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CLASSIFICATION. Grouping Organisms. Objectives. Describe how the classification system works in order to group organisms. Observe and classify according to visible similar features Draw and use a dichotomous key. Biological classification.
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CLASSIFICATION Grouping Organisms
Objectives • Describe how the classification system works in order to group organisms. • Observe and classify according to visible similar features • Draw and use a dichotomous key
Biological classification • Biological classification, or scientific classification in biology, is a method by which biologists categorize these organisms. • All these organisms can be classified into appropriate groups ( based on similar characteristics)
Order of classification • The science of placing organisms into the correct groupings is called taxonomy. • There are specific taxonomic terms in this process.
Example: species • Species- a group of organisms that can interbreed and produce offspring.
Taxonomic terms • Species that are obviously similar are placed together in larger groups called GENUS. • The name of the genus and the name of the species a particular organism belongs to, give the scientific name of the organism.
Scientific names • An 18th century biologist named Linnaeus. • He devised a system of binomial nomenclature . • The name of all organisms must be Latin or Latinized and are printed in italics or underlined when handwritten. • The genus name is capitalized and must be a single word. • The species name can be either a single word or a compound word.
Biological classification of Humans Kingdom:AnimaliaPhylum:ChordataClass:MammaliaOrder:PrimatesFamily:HominidaeGenus:HomoSpecies:H. sapiens Binomial name:- Homo sapiens * Check text
Dichotomous Keys • A dichotomous key is a tool that allows the user to determine the identity of organisms in the natural environment. • "Dichotomous" means "divided into two parts". Therefore, dichotomous keys always give two choices in each step.
Choices • Each choice is a highly descriptive statement. • A couplet consists of (typically) two descriptions which should represent mutually exclusive choices. • Both choices are read carefully and compared with the specimen to be identified.
Decisions • Once a decision is made, that selection directs you to another couplet (either the next in order or one further on in the key). • This process is repeated until a conclusion (successful identification) is reached. • If the description seems satisfactory, a correct identification probably has been achieved
Worked example-Items from a pencil case • Look at the group of objects or organisms and separate them into two groups based on a single distinguishing characteristic. • Continue to separate each of the groups until each object has its own separate set of characteristics.