Using a 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

Using this dichotomous key, identity the name of the circled fish.

• band-tail puffer
• spotted goat fish
• peacock flounder
• trumpet fish

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

Tags

NGSS.MS-LS4-2

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.

Which leaf is shown in the drawing?

• Magnolia

• Redbud

• Sweetgum

• None of the above

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

• physical features
• weather patterns
• environment
• diet