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Name: ____________________________________________ Questions 1 through 3 refer to the following: The variety of organisms known as plankton contributes to the unique nutritional relationships in an ocean ecosystem. Phytoplankton include algae and other floating organisms that perform photosynthesis. Plankton that cannot produce food are known as zooplankton. Some nutritional relationships involving these organisms and several others are shown in the table below. 1) Humans are currently overfishing codfish in the North Atlantic. Explain why this could endanger both the shark population and the squid population in this community. 2) According to the table, which organism can be classified as both an herbivore and a carnivore? 3) Complete the food web below by placing the names of the organisms from the table into the correct locations. 2133 ­ 1 ­ Page 2
4) A food web is shown below. State what would happen to the plant population if the number of decomposers decreased and explain why this would happen. 5) The diagram below represents a food web. Select and record the name of one species in the food web, and explain how its removal could affect one of the other species in the food web. 2133 ­ 1 ­ Page 3
6) The food web below shows some of the relationships that exist between organisms in a field and pond ecosystem. (a) Write one or more paragraphs describing some of the relationships in this food web. In your answer be sure to: (1) identify a carnivore from the food web (2) describe the complete path of energy from the Sun to that carnivore (3) explain why decomposers are necessary in this food web (b) A significant decrease in the wolf population occurs. After a period of one year, what change in the grass population would most likely be observed? (c) A farmer sprayed pesticides on a field next to the pond. Using one or more complete sentences, explain why several years later the fish population would contain higher pesticide levels than any other pond organisms would contain. Questions 7 through 9 refer to the following: The food web and graph below represent the interaction of two different populations, A and B, in the food web. 7) In the given food web, population A is made up of living animals. The members of population B feed on these living animals. The members of population B are most likely A) autotrophs 8) B) predators C) parasites Identify one heterotroph from the given food web that could be a member of population A. D) scavengers 2133 ­ 1 ­ Page 4
9) An energy pyramid is shown below. Identify one organism shown in the food web that would be found at level X. Questions 10 through 12 refer to the following: The diagram below shows a food web. 10) What is the original source of energy for this food web? A) enzymatic reactions B) the Sun 11) Which organisms are not shown in this diagram but are essential to a balanced ecosystem? A) producers 12) C) chemical bonds in sugar molecules D) chemical reactions of bacteria B) decomposers C) autotrophs D) heterotrophs State one example of a predator­prey relationship found in the food web. Indicate which organism is the predator and which is the prey. 2133 ­ 1 ­ Page 5
Questions 13 through 15 refer to the following: 13) A pesticide is sprayed to kill the crickets. State one effect this spraying might have on the food web. 14) What is the significance of the arrow between the trees and the deer in the food web? 15) State the role of the decomposers in the food web.