Name KEY Period Date Food Web Review The flow of matter and energy in an ecosystem is the result of predator-prey relationships. These relationships establish a long chain of events. They always begin with a producer and end with s. grass grasshopper frog snake eagle producer herbivore omnivore first carnivore top carnivore producer primary secondary teriary quaternary 1. Put the following 10 labels in the correct spaces above: herbivore top carnivore omnivore producer first carnivore tertiary quaternary primary secondary producer 2. At each level in this food chain, energy is lost. Approximately 90% of the energy consumed by the grasshopper is used in its day-to-day metabolism, and only 10% can be passed on to the frog that eats it. Fill in the chart below with the units of energy available to each organism if the grass begins with 1000 units of energy. grass grasshopper frog snake eagle 1000 units 100 10 1 1/10 =.1 3. Food chains rarely go beyond 5 trophic levels. Using energy in your answer, explain WHY.
4. Complete each of the following food chains with an appropriate animal: a. In a wood lot: Leaves Worm b. In a pond: Algae Insect c. In a forest: Grass Rabbit Bird Frog Bobcat 5. Consider a food chain that is common in Ontario: sapling deer wolf a. If the deer population increases, what will happen to the sapling population? Decreases b. If the deer population increases, what will happen to the wolf population? Increases c. The resulting changes in the sapling and wolf population (a & b) will cause a new change in the number of deer. What happens to the deer population as a result? Decreases because less food Decreases because eaten d. As a result of the change in (c) what will now happen to the sapling population? Sapling increases because fewer deer eating it e. As a result of the change in (c) what will now happen to the wolf population? Wolf decreases because fewer deer 6. One important organism omitted from our food chain and food web is the decomposer. a. What is the role of a decomposer? Break down dead matter into smaller parts molecules back into atoms b. Why are decomposers important? They make the needed nutrients for plants/producers to grow
7. The area of Ontario in which this food chain occurs contains other organisms such as grass, mice, rabbits, hawks, frogs, snakes, and insects. We can connect all these animals together in a food web: The food web represents a more realistic situation. In the above food chain; a. What are the two foods that the deer eats? Sapling & grass b. What does the wolf feed on? Mouse, deer, & rabbit c. Why is it advantageous for the deer and the wolf to have more than one food source? If something happens to one food source, the wolf has something else it can eat d. Are there any omnivores in the above food web? If so, name them. Not according to the web e. The above food web contains 16 food chains. Identify 4 of these chains: grass rabbit hawk sapling deer wolf sapling mouse snake hawk grass insect snake hawk f. If the number of rabbits were to increase, what would happen to each of the following populations: I. grass (increase or decrease) II. hawks (increase or decrease) g. Will the changes in (f) have any effect on the number of mice in the area? EXPLAIN. Number of mice will decrease as hawks increase
8. Consider the food chain pictured below: a. Identify all the producers. Star grass, red oat grass, acacia b. Construct a food chain that has four (4) trophic levels. star grass harvester ant aardvarl hyena c. Identify three (3) herbivores. Grasshopper, harvester ant, Topi, hare, warthog, impala, Thompson s gazelle d. Identify three (3) secondary s. Aardvark, pangolin, Mongoose e. Identify all omnivores (if there are any). Wildebeast (grasshopper assuming the line goes to him without an arrow + red oat) 9. List all the organisms that are affected if a disease dramatically reduces the hare population. Star grass and red oat grass not consumed; Tawny eagle, Serval, Cheetah, Wild dog, Lion, Caracal lose a food source a. Describe what might happen to the producers you listed. Star grass and red oat increase in population b. Describe what might happen to the top level carnivores you listed. Could decrease in population, start overeating other species!
10. Draw a food web for the following ecosystems. Label each organism as one of the following: Producers (first trophic level) Primary s (second trophic level) Secondary s (third trophic level) Tertiary s (fourth trophic level) a. In a pond, floating plants are found on the surface and phytoplankton (algae) are found just below the surface. The floating plants serve as food for muskrats, which are eaten by snapping turtles. The phytoplankton is food for both tadpoles and minnows in the pond. Both the tadpoles and minnows are eaten by the Kingfisher bird. Snapping turtles also eat the tadpoles. b. In a forest ecosystem, land plants act as producers and provide food for mice, bears, insects, and grouse (a bird). The mice, in turn, are eaten by hawks and snakes. The insects are eaten by both grouse and spiders. The grouse are eaten by foxes. Black bears in the area feed on plants and fish. The fish eat crayfish in the streams, while the crayfish eat microscopic plants in the water.