Saran's Learn Microbiology

  PHYLOGENETIC HIERARCHY ·        Phylogenetics is the study of the ancestral relatedness of groups of organisms, whether alive or extinct. ·    A Phylogenetic tree is a diagram that represents evolutionary relationships among organisms. Phylogenetic trees are hypotheses, not definitive facts. ·        Phylogenetic Hierarchy implies that a group of organisms evolved from a common ancestor. ü   Some of the information used to classify comes from fossils. ü   Fossil evidence not available for most Prokaryotes. ü   Phylogeny for Prokaryotes based on DNA Hybridization and rRNA Sequencing. GENETIC CLASSIFICATION ·        Classification of organisms based on evolutionary as well as genetic relationship is known as Cladistics. ·        Cladistics is a method in which the organisms are classified using different criteria on the b...

CAVALIER - SMITH’s EIGHT KINGDOM CLASSIFICATION ·        The Kingdom Protista was still too diverse to be taxonomically useful. Many attempts have been made to divide Protists into better-defined kingdoms and in this regard, an eight-kingdom system was given by Thomas Cavalier-Smith in 1987. ·        In 1981, before proposing Eight Kingdom Classification, Cavalier-Smith had divided all the eukaryotes into Seven Kingdoms. In it, he created Chromista for a separate Kingdom of some Protists . ·        Cavalier-Smith gave the Eight kingdom system of classification by revising Whittaker's Five Kingdoms of Classification. ·      Using ultrastructural characteristics as well as rRNA sequences, Cavalier-Smith divides all organisms into 2 Empires and 8 Kingdoms. ü   2 Empires a)      Empire B...