Classification Taxonomy science of naming and classifying organisms

Classification

Taxonomy – science of naming and classifying organisms Organisms are classified based on physical and structural similarities

Binomial nomenclature – system that gives each species a 2 part scientific name (in Latin) 1 st word (genus) Homo 2 nd word (species) sapiens Scientific names allow scientists around the world to communicate clearly about living things

Canis lupus Canis latrans Canis familiaris Felis chaus Felis catus

Linnaean classification has 7 levels: Kingdom Phylum Class Order Family Genus Species

Limitations of classification – Uses physical characteristic Some species look similar but are NOT closely related To make grouping organisms more accurate – we now use genetics to help classify

Dichotomous key

Candy Classification Choose 8 types of candy Create a dichotomous key to classify each type of candy

Phylogeny – evolutionary history for a group of species Cladistics – classifying organisms based on common ancestry Cladogram – evolutionary tree that proposes how species may be related through common ancestry Derived characteristic – traits found in some species but not others; help determine how closely related different species are

Important note: genetic (molecular) evidence is more reliable than physical similarities in determining how closely related 2 species are The more similar the DNA is – the more closely related the species are

Domains Grouping LARGER than the KINGDOM 3 domains All organisms fall into these 3 broad categories

Domain 1: Bacteria Contain single celled prokaryotes One of the largest groups of organisms on Earth Cell walls contain peptidoglycan Ex: E. coli, Staph, Yersinia pestis

Domain 2: Archaea Single-celled prokaryotes Live in EXTREME environments Ex: deep sea vents, hot geysers, Antarctic water, volcanoes

DOMAIN 3: Eukarya Contains all organisms with Eukaryotic cells Plants, Animals, Protists, Fungi Ex: peony flower, salamander, shitake mushroom

KINGDOMS 1. Eubacteria 2. Archaea 3. Animalia 4. Plantae 5. Fungi 6. Protista

1. Eubacteria Contain single-celled prokaryotes Usual, everyday bacteria Ex: staph, E. coli, strep

2. Archaea Single-celled prokaryotes Extreme environments Ex: extremophiles, thermophiles, sulfolobus

3. Animalia Multi-cellular Eukaryotic Heterotrophs (need to ingest food) Motile (can move around) Ex: cockroach, snake, dolphin, human

4. Plantae Multi-cellular, Eukaryotic Autotrophs - photosynthetic (make food from sun) Non-motile – can not move around Ex: sunflower, daisy, apple tree

5. Fungi Some unicellular but most multicellular Eukaryotic Heterotrophs (absorb nutrients) Mushrooms, yeast and mold

6. Protista Most Single celled with a few multi-celled; Eukaryotes Odds and ends category – for those organisms that can not be classified as plants, animals or fungi Ex. Algae, malaria parasite