Unit 11: Classification Ch. 3 Classification Taxonomy = branch of biology that deals w/ naming & classifying organisms. 200

Why Things Are Classified What does it mean to classify? –to group based on similarities Examples of classifying in everyday life…? Why are organisms/objects classified? –easier to “find” –show shared traits –show relationships among living & extinct species

Why Things Are Classified What is a dichotomous key? –a tool used for classification At each step, the user is given two choices (either/or). –Each alternative leads to another question… »until the item is identified. What are two ways to make a dichotomous key? –branching “tree” diagram –list format

Why Things Are Classified How are organisms classified? –very broad characteristics  very specific Based on…? –evolutionary relationships –What is a group of organisms called? taxon (plural = taxa) –How many taxa are there? »8 (Domain  species) Domain

Who devised the 1 st classification system? –Aristotle How did he classify organisms? –2 taxa »1. plants (by type of stem) »2. animals (by environment in which they live) Early Classification According to Aristotle, which of these 3 animals would be classified more closely?

Who was the “Father of Modern Taxonomy”? –Carolus Linnaeus How did he classify organisms? –2 main groups = kingdoms »plants »animals –Also used other taxa (groups) including: »genus ~similar species »species ~organisms w/ similar traits Beginning of Modern Classification

What is a species? –group of organisms capable of mating with one another in nature to produce fertile offspring Beginning of Modern Classification

How did Linnaeus name organisms? –used binomial nomenclature 2 name system –written: Genus species or Genus species »Genus = 1st name, capitalized »species = 2nd name, lower case & descriptive –Ex. Common nameGenus & species »Humans Homo sapiens »White Oak tree Quercus alba »Red Oak tree Quercus rubra »Bottlenose dolphinTursiops truncatus Beginning of Modern Classification

Why don’t we use common names? 1.two organisms can have same common name, but not sci. name 2.scientific names rarely change 3.scientific names are written in same language around the world Beginning of Modern Classification

What do current classification systems reflect? –relationships based on evolutionary ancestry Ex. According to the phylogenetic tree on the right, who are humans most closely related to? How Scientists Classify Today

Can classification systems change? –Yes. Why? –With scientific advancements, we gain new data & learn more about organisms… How Scientists Classify Today

Classification systems we’re going to discuss: –5 Kingdom system Monera, Protista, Fungi, Plantae, Animalia –6 Kingdom system Monera split into Archaebacteria & Eubacteria… other 4 kingdoms (Protista, Fungi, Plantae, Animalia) stay same –3 Domain system Archaea, Bacteria, Eukaryota (Eukarya) –4 kingdoms (Protista, Fungi, Plantae, Animalia) grouped in Eukaryota How Scientists Classify Today

Did  Domain Katy  Kingdom Perry  Phylum Come  Class Over  Order For  Family Good  Genus Sushi?  species How Scientists Classify Today Trick to help you remember major classification groups in the domain system…

Where would Domain belong in this diagram?

What is the relationship among the levels? –from Domain down, each level has a new set of criteria that must be shared –Organisms that are more closely related  share… more levels DOMAIN Eukaryota How Scientists Classify Today

Once an organism shares a more specific taxon (lower group) it MUST share the more unifying taxa (higher groups) How many levels of classification do we share with dolphins?

How Scientists Classify Today When using the 5 or 6 Kingdom system… –Which group is largest & most inclusive? Kingdom –Which is smallest & least inclusive? species

How Scientists Classify Today When using the 3 Domain system… –Which group is largest & most inclusive? –domain –Which group is smallest & least inclusive? –species Eukaryota Domain

Domain: Archaea 6 Kingdom system: Archaebacteria 5 Kingdom system: Monera prokaryotic unicellular feeding –heterotrophic or autotrophic other characteristics –older, less complex bacteria –live in extreme environments examples –bacteria: in salt lakes at hydrothermal vents

Staphylococcus cyanobacteria Domain: Bacteria 6 Kingdom system: Eubacteria 5 Kingdom system: Monera prokaryotic unicellular feeding –heterotrophic or autotrophic other characteristics –modern, more complex bacteria evolved from Archaea –most common & very diverse –free-living or pathogenic examples –Staphylococcus –E. coli –cyanobacteria

Domain: Eukaryota All are eukaryotic 4 of the 5 (or 6) kingdoms –1. Protista –2. Fungi –3. Plantae –4. Animalia

Domain: Eukaryota 1. Kingdom: Protista eukaryotic mostly unicellular feeding –heterotrophic or autotrophic other characteristics –can be plant-like, animal- like, or fungus-like examples –Amoeba –Paramecium –Euglena –algae Amoeba Paramecium Euglena algae

eukaryotic multicellular*** feeding –heterotrophic digest food outside & absorb nutrients other characteristics –cell walls made of chitin –decomposers & parasites examples –mushrooms –molds –yeast (*** unicellular) Domain: Eukaryota 2. Kingdom: Fungi

eukaryotic multicellular feeding –autotrophic photosynthesis other characteristics –cell walls made of cellulose –produce oxygen examples –mosses –ferns –grasses –shrubs –trees Domain: Eukaryota 3. Kingdom: Plantae

eukaryotic multicellular feeding –heterotrophic other characteristics –no cell wall Domain: Eukaryota 4. Kingdom: Animalia examples –invertebrates insects worms sponges corals –vertebrates fish birds amphibians reptiles mammals

Links