Chapter 17

Review of “Classification”

Classification

• Grouping things according to similar characteristics, and separating them from others by differing characteristics

• The science of classifying living things is taxonomy

Used to classify organisms:

• Cells and their organelles

• Growth and development

• Blood chemistry

• DNA

• Energetics

• Body structures/organs

Early Systems of Classification

• Aristotle – for animals 2000 years ago

• Theophrastus – for plants 2000 years ago

• Linnaeus (Karl von Linne) – all organisms in the 1700’s

• Linnaeus is known as the “father of modern taxonomy”

Aristotle

Theophrastus

What is the common theme that you observe between the systems of

teacher and student?

Pairs of choices – either this or that……..each

step has just two choices!

Linnaeus continued that in his

development of a

“dichotomous key”

How to use the dichotomous key

Variations have been

developed over time!

Classification Levels• All organisms are placed in one of 5

kingdoms

• Kingdoms are divided into several phyla (phylum) or divisions

• Phyla are subdivided into classes

• Classes are divided into several orders

• Order contain several families

• Each family has several genera (genus)

• Each genus is made up of related species

(Division)

Species sometimes have “varieties”

The definition of a species is groups that can breed to form fertile offspring

Human Classification

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

Binomial Nomenclature

• Each organism has a two-part Latin name in Linnaeus’ system

• Capitalized Genus

• Lower case species

• Homo sapiens, Acer rubrum, Pseudotsuga heterophylla, Bacillus cereus, Canis familiaris, Felis domesticus, Equus asinus

• Discoverer gets to name it !

Kingdoms of Living Things

• Monera• Protista• Fungi• Animalia• Plantae

• Whittaker in 1969• Nucleus or not• Uni/multicellular• How they obtain food

Monera

• Simple, unicellular, prokaryotic

• Bacteria

• Now– Archeabacteria– Eubacteria

Protista• Simple,

unicellular or multicellular

• Eukaryotic

• Amoeba, euglena, paramecia

Fungi

• Uni- or multicellular, plant-like

• Eukaryotic

• Feed on dead matter

• Mushrooms, mold and yeast

Plantae

• Multicellular

• Eukaryotic

• Photosynthetic

• Flowers, shrubs, trees

Animalia

• Multicellular

• Eukaryotic

• Eat other organisms

• Man, fish, bird

How are organisms named?

• From Latin and Greek– Planta from Latin for “plant”– Moneres from Greek for “single”– Genus is Latin for “type”

• Latin prefixes and suffixes to further describe the basic root words

What does archeaphyte mean? Arthropod? Rhodophyta?

Ciliderm? Eubacteria?

• Archea = ancient• Arthr = joint• Chlor = green• Cili = small hair• Con = cone• Derm = skin• Eu = true

• Myc = fungus• Oo = water• Platy = flat• Por = pore• Pod = foot• Phyt = plant• Rhod = red

What about viruses?

Non-living particle (consider characteristics of “life”)

Bacteriophage

Lytic Cycle

Classified?

• Not in organic classification system

• Formerly classified by host

• New system by shape and structure– Capsid structure– Nucleic acid type– Method of reproduction