C L A S S I F I C AT I O N N O T E S

HANDOUT 86

GUIDING QUESTIONS

1.  How do scientists classify organisms? 2.  Why do scientists classify organisms?

WHY CLASSIFY?

•  Millions of organism species have been identified. It is important to have a classification system to help organize them. Scientists classify living things because: •  1. It makes it easier to study the organisms •  2. It makes it easier to see evolutionary history •  3. It makes communicating about organisms easier.

NAMING ORGANISMS

•  All organisms are given a two-part name by a system called binomial nomenclature. •  The first part of the name is called the genus •  The second part of the name is called species •  Example: Homo sapien, Felius domesticus

NAMING ORGANISMS

•  Hopefully you noticed something about the names from binomial nomenclature: •  1. The names are always in Latin •  2. The genus is always first and capitalized •  3. The species is always second and in lowercase

NAMING ORGANISMS

•  But, that (the genus and species) is not the full name of the organism. Using the genus/species is the common way to refer to them (ex: Mr. Ower instead of my full name: •  The Honorable Professor Instructor Sir (soon to be)

Doctor Prince Peter Horatio Eratosthenes Buttercup de Chicago Ower, esquire. •  So, what is the full name of a human?

NAMING ORGANISMS

•  Eukarya •  Animalia •  Chordata •  Mammalia •  Primates •  Hominidae •  Homo •  sapien

NAMING ORGANISMS

•  So why use such a large name? It prevents confusion amongst scientists. And, each part of the name indicates that the organism belongs to a group that contains similar organisms. •  Let me show you.

NAMING ORGANISMS

•  Eukarya •  Animalia •  Chordata •  Mammalia •  Primates •  Hominidae •  Homo •  sapien

•  Domain: it’s eukaryotic •  Kingdom: heterotrophic •  Phylum: vert. and nerve cord •  Class: it’s a mammal •  Order: it’s a primate •  Family: specifically it’s an ape •  Genus: it’s human •  Species: it’s wise (hurrah!)

NAMING ORGANISMS

•  Let’s look at one category more closely: it’s class. The class of humans is “mammalia” or mammal. What characteristics does that tell us about humans? •  They’re warm blooded. •  Have hair •  Have mammary glands •  Are placental •  Have specialized teeth

NAMING ORGANISMS

•  Typically you can just say the genus/species name. But using common names like “robin” or “daddy long legs” leads to problems. In the US and UK, a daddy long leg means different animals.

MODERN CLASSIFICATION

•  There are several classification systems. We will focus on the modern domain system. There are eight taxons (classification levels) in the current system. •  Domain -> Kingdom -> Phylum -> Class -> Order ->

Family -> Genus -> Species

MODERN CLASSIFICATION

•  The domain is the highest level of classification. This means it has the most organisms in it. The next taxon has fewer organisms in it than the previous taxon. The species is the most specific (hence the name). Each species only has one organism in it.

MODERN CLASSIFICATION

MODERN CLASSIFICATION

•  There are three domains: bacteria, archaea, and eukarya. Each domain has one or more kingdoms. •  Please add this in the margin of your notes: domains

are based on cell type.

MODERN CLASSIFICATION

•  Domain Archaea: •  Description: unicellular prokaryotes that are more

complex than bacteria. •  Kingdom: Archaebacteria

MODERN CLASSIFICATION

•  Domain Bacteria: •  Description: unicellular prokaryotes •  Kingdom: Bacteria

MODERN CLASSIFICATION

•  Domain Eukarya: •  Description: unicellular and multicellular eukaryotes •  Kingdom: Plant, Animal, Fungi, and Protists

THE KINGDOMS

•  Each of the kingdoms was formed based on similar characteristics of the organisms in it. •  Side note: the kingdom Protista is hotly debated in

science. Many scientists believe it should be divided into more kingdoms. Just as we learned in our Protist unit, we will recognize it to make learning about classification easier!

THE KINGDOMS

•  Kingdom Archaebacteria (see details from before) •  Examples: halophiles, thermophiles, extremophiles,

methanogens, etc. •  Kingdom Bacteria •  Description: unicellular prokaryotes •  Examples: E. Coli, S. Pharyngitis, Anabaena,

Merismopeadia

THE KINGDOMS

•  Domain: Eukarya •  Description: Multicellular autotrophic eukaryotes

with cell walls made of cellulose •  Examples: Trees, Venus fly traps, Dandelions, Moss,

Ferns, etc.

THE KINGDOMS

•  Animal •  Domain: Eukarya •  Description: Highly adapted multicellular

heterotrophic eukaryotes, usually complex •  Examples: Honey badger, reptiles, birds, sponges,

jelly fish, fish, mammals, etc.

THE KINGDOMS

•  Fungi •  Domain: Eukarya •  Description: Uni- or multicellular heterotrophic

decomposers, cell walls made of chitin •  Examples: Mushrooms, molds, yeast

THE KINGDOMS

•  Protists •  Domain: Eukarya •  Description: It’s a hot mess. Uni and multicellular

eukaryotes that contain simple autotrophs, heterotrophs, decomposers. •  Examples: Euglena, Paramecium, Slime Molds