Classifying Organisms 7th Grade Science

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

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

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

Scientific Naming Why? Binomial Nomenclature General Rules Canis lupis 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

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

3.1 Classifying life Taxonomy is the process of identifying and classifying living things. A Swedish scientist and explorer named Carolus Linnaeus (1707–1778) developed a system of classification in the 1700s. There are currently seven levels of classification.

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?

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

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

Classification Tools Suppose you to fishing and catch a fish you don’t recognize. How could you figure out what type of fish you have caught?

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

Divides a larger group in smaller groups Dichotomous Key Divides a larger group in smaller groups Typically, it may separate objects into groups that “have it” and those that “don’t have it”

Divides a larger group in smaller groups Dichotomous Key Divides a larger group in smaller groups Typically, it may separate objects into groups that “have it” and those that “don’t have it”

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

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

Look at these Pictures

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?

What do they have in Common?

Copy this diagram

Dichotomous Key of Transportation Vehicles Vehicles with wheels:

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

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

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

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

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

What are These?

Animals

Dichotomous Key of Animals Animals with 4 legs

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

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

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

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

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

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

Class Activity Fish Classification

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

Domains Major Groups Three domains Bacteria Archaea Eukarya

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