Taxonomic categories or taxa (singular – taxon) are the levels that have created to group similar organisms. There are seven main taxonomic categories:
Species (used both as singular and plural) is a natural population of individuals or group of population which resemble one another in all essential morphological and reproductive characters so that they are able to interbreed freely and produce fertile offspring. The scientific name of mango is Mangifera indica, where “Mangifera” is the genus and Indica” is the species. The scientific name of potato is Solanum tuberosum, where “Solanum” is the genus and “tuberosum” is the species.
It is a group or assemblage of related species that resemble one another in certain correlated characters. Correlated Characters are those similar or common features that are used in the delimitation of a taxon above the rank of species. All the species of a genus are presumed to have evolved from a common ancestor.
It is a taxonomic category that contains one or more related genera. All the genera of a family have some common features or correlated characters. They are separable from the genera of a related family by important and characteristic differences in both vegetative and reproductive features.
Example: The genera of cats (Felis) and leopards (Panthera) are included in the family Felidae.
The category includes one or more related families. Thus the family Solanaceae is placed in the order Polemoniales along with four other related families (Convolvulaceae, Boraginaceae, Hydrophyllaceae, and Polemoniaceae). Similarly, the families Felidae and Canidae are included under the order carnivore along with Hyaenidae (hyaenas) and Ursidae (bears).
A class is made of one or more related order.
Example: The class dicotyledonous (Dicotyledonae, dicotyledons) of flowering plants contains all dicots which are grouped into several orders.
Examples: Rosales, passiflorales, polemoniales, sapindales, ranales, etc.
Likewise, class mammalian of animals includes all mammals which range from bats (order Chiroptera), kangaroos (order Marsupialia), - rodents (order Rodentia), whales (order cetacean), and carnivores (order Carnivora) to great apes and man (order primate).
6. Division of Phylum:
It is a category higher than that of class. The term phylum is used for animals, while division is commonly employed for plants. A division of phylum is formed of one or more classes. The phylum chordate of animals contains not class mammalian but also Aves (birds), reptilian (reptiles), amphibians (amphibians), Cyclostomata, Chondrichthyes, Osteichthyes (fishes), etc.
It is the highest taxonomic category. All plants are included in kingdom Plantae while all animals belong to kingdom Animalia. There are some extra categories, like subdivision, suborder, subfamily, tribe, sub-tribe, etc. They are not regularly used. They are used only when they are needed.
Try yourself:Find the correct sequence of taxonomic categories.
Species → Genus → Family→ Order
- Techniques, procedures and stored Information that are useful in the identification and classification of organisms are called taxonomic aids. They are required because the taxonomic study of plants, animals and other organisms is basic to almost all biological studies branches for their proper identification and finding their relationships with others.
- Herbarium, botanical gardens, museum, zoological parks (zoos) and keys are important tools used in the identification of plants and animals.
- The herbarium is a place where dried and pressed plants specimens, mounted on sheets are kept systematically according to a widely accepted system of classification.
- The herbarium is a repository or storehouse for future use. Every institute teaching botany, school, college or university, has a small or large herbarium. Very large herbaria are maintained by botanical gardens and institutes connected with plant systematic.
- Every student of botany is required to collect plant specimens and prepare herbarium sheets.
- Equipment: Digger and pruning knife, a sickle with a long handle, vasculum, polythene bags, magazines or newspapers, bolting papers, plant press, field notebook, herbarium sheets, glue, labels, small transparent polythene bags.
➢ Different Types of Specimen (Herbarium Sheet)
- Holotype: Herbarium sheet on which the first description of the plant is based.
- Lectotype: If the holotype is lost, the second herbarium sheet prepared from the original plant is called a Lectotype.
- Neotype: In case holotype and the original plant is lost, then the herbarium sheet is prepared from some other plant of the same type.
- Syntype: If holotype and original plant are lost, then many herbarium sheets prepared from many plants of the same species are called Syntypes.
- Isotype: Duplicate of holotype - In the presence of holotype, a second herbarium sheet prepared from the original plant is called Isotype.
- Paratype: Additional herbarium sheet used in the first description of the plant is called Paratype. It is prepared from some other plant of same species having some variations.
➢ Method of Specimen Collection and Mounting
- An area is selected for the botanical excursion. It is preferable to visit the same site in different seasons.
- For herbaceous species, the entire plant with the intact part is collected. For others, shoots having flowers, leaves and fruits are selected and cut with the help of pruning knife.
- Sickle with a long handle is used if the desired twigs are present at a height. Diggers are used to obtain underground part like a root system, tuber, bulb, corm, rhizome, etc.
- The collected material can be placed in polythene bags or vacuum.
➢ Important Herbaria
2. Botanical Gardens
- Botanical gardens are efficiently large size tract where plants of different types and areas are grown for scientific and educational purposes.
- The first real mechanical garden was developed by Theophrastus (370-285 B.C.). Of course, the garden was part of Indian Chinese and Roman cultures. “Hanging Garden” of Babylon was considered to be wonders of ancient time.
- Modern-day Botanical Gardens contain outdoor plants, greenhouse, library, research laboratory, herbarium with documented collections of various taxa.
- There is an international association of botanical gardens (established in 1962) which coordinate research and exchange of plant materials.
➢ The Important Functions of Botanical Gardens
- Growing important plants of local flora.
- Keeping a record of local flora.
- Providing living plant material for systematic work.
- Supplying seeds and materials for different aspect of Botanical research.
- Growing and maintaining rare and endangered plant.
➢ Some Major Botanical Gardens of the World
- Main botanical garden Moscow. The largest garden spread over an area of 900 acres.
- Bundes garden, Vienna. It is spread over an area of 400 acres.
- Royal Botanical Garden, Kew London. It has an area of 300 acres but grows a very large number of plants.
- Kebun Raya (Botanical Garden)Bojor Java. Spread over an area of 200 acres, the garden has a section with virgin rain forest.
- Indian Botanical Garden Sibpur, Kolkata. It is the largest botanical garden of Asia spread over 273 acres, which is famous for its Great Banyan tree, Palm house, Succulent Plants, Indian Grasses etc.
- The word museum comes from the Greek word mouseion. In ancient Greek mouseion was the temple of Muses. The goddess of arts and sciences.
- A museum is an institution where artistic and educational materials are exhibited to the public.
- The materials available in the exhibition for study are called collections. A Collection may include scientific specimen, works of art and exhibits and information on the history of technology.
- There are five main kinds of museums, namely art museum, history museums, applied science museums, natural science museums and general museums.
➢ Museums Perform Various Functions
Acquisition of materials: Every new object that a museum adds to its collection is called Acquisition. Museum acquires object in several ways, of which field collection is the most useful. The scientific and technician go outside to gather specimens and data on a particular subject, which is with the scope of the museum.
Recording of Materials: Each acquisition is listed carefully by specialist staff. As soon as objects are received, the data, the source, the method of acquisition and other available information are entered in to record register.
Preservation of Materials: The primary purpose of the museum is to preserve selected objects that are received. Curators (person in charge of museum) know that no specimens will last forever. What museums undertake to do is to prolong the lifetime of the objects.
Preservation in a museum consists of two steps:
(i) Specimens must be put into a condition that checks deterioration.
(ii) The specimens must be protected.
Research: One important use of the museum is to extract as much knowledge as possible. Many museums published scholarly journals, series of papers and books to make available result of research on collections.
Exhibitions of Materials: Various members of museum staff prepare acquisitions for exhibitions. The specimens selected for exhibition are put on a view in numerous ways. The choice of approach and techniques depends on the purpose of exhibits.
Education: A Number of universities conduct some courses in certain subjects as museum university advantage of the collections. Thus museums help in spreading education.
4. Zoological Parks (Zoos)
Tigers at Zoo
- A Zoo is a place where various living animals are kept within enclosures and are displayed to the public and may be used for the study. Animals may also be bred.
- In fact, the concept of ZOO has changed instead of Zoos, Zoological parks or zoological gardens established where a high standard of care is observed and the animal live under more natural conditions.
- The animals provide better recreation to visitors.
- Nehru Zoological Park (also known as Hyderabad Zoo or Zoo Park) is a zoo located near Mir Alam Tank in Hyderabad, Telangana, India.
➢ The Role of Zoological Parks in Wildlife Conservation
- The regular zoo movement in India began in the year 1885 when the first zoo was set up in Chennai.
- In the Zoological Park, animals enjoy protection, fine sunshine, fresh air and above all, ample open space to play about.
- They have now become repositories of threatened wildlife and a storehouse of the knowledge on animal behaviour, breeding habits, etc.
- Zoological Park is the place where they are assured of food, medical care and treatment and where they also feel safe from their natural enemies.
- Zoological Parks are very useful in spreading knowledge of the wildlife wealth of the country.
Try yourself:In zoological parks, animals are
Zoological parks, animals are kept in protected environments under human care.
Some Definition Related to Species
- Linnean Species: Those taxonomic species whose determination is based on morphology. They are called as in neon species. They are also called morpho-species or taxonomic species.
Example: Most of the species in taxonomy are in neon species
- Microspecies or Jordan's Species: Those species in which variations are very less. They reproduce asexually, so they have very few variations.
- Sibling Species or Cryptic Species: Members of species that are morphologically similar but reproductively isolated area known as sibling species i.e. they can not interbreed among themselves.
Sibling species is one taxonomic species (because these members have similar morphology), but they are different biological species. [Because they can not interbreed]
Example: Brassica oleracea
- Allopatric Species: The species found in different geographical regions and have geographical barriers between them are known as allopatric species. Geographical barriers like hills, oceans, Himalayan Mountains.
- Sympatric Species: The species found in similar geographical regions.
- Allochronic Species: The species found in different time periods or eras.
Example: Man and Dinosaurs
- Synchronic Species: Those species that are found in the same era.
Example: Dinosaurs and Archaeopteryx
- Palaeo Species: Those species that are extinct now and are found in the form of fossils.
- Neontological Species: Those species which are living presently.