Dichotomous Key

When using a Dichotomous Key what do you look at?

• Their genes

• Their environment

• Their diet

• Their looks or phenotype

What tool do Taxonomist use to identify an unknown organism?

• Dichotomous Key

• Scientific Name

• Punnet Square

• Binomial Key

What is the purpose of a dichotomous key?

• To find a common ancestor

• To see what organisms eat

• To show the evolution of organisms

• To identify organisms

Which of the following characteristics would be useful in determining the identify of a tree in a dichotomous key?

• It provides shade

• It has a nest

• It has several birds in it

• Its leaves are long and narrow

A student discovers an organism with a segmented abdomen, long legs, and a tail with no stinger.

The student uses the dichotomous key below to identify it.

1. a) Abdomen segmented.............go to 2

b) Abdomen not segmented ......go to 4

2. a) Abdomen with tail....................go to 3

b) Abdomen without tail...............go to 5

3. a) Tail with stinger..........................Scorpion

b) Tail without stinger.....................Whip scorpion

4. a) Legs longer than body.............Daddy Long Legs

b) Legs not longer than body……….Wind scorpion

5. a) Covered with spines .......................Mite

b) Few spines.....................................Tick

• Whip Scorpion

• Mite

• Daddy Long Legs

• Tick

Tags

NGSS.MS-LS4-2

A student discovers an organism with a segmented abdomen, an abdomen without a tail, and is covered with spines.

The student uses the dichotomous key below to identify it.

1. a) Abdomen segmented.............go to 2

b) Abdomen not segmented ......go to 4

2. a) Abdomen with tail....................go to 3

b) Abdomen without tail...............go to 5

3. a) Tail with stinger..........................Scorpion

b) Tail without stinger.....................Whip scorpion

4. a) Legs longer than body.............Daddy Long Legs

b) Legs not longer than body……….Wind scorpion

5. a) Covered with spines .......................Mite

b) Few spines.....................................Tick

• Whip Scorpion

• Mite

• Daddy Long Legs

• Tick

Tags

NGSS.MS-LS4-2

A student discovers an organism with a non-segmented abdomen and legs that are longer than its body.

The student uses the dichotomous key below to identify it.

1. a) Abdomen segmented.............go to 2

b) Abdomen not segmented ......go to 4

2. a) Abdomen with tail....................go to 3

b) Abdomen without tail...............go to 5

3. a) Tail with stinger..........................Scorpion

b) Tail without stinger.....................Whip scorpion

4. a) Legs longer than body.............Daddy Long Legs

b) Legs not longer than body……….Wind scorpion

5. a) Covered with spines .......................Mite

b) Few spines.....................................Tick

• Whip Scorpion

• Mite

• Daddy Long Legs

• Tick

A student discovers an organism with a segmented abdomen, abdomen without a tail, and few spines.

The student uses the dichotomous key below to identify it.

1. a) Abdomen segmented.............go to 2

b) Abdomen not segmented ......go to 4

2. a) Abdomen with tail....................go to 3

b) Abdomen without tail...............go to 5

3. a) Tail with stinger..........................Scorpion

b) Tail without stinger.....................Whip scorpion

4. a) Legs longer than body.............Daddy Long Legs

b) Legs not longer than body……….Wind scorpion

5. a) Covered with spines .......................Mite

b) Few spines.....................................Tick

• Whip Scorpion

• Mite

• Daddy Long Legs

• Tick

What is true about dichotomous keys?

• They tell you what the object or organism is

• It tell you the weather

• It tells you what day it is.

• It tells you what their parents look like

In your own words what is a dichotomous key?