited growth. In the protoplast of fungal cells, ribosomes, a nucleus, and mitochondria are distinguishable; the Golgi complex is poorly developed. Fungi reproduce vegetatively (parts of mycelium), asexually (spores) and sexually (gametes).
Mushrooms also play a positive role in human life: they are widely consumed as food (ceps, boletuses, boletus, milk mushrooms, etc.); yeast is used in fermentation processes (baking, brewing, etc.); many fungi produce enzymes, organic acids, vitamins, and antibiotics. A number of species (ergot, chaga) are used to obtain medicines
Plants – Plantae
Plants - Plantae - are a kingdom of eukaryotic organisms characterized by photosynthesis and dense cellulose membranes, a reserve nutrient - starch.
The plant kingdom is divided into three subkingdoms: algae (Rhodobionta), true algae (Phycobionta) and higher plants (Cormobionta).
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