Question

• a food web shows how energy and nutrients are exchanged between organisms within an ecosystem.
• understanding food webs helps us to track animal movements and determine the impact of both natural and human-made events on specific ecosystems.

activate prior knowledge
in this lesson you will learn about food webs and the role they play in a healthy ecosystem. use the chart below to record what you already know about these topics. after you complete the lesson, use the chart to record new information you learned.

before reading and trying the activities in your textbook, think about the questions below. record what you know about each topic in the what i know column of the chart.

question	what i know	what i learned
why is the sun important in marine ecosystems?
how can humans affect food webs?
why is satellite imagery helpful to understanding food webs?

Explanation:

This is an activation of prior knowledge and post-lesson reflection activity about food webs. The "What I Know" column is for pre-lesson existing understanding, and "What I Learned" is for new information gained after the lesson. Below is a sample completion based on standard ecological knowledge:

1. For "What is a food web?": Pre-lesson knowledge can be a basic definition, while post-lesson adds more detail about energy/nutrient flow.
2. For "Why is the Sun important in marine ecosystems?": Pre-lesson can note it's a energy source, post-lesson specifies its role for producers.
3. For "How can humans affect food webs?": Pre-lesson can list common human actions, post-lesson adds specific ecosystem impacts.
4. For "Why is satellite imagery helpful to understanding food webs?": Pre-lesson can note large-scale observation, post-lesson adds specific monitoring uses.

Answer:

Question	What I Know	What I Learned
Why is the Sun important in marine ecosystems?	It gives energy to ocean life	It fuels phytoplankton (base of marine food webs) via photosynthesis
How can humans affect food webs?	Pollution and overfishing change them	Overfishing removes top predators, causing trophic cascades; pollution kills primary producers, collapsing lower food web levels
Why is satellite imagery helpful to understanding food webs?	It can see large ocean areas	It tracks phytoplankton blooms, monitors habitat changes, and maps animal movement to study food web dynamics