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Download Classification Notes - Valhalla High School
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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 The Three-Domain System The Three-Domain System Molecular analyses have given rise to a new taxonomic category that is now recognized by many scientists. The domain is a more inclusive category than any other — larger than a kingdom. Copyright Pearson Prentice Hall The Three-Domain System The three domains are: • Eukarya, which is composed of protists, fungi, plants, and animals. • Bacteria, which corresponds to the kingdom Eubacteria. • Archaea, which corresponds to the kingdom Archaebacteria. Copyright Pearson Prentice Hall Domain Bacteria Domain Bacteria Members of the domain Bacteria are unicellular prokaryotes. Their cells have thick, rigid cell walls that surround a cell membrane. Their cell walls contain peptidoglycan. Copyright Pearson Prentice Hall Domain Archaea Domain Archaea Members of the domain Archaea are unicellular prokaryotes. Many live in extreme environments. Their cell walls lack peptidoglycan, and their cell membranes contain unusual lipids not found in any other organism. Copyright Pearson Prentice Hall Domain Eukarya Domain Eukarya The domain Eukarya consists of organisms that have a nucleus. This domain is organized into four kingdoms: – – – – Protista Fungi Plantae Animalia Copyright Pearson Prentice Hall 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
