Understanding:
5.3.U4: All organisms are classified into three domains. [Archaea, eubacteria and eukaryote should be used for the three domains. Members of these domains should be referred to as archaeans, bacteria and eukaryotes. Viruses are not classified as living organisms.] Objectives:
|
Currently, all living organisms are classified into three domains:
Members of these domains should be referred to as archaeans, bacteria and eukaryotes.
- Eukarya – eukaryotic organisms that contain a membrane-bound nucleus (includes protist, plants, fungi and animals)
- Archaea – prokaryotic cells lacking a nucleus and consist of the extremophiles (e.g. methanogens, thermophiles, etc.)
- Eubacteria – prokaryotic cells lacking a nucleus and consist of the common pathogenic forms (e.g. E. coli, S. aureus, etc.)
Members of these domains should be referred to as archaeans, bacteria and eukaryotes.
- The Archaea and Bacteria domains are prokaryotes. These are organisms that do not have a membrane bound nucleus and their DNA is not associated with proteins.
- The Bacteria domain consists of Eubacteria and archaebacteria are classified as Archaeans.
- The Eukarya domain includes eukaryotes, or organisms that have a membrane bound nucleus. This domain is further subdivided into the kingdoms Protista, Fungi, Plantae, and Animalia
- Groups organisms primarily based on differences in ribosomal RNA structure. Ribosomal RNA is a molecular building block for ribosomes.