1. You will understand how to use dichotomous keys
Objectives:
You will be able to demonstrate your understanding of classification with a dichotomous key.
You will understand how to use dichotomous keys
You will create your OWN dichotomous key

2. Question:
Why do we classify things (like at the shoe store or the grocery store)?
To make things easier!

3. Question:
Why do scientists classify things?
TO MAKE THINGS EASIER

4. Dichotomous Key
What is it? A system used by scientists to CLASSIFY unknown organisms.
How does it work? First you must examine the characteristics of an organism and then determine to which group that unknown organism should be placed based upon those characteristics.

5. 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”

6. Look at these Pictures

7. What do they have in
Common?

9. Dichotomous Key of Transportation Vehicles
Vehicles with wheels:

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

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

12. 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

13. 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:

14. 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

15. What are These?

16. Animals

17. Dichotomous Key of Animals
Animals with 4 legs

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

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

20. 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

21. 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:

22. 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

23. 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