Classification Chapter 18
18-1 Order in Diversity: A classification system is used to name organisms and group them in a logical manner Taxonomy: giving names to organisms that are accepted world wide Eliminates problems with common names Ex. the puma, cougar, mountain lion and panther are all names for the same animal Can be confusing to mix names up when speaking about the same animal to other people
Binomial nomenclature: Developed by Linnaeus Used for scientific names of organisms 2 part names (Consisting of the genus and species) always written in italics 1st name is always capitalized, while the 2nd is always lower case Ex. Homo sapiens
Classification System (7 main parts) King Phillip Came Over For Great Soup Kingdom (largest) Phylum Class Order Family Genus Species (smallest) Each higher category contains all the organisms in the groups below it
Dichotomous Keys Wacky People Key 1a Two feet 2 1b Some other number of feet 3 2a Does not look at all human 4 2b Looks a lot like a human 5 3a One leg 6 3b Three or four legs 7 4a Fly-like Mosk Cara 4b Not fly-like 8 5a Seems to be a girl Rita Nita 5b Not a girl 9 6a Leg is curled , two feet Ru-ela.Brella 6b Leg is straight, one foot Giggles
18-2 Modern Evolutionary Classification: In the past, there were problems with classifying organisms Anatomical similarities vs. evolutionary/genetic similarities Organisms are now grouped based on evolutionary descent, not just a physical similarity Known as Evolutionary classification
Modern Evolutionary Classification cont’d Cladograms are used to show relationships among a group of organisms Lists derived characters along its branches: Characteristics that show up in recent parts of the lineage. Ex. Segmentation of parts, molted exoskeleton etc.
Cladograms
Modern Evolutionary Classification cont’d DNA and RNA are now used to link organisms at the molecular level. Can link organisms based on the existence (or lack of) certain molecules If similar proteins are present in random organisms, they may be related The more proteins present in common, the more closely related the organisms are.
18-3 Kingdoms and Domains: Originally only the Plant and Animal kingdoms Now there is more involved to the process of distinguishing organisms Bumped to 5 categories (for a while) Plant Animal Fungi-mushrooms etc. Protista-mostly single cellular eukaryotes Monera-single cellular prokaryotes
5 Kingdoms
Recent Changes Currently 6 kingdoms exist in 3 domains Monera (from above) was split into bacteria and archaebacteria Based on how the organisms have evolved independently
Domains- A step above the Kingdom Domain Bacteria: Unicellular prokaryotic cells with a thick cell wall containing peptidoglycan Contains the kingdom Eubacteria Domain Archae: Unicellular prokaryotic cells with a cell wall lacking peptidoglycan, while the cell membrane contains lipids not found in any other organism Contains the Kingdom Archaebacteria
Domains- A step above the Kingdom-cont’d Domain Eukarya: Contain all cells with a nucleus Contains 4 kingdoms Kingdom Plantae: photosynthetic autotrophs with cell walls containing cellulose Autotrophs-can make their own food Ex. Photosynthetic/Chemosynthetic organisms Kingdom Animalia: heterotrophs with no cell walls Heterotrophs-can not make their own food and need to consume it
Domains- A step above the Kingdom-cont’d Kingdom Fungi: heterotrophs with most feeding on dead/decaying matter such as mushrooms and yeast Kingdom Protista: eukaryotic organisms not classified as animals, plants or fungi Some are photosynthetic, while others are heterotrophs This could possibly be broken down into more Kingdoms in the future