1. If your notes are out before the bell rings you may use them on the quiz!

2. Standard: B8B Categorize organisms using a hierarchical classification system based on similarities and differences shared among groups
Essential Question: How are different organisms or objects sorted into meaningful categories?

3. Scientists use dichotomous keys and field guides to help people identify organisms
Dichotomous keys – asks a series of questions that can be answered in only two ways
When using a dichotomous key, each answer leads to another question which will eventually narrow down to the identification of the item
Sometimes represented as a flow chart

4. Dichotomous Key

6. 1a Candy is not hard ……………………………………………
1a Candy is not hard …………………………………………….2 1b Candy is hard ……………………………………………………..7 2a Candy is wrapped ……………………………………………….3 2b Candy is not wrapped ………………………………………..Ursa gummus 3a Candy is rounded …………………………………………………..4 3b Candy is not rounded ……………………………………………5 4a Wrapper is all white and semi-transparent…………………………Saltus taffina 4b Wrapper is not all white …………………………………………….5 5a Wrapper is mostly brown and white …………………………………..Tutus rollus 5b Wrapper is not brown and white ………………………………………6 6a Wrapper is silver ………………………………………………………Chocolatus cyssan 6b Wrapper varies in color ……………………………………………Steorra explodus 7a Candy is spherical (ball-shaped) …………………………………………….8 7b Candy is not spherical ……………………………………………………….9 8a Candy is wrapped ……………………………………………………………11 8b Candy is not wrapped ……………………………………………….Mandibulus crackus 9a Wrapper is transparent (see-through) with no writing …………………….10 9b Wrapper is transparent and tells flavor ………………………….Joyous rancheria 10a Wrapper is clear ……………………………………………………..Mintus stripus 10b Wrapper is yellow ………………………………………………Rannunculus schotchus 11a Candy is on a stick ………………………………………………………..Moronus moronus 11b Candy is not on a stick ……………………………………………………Spherus combustus

7. Alien Dichotomous Key practice!
Do the best you can to finish before the bell!
How well ya’ll work depends on if we spend time on this tomorrow or not!

8. A dichotomous key
EXPLORE: Introduce your students to the dichotomous key. Together, use the key to identify the group to which each organism belongs.
Assign the student reading. You may also wish to direct your students’ attention to the “Kingdoms” animation which is accessible from the multimedia lesson home page.

9. Dichotomous Key for conifers

10. Whose shoes? A class dichotomous key
ELABORATE: This fun class activity requires very little set up and provides additional practice in writing and using dichotomous keys.

11. How do you create a dichotomous key?
Time to investigate!
How do you create a dichotomous key?
EXPLORE:
Lead the lesson investigation: Dichotomous Keys.

12. Time for Practice!
You and a partner create your own dichotomous key using 12 things you find in your binder/backpack
Some hints for writing a dichotomous key:
Write the part name first, then the descriptive term (for example “Tail short and straight,” not “Short and straight tail”).
Start both choices in a pair with the same word.
Use measurements rather than vague terms like “big” and “little.”
Use characteristics that are true of all individuals in a group (for example, use fur color only if all individuals have the same color markings).
EXPLAIN:
Guide students as they complete the practice worksheet.

13. Make a dichotomous key to identify 6 macroinvertebrates
Stone fly larvae
Leech
Riffle beetle
Dobson fly larvae
Mayfly larvae
Crane fly larvae

14. Complete the dichotomous key practice by the end of class