Introduction #
- Diversity is the variety of living organisms
- Organisms have been grouped together for studies of their characteristics
- The grouping of organisms is called classification
- classification is based on agreed name of each organism
Hierarchy of classification #
- Systems of classification are hierchial i.e each successive group contains more and more different kinds of organisms
- Taxon is the general name given to each classification grouping
- Taxonomy is the science of classification of organisms into groups called taxons
- The longest taxon is the species and the most increasive or highest taxon is the kingdom
- Phylogeny is the study of evolutionary traits
- Natural classification of organisms is based on evolutionary relationships
Terminology used. #
- Kingdom is the largest grouping of organisms. Common kingdoms include Animalia (animals), Plantae (plants), Fungi, Protista (single-celled eukaryotes), Archaea, and Bacteria.
- Phylum consists of organisms with many similarities e.g bryophyte, cnidarians etc.
- Class consists of organisms which are grouped into several orders with few similarities.
- Order is a group of apparently related families
- Family is a group of apparently related genera
- Genus is a group of similar and closely related species
- Species is a group of organisms capable of interbreeding to produce fertile off springs. Homo sapiens, representing modern humans, is an example of a species.
Taxonomic Hierarchy Example
The classification of humans
- Kingdom: Animalia
- Phylum: Chordata
- Class: Mammalia
- Order: Primates
- Family: Hominidae
- Genus: Homo
- Species: sapiens
- Scientific Name: Homo sapiens
Binomial nomenclature #
- in this system each organism has two latin names, a generic name first capitalised and the specific name with a lowercased later
- the latin name is internationally agreed and avoid the confusion of local variation in local names
- eg humans are named Homo sapiens
genus-homo
species-sapiens - The generic name is shared with other related species considered to be sufficiently similar to be grouped in the same genus e.g Homo erectus, Homo habilis
The taxonomic hierarchy #
- Linnaeus extended binomial system of classifying organisms to introduce more groups than just the genus and species
- there are arranged in a hierachy with the largest group the kingdom at the top to the species
- kingdom → phylum → class → order → family → Genius → species
Multiple choice questions #
1.Which of the following taxonomic levels is the most specific and represents a group of organisms capable of interbreeding and producing fertile offspring?
a) Kingdom
b) Family
c) Genus
d) Class
2. In the scientific name “Canis lupus,” what does “Canis” represent?
a) Family name
b) Order name
c) Genus name
d) Species name
3. Which taxonomic level lies between Order and Family in the classification hierarchy?
a) Phylum
b) Class
c) Genus
d) Phylum
4. Which of the following organisms would likely share the most recent common ancestor with a human (Homo sapiens)?
a) Gorilla (Gorilla gorilla)
b) Chimpanzee (Pan troglodytes)
c) Orangutan (Pongo pygmaeus)
d) Rhesus macaque (Macaca mulatta)
5. Which of the following classification levels can encompass multiple species within a single genus?
a) Family
b) Phylum
c) Order
d) Class
6. Which taxonomic level is broader in scope than Class but more specific than Phylum?
a) Order
b) Genus
c) Kingdom
d) Family
