Define a Taxon. Give some examples of taxa at different hierarchical levels.

A taxon (plural: taxa) is a term used in biological classification or taxonomy to represent a group of organisms that share common characteristics and are classified together within a hierarchical system. Taxa are organized into a hierarchy from broader, more inclusive groups to narrower, more specific ones. The main taxonomic ranks, from highest to lowest, are as follows:

Domain
Kingdom
Phylum (in animals) or Division (in plants and fungi)
Class
Order
Family
Genus
Species
Here are some examples of taxa at different hierarchical levels:

Domain:

Bacteria
Archaea
Eukarya
Kingdom:

Animalia (animals)
Plantae (plants)
Fungi (fungi)
Protista (protists)
Monera (now split into Bacteria and Archaea)
Phylum/Division:

Chordata (in animals, includes vertebrates)
Arthropoda (in animals, includes insects, spiders, etc.)
Angiosperms (in plants, includes flowering plants)
Gymnosperms (in plants, includes conifers)
Class:

Mammalia (in animals, includes mammals)
Insecta (in animals, includes insects)
Aves (in animals, includes birds)
Reptilia (in animals, includes reptiles)
Order:

Carnivora (in animals, includes carnivorous mammals like cats and dogs)
Lepidoptera (in animals, includes butterflies and moths)
Primates (in animals, includes monkeys and apes)
Rodentia (in animals, includes rodents like mice and rats)
Family:

Felidae (in animals, includes cats)
Rosaceae (in plants, includes roses)
Fabaceae (in plants, includes legumes like beans and peas)
Canidae (in animals, includes dogs)
Genus:

Panthera (in animals, includes big cats like lions and tigers)
Homo (in animals, includes modern humans)
Rosa (in plants, includes rose species)
Canis (in animals, includes wolves and domestic dogs)
Species:

Panthera leo (African lion)
Homo sapiens (modern human)
Rosa gallica (Gallic rose)
Canis lupus (gray wolf)
These examples demonstrate how organisms are grouped into various taxa based on their shared characteristics, with the hierarchy becoming increasingly specific as you move down the list. The scientific names (binomial nomenclature) of species consist of both the genus and species names and are used universally in biology to uniquely identify and classify individual species.