Dichotomous Key Lesson

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

Which of the following characteristics will most likely be helpful in identifying a butterfly using a dichotomous key?

• Migrates north every spring
• hangs on branches
• flutters wings fast on hot days
• Wings have long extensions

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

• Coleoptera
• Heteroptera
• Diptera
• Lepidoptera

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. Which arachnid has the student found?

• Whip Scorpion
• Wind Scorpion
• Daddy long legs
• Scorpion

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

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

Tags

NGSS.MS-LS4-2

A labeled diagram of a fiddler crab is provided. Which of the following is an accurate observation of the structures of a fiddler crab? Fiddler crabs have -

• five pairs of walking legs on each side.
• an enlarged propodus on both front legs.
• a pair of eyes on stalks at the top of the body.
• two pairs or chelipeds for a total of four.

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

Tags

NGSS.MS-LS4-2

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

• 1
• 2
• 3
• 4

A botanist discovers a new plant in the jungle. Which of the
following observations of the plant’s characteristics would be useful in determining its identity with a dichotomous key?

• It was discovered in the summertime
• It is wet from a recent rain storm.
• Its leaves curl up on the edges.
• It is eaten by native jungle ants.

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

• physical features
• weather patterns
• environment
• diet