Score Level 1 Anchor Paper

There is evidence in this response that the student has some understanding of the question. The student interprets information from the graph (if the algae population goes up than the snail population goes up), but does not identify the ecological role of the snails and algae. The trophic level that each species occupies is not identified, but the student suggests this concept (snails need algae to survive). The student uses minimally effective details to explain how both populations would be affected by a landfill and interprets some relevant information from the graph (environment…there would be less and less snails; algae population is more than the snail population; as the algae increases rapidly, the snail population increases as much, but not as much as the algae).

Score Level 1 Anchor Paper

There is evidence in this response that the student has some understanding of the question. The student interprets information from the graph (when the algae population grows, the snail population grows). While the ecological role and trophic levels of the organisms are not identified, the student does make a relevant statement (because of the snails feeding off the algae) that helps to explain the relationship between the two species. The student addresses an ecological factor that may affect the population size of the two species (if the algae stops growing because of an environmental change, snail population will decrease because there is not enough algae to supply them food). The student also attempts to address how both populations would be affected by a landfill (more garbage to create bacteria which creates algae for the snails to feed on which would increase both populations of the snail and algae). The supporting details are only minimally effective.

Score Level 2 Anchor Paper

There is evidence in this response that the student has a basic understanding of the question. The ecological roles of the two species are identified (algae produce and the snails consume). Ecological factors are listed (weather, seasons, and other consumers) that may affect population size. (If the weather is to harsh they die or if they are all consumed they all die.) The student also attempts to address how both populations would be affected by a landfill (snails would most likely die…not being able to move or breath; algae would probably stay the same). The supporting details are adequate.

Score Level 2 Anchor Paper

There is evidence in this response that the student has a basic understanding of the question. The student interprets data from the graph (when there is more algae there are more snails). An ecological factor (sunlight) is identified, and the effect on the population sizes of the two species is addressed (the more algae that grows means that the snail population will increase). The student understands that algae gets its energy from sunlight, a concept relevant to both ecological role and trophic level. The student addresses how both populations would be affected by a landfill (polluted; kill the snails which means the algae would overcrowd the surface of the lake because there would be no snails to eat it). The overall supporting details are adequate.

Score Level 2 Anchor Paper

There is evidence in this response that the student has a basic understanding of the question. The student addresses the ecological roles (algae produces food from energy given by the sun; snails consume the algae for energy). Trophic levels for each species are identified (algae is at the lowest trophic level being a producer; snail is just above in the next trophic level to eat the algae but be eaten by bigger predators). An ecological factor is identified (snail predators), and its effect on population size is explained (if more snails were eaten then their population would decrease allowing the algae's population to increase). The last part of the question is not addressed, but the supporting details are adequate overall. More support would be needed for a higher score.

Score Level 3 Anchor Paper

There is evidence in this response that the student has a good understanding of the question. The student identifies the ecological role and trophic level of algae (autrophic producer; the 1^st trophic level of producers) and the snail (consumer; the 2^nd trophic level of herbivores). The discussion of ecological factors shows some synthesis (population size of these two species was mainly affected in the same way because the snails rely on algae for food; the algae population decreased, the snail population decreased along with it because the snail relies of the algae to produce energy as a food source). Several ecological factors are identified (amount of sunlight received, temperature, and habitat), but only sunlight is briefly explained (if the amount of sunlight received went down, for example, the snail would have less algae to consume). The student addresses how both populations would be affected by a landfill (both…would dramatically decrease…because some of the algae may get covered up and be unable to reach sunlight). The use of accurate scientific terminology (producers; consumer; herbivores) strengthens the response.

Score Level 3 Anchor Paper

There is evidence in this response that the student has a good understanding of the question. The student identifies and explains the ecological roles of the snail (consumer; can not produce their own food and must therefore feed on others) and the algae (producers; produce their own food by photosynthesis and others feed off of them), showing some synthesis of information. The trophic level that each species occupies is identified (primary consumer; herbivore; producer). Two ecological factors (sunlight; temperature) are given, and their effects on population sizes (algae cannot grow; snails will go down; algae could freeze; no food for the snails) are explained. The student addresses how both populations would be affected by a landfill (contaminate the water and kill off the algae; the snails would be soon to follow). The supporting details are generally complete throughout. The use of accurate scientific terminology (producer-consumer; photosynthesis; herbivore) strengthens the response.

Score Level 4 Anchor Paper

There is evidence in this response that the student has a full and complete understanding of the question. Pertinent and complete supporting details demonstrate an integration of ideas throughout the response. The ecological roles are identified (producer consumer) and explained (algae goes through photosynthesis, and can make its own food; passes its energy onto the herbivores who eat it; the snails…will get eaten by the carnivores). The identification of trophic levels includes a definition of "ecosystem" and an explanation of how the organisms in the different trophic levels interact. Complete details on how energy is transferred (producers…recieve the most energy; herbivores…receive only 10% of the energy from the producers; carnivores…receive 10% of the energy from the herbivores) are provided. An ecological factor is given (decrease in the carnivores), and its effect is explained (algae will decrease because there are more snails). The effect of a landfill on the population of each species is addressed (algae would decrease…causing the snails to decrease). The use of accurate scientific terminology (producer; consumer; photosynthesis; herbivores; carnivores; food chain) enhances the response. The response reflects a complete synthesis of information.