Classification Notes Taxonomy Naming and grouping organisms according

Classification Notes

Taxonomy • Naming and grouping organisms according to their characteristics and evolutionary history.

Aristotle • Greek philosopher who first attempted to classify living organisms • Over 2000 years ago

Aristotle • He classified living things into two groups: – Plants – Animals

Aristotle • Why did his system create problems? – Not all living things are plants and animals – Even plants and animals are very diverse – Our knowledge of life has changed

Carolus Linnaeus • Swedish scientist who developed our modern system of classification. • 1707 - 1778

Carolus Linnaeus • Used morphology (form and structure) to categorize organisms

Carolus Linnaeus • Developed a hierarchy of levels in his system – Kingdom – Phylum – Class – Order – Family – Genus – Species King Phillip Came Over For Good Soup

Species • Remember that a species is a group of organisms that can mate and reproduce fertile offspring • Not a clear cut definition

Common Names • Most people use common names for organisms • This causes problems – 13 lined ground squirrels are often called gophers

Scientific Names • Scientific names solve the naming problem • Latin is used for most scientific names.

Binomial Nomenclature All organisms are given a genus and a species name. This way all people can use the same name to identify organisms

Genus and Species • The genus name comes first and begins with a capital letter. – Ex. Felis (it can be abbreviated as F. • The species names comes second and begins with a lower case letter. – Ex. domesticus *Both the genus and species names are usually italicized and often underlined. Ex. Felis domesticus

How do we classify organisms today? • Not so much on physical similarities (can be based too much on opinions). • Scientific evidence is a better way to do this.

Evidence for Classification • • • Chromosome Structure Biochemical Similarities Embryology DNA Sequencing Reproduction

Systems of Classification • Linnaeus used 2 Kingdoms – Plant – Animal

Modern Kingdoms • • • Animalia Plantae Fungi Protista Archaebacteria Eubacteria

Animalia • Multicellular heterotrophs

Plantae • Multicellular autotrophs

Fungi • Most are multicellular • Yeast is unicellular • Absorb food through cell walls

Archaebacteria • Unicellular prokaryotes • Related to first life forms • Live in harsh environments

Eubacteria • Unicellular prokaryotes • Includes most bacteria

Classification of a human • • Kingdom = Animalia Phylum = Chordata Class = Mammalia Order = Primate Family = Hominid Genus = Homo Species = sapien