Biological Classification and Nomenclature

Study Notes

Organisms are grouped into categories based on shared characteristics.
This hierarchical organization is called a taxonomic hierarchy.
Key terms include domain, kingdom, phylum, class, order, family, genus, and species.
Similarity increases as you move down the hierarchy.
Species are the most specific group, containing organisms that can interbreed to produce fertile offspring.

Classification systems help biologists study the relationships between organisms.
Classification is important for agriculture, forestry, and medicine.
There are potential economic benefits from identifying new plant and animal resources that could provide materials for lumber, food, medicine, and energy.
Taxonomists study evolutionary relationships and genetic similarities of organisms.
The Linnaean system of nomenclature is used to scientifically name organisms.

Scientific names use Latin, a universal language.
Scientific names are written using the genus and species names (e.g., Homo sapiens).
The first name is capitalized, the second is lowercase. Both names are italicized or underlined.

Whittaker's five-kingdom system includes Monera, Protista, Fungi, Plantae, and Animalia.
This system categorizes organisms based on their cell structure, body organization, mode of nutrition, and evolutionary relationships.

Includes bacteria, which are unicellular and prokaryotic (lack a nucleus).
Bacteria can be heterotrophic (consuming other organic material) or autotrophic (producing their own food).
Bacteria live in many different habitats.

Includes all multicellular and heterotrophic organisms.
Animals have specialized cells (i.e., muscle and nerve cells).
Animals can move and process sensory input.
Animalia is broadly separated into invertebrates (no backbone) and vertebrates (with a backbone).