Sea Otters, Urchins & Kelp Forests

These questions are answered using the reading “Sea Otter, Urchins & Kelp Forest” and 3 different on-line sources. Be sure to pay attention to the source before answering each question.

Questions from the reading:

1. Provide at least 3 supported reasons why kelp forests are such important ecosystems.2. Briefly explain the causes of the changes in the sea otter population over time.3. Explain the trend being shown and the difference between the 2 lines on the “Southern sea otter

counts” graph.4. Clearly explain why is the sea otter considered a “keystone species”.5. What is an “urchin barren”, what causes them and what consequences do they have?6. Draw an accurate energy pyramid using at least 4 different species mentioned in the article.

Questions from, “Exploring Ecosystems Coastal Food Webs” https://www.youtube.com/watch?v=LVJ5BKcAhAg

7. At 2:35, pause the video. Draw the following graph accurately in your notebook using a ruler and colored pencils. Predict what you expect to happen between 1920 and 1950 based on what you have read in the lab reading and what you have heard in this video so far.

8. Advance to 2:37 and graph the lines. What change has actually occurred between 1920 and 1950? 9. What do you predict will happen next (1969)?

10. Advance to 2:39 and graph the lines up to 1965.This shows an example of both a direct and an inverse correlation. Which organisms show a direct correlation and what is causing it? Which organisms show an inverse correlation and what is causing it?

11. Advance to years 2000-2016 on the graph, what trend is the graph suggesting? 12. Write a summarizing statement for the entire graph. How are urchins, sea otters and kelp connected?13. Advance to 3:15 Draw the food web as it is. Predict how the complete removal of sea otters will impact

the flow of energy? (Energy arrows are drawn from the food source TO the (stomach of) the consumer.

14. Which species will be negatively impacted? (mark with -) Will any be positively impacted, if so, which ones (mark with +)?

15. “Removal of a keystone species such as sea otters, has cascading effects.” Explain this statement. What was impacted? What was disrupted?

16. Identify the “producers” in your food web, what are they providing for the consumers and where/how did they get it?

17. List types of energy that are being “lost” from the food chain as energy moves from one organism to the next.

18. What materials are being “recycled” as they move from organism to organism through the food chain?