Dichotomous

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

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

• Coleoptera

• Heteroptera

• Diptera

• Lepidoptera

The primary purpose of a dichotomous key in biology: (a)   . When using a dichotomous key to identify organisms, we look at: ​ (b)  

• To predict the evolutionary future

• A step-by-step way to identify organisms

• To classify organisms based on genetics

• To determine the age of fossils

• physical features

• genetics

• habitat and population

• fossils

Use the dichotomous key to identify Bird X?

• Certhidea

• Geospiza

• Camarhynchus

• Platyspiza

Tags

NGSS.MS-LS4-2

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

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

• Class Insecta

• Order Amblygygi

• Order Araneae

• Order Scorpiones

This is a good example of a:

• Binomial Nomenclature

• Field Guide

• Dichotomous Key

How many options should every branch in a dichotomous key have?

• 1

• 2

• 3

• 4