Lesson 8 of 8 · 11 min
Chapter review
Watch a class
The whole chapter on YouTube
PW Class 11 ScienceWhole chapter · Hinglish
Whole chapter revision, naming to hierarchy
Loading the full lesson
Must-know facts
18 facts
- 01Known and described species number 1.7 to 1.8 million, and new ones are still being found.
- 02Plant names follow ICBN; animal names follow ICZN.
- 03Binomial nomenclature was given by Carolus Linnaeus: generic name + specific epithet.
- 04Genus starts with a capital letter, specific epithet with a small letter: Mangifera indica.
- 05Printed names are italic; handwritten names have each word underlined separately.
- 06Mangifera indica Linn.: 'Linn.' is the abbreviated author, showing Linnaeus first described it.
- 07Four processes basic to taxonomy: characterisation, identification, classification, nomenclature.
- 08Systematics comes from Latin 'systema'; Linnaeus wrote Systema Naturae; systematics considers evolutionary relationships.
- 09Order of categories upward: species, genus, family, order, class, phylum (division in plants), kingdom.
- 10Species is the lowest category; kingdom is the highest.
- 11Going up the hierarchy, the number of shared characters decreases.
- 12Solanum, Petunia and Datura are in Solanaceae; Solanaceae and Convolvulaceae are in order Polymoniales.
- 13Panthera and Felis are in family Felidae; Felidae and Canidae are in order Carnivora.
- 14Order Primata and order Carnivora are both in class Mammalia.
- 15Chordata is defined by a notochord and a dorsal hollow neural system.
- 16Housefly: Muscidae, Diptera, Insecta, Arthropoda.
- 17Man: Hominidae, Primata, Mammalia, Chordata.
- 18Mango: Anacardiaceae, Sapindales, Dicotyledonae, Angiospermae; wheat: Poaceae, Poales, Monocotyledonae, Angiospermae.
Common traps
Where marks are lost
Key terms
17 terms
- Biodiversity
- The number and kinds of organisms present on earth.
- Species
- A group of individuals with fundamental similarities, set apart from close relatives by distinct morphological differences; the lowest taxonomic category.
- Identification
- Describing an organism correctly so that we know which organism a name refers to.
- Nomenclature
- Standardised naming, so that an organism has the same name all over the world.
- ICBN
- International Code for Botanical Nomenclature, the rules for naming plants.
- ICZN
- International Code of Zoological Nomenclature, the rules for naming animals.
- Binomial nomenclature
- Naming each organism with two words, the generic name and the specific epithet, as introduced by Linnaeus.
- Specific epithet
- The second word of a scientific name, marking the particular species within the genus.
- Classification
- Grouping into convenient categories on the basis of easily observable characters.
- Taxon
- A group of organisms at any rank of classification, such as dogs, mammals or animals; plural taxa.
- Taxonomy
- Classifying organisms into taxa on the basis of their characteristics.
- Systematics
- The study of the diversity of organisms and the relationships among them, including evolutionary ones.
- Taxonomic hierarchy
- All the taxonomic categories arranged in order of rank, from species to kingdom.
- Genus
- A group of closely related species that share more characters than they do with species of other genera.
- Family
- A group of related genera, characterised in plants on vegetative and reproductive features.
- Order
- An assemblage of families that show a few similar characters.
- Division
- The plant category equivalent to a phylum, grouping related classes.