Classification of Organisms Why Classify To make it

Classification of Organisms

Why Classify? • To make it easier to study life! • Taxonomy- the assigning of a universally accepted name to a species. • Binomial nomenclature- An organism’s classification is based on its Genus and species names. The Genus is ALWAYS capitalized, and the species name is NEVER capitalized. – E. g. Homo sapiens (humans), Odocoileus virginianus (Whitetailed deer)

Linnaeus • We use a system today that was originally created by Carl Linnaeus. • Linnaeus- (1707 -1778) A botanist who created a classification system of organisms based on their physical similarities with each other. • Originally, Linnaeus only had two Kingdoms, or major categories-Plant and Animal.

Linnaean System • King Phillip Came Over For Grasshopper Soup • Kingdom – Phylum • Class – Order » Family » Genus » Species

Linnaeus vs. Modern Classification • Linnaeus – 2 Kingdoms – Based on physical similarities – Uses only biologists observations and knowledge of organisms • Modern – 5 or 6 kingdoms – Based on physical similarities AND genetic similarities – Uses observations, knowledge of organisms, molecular clocks, and other genetic techniques

Modern Classification • Five Kingdom System: Older system, lumps all prokaryotic species into one kingdom: Monera Animal Plant Protist Fungi Monera

Six Kingdom Classification • Keeps Animal, Plant, Fungi and Protista, and splits Monera into two Kingdoms: – Eubacteria-normal everyday prokaryotes found on Earth – Archeabacteria- prokaryotes that are only found in extreme environmental conditions, like in a salty lake, or in extreme temperatures; also called extremophiles.

Three Domains: Six Kingdoms • Eukarya – – Animal Plant Fungi Protista All have organisms made of eukaryotic cells • Bacteria – Eubacteria • Peptidoglycan in the cell walls Prokaryotic single celled organisms • Archea – Archeabacteria • No peptidoglycan in the cell walls Prokaryotic single celled organisms that live in extreme environments

An Example of Classification • The Leopard: Panthera pardus

Fungi • All members are heterotrophic (they have to eat other organisms for their food) • Most are multicellular, and secrete digestive enzymes into their food source, then absorb the smaller food molecules • Mushrooms are most common

Protista • “Junk” drawer Kingdom • Mostly unicellular eukaryotic organisms, but some multicellular, like kelp. • VERY diverse array of organisms, from diatoms to algae. • Some are autotrophs (make own food) and some are heterotrophs.

Dichotomous Keys • In the field, biologists use dichotomous keys to identify organisms. • Dichotomous key-A chart that identifies organisms based on their characteristics. Its used by excluding organisms based on their OBSERVABLE features.