Classification

Classification

• Classification: process of grouping things based on their similar characteristics

• Why Classify? – identifies related organisms– Makes organisms easier to identify

• Taxonomy: the science of describing, classifying, and naming living things

How do we classify?

• Linnaeus: classification system uses physical characteristics

– created binomial nomenclature: a two word naming system for a species more on this later

How do we classify?

– developed a system of taxonomy based on groups (taxa) that fit inside one another

– Species is the smallest and Domain is the largest

Taxa

–species (smallest) fits into Genus

–Genus fits into Family

–Families fit into Orders

–Orders fit into Classes

–Classes fit into Phylum (pl. phyla)

–Phyla fit into Kingdoms

–Kingdoms fit into Domains (largest)

Domain

Kingdom

Phylum

ClassOrder

Family

Species

Genus

Make a list of Characteristics that all the organisms share at the Kingdom level

What about at the Class level?

Can anyone tell me what is the same for all the organisms at the Domain Level?

Grizzly bear Black bear Giant panda

Red fox Abert squirrel

Coral snake

Sea star

KINGDOM Animalia

PHYLUM Chordata

CLASS Mammalia

ORDER Carnivora

FAMILY Ursidae

GENUS Ursus

SPECIES Ursus arctos

Section 18-1

Figure 18-5 Classification of Ursus arctos

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On what is our Classification system based?

• Shared characteristics

• DNA

Why use Scientific Names?

• common names are often misleading

• binomial nomenclature:

1st word: Genus (always uppercase)

2nd word: species (always lowercase)

EX: Homo sapien or Homo sapien

Both italicized or

underlined

Dichotomous Keys

• Def: Identification guide that uses paired questions or statements to identify an organism

• 1a. Item is 10 cm or more in any dimension........ go to 2• 1b. Item is less than 10 cm in any dimension ..... go to 5

• 2a. Item has wooden parts ................................ go to 3• 2b. Item does not have wooden parts ................. go to 5

• 3a. Item has a pointed edge .............................. Widget• 3b. Item does not have a pointed edge ............... go to 4

• 4a. Item is flat ................................................. Gadget• 4b. Item is rounded .......................................... Wadget

• 5a. Item has a spherical shape .......................... go to 6• 5b. Item is not spherical ................................... go to 7

Domain and Kingdom Taxonomy:

• Constantly changing with each scientific discovery

• There are 3 Domains in which the Kingdoms fit into

Domain Archaea• Characteristics:• Archaea means “Ancient” prokaryotes (no

nucleus)• They are heat lovers, salt lovers, and methane

lovers. • These guys live where nothing else can, in the

harshest environments (ice, boiling heat)• Unicellular• Cell walls are present in some• Autotrophic: make their own food and

Heterotrophic: consume food• Some can move

Domain Bacteria

• Prokaryotic (no nucleus) and unicellular• Can be found in : soil, water, even on and

in the body• Some can cause disease, others can be

helpful• Have cell walls, which is how they can

survive in your stomach• Can be autotrophic or heterotrophic• Some can move, others can not

Harmful Helpful

Domain Eukarya

• All of the organisms in this domain are eukaryotic (have a nucleus)

• The Kingdoms in this Domain:1. Protists

2. Fungi

3. Plants

4. Animals

Kingdom Protists

• Can be unicellular or multicellular

• Have a cell walls

• Can be heterotrophic or autotrophic

• Some can move, others can not

Kingdom Fungi

• Most are multicellular and all have a cell wall

• All are heterotrophic

• None can move

Kingdom Plants

• All contain chlorophyll to make their own food

• All have cell walls and are multicellular

• None can move

Kingdom Animals

• All are multicellular and none have cell walls

• All consume their food

• Mostly all animals can move at some stage of their life