INVESTIGATION : What Is an Ecosystem?

Transcription

1 1 INVESTIGATION : What Is an Ecosystem? OBJECTIVES: To view an ecosystem as a unit To identify the relationships of the components of an ecosystem To understand the pyramid of energy ANALYSIS OF AN ECOSYSTEM Procedure and Observations By now, you may be familiar with the structural adaptations and the nutritional requirements of many plants and animals. You may also be familiar with many cycles that occur between living and nonliving things. How do all of these factors fit together in an ecosystem? Below is a diagram of an ecosystem.

2 2 (a) Look up the following and give one example for each where possible. For each example include a sketch of what it looks like and describe its niche: i) Duckweed ii) Plankton iii) Diatoms iv) Copepods v) Algae vi) Flatworms vii) Roundworms viii) Protozoans ix) Water Strider

3 3 (b) How many populations are represented? (circle your answer) over 30 (c) Name the components of the physical environment (abiotic environment) you can identify in the figure. Draw a line from the diatoms to the copepods to the sticklebacks to the duck, and to the hawk. (d) What is the relationship between these organisms? This represents a food chain. Now, draw a line connecting the diatoms to their source of energy. (e) What is it? (f) What might happen to the hawk to show that a cycle of matter exists in the ecosystem? (g) In this food chain, which organism is considered the producer? Write the name of the organism at the base of the pyramid (SEE THE NEXT PAGE). Then, fill in the remaining layers of this pyramid with the organisms in this particular food chain. The total amount of a particular community is called the biomass. (h) (i) Which level of this pyramid represents the greatest biomass? Which level represents the least biomass?

4 4 This pyramid would indicate that the total weight of the diatoms would be more than the total weight of the hawks in the ecosystem. However, this may not actually be the case. Let's find out why! Draw a line from the water lilies to the snails to the bass, to the raccoon, to the hawk. (j) (k) This series of connections represents another What is the link between these two food chains you have drawn? (1) If we were to construct another food pyramid, then, what would be at the bottom? (m) at the top? The hawk, then, is dependent upon more than one producer. The pyramid is also called a "pyramid of energy." (n) Why is this also a good term? Now, draw other lines connecting organisms by nutritional relationships. (o) Are there many overlappings of relationships indicated? This is called a food web. (p) In the ecosystem, what happens to the wastes and dead organisms?

5 5 (q) Name the scavengers in the figure of the ecosystem. (r) What is their role in the ecosystem? Summary (a) A food chain involves energy transfer. Does energy cycle? Explain. (b) The sun is actually the base that supports the pyramid of energy. Explain this statement. Test your understanding of the concepts learned by matching the words in column A to the statements in column B. You may use the words more than once, or not at all. See the next page

6 6 COLUMN A 1. decomposer 2. ecosystem 3. food chain 4. food web 5. physical environment 6. population 7. pyramid of energy 8. scavengers 9. sun COLUMN B (c) beginning source of energy (d) water-lilies to snails to ducks (e) represented by the drawing of the lake (f) food chains have many interconnecting links (g) live off energy of dead or decaying organisms (h) all the snails in the lake (i) carnivore communities possess less energy than the producer communities (j) return minerals to the ecosystem (k) water, light, temperature, sand, rocks