Using Classification
Practice using binomial nomenclature
• Which of these names is written correctly in
binomial nomenclature?
A. felis domesticus
B. Felis domesticus
C. Felis Domesticus
D. felis Domesticus
Now that we know why and how
organisms are classified, we will see
how scientists use dichotomous keys
to help identify organisms.
Let’s say you come across a really cool
insect you’ve never seen before and
you want to know what kind it is –
how do you find out?
Dichotomous key – a guide that asks a
series of paired questions to find the
identity of an organism
How to Use a Dichotomous Key
• At each step, you choose the statement that
best describes your organism and follow
where to go.
• Always start with number 1!
• If done correctly, a dichotomous key will lead
you to the identity of an organism.
1a. long, tubular object………………………….……………...go to number 2
b. short, non-tubular objects…………………………….….go to number 4
2a. constructed from plastic………………………………..….go to number 3
b. constructed from wood…………………………………....pencil
3a. produces a yellow color……………………………………..highlighter
b. produces a blue ink………………………………………….…pen
4a. is rectangular and contains a metal blade………….pencil sharpener
b. is made of silver metal……………………………………….paper clip
Assignment:
• Help! Scientists have discovered quite a few
new creatures on planet Pamishan. They need
your help to identify and classify them. Use
the dichotomous key to identify these
creatures
Making a Dichotomous Key
• It’s all about putting things into groups!
You have your two groups
Now it’s time to write a key
• Remember, each step has two
statements
• After each statement, you are told either
where to go or the name of your object
• When writing your key, it’s easiest to
focus on one group at a time.
Let’s look back
• How did you divide the money into two
groups?
Your Dichotomous Key
Made of paper
Go to 2
• 1. a. _______________
……….. _____________
Made of metal
b. _______________
……….. _____________
• 2. a. _______________ ……….. _____________
b. _______________ ……….. _____________
• 3. a. _______________ ……….. _____________
b. _______________ ……….. _____________
Your Dichotomous Key
Made of paper
Go to 2
• 1. a. _______________
……….. _____________
Made of metal
Go to 3
b. _______________
……….. _____________
2 in the corners ……….. _____________
$2 bill
• 2. a. _______________
1 in the corners ……….. _____________
$1 bill
b. _______________
• 3. a. _______________ ……….. _____________
b. _______________ ……….. _____________
Your Dichotomous Key
Made of paper
Go to 2
• 1. a. _______________
……….. _____________
Made of metal
Go to 3
b. _______________
……….. _____________
2 in the corners ……….. _____________
$2 bill
• 2. a. _______________
1 in the corners ……….. _____________
$1 bill
b. _______________
Copper in color
Penny
• 3. a. _______________
……….. _____________
Silver in color
Go to 4
b. _______________
……….. _____________
Your Dichotomous Key
Copper in color
Penny
• 3. a. _______________
……….. _____________
b. _______________
……….. _____________
Silver in color
Go to 4
Smooth outer edges ……….. _____________
Nickel
• 4. a. _______________
Rough outer edges ……….. _____________
Go to 5
b. _______________
• 5. a. _______________ ……….. _____________
b. _______________ ……….. _____________
Your Dichotomous Key
Copper in color
Penny
• 3. a. _______________
……….. _____________
b. _______________
……….. _____________
Silver in color
Go to 4
Smooth outer edges ……….. _____________
Nickel
• 4. a. _______________
Rough outer edges ……….. _____________
Go to 5
b. _______________
Large in size
Quarter
• 5. a. _______________
……….. _____________
Small in size
Dime
b. _______________
……….. _____________
Once you have finished your key…
TRY IT!
make sure it works
Assignment
• Work in groups of
2
• Create a dichotomous key of every
person in this class