Classifying Organisms
Introduction
Task
Process
Resources
Introduction
• Suppose you had only 10 minutes to run into a
supermarket to get 20 items. Could you do it?
• In most supermarkets this would be an easy task. You
would probably head straight to the area where the items
were located. But what if you had to shop for the same
items in a market where things were randomly placed
throughout the store. Where would you begin?
• You would have to search through a lot of things before
you found what you needed! You could be there for a
long time!
• Biologists have organized living things with similarities
into groups so that the organisms are easier to study.
This process is called classification.
Why Do Scientists Classify?
Classification is the process of grouping
things based on their similarities.
Biologists use classification to organize
living things into groups so that the
organisms are easier to study.
The scientific study of how living things are
classified is called taxonomy.
Classify Organisms Based on Physical
Features
• How might you classify a sunflower, a robin,
a lizard, a blue jay, and a tree? Copy the
table on paper and fill in your answers.
Plants
Animals
Classify Organisms Based on Physical
Features
What characteristics
may have been
used to group these
beetles?
Write answers on your
paper.
1.
2.
3.
4.
5.
6.
Levels of Classification
Species
Organisms are
grouped by their
shared
characteristics.
Genus
Family
Order
Class
Phylum
Kingdom
Understanding Classification
Imagine a room filled with everybody from the state of Oklahoma.
There may be some people from Broken Arrow.
There may be some people from your neighborhood.
There may be some people that live on your street.
You will be the only one that lives in your house.
Oklahoma
Broken Arrow
Neighborhood
1st Street
#123
The most general
group you belong to is the state.
The most specific group you belong to is
the house.
The more levels you share with others,
the more you have in
common.
Binomial Nomenclature
• Linnaeus devised a system of naming organisms.
Linnaeus placed organisms in groups based on their
observable features. Each organism has a unique, twopart scientific name containing their genus and species.
This naming system is called binomial nomenclature.
Canis lupus
familiaris
Dog
Canis
latrans
Coyote
Canis
simensis
Ethiopian Wolf
Senario
• Imagine you are a biologist walking
through the woods. You have been
walking for hours and are out of food. You
come across a fruit, but you don’t know
what the fruit is. You need to figure it out
before eating it. How would you figure this
out?
Taxonomic Keys
• Taxonomic Keys are tools used by
scientist to help determining the identity of
an organism.
• You take what you can observe from the
organism and follow the key to determine
the identity of the object
What you know about the fruit
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It grows on its own
The skin sticks to the flesh of the fruit
It only has one seed.
The skin is smooth.
Example of Taxonomic Key
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1. Fruits occur singly ....................................................... Go to 3
1' Fruits occur in clusters of two or more ......................... Go to 2
2. Fruits are round ....................................................... Grapes
2' Fruits are elongate ................................................... Bananas
3. Thick skin that separates easily from flesh .............Oranges
3' Thin skin that adheres to flesh .............................. Go to 4
4. More than one seed per fruit ............................ Apples
4' One seed per fruit ............................................ Go to 5
5. Skin covered with velvety hairs .................... Peaches
5' Skin smooth, without hairs ........................... Plums
It grows on its own
The skin sticks to the flesh of the fruit
It only has one seed.
The skin is smooth.
Practice
A
Dichotomous Key on Norns
1. Has pointed ears ............................. go to 3
....Has rounded ears .............................go to 2
2. Has no tail .................................... Kentuckyus
....Has tail .......................................... Dakotus
3. Ears point upward ............................. go to 5
....Ears point downward ..........................go to 4
4. Engages in waving behavior .................. Dallus
....Has hairy tufts on ears ........................Californius
5. Engages in waving behavior ............... WalaWala
....Does not engage in waving behavior........go to 6
6. Has hair on head ................................... Beverlus
....Has no hair on head (may have ear tufts) ..go to 7
7. Has a tail ................................................... Yorkio
....Has no tail, aggressive ............................ Rajus
B
C