Where are Plants Getting Food From?

Part 1: Revising Initial Models

How did the lettuce get the food molecules that we then eat?

Lettuce grows in the ground, and we eat its leaves. We have collected a lot of evidence about where plants get their food molecules and are updating a model to demonstrate how all the evidence fits together. Answer the following questions to explain how your revised model shows how plants get food molecules.

Use your most updated model in your notebook to explain what is happening in the lettuce leaves. Be sure to identify inputs and outputs and any changes if there are any.

Construct a scientific explanation for how inputs enter the leaf. Be sure to identify all necessary inputs in your response.

Construct a scientific explanation for how a leaf uses the inputs to produce different outputs. Be sure to explain where in the leaf this happens and identify all the inputs and outputs.

Choose one of the input variables. Explain what would happen to the outputs if you increased or decreased that input variable.

Part 2: Argue from Evidence: A New Scenario

This is an actual headline from a newspaper:

"Living in a box: Scientist to spend 48 hours in an airtight container with 160 plants to keep him alive."

The scientist survived! And he set up an experiment where he collected data before and during the time he was spending the 48 hours in the container. Throughout the study, the scientist kept the lights on and measured carbon dioxide, oxygen, and humidity (water in the air). Here we will look at three sets of data from this experiment.

Make a claim that answers the question: Why was the scientist able to survive in an airtight (closed) space with plants? Keep in mind that he brought with him all the food and water he needed and did not eat any of the plants.

Justify your claim by using evidence from the graphs above. Then, state your reasoning for why your evidence supports your claim.