1. Press the F5 button on the keyboard to start this tutorial

2. Start from the beginning
The Phosphorus Cycle
Start from the beginning
Make it Rain!
The Producers
The Consumers
The Decomposers
The Quiz
The Human Factor

3. Why is Phosphorus Important?
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DNA molecules are made from three smaller molecules:
Sugar
Nitrogen base
???
What is the 3rd molecule of DNA?
Fatty acid
Phosphate group
Mono-saccharide
No. Fatty acids are in lipids.
No. Monosaccharaides are in carbohydrates.
correct

4. Why is Phosphorus Important?
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ATP is a molecule needed by cells for _______. ATP stands for Adenosine Tri________?
Energy
Food
Releasing CO2
Hint: What does the mitochondria create?
Hint: What does the mitochondria create?
correct
prokaryote
Poly-saccharide
phosphate
Which choice looks like “phosphorus?”
Which choice looks like “phosphorus?”
correct

5. Why is Phosphorus Important?
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Which part of a cell is semi-permeable and allows some materials to enter/exit the cell? The cell membrane is made from a double layer of lipids called “phospholipids.” Which element is implied by the prefix “phospho?”
Mito-chondria
Cell membrane
Rough ER
Hint: What does the mitochondria create?
Hint: What does the mitochondria create?
correct
waste
waste
waste
Phosphorus
Potassium
Plutonium
glucose
glucose
Phospho…cmon!
Phospho…cmon!
correct
glucose

6. Why is Phosphorus Important?
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Our cells need phospholipids, DNA, and ATP. They each have phosphorus in them. So where does the phosphorus come from? Phosphorus come from rocks. Rocks are solid lumps of minerals, and some of those minerals are phosphorus. So when rocks crumble and erode, phosphorus is released from the rocks. The weather causes rocks to crumble. Wind, cold, and rain cause dust sized fragments of rocks to chip off, thus releasing phosphorus into the ground

7. Snails don’t have roots.
Make it Rain!
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The weather causes phosphorus to be released from rocks. Click the cloud to make it rain. Small bits of phosphorus are released into the ecosystem due to the weather. Click the cloud to make it stop raining. Now that there is phosphorus in the soil, click on the land organism that can absorb it through their roots. P P P P P P
Snails don’t have roots.
Roots… think roots

8. Decomposers feed on the dead. This plant is alive.
The Producers
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Of course! Plants simply absorb the phosphorus through their roots. Click on the roots to proceed. Now that plants have phosphorus they can use it to make their DNA, ATP, and phospholipids. Click on the herbivore (primary consumer) in the diagram. P P P P P
Decomposers feed on the dead. This plant is alive. P

9. The Consumers
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Of course! The snail is an herbivore so it eats the plant. This is how animals get the phosphorus to make their DNA, ATP, and phospholipids. Phosphorus simply moves up the food chain. Which organism would likely eat snails? P P P
Maybe accidentally, but cows are herbivores too. P P P P P P
Wolves are hunters. I don’t think they would hunt snails.

10. Up the Food Chain
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The snail eats the plant… The frog eats the snail… Which would likely eat the frog? You got it. Phosphorus moves up the food chain.
I’m an herbivore.
I’m an herbivore.

11. The Decomposers
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Like any organism, decomposers make waste. They release their waste into the ecosystem. Some of their waste even contains phosphorus.
This whole thing started with crumbling rocks…remember? Decomposers are organisms such as mushrooms and bacteria. They have DNA, ATP, and phospholipids also, so that means they need phosphorus too. Will decomposers feed on dead plants? You got it. Will they feed on dead snails? We’re almost done.
Examine the picture… if decomposers release phosphorus into the soil, which organism can reuse the phosphorus? P P
I hope you see why it’s called the phosphorus cycle. P
The plants P
yes no
The rocks P P P P P
Rocks aren’t organisms
The snails P
yes no
What do snails eat? P

12. The Quiz
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1. Which molecule does not contain phosphorus? 2. How does phosphorus get into the soil in the first place? 3. Where do herbivores get phosphorus from? 4. Where do carnivores get phosphorus from? 5. Where do decomposers get phosphorus from?
DNA
ATP
Carbohydrate
Phospholipid
From rocks
From decomposers
From consumers
From producers
From rocks
From decomposers
From consumers
From producers
From rocks
From decomposers
From consumers
From producers
From any dead organism
From decomposers only
From consumers only
From producers only

13. The Human Factor Back Home
Sadly, human actions are disrupting the phosphorus cycle. Humans, like this farmer, routinely add extra phosphorus to soil because phosphorus is a fertilizer. What do you think the extra phosphorus does for the farmer’s crops?
No. Weed killer kills weeds.
Kill weeds
Kill bugs
No. Pesticides kill bugs.
Stimulates growth
Yes, exactly! P P P P P P P P P P
So if phosphorus helps crops grow, why is this bad? P

14. Why is this Bad? Back Home
The extra phosphorus is intended to help crops grow better, but often the phosphorus is washed away into rivers, lakes, and ponds when it rains.
Rain Rain Go Away
Make it rain
The extra phosphorus got washed away and is collecting in this pond. Since the phosphorus is a fertilizer, it causes algae in the pond to grow at an extreme rate. These extreme algae growths are called “algal blooms.” As the algae eventually die, the decaying process uses up the oxygen in the pond, thus all the fish die. Once the fish die, so does the rest of the ecosystem. P P P P P P P

15. Wanna go for a swim?
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16. Wanna go for a swim?
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17. Wanna go for a swim?
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18. Is There Any Hope?
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You can help stop this problem. Purchasing organic food supports farmers who do NOT use extra fertilizers.

19. Is There Any Hope?
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You can help stop this problem. Purchasing organic food supports farmers who do NOT use extra fertilizers. Not using fertilizers in your home garden prevents the spread of excess phosphorus.

20. Short Term vs. Long Term
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Plants absorb phosphates from water or soil
Phosphorus is carried by rivers or lakes to the ocean bottom
Phosphorus is stored for long periods of time in sediment and sedimentary rock
Consumers obtain phosphorus by eating plants or eating other consumers
Decomposers break down animal waster and decaying organisms and return phosphates to soil
Stored phosphorus is eventually returned to soil through erosion, weathering, or human construction
The image above illustrates the two cycles of phosphorus Short-term cycle: cycles phosphorus from soil to producers to consumers to decomposers back to soil. Long-term cycle: weathering or erosion of rocks slowly adds phosphorus to soil.

21. The End
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