BIOLOGY 20 INVESTIGATION 5.1
Class investigation

OBSERVE · COMPARE · IDENTIFY

Using a Classification Key

Biology 20 Investigation 5.1

A dichotomous key identifies an organism through pairs of statements. Read both statements, choose the one matching the organism, and follow the next step until a name is reached.

Teeth or baleen?

Toothed whales use teeth to catch prey. Baleen whales have hanging plates with fringed edges that strain food from seawater.

Use visible features as evidence.

Labelled orca diagram: anterior at the head, posterior at the tail, dorsal above, ventral below, mouth at the head, dorsal fin on the back, pectoral fin on the side, tail fin at the rear.
Figure 1 · body structures from the textbook
Begin the investigation ↓

CLASS INVESTIGATION

Seven whales. One key.

Tap photograph to enlarge
Figure 2 · textbook body outline

READ BOTH STATEMENTS

Keyboard: Tab to a control, then Enter or Space. A / B selects a statement; ← / → changes whale; ↑ / ↓ scrolls in fullscreen. Escape closes a panel. Shortcuts pause while typing or viewing a panel.

THINK TOGETHER

Class discussion

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Optional Extension Questions

Independent research and key-building activities.

Figure answer key · contains answers

Figure answer key

Based on Investigation 5.1, “Using a Classification Key,” Nelson Biology Alberta 20–30, pp. 162–163.

Image credits · contains species names

Figure 1 and the seven whale body outlines are extracted directly from Nelson Biology Alberta 20–30, pp. 162–163, from the provided textbook PDF.

Full classification key

Branching classification key

Print / Save PDF
Branching whale classification key. The same complete key is also available through Show Full Key.

Whale features · look closely

Use these views to compare features. Tap any photograph to enlarge.

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