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7 th Grade Science Classifying Organisms

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Objectives: 1. You will be able to explain why classification systems are important. 2.You will be able to demonstrate your understanding with a dichotomous key.

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Why do Scientists Classify? Why? Easier to study Less confusion Easier to see connections How? Physical characteristics DNA

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Types of Cells Prokaryotes No Nucleus Very small Bacteria Domains: Bacteria and Archaea Eukaryotes Cells contain a nucleus Larger than prokaryotes Domain Eukarya

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Scientific Naming Why? Reduces confusion Binomial Nomenclature Two words for every name Greek or Latin Genus species (ex. Canis lupis) General Rules Always use italics or underline when written Capitalize genus Lowercase for species Canis lupis

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Taxonomy Taxonomy: Classification of organisms based on characteristics 8 levels Each level has fewer organisms Which organisms are more similar? Same genus Same family

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3.1 Classifying life Taxonomy is the process of identifying and classifying living things. A Swedish scientist and explorer named Carolus Linnaeus (17071778) developed a system of classification in the 1700s. There are currently seven levels of classification.

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3.1 Levels of classification For animals, the levels of classification are: kingdom, phylum, class, order, family, genus, and species. At what level are these two animals classified differently?

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Kingdoms of Life Separated by common characteristics 6 kingdoms Archaebacteria Eubacteria Protista Fungi Plantae Animalia

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Topic: Classification Tools What tools can scientist use to classify organisms?

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Classification Tools Suppose you to fishing and catch a fish you dont recognize. How could you figure out what type of fish you have caught?

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Is a series of descriptions arranged in pairs that lead the user to identification.

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1.Divides a larger group in smaller groups 2.Typically, it may separate objects into groups that have it and those that dont have it

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1.Divides a larger group in smaller groups 2.Typically, it may separate objects into groups that have it and those that dont have it

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3.2 Dichotomous Keys A dichotomous key turns questions into paired statements.

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Classification Today Scientists use shared characteristics to hypothesize how closely related living things are The more shared characteristics organisms have, the more closely related they are Cladograms: branching diagrams showing the similarities and differences between organisms

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3.2 Dichotomous Keys Most dichotomous keys are designed to identify small groups like trees, butterflies, and song birds. Can you suggest a way to tell these arthropod classes apart?

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Dichotomous Key of Transportation Vehicles Vehicles with wheels:

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Unicycle, skates, a/p, bike, train, car, bus Canoe, boat, sailboat, Dichotomous Key of Transportation Vehicles Vehicles with wheels:

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Wheels made of rubber/plastic: Unicycle, skates, ap, bike, train, car, bus Canoe, boat, sailboat, Dichotomous Key of Transportation Vehicles Vehicles with wheels:

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Wheels made of rubber/plastic: Unicycle, skates, ap, bike, train, car, bus Canoe, boat, sailboat, Unicycle, skates, ap bike, car, bus train Dichotomous Key of Transportation Vehicles Vehicles with wheels:

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Wheels made of rubber/plastic: Unicycle, skates, ap bike, train, car, bus Canoe, boat, sailboat, Unicycle, skates, ap bike, car, bus train Carries over 10 people: Dichotomous Key of Transportation Vehicles Vehicles with wheels:

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Wheels made of rubber/plastic: Unicycle, skates, bike, train, car, bus Canoe, boat, sailboat, Unicycle, skates, bike, car, bus train Carries over 10 people: Bus, apUnicycle, skates bike, car Dichotomous Key of Transportation Vehicles Vehicles with wheels:

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Dichotomous Key of Animals Animals with 4 legs

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Horse, gorilla, cow Ostrich, worm, shark, man, rooster Dichotomous Key of Animals Animals with 4 legs:

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Animals with tail: Horse, gorilla, cow Ostrich, worm, shark, man, rooster Dichotomous Key of Animals Animals with 4 legs :

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Animals with tail: Horse, gorilla, cow Ostrich, worm, shark, man, rooster Horse, cowgorilla Dichotomous Key of Animals Animals with 4 legs:

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Animals with a tail: Horse, gorilla, cow Ostrich, worm, shark, man, rooster Horse, cowgorilla Animals with utters: Dichotomous Key of Animals Animals with 4 legs:

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Ostrich, worm, shark, man, rooster Animals with a tail: Horse, gorilla, cow Horse, cowgorilla Animals with utters: cowhorse Dichotomous Key of Animals Animals with 4 legs:

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Tips for Classifying Carefully observe objects to notice similarities and differences Place objects into either one group or another not both groups Examine each group you create to see if it can be further subdivided

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Class Activity Fish Classification

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Levels of Classification 8 Levels Domain Kingdom Phylum Class Order Family Genus Species Mnemonic Device?

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Domains Major Groups Three domains Bacteria Archaea Eukarya

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Review Naming: Binomial Nomenclature Levels of Classification 3 domains Types of Cells Kingdoms of Life