Unit: Classification How are living things classified. SB3b Unit: Classification How are living things classified? SB3b. Examine the evolutionary basis of modern classification systems
Unit: Classification How are living things classified. SB3b Unit: Classification How are living things classified? SB3b. Examine the evolutionary basis of modern classification systems
How are living things classified? Classification – grouping of objects, information, objects & organisms based on similarities
How are living things classified? Taxonomy – grouping and naming of organisms(living things) - Linnaeus developed the present method of classification - classified organisms by their physical and structural similarities-THEN NOW-scientists use evolutionary relationships to classify organisms
How are living things classified? Organisms are named using a ___2_____ - word system (scientific names)binomial nomenclature Rules: Scientific names are always italicized or underlined Scientific names are Latin Scientific names are made of 2 words: Genus name is the first word – it starts with capital letter - species name is the __second_ word – it starts with a lowercase letter Ex: Homo sapiens = Humans OR Ursus maritimus = Polar Bear
How are living things classified? Organisms are classified ( organized) based on: 1) Physical similarities (ex: homologous structures) 2) Fossil evidence that show common ancestry 3) similarities in embryological stages (ex: embryos of different species have tails & gills) 4) similarities in DNA and proteins (molecular biology/ biochemistry)
How are living things classified? Linnaeus’ System of Classification Linnaeus’ system has 7 taxa a.k.a. levels ( taxon – singular)
Taxon Pneumonic Example: Humans Kingdom _________________ Animalia Phylum _________________ Chordata Class _________________ Mammalia Order _________________ Primate Family _________________ Hominidae Genus _________________ Homo Species _________________ sapiens
How are living things classified? ** The more classification levels 2 organisms have in common, the more closely related they are ** The less classification levels 2 organisms have in common, the more __distantly___ related they are
3 Domains of Life Domains-more general than kingdoms 1. 2. 3.
Sizes in biology
Are viruses classified?
Are viruses living? Growth No Yes Cells No Yes Homeostasis No Yes Characteristic of Life Virus Cell Growth No Yes Cells No Yes Homeostasis No Yes Energy No Yes Mutation Yes Yes Nucleic Acid DNA or RNA DNA Reproduction only within host cell independently by cell division Structure DNA or RNA protein Cell membrane wrapped in protein cytoplasm, ribosomes