Biodiversity Loss Is a Rate Argument

Lab Brief #5

🎯 Your mission

Set it up. Test it. Be amazed.

⚡ The twist

Living things break the rules of non-living things — find the rule they break.

What you'll learn

Extinction is normal: the background rate over geological time is roughly one species per million species per year. Current rates are estimated at tens to hundreds of times that figure, driven mainly by habitat loss and fragmentation rather than by direct hunting. The scientific argument for concern is therefore not that species are disappearing at all, but that they are disappearing far faster than speciation can replace them.

Key words

background extinction rate
The long-term normal rate of extinction, about one species per million species per year.
habitat fragmentation
The breaking of a continuous habitat into isolated patches, which is the main current driver of extinction.

Make a hypothesis first

Predict: what will happen to the plant if you change the water?

Say your guess out loud — then find out if you were right.

Get ready

🧰 What you need

large paper sheet
scissors
ruler
species-area data table

⚠️ Safety first

Use scissors carefully and cut away from your fingers.

Step 1 of 4 · Read

Think about what you just learned: say what "background extinction rate" and "habitat fragmentation" mean in your own words before you start.

Step 2 of 4 · Do

Cut a large paper 'habitat' into progressively smaller isolated patches and calculate the edge-to-area ratio at each stage. Use a species-area data table to estimate how many species each fragmented arrangement could support.

Step 3 of 4 · Observe

Record what actually happened, including anything that did not match what you expected.

Step 4 of 4 · Record

Write a conclusion that answers the question this lesson opened with, and state your uncertainty.

Question 1 of 3

The background extinction rate is roughly:

How sure are you?😐 maybe

Question 2 of 3

The main current driver of extinction is:

How sure are you?😐 maybe

Question 3 of 3

The concern about current extinction is best stated as a problem of:

How sure are you?😐 maybe

Mind = blown

🦠 You have more bacterial cells in your body than human cells.

Nice work!

You got 0 of 3 right.

All lessons

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✨ More to explore

🌍 Where you see this in real life: This is why plants grow toward windows and why scabs form.

🏆 Stretch challenge (try it this week): Watch a plant or pet for 5 minutes today and write down what you noticed.

👨‍👩‍👧 For the dinner table: “Tell me something you noticed about your own body today.”

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Biodiversity Loss Is a Rate Argument

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