Classifying Organisms Section 1 Biodiversity Chapter 17 Classifying Organisms Naturalists have invented several systems for categorizing biodiversity, which is the variety of organisms considered at all levels from populations to ecosystems.

Section 1 Biodiversity Chapter 17 Taxonomy Naturalists replaced Aristotle’s classification system because it did not adequately cover all organisms and because his use of common names was problematic. Taxonomy is the science of describing, naming, and classifying organisms. A taxon is any group within a taxonomic system. Aristotle had a 2 taxa system - plants and animals.

Chapter 17 Taxonomy, continued The Linnaean System Section 1 Biodiversity Chapter 17 Taxonomy, continued The Linnaean System Carolus Linnaeus devised a seven-level (now 8-level) hierarchical system for classifying organisms according to their form and structure. From the most general to the most specific,the levels are kingdom, phylum, class, order, family,genus, and species. All scientific names are in Greek because everyone around the world will know the name. Common names are unique to areas, but the scientific name is universal.

Classification Hierarchy of Organisms Section 1 Biodiversity Chapter 17 Classification Hierarchy of Organisms Dear King Philip Came Over For Great Spaghetti Make up a mnemonic device on your own. (school appropriate)

Levels of Classification Section 1 Biodiversity Chapter 17 Levels of Classification Binomial Nomenclature An important part of Linnaeus’s system was assigning each species a two-part scientific name—a genus name, such as Homo, and a species identifier, such as sapiens. Notice how both words are in italics and the first work is capitalized and the second is lowercase. This system of a two-part name is known as binomial nomenclature.

Section 2 Systematics Chapter 17 Phylogenetics - the analysis of evolutionary/ ancestral relationships among taxa A modern approach to taxonomy is systematics, which analyzes the diversity of organisms in the context of their natural relationships. When classifying organisms, scientists consider fossils, homologous features, embryos, chromosomes, and the sequences of proteins and DNA. A phylogenetic diagram displays how closely related a subset of taxa are thought to be.

Chapter 17 Phylogeny Section 2 Systematics Click below to watch the Visual Concept. Visual Concept

Phylogenetics, continued Section 2 Systematics Chapter 17 Phylogenetics, continued Evidence of Shared Ancestry Homologous features as well as similarities in patterns of embryological development provide information about common ancestry. Cladistics uses shared, derived characters as the only criterion for grouping taxa.

Cladogram: Major Groups of Plants Section 2 Systematics Chapter 17 Cladogram: Major Groups of Plants

Chapter 17 Cladistics, continued Molecular Cladistics Section 2 Systematics Chapter 17 Cladistics, continued Molecular Cladistics information on evolutionary relationships. Molecular similarities (such as similar amino acid or nucleotide sequences), as well as chromosome comparisons, can help determine common ancestry. Chromosomes Analyzing karyotypes can provide more information on evolutionary relationships.

Similarities in Amino Acid Sequences Section 2 Systematics Chapter 17 Similarities in Amino Acid Sequences

Chapter 17 Cladistics Section 2 Systematics Click below to watch the Visual Concept. Visual Concept

Phylogenetic Diagram of Mammals Section 2 Systematics Chapter 17 Phylogenetic Diagram of Mammals

Chapter 17 The Tree of Life Revising the Tree Section 3 Modern Classification Chapter 17 The Tree of Life Revising the Tree The phylogenetic analysis of rRNA nucleotide sequences by Carol Woese led to a new “tree of life” consisting of three domains aligned with six kingdoms. The three domains are Bacteria, Archaea, and Eukarya.

Chapter 17 Three Domains of Life Domain Bacteria Section 3 Modern Classification Chapter 17 Three Domains of Life Domain Bacteria Domain Bacteria aligns with Kingdom Eubacteria, which consists of single-celled prokaryotes that are true bacteria. Domain Archaea Domain Archaea aligns with Kingdom Archaebacteria, which consists of single-celled prokaryotes that have distinctive cell membranes and cell walls. Domain Eukarya Domain Eukarya includes the kingdoms Protista, Fungi, Plantae, and Animalia. All members of this domain have eukaryotic cells.

Phylogenetic Diagram of Major Groups of Organisms Section 3 Modern Classification Chapter 17 Phylogenetic Diagram of Major Groups of Organisms

Section 3 Modern Classification Chapter 17 Six Kingdoms

Kingdom and Domain Characteristics Section 3 Modern Classification Chapter 17 Kingdom and Domain Characteristics