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Taxonomy• Taxonomy- the practice and science of
classification– Why do scientists classify organisms?• Used to organize living things into groups so that they
are easier to study• Helps identify the relationship between organisms• Helps to avoid confusion in naming and identifying
organisms
• Taxon- divisions with subdivisions; from the most specific taxon (species) to the most general (kingdom)
• Naming species– Species- group of organisms capable of interbreeding and
producing fertile offspring– Each species is identified by a binomial Latin name, which
refers to both the genus and species, with genus capitalized and species in lower case. The whole thing is italicized or underlined• Human = Homo sapiens• Great White Shark = Carcharodon carcharias• Megalodon Shark = Carcharadon megalodon
• Current classification system– Three Domains- all life dividing into 3
Domains1. Bacteria- single- celled microorganisms; they
are prokaryotes, which means they have no nucleus or organelles in their cells
2. Archaea- single celled microorganisms; also prokaryotes. When first discovered (1977), considered bacteria. After further research, they have no close relationship to bacteria
3. Eukarya- organism with eukaryotic cells (nucleus and other membrane bound organelles)
• 6 kingdoms1. Eubacteria- prokaryotes, unicellular; found in
every habitat on earth2. Archaebacteria- prokaryotes; unicellular; more
closely related to eukaryotes than bacteria; many species found in ocean
3. Protista- simple eukaryotes; either uni or multicellular without specialized tissues
4. Fungi- eukaryotes; unicellular and multicellular; heterotrophic decomposers
5. Plantae- eukaryotes; multicellular; cell walls; autotrophic photosynthesizers
6. Animalia- eukaryotes; multicellular; no cell walls; heterotrophic consumers
• How scientists classify organisms– Methods: organisms can be placed into certain
taxonomical groups based on their…• Morphology and anatomical structure• Biochemical structure (RNA, DNA, Protein sequences)
• How scientists classify organims– Phylogeny-evolutionary history of organism• Phylogenetics- study of evolutionary relatedness
among various groups of organisms, which is discovered through molecular sequencing data and morphological data• Phylogenetic tree- diagram showing the evolutionary
relationships among various biological species or other entities that are known to have a common ancestor