Johnson - The Living World: 3rd Ed. - All Rights Reserved - McGraw Hill Companies How We Name Living Things Chapter 12 Copyright © McGraw-Hill Companies Permission required for reproduction or display

Johnson - The Living World: 3rd Ed. - All Rights Reserved - McGraw Hill Companies Outline Linnaean System Species Names Species Definition Building Family Trees  Cladograms  Traditional Models  Kingdoms Domains

Johnson - The Living World: 3rd Ed. - All Rights Reserved - McGraw Hill Companies Invention of the Linnaean System Classification - Multilevel grouping of individuals.  Organisms first classified by Aristotle over 2,000 years ago. - Eventually groups started to be formed and referred to as genera (singular, genus).  Starting in middle ages, names began to be systematically written down using Latin.

Johnson - The Living World: 3rd Ed. - All Rights Reserved - McGraw Hill Companies Invention of the Linnaean System Classification scheme of the Middle Ages (polynomial system) was used replaced with a binomial system by Linnaeus about 250 years ago.  Polynomial - Strings of latin words and phrases containing up to 12 words.  Binomial - Two-part name for each species.

Johnson - The Living World: 3rd Ed. - All Rights Reserved - McGraw Hill Companies Species Names Taxa - Group of organisms at a particular level in a classification system (Taxonomy). By convention:  First word of binomial name is genus and is always capitalized.  Second word refers to particular species and is not capitalized. - Together form Scientific Name, written in italics.

Johnson - The Living World: 3rd Ed. - All Rights Reserved - McGraw Hill Companies Higher Categories Species Genus Family Order Class Phylum Kingdom Kindly Pay Cash Or Furnish Good Security.

Johnson - The Living World: 3rd Ed. - All Rights Reserved - McGraw Hill Companies Hierarchical Classification System

Johnson - The Living World: 3rd Ed. - All Rights Reserved - McGraw Hill Companies Species Definition Biological Species Concept (Ernst Mayr)  Species are groups of actually or potentially interbreeding natural populations which are reproductively isolated from other such groups. - Problems  Assumes regular outcrossing  Assumes strong reproductive barriers  Hybrids ?

Johnson - The Living World: 3rd Ed. - All Rights Reserved - McGraw Hill Companies Building A Family Tree Systematics - Reconstruction and study of evolutionary trees (Phylogenetic trees).  Clade - Organisms related by descent. - Cladistics - Constructing phylogeny according to similarities derived from common ancestor.  Produce branching cladogram.  Compare outgroup (different organism) to the ingroup.

Johnson - The Living World: 3rd Ed. - All Rights Reserved - McGraw Hill Companies Cladogram of Vertebrate Animals Copyright © McGraw-Hill Companies Permission required for reproduction or display

Johnson - The Living World: 3rd Ed. - All Rights Reserved - McGraw Hill Companies Building A Family Tree Because evolutionary success depends on high-impact events, modern cladistics attempts to weight evolutionary significance of characters. Traditional Taxonomy  Phylogenies constructed based on vast amount of information about morphology and biology of the organism gathered over a long period of time.

Johnson - The Living World: 3rd Ed. - All Rights Reserved - McGraw Hill Companies Two Methods Of Classification Copyright © McGraw-Hill Companies Permission required for reproduction or display

Johnson - The Living World: 3rd Ed. - All Rights Reserved - McGraw Hill Companies The Better Approach is….. Traditional taxonomy is the better approach when a great deal of information is available to guide character weighting. Cladistics is the better approach when little information is available about how the character affects the life of an organism.

Johnson - The Living World: 3rd Ed. - All Rights Reserved - McGraw Hill Companies Kingdoms of Life Most Biologists use a six-kingdom system.  Animalia  Plantae  Fungi  Protista  Archaebacteria  Eubacteria Domains - taxonomic level above kingdoms.

Johnson - The Living World: 3rd Ed. - All Rights Reserved - McGraw Hill Companies Domain Archaea Share key characteristics:  Cells wall lack peptidoglycan  Possess unusual lipids and ribosomal RNA Three General Categories  Methanogens - Obtain energy by using hydrogen gas to reduce carbon dioxide to methane gas.

Johnson - The Living World: 3rd Ed. - All Rights Reserved - McGraw Hill Companies Domain Archaea (Archaebacteria) Extremophiles - Grow under extreme conditions.  Thermophiles - Heat  Halophiles - Salt  Pressure-tolerant Nonextreme Archaebacteria - Grow in same environment as eubacteria.

Johnson - The Living World: 3rd Ed. - All Rights Reserved - McGraw Hill Companies Evolutionary Relationship

Johnson - The Living World: 3rd Ed. - All Rights Reserved - McGraw Hill Companies Domain Bacteria (Eubacteria) Most abundant organisms on earth. Most taxonomists recognize major groups. Copyright © McGraw-Hill Companies Permission required for reproduction or display

Johnson - The Living World: 3rd Ed. - All Rights Reserved - McGraw Hill Companies Domain Eukarya (Eukaryotes) Appear in fossil record only about 1.5 billion years ago. Complex cellular organization.  Fungi, Plants, and Animals are well- defined evolutionary groups. - Largely multicellular  Diversity among protists is much greater than within or between Fungi, Plants, and Animals.

Johnson - The Living World: 3rd Ed. - All Rights Reserved - McGraw Hill Companies Domain Eukarya (Eukaryotes) With few exceptions, all modern eukaryotic cells possess energy-producing organelles (Mitochondria).  Some protist phyla have also acquired chloroplasts and are photosynthetic. - Mitochondria and chloroplasts are both believed to have entered early eukaryotic cells by endosymbiosis.

Johnson - The Living World: 3rd Ed. - All Rights Reserved - McGraw Hill Companies Viruses Viruses do not satisfy the basic criteria of life, thus are not living organisms.  Appear to be fragments of nucleic acids originally derived from genome of a living cell. - Infect organisms at all taxonomic levels.

Johnson - The Living World: 3rd Ed. - All Rights Reserved - McGraw Hill Companies Evolutionary Relationships Among Kingdoms

Johnson - The Living World: 3rd Ed. - All Rights Reserved - McGraw Hill Companies Review Linnaean System Species Names Species Definition Building Family Trees  Cladograms  Traditional Models  Kingdoms Domains

Johnson - The Living World: 3rd Ed. - All Rights Reserved - McGraw Hill Companies Copyright © McGraw-Hill Companies Permission required for reproduction or display