• This assignment is worth a maximum of 12 points.
• Refer to the information below and on the following pages as well as your textbook worksheets to fill out your assignment worksheets for the "Food Web" assignment.
• Because this is an internet-based lab activity, you can complete it anywhere that you have internet access.
• Be sure to complete and turn in this assignment before the Deadline for this assignment. See your syllabus, look on the Deadline page, or ask at the front desk for this date.

Options for turning in your completed assignment:

1. There are worksheets for this assignment linked to the Unit 12 webpage. Turn in your completed assignment worksheets at the front desk in the Biology Learning Center. Don't forget to initial and date the Assignment Check-in Sheet. Your instructor will grade the worksheets and return them in a few days.
or
2. Use the online submission form to submit your answers. Please print a copy for yourself! Your instructor will grade your online submission and email you your graded assignment in a few days.

PRIMARY PRODUCTIVITY AND FOOD WEBS

Oceanographers are interested in understanding primary production and marine food webs for three major reasons. A fundamental understanding of plant and animal interactions within a particular ecosystem is a first order concern. The ecological zones of the ocean (pelagic vs. benthic; coastal vs. open ocean) have distinct ecosystems with characteristic assemblages of organisms that form a rich and dynamic web of life. How these ecosystems respond to natural perturbations, like El Niño events, or to human-made perturbations, like pollution, are important questions. Second, the magnitude of primary production and the efficiency of transfer of energy along the pathways through an ecosystem ultimately determine the magnitude of the fish stocks, which are of great economic importance to people. Third, primary production is one important means of removing CO2 from the atmosphere and storing it in long term reservoirs in the ocean. With the increasingly urgent interest in the greenhouse effect, it is clear that we need a better understanding of the role of the oceans in the CO2 cycle.

OBJECTIVES

This assignment focuses on marine trophic dynamics, with these specific objectives:

• To become familiar with the primary producers and their positions in the food web
• To examine the inter-relationships of organisms in an ecosystem
• To understand the flow of carbon from one trophic level to another
• To evaluate how this carbon flow can be disrupted by humans or nature.

http://dtc.pima.edu/blc/183/
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