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Classification. Classification of Living Things with Tim and Moby. http://www.brainpop.com/science/diversityoflife/classification/. So much to discover!!!.
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Classification of Living Thingswith Tim and Moby http://www.brainpop.com/science/diversityoflife/classification/
So much to discover!!! Scientists have identified more than 2.5 million kinds of organisms . You may be surprised to learn that this catalog of life isn’t even close to being complete! Some biologists estimate that there may be another 20 million or so unknown species still out there. These species include insects living in tropical rain forests, odd creatures living in the unexplored depths of the sea, and the microorganisms all around us.
No one can think about that many organisms at once, and certainly no one can keep track of them by their names alone. The only way to study this great diversity of organisms is to divide living things into manageable groups.
To work with the diversity of life we need a system of biological classification that can name and order organisms in a logical way!
Scientific classification Scientific classification or biological classification refers to how biologists group and classify extinct and living species.
Linnaeus Modern classification has its roots in the system of Carolus Linnaeus (Swedish botanist, 1707-1778). Linnaeus grouped species according to sharedphysical characteristics.
Changes These groupings have been revised since Linnaeus to improve reliability with the Darwinian principle of commondescent.
Linnaeus Naming Scientists name organisms using binomial nomenclature (bigh-NOH-mee-uhl NOH-muhn-klay-cher), where each organism is given a two-part scientific name.
Genus name + species name • The Genus name IS capitalized. • The species name is NOT capitalized • Both names are in italics OR underlined. (not both!) • Ex. Acer rubrum = red maple tree • (in Latin, Acer= maple; rubrum = red)
Acer palmatum maple tree with leaf that looks like a hand ( in Latin, Acer = maple; palmatum= hand) Note: the species name is usually a Latin description of some important characteristic of the organism
Linnaeus Classification Linnaeus grouped organisms together according to shared physical characteristics (body structures). The groups to which Linnaeus assigned organisms are called taxa (singular: taxon). The science of naming organisms and assigning them to these groups is called taxonomy .
The Taxa • Kingdom • Phylum (animals) or Division (plants) • Class • Order • Family • Genus • Species
Mnemonics • Kings Play Chess On Funny Green Squares
Mnemonics • King Phillip Came Over For Good Spaghetti
Mnemonic • K________________ • P________________ • C________________ • O________________ • F________________ • G________________ • S________________
How Living Things are Classified • Example – Sciurus Niger • Start at time stamp for 9:00.
Taxonomy Today • Taxonomy is not as simple as it might seem. Ideas about the arrangements of organisms into families, orders, phylas, and kingdoms have changed dramatically since the time of Linnaeus.
Thinking Question • How and why has taxonomy changed so much?
The only taxon that has a clear biological identity is the species. Members of a species share a common gene pool because they reproduce with one another. The other taxa, however, do not have a clear identity. Taxonomists try to create taxa that group organisms according to biologically important characteristics, but different scientists have different ideas about which characteristicsare most important. As a result, organisms have sometimes been “moved” from one taxon to another as scientists learn more informationabout the organism.
Taxonomists group organisms according to: Evolutionary relationships • Fossil record • Homologous structures • Embryological relationships Biochemical relationships • Similarities in DNA, cytochrome c
Fossils • Fossils show the history of life on earth and how different groups of organisms have changed over time
Primate Fossils Australopithecus Homo erectus Homo sapien
Homologous Body Structures Turtle • Structures that came from the same embryonic tissues in different organisms (common ancestor) • Structures are similar, but functions are different. • ex. Wing of bat, human arm, leg of turtle Alligator Bird
Similarities in Embryology • In early stages of development most animals look similar • showing that they share a common ancestry.
Biochemical Relationships Similarities in DNA • The genes of organisms show many similarities at the molecular level • These similarities can show how related separate organisms are and thus help classify them.
Biochemical Relationships • Eg. Our DNA is closer to dolphins than it is to pigs, horses, or cows.
Biochemical Relationships • Cytochrome C – A protein in ALL organisms, can compare the amino acid sequence and compare where mutations are to see how closely related organisms are.
Class work and Homework • Use notes and text to answer questions. • Make up your own mnemonic from remembering KingdomPhylumClass OrderFamilyGenusSpecies to share with the class tomorrow. • BRING YOUR TEXTBOOK
How would you classify these organisms (which two would you place together)? barnacle crab limpet
Phylogeny based on physical similarity (wrong!) Phylogeny based on evolution (correct!)
The Six Kingdoms http://www.brainpop.com/science/diversityoflife/sixkingdoms/ With Tim and Moby
How many? There have been many classifying schemes developed through time, changing from 2 kingdoms to 3 to 4 and to the present 6 kingdom system. • Plant - Animal • Plant - Animal - Fungi • Microorganisms - Plant - Animal - Fungi • Monera - Protista - Plant - Animal - Fungi
The Six Kingdom System of Classification - Current System (you must know this) • Archaebacteria • Eubacteria • Protista • Fungi • Plant • Animal
The Three Domains – Reviewing Prokaryotes and Eukaryotes • The six kingdoms of living things are grouped into three major groups or Domains, which are Archaea, Bacteria, and Eukarya
Domain Archaea contains the Kingdom Archaebacteria • They have all the characteristics of prokaryotes and they live in most extreme and harsh environments (volcanoes, hot springs, ocean vents). Some of the most ancient organisms on earth. Cell walls do NOT contain peptidoglycan