Organizing Life

Classification, Taxonomy & Dichotomous Key

A brief review…..

Classification

K in g d om : A n im a lia

C lass :A rach n id a

C lass :In sec ta

P h ylu m :A rth rop od a

F am ily:C an ad ae

O rd er:C arn ivora

O rd er:P rim ates

C lass : M am m alia C lass : A ves

P h ylu m : C h ord a ta

Classification

• CLASSIFICATION is a manmade system for grouping living organisms with similar characteristics.

• TAXONOMY is the branch of biology that assigns names to all the various living organisms.

Binomial Nomenclature

Carolus Linnaeus (1707-1778) developed the system which gives a two part scientific name to each kind of organism.

Rana pipiens or Rana pipiens

Binomial Nomenclature

Linnaeus’s system that gives each organism two names:

-First word – genus; always capitalized-Second word – species; lowercase-Both words are italicized or underlined-Example: Homo sapiens (humans); if you

were writing the name you would underline the words – Homo sapiens

Binomial Nomenclature• Scientists agreed to use a single name for

each species. Because eighteenth-century scientists understood Latin and Greek, they used those languages for scientific names.

• Genus – (first word) a group of closely related species

• Species – (second word) unique to each species within the genus

Taxonomy

• Categories of organisms are referred to as Taxon or TAXA. !

Background Image: http://www.funny-potato.com/images/animals/jellyfish/jellyfish.jpg

Dichotomous Key• special guides to help identify organisms. • consists of several pairs of descriptive statements

CLASSIFICATION

• Linnaeus’s system of classification includes seven levels.

• Listed from largest to smallest

S p ec ies

G en u s

F am ily

O rd er

C lass

P h ylu m

K in g d om

Classification

• Biologists place living things in the classification system based on phylogeny (evolutionary relationships, structure, development, biochemistry, and behavior.

The Six Kingdoms

Organizing life in infinite varieties

Kingdom Eubacteria

• True bacteria: prokaryotic, microscopic, unicellular

• more than 10,000 species identified

Kingdom Archaebacteria

• Ancient bacteria found in extreme environments like salt lakes, deep ocean vents and geysers.

• Unicellular• Prokaryotic – live in

the absence of oxygen

Kingdom Protista

• Unicellular & multicellular

• some plantlike & some animallike, but are not plants, animals or fungi

• Eukaryote that lacks complex organ systems

• Amoeba, Paramecium, slime molds, giant kelp

Kingdom Protista

• No single trait is unique to protist

• Protists can be autotrophs or heterotrophs, and a few can switch between modes

• Some single-celled protists can develop into a nonmotile, dormant cyst during hard times

Kingdom Fungi

• Decomposers• Unicellular or

multicellular• eukaryotic• Heterotrophic• Mushrooms,

yeast

Kingdom Plantae• Multicellular oxygen

producers• stationary eukaryotes• most have cellulose

cell walls• Chloroplasts• Mosses, ferns,

flowering plants

Kingdom Animalia

• Multicellular consumers; most able to move• no cell walls• most have specialized tissues & organs• Eukaryotic• Sponges, worms, insects, fishes, mammals