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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

Why is Phosphorus Important? Back Home 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

Why is Phosphorus Important? Back Home 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

Why is Phosphorus Important? Back Home 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

Why is Phosphorus Important? Back Home 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

Snails don’t have roots. Make it Rain! Back Home 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

Decomposers feed on the dead. This plant is alive. The Producers Back Home 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

The Consumers Back Home 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.

Up the Food Chain Back Home P P P 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.

The Decomposers Back Home 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

The Quiz Back Home 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

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

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

Wanna go for a swim? Back Home

Wanna go for a swim? Back Home

Wanna go for a swim? Back Home

Is There Any Hope? Back Home You can help stop this problem. Purchasing organic food supports farmers who do NOT use extra fertilizers.

Is There Any Hope? Back Home 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.

Short Term vs. Long Term Back Home 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.

The End Back Home