Over the years, scientists have developed several systems for the classification of organisms. From the late 1960s, organisms had been classified
according to a five-kingdom system. This classification system model was based on principles developed by Swedish scientist Carolus Linnaeus, whose
hierarchical system groups organisms based on common physical characteristics. This system recognized five kingdoms: Monera (bacteria), Protista,
Fungi, Plantae, and Animalia. The scheme divided life into two main divisions based on cell structure: the Prokaryotae (bacteria) and the Eukaryota
(animals, plants, fungi, and protists). As scientists learned more about organisms, classification systems changed. Genetic sequencing has given
researchers a new way of analyzing relationships between organisms. The current system, the three-domain system, classifies organisms primarily
based on differences in ribosomal RNA (rRNA) structure. Under this system, organisms are classified into three domains and six kingdoms. The domains
are Archaea, Bacteria, and Eukarya: two prokaryotic domains and one eukaryotic. Recent work in the classification of life has shown that what was once
called prokaryotes are much more diverse than previously suspected. The prokaryotic domains also represent two distinct kingdoms, the Eubacteria,
and the Archaebacteria, and are as different from each other as either is from the Eukaryota. The kingdoms are Archaebacteria (ancient bacteria),
Eubacteria (true bacteria), Fungi, Plantae, Protista, and Animalia. The Eukarya domain includes eukaryotes or organisms that have a membrane-bound
nucleus. Eukaryotes have rRNA that is distinct from bacteria and archaeans.
Can you distinguish life in the thee domains and kingdoms?
The single feature that separates the domains in the cladogram is cell structure.
Based on this classification system, we can say that plants and animals are more alike than plants and
bacteria.
The domains Archaea and Bacteria differ from each other biochemically.
The domains Archaea and Bacteria both have organisms composed of prokaryotic cells.
The Archea are more closely related to the Eukarya than they are to the Bacteria.
According to this cladogram, scientists believe that all kingdoms evolved from a common ancestor HELP!!!!!