Classification Chapter 18

Non-Science Example of Classification  The item in this picture is  Automobile:  Truck, Car, or SUV? Car  Made by? Ford  Type of Ford car? Mustang -Was made in what year? Is it Convertible? No -Color? Silver

Classification: Goes from General to Specific Automobile – Biggest Car Ford Mustang Non Convertible -Silver - Specific

How are living things organized for study?

Classification  To study the diversity of life, biologists use a classification system to name organisms and group them in a logical manner  Why?  Common names can be confusing (buzzard) or misleading (starfish)  Taxonomy: discipline of classifying organisms and assigning each organism a universally accepted name  In science we use Binomial Nomenclature, a 2- part naming system developed by Carolus Linnaeus (1700s).

Early Classification – Aristotle B.C.  2 Groups: Plants and Animals  Plants – Green, Non Mobile  Animals – Not Green, Mobile

How would you classify this using the Plant/Animal system? Praying Mantis Green but.. Mobile Aristotle’s Grouping of life not specific enough

Binomial Nomenclature  Rules:  Both words must be in italics or underlined.  The first letter of the first word (the Genus) is CAPITALIZED.  The second word (the species) is in lower case.  Example  Felis catus

Kingdoms and Domains There are 2 different Systems of Classification: 1) The 5-Kingdom System (now 6 kindoms) 1) Monera  Eubacteria  Archaebacteria 2) Protista 3) Fungi 4) Plantae 5) Animalia 2) The 3-Domain System (“superkingdoms”) 1) Archaea 2) Bacteria 3) Eukarya

Which is the most primitive? 3 Domains

3 Domains contain 6 Kingdoms Classification

5 Kingdoms turns into 6 Monera is now Eubacteria and Archaeabacteria Just another example of changes in science

Classification System  Linnaeus created a classification system based on organism’s form and structure.  He created 7 taxa (classification “groups”, domain added later) from broadest to most specific:  Domain  Kingdom  Phylum  Class  Order  Family  Genus  Species  Kings Play Cards On Fat Green Stools

Brown Squirrel  Kingdom: Animalia (“is an animal”)  Phylum: Chordata (“has a spine”)  Class: Mammalia (“nurses its young”)  Order: Rodentia (“has long sharp front teeth”)  Family: Scuridae (“has a bushy tail”)  Genus: Tamiasciurus (“climbs trees”)  Species: hudsonicus (“has brown fur on its back and white fur on its underparts”)

How do we determine how similar or how dissimilar certain organisms are?

Cladistics  Cladistics is one method of reconstructing phylogenies (how they are related) based on derived traits.  Patterns of shared characteristics  Derived traits are new characteristics that arise as lineages evolve over time.  These derived traits are displayed on a cladogram.  Shows the evolutionary relationships among a group of organisms

Cladogram

DICHOTOMOUS KEY  A tool used to identify objects or organisms.  A list of characteristics become more narrow as they describe the particular item of interest.  Forced-choice selection between two characteristic options  Follow directions next to characteristic until you get to a species

Practice Let’s look at an example together…..

 Domain Bacteria  Unicellular Prokaryotic (No Nucleus)  Ecologically Diverse – live everywhere!  Cell Walls contain substance called Peptidoglycan – special protein and sugar  Target of many Antibiotics ex. Strep Throat and Food Poisoning  Not all bad….used to turn grapes into wine  Ex. Cyanobacteria, blue-green algae, Streptococcus, E. coli Kingdom Eubacteria

Kingdom Archaeabacteria  Domain Archaea  Unicellular Prokaryotes (No Nucleus)  Heterotrophs and Autotroph  Cells Walls without peptidogylcan  Live in Extreme environments like those of early Earth ex. Volcanic Hot Springs….. some even live in your gut Examples: halophiles, Methanogens

Summary of Bacteria  All Unicellular Prokaryotes (No Nucleus)  Heterotrophs or Autotrophs  What is the big difference? Cell Wall – Does it have Peptidoglycan? Bacteria – With Peptidoglycan Archaea – Without Peptidoglycan Archaebacteria

Domain Eukarya Contains Multiple Kingdoms: Protista, Fungi, Plantae, Animalia  Eukaryotic – Has a nucleus  Single or multi-cellular  Most visible life  Humans are in Domain Eukarya Diatom

Kingdom Protista  Domain Eukarya  Eukaryotic  Majority are unicellular, but some are colonial or multicellular.  Heterotrophs and autotrophs  May or may not have a cell wall  Extreme diversity! Can be plant like or animal like.  Examples: Algae, Amoeba, Paramecium, Euglena, Volvox, giant kelp, slime molds.

Kingdom Fungi - Mushrooms All in the same domain as us!

Kingdom Fungi  Domain Eukarya  Eukaryotic; cell walls of chitin.  Majority multicellular; few unicellular.  Heterotrophs; feed on dead or decaying  organic matter. (_Decomposer_)  Examples: Mushrooms, yeast, bread mold. Bread Mold

Kingdom Plantae  Domain Eukarya  Eukaryotic, multicellular, cell walls of cellulose.  Autotrophs; photosynthesis  chloroplast.  Examples: Mosses, ferns, flowering plants, cacti.

Kingdom Animalia  Domain Eukarya  Eukaryotic, multicellular, no cell walls.  Heterotrophs  Extreme diversity is found in this kingdom  Examples: Sponges, worms, insects, fishes, mammals, reptiles.