Classification of Living Organisms Learning Outcome B1 Learning Outcome B1 Apply the Kingdom System of classification to study the diversity of organisms. Student Achievement Indicators Students who have fully met this learning outcome will be able to: Explain how the following principles are used in taxonomy to classify organisms: evolutionary relationships biochemical relationship homologous structures embryological relationships Compare characteristics of prokaryotic cells with those of eukaryotic cells Student Achievement Indicators Describe the unifying characteristic of organisms in each of the following kingdoms: Monera Protista Fungi Plantae Animalia Classify selected organisms using the following taxons: kingdom, phylum (sub-phylum), class, order, family, genus and species Apply binomial nomenclature to name selected organisms Taxonomy: Scientific Classification The science of classifying organisms is taxonomy Scientific classification refers to how biologists categorize extinct and living species Carolus Linnaeus modelled modern classification by grouping species according to shared physical characteristics. These groupings have been revised to improve consistency between Darwin s principle of common decent. 1
Aristotle (384-322 BC) Classified animals based on their means of transportation Example land, water or air Jan Swammerdam (1637-1680) A Dutch naturalist and microscopist; was among the first to recognize cells in animals and view red blood cells. Robert Hooke (1635-1702) English scientist that observed the cellular structure of cork with an early microscope. John Ray (1627-1705) Was an English naturalist who worked on plant, animal and natural theology. His classification of plants in Historia Plantaruim was an important step towards modern taxonomy. He classified plants according to similarities Carolus Linnaeus (1707-1778) A Swedish botanist who proposed the modern system of biological nomenclature. He assigned names to plants and animals using a two part system known as binomial nomenclature Each organism received a two part latin name (aka scientific name) Example - Homo sapien Common language for scientists First name is genus and groups similar organism (capitalized) Second part is the species Two part name indicated similarities in anatomy, embryology and likely evolutionary ancestry Carolus Linneus Kingdom Phylum Class Order Family Genus Species Linnaeus System Basis for Classification Taxonomists use phylogenetic trees to show evolutionary relationships among biological groups. All organisms are descendants of a common ancestor the basic cell. So all organisms, living or extinct are related to some degree. Today scientists use fossil records and biochemistry to classify relationships between organisms. 2
Phylogenetic Tree Basis for Classification Dichotomous keys are used to identify organisms; these keys list specific observable traits. For each trait the key list two contrasting traits. See pg. 197 Extinction is the natural by product of evolution however the rate of extinction has significantly increased in the late decade This classification is constantly changing Kingdom Monera Includes bacteria and cyanobacteria (blue-green algae) Unicellular Prokaryotic Kingdom Monera 3
Kingdom Protista Kingdom Protista Includes algae and protozoa Unicellular Kingdom Fungi Includes mushrooms, yeast and bread molds Unicellular and multicellular Kingdom Fungi Kingdom Plantae Kingdom Plantae Includes seaweed, mosses, ferns, conifers and flowering plants Multicellular 4
Kingdom Animalia Includes the sponges, worms, lobster, starfish, wolves and humans See pg 198 Multicellular Kingdom Animalia Other Theory: Six Kingdoms of Life A six kingdom system is often used. An additional kingdom known as the Kingdom Archae, which includes ancient bacteria that live in extreme environments The five kingdoms of living things are divided into two major groups: the prokaryotes and eukaryotes. There is 1 kingdom of prokaryote, while there is 4 kingdoms of eukaryotes. Eukaryotes have a separate membrane bound nucleus, numerous mitochondria and other organelles Prokaryotes do not have a nucleus or membrane bound organelles Kingdom Archae Possible 6 th kingdom. This pictures shows a type of bacteria that lives in extreme environments such as oceanic vents. This type of bacteria is known as a halophile 5