Web of Life Unit Assessment

The image above is a simple model of how energy flows through a dinosaur food chain. The arrows represent energy moving through the food chain. Use this model to answer Questions 1 & 2.

1. Scientists think that Tyrannosaurus rex was able to run at a speed of 12 miles per hour. Where did T. rex get the energy that it used to run when it was alive?

• T. rex got its energy from Triceratops. That energy is not connected to the Sun.

• T. rex got its energy from green plants, which got their energy from the Sun.

• T. rex got its energy from eating Triceratops. Triceratops ate green plants and green plants got their energy from the Sun.

• T. rex got its energy directly from the Sun.

2. Scientists think that the dinosaurs went extinct because an asteroid hit the Earth and created a giant dust cloud that covered up the Sun. Diego doesn’t think this explanation makes sense. He says, “Some dinosaurs ate other dinosaurs to get their energy. Why would removing the Sun cause the carnivores to go extinct?” Explain to Diego why carnivores would go extinct without the Sun. You can use evidence from the energy model above.

The images above show organisms that are part of a forest ecosystem. Use these images to answer Questions 3, 4, and 5.

3. Connect the organisms of the forest ecosystem with arrows to create food chains. Each arrow should point in the direction of how material (matter) travels in each food chain. For example, a squirrel eats acorns from an oak tree, so you would draw an arrow from the oak tree to the squirrel.

4. Scientists are worried that a disease that kills oak trees will spread into this forest. What would happen to this ecosystem if all the oak trees suddenly disappear? Choose all correct answers.

• If there aren’t any oak trees, the squirrels will not have anything to eat. They will need to find another food source or they will not survive.

• If there aren’t any oak trees, the robins will not have anything to eat. They will need to find another food source or they will not survive.

• If there aren’t any oak trees, the hawks may not have anything to eat because the squirrels and robins may not survive.

5. Amir released some pet frogs into the forest ecosystem shown above. These frogs eat earthworms and crickets. Hawks, robins, and squirrels do NOT eat these frogs. What will happen to this ecosystem if the frogs start living here? Choose all correct answers.

• The dead leaves will pile up because the frogs will eat all the decomposers. The decomposers will not be there to eat the leaves.

• The squirrels will not have anything to eat. They will need to find another food source or they will not survive.

• The robins will not have anything to eat. They will need to find another food source or they will not survive.

• The hawks will not have anything to eat. They will need to find another food source or they will not survive.

6. Ana wants to open a plant store, but she’s worried that it will cost too much money. Ana thinks that as plants grow, they use the material from the soil to get bigger. Potting soil costs a lot of money. Ana is worried she will need to buy a lot of soil to feed her plants. She decides to set up an experiment. Ana grows one plant in a pot for 3 weeks. She weighs the plant and the soil at the start and end of the experiment. The results of Ana’s experiment are shown to the right. What did Ana find out with her experiment? Select TRUE or FALSE for each of the sentences below.

The plant weighed the same at the start and end of the experiment.

• True
• False

The plant weighed more at the end of the experiment..

• True
• False

The soil weighed the same at the start and end of the experiment.

• True
• False

The soil weighed less at the end of the experiment.

• True
• False

Ana decides to do another experiment. She starts with two plants, Plant A and Plant B. Each plant weighs 300 grams. She attaches Plant A to a vacuum. The vacuum pumps all of the air out of the container around Plant A. Plant B is not attached to a vacuum, so it has air around it. Ana gives Plant A and Plant B the exact same amount of water. She runs the experiment for 3 weeks and then weighs the plants at the end of the experiment.

8. Looking at Ana’s experiments, what is a claim that you can make about plants and their growth?

• Plants mostly use materials from the soil for their growth.

• Plants mostly use materials from water for their growth.

• Plants mostly use materials from sunlight for their growth.

• Plants mostly use materials from the air for their growth.