Practice Dichotomous KEY

What is the purpose of a dichotomous key?

• to find a common ancestor
• to show the evolution of organisms
• to show relationships between organisms
• to identify organisms

A dichotomous key for trees is provided. Hikers found a tree that has large brown cones and single sharp needles. What species of tree have the hikers found?

• Juniper
• Pine
• Spruce
• Fir

What step do we always start with when using dichotomous keys?

• 1
• 2
• 3
• 4

When using a dichotomous key to identify organisms, what do we look at?

• physical features
• weather patterns
• environment
• diet

A dichotomous key for insects is given. To what order does an insect with two pairs of scaly wings belong?

• Coleoptera
• Heteroptera
• Diptera
• Lepidoptera

An illustration and a dichotomous key are given. What is the correct classification for this organism?

• Class Insecta
• Order Amblygygi
• Order Araneae
• Order Scorpiones

A table of arachnid and insect characteristics is shown. Which characteristic could be used to distinguish between
arachnids and insects?

• Jointed legs
• Body segments
• Presence of eyes
• Presence of antennae

A student discovers an arachnid without a segmented abdomen, and legs longer than its body. The student uses the dichotomous key below to identify it. Which arachnid has the student found?

• Whip Scorpion

• Wind Scorpion

• Daddy long legs

• Scorpion

A student discovers an arachnid 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

• Daddy Long Legs

• Mite

• Tick

To what order does a two pairs of wings, rigid and leathery and mouth for sucking belong to?

• Diptera

• Lepidoptera

• Heteroptera

• Coleoptera