ClassificationHow we group things

Why do we classify living things?

We have about 1.5 million NAMED & classified species.

There may be over 30 million species on Earth!!

We organize so we can communicate, share information & find information.

Taxonomy

…branch of biology for naming & grouping of organisms

Can be grouped according to:

1) their characteristics

2) their evolutionary history

History of taxonomy

Aristotle – had 2 groups, plants & animals

Linnaeus – developed a Hierarchy of levels, according to morphology (physical appearance)

Problems with using morphology to classify

1) Some things may look different but still be a member of the same species.

2) Injuries or other events may alter the physical appearance

3) Some things look alike but are not related (dolphins & fish)

Hierarchy of taxonomyAcronym: King Phillip Came Over For Grape Soda

Humans are:

• Kingdom- Animalia• Phylum- Chordata• Class- Mammalia• Order- Primates• Family- Homidae• Genus- Homo• Species- sapiens

Binomial Nomenclature

…is the ”2 part scientific name” of an organism

RULES1) 1st word = genus name, always capitalize 1st

letter2) 2nd word = species name, all lower case3) Both are italicized or underlined4) Written in Latin

Example: Felis domesticus is a house cat.

EXAMPLES

Home sapien = humans

Felis leo = lion

Phylogeny

..classifying organisms according to their evolutionary

history. Uses systematics.

How does systematics work?

Use evidence from many sources:

1) fossils

2) morphology (physical appearance)

3) embryological development

4) chromosomes & DNA

The 6 Kingdoms

Characteristics of each….

Kingdom Archaebacteria

• Prokaryotes• Single celled• Has a cell wall (no

peptidoglycan)• Some autotrophs &

heterotrophs• Live in extreme environments• EX: halophiles,

thermoacidophiles, methanogens

Kingdom Eubacteria

• Prokaryotes• Single celled• Has cell wall with

peptidoglycan• Some autotrophs &

heterotrophs• EX: E. coli, S. pyogenes

(causes strep throat), C. tetani (causes tetanus)

Kingdom Protista

• Eukaryotes• Mostly single celled, some

multicelled• Cell walls (some)• Autotrophs & heterotrophs• EX: Amoeba, paramecium,

some algae• Some are free-living and

some are parasitic!

Kingdom Fungi

• Eukaryotes• Multicelled (except for

yeast!)• Cell wall with chitin• Heterotrophs• EX: mushrooms, some

molds, yeast• Some are parasitic!

Kingdom Plantae• Eukaryotes• Multicelled• Cell wall with cellulose• Autotrophic• EX: oak trees, rose,

ferns

Kingdom Animalia

• Eukaryotes• Multicelled• No cell walls• Heterotrophic• EX: insects,

sponges, humans, frogs, etc…