1. Glue Notes here when done
183
Dichotomous Keys notes
184
2/24/15
2/24/15
Practice:
Glue Notes here when done
Application:
Leaf Dichotomous Key
Starter:
What cell structure is used to classify organisms into Domains?
Connection/exit:
Explain what a dichotomous key is used for.

2. 1. Starter 2. Notes 3. Dichotomous Key
February 24, 2015 AGENDA   Objective 7.11A Examine organisms or their structures such as insects or leaves and use dichotomous keys for identification by completing an activity.

3. Dichotomous
Keys

4. A dichotomous key is a tool that scientists can use to identify an unknown organism or specimen.
Keys

5. Examples include…
insects
Dichotomous
Keys

6. trees
Dichotomous
Keys

7. rocks
Dichotomous
Keys

8. and shells.
Dichotomous
Keys

9. The word dichotomous means “divided in two parts.”
Keys

10. Characteristics of a Dichotomous Key
Keys

11. Consists of a series of two part characteristics of a specimen.
statements that
describe the
characteristics of a specimen.
Dichotomous
Keys

12. Dichotomous
Keys

13. The user is presented with two choices.
Dichotomous
Keys

14. Dichotomous
Keys

15. As the user makes a choice, they are led to a new branch of the key.
Dichotomous
Keys

16. Dichotomous
Keys

17. In the end, the user is led to the name of the specimen.
Dichotomous
Keys

18. Dichotomous
Keys

19. Constructing a Dichotomous Key
Keys

20. Separate the specimens into two groups based on one characteristic.
Dichotomous
Keys

21. Example:
A deck of playing cards could be separated into black cards and red cards.
Dichotomous
Keys

22. Continue to separate the groups until each specimen has its own set of characteristics.
Dichotomous
Keys

23. Red cards can be separated into hearts / diamonds, then
Example:
Red cards can be separated
into hearts / diamonds, then
picture / number cards then
male / female cards, etc.
Dichotomous
Keys

24. Make the choice a positive one –
for example,
something “is”
instead of “is not.”
Dichotomous
Keys

25. Dichotomous Keys Example: 2a.Black card is a spade…….4
2b.Black card is a club……….5
4a.Spade is a picture card…6
4b.Spade is a number card…7
6a.Picture card is male……….8
6b.Picture card is female…..9
Dichotomous
Keys

26. Start both choices in a pair with the same word.
Dichotomous
Keys

27. Example: Dichotomous Keys 2a.Red card is a heart……….4
2b.Red card is a diamond……5
Dichotomous
Keys

28. Start the next pair with different words.
Dichotomous
Keys

29. Example: Dichotomous Keys 2a.Red card is a heart……….4
2b.Red card is a diamond……5
4a.Heart is picture card…….6
4b.Heart is number card…….7
6a.Picture card is male……….8
6b.Picture card is female……9
Dichotomous
Keys

30. There should be one less step than the total number of
specimens to be
identified.
Dichotomous
Keys

31. Glue Notes here when done
183
Dichotomous Keys notes
184
2/24/15
2/24/15
Practice:
Glue Notes here when done
Application:
Leaf Dichotomous Key
Starter:
What cell structure is used to classify organisms into Domains?
Connection/exit:
Explain what a dichotomous key is used for.