Dichotomous keys for identification
Practice Flashcards
Flip to reveal answersDefine a dichotomous key.
Track your progress — Sign up free to save your progress and get smart review reminders based on spaced repetition.
All 12 Flashcards — Dichotomous keys for identification
Sign up free to track progress and get spaced-repetition review schedules.
Question
Define a dichotomous key.
Answer
An identification tool made of **paired either/or choices** about observable features, each leading to another step or to an organism's **name**.
Question
What does 'dichotomous' mean?
Answer
**Split into two** — every step offers exactly **two** opposite choices.
Question
Where do you always start when using a key?
Answer
At **Step 1** (the top), then follow the matching choices in order.
Question
Define an observable feature.
Answer
A characteristic you can **see or measure** directly — e.g. legs, shell, scales, wings.
Question
What does it mean when an organism 'keys out'?
Answer
The key has reached the point that **names (identifies)** the organism.
Question
How many choices does each step of a dichotomous key give?
Answer
**Two** — a pair of opposite either/or statements.
Question
Why must key choices be opposite and clear?
Answer
So every organism fits **exactly one** side at each step, with **no overlap**.
Question
Why is 'lives in a pond' a poor choice for a key step?
Answer
Habitat is **not a body feature** — a key must use features you can **observe** on the organism.
Question
How should you move through a key at each step?
Answer
Follow **only the choice that matches** your organism, then go to the step or name it points to.
Question
Why is it useful to write down your route through a key (e.g. 1 → 3 → snail)?
Answer
It shows the **correct path** for the marks and helps you **avoid careless slips**.
Question
Should you identify an organism from its name or its features?
Answer
From its **observable features** — follow the key; never guess from the name.
Question
What is a couplet (step) in a key?
Answer
One **numbered pair** of opposite statements; you pick the one that matches the organism.
Read the notes
Full study notes for Dichotomous keys for identification
Topic 1.6 hub
Diversity of organisms
More from Topic 1.6
All flashcards in this topic
Biology exam skills
Paper structures & tips
Track your progress with spaced repetition
Sign up free — Aimnova tells you exactly which cards to review and when, so you remember everything before your IB exam.
Start Free