Dichotomous Keys

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

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

Tags

NGSS.MS-LS4-2

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

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

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 of the following is an accurate description of the fiddler crab?

• 3 Paris of walking legs on both sides

• Two propodus

• 3 Chelipeds

• A pair of eyes

Tags

NGSS.MS-LS4-2

In a dichotomous key, organisms should be classified based on their

• diet

• habitat

• observable features

• sounds they make