Activity 85: Is There Room for One More?

1. Activity 85: Is There Room for One More?

2. Activity85:Is There Room for One More? • Challenge What is carrying capacity? Key Vocabulary: • Carrying capacity • Fluctuation • Population

3. Getting Started… • What factors might affect the amount of room available for a species in an ecosystem? • Read the Introduction on page E-70.

4. Lets Define Carrying Capacity: • Carrying Capacity is the maximum population of a species that can be supported by its environment.

5. Stopping to Think 1 (E-71) • A. What is happening to the quantity of plankton at point A? • There must be enough plankton to feed the growing population of zebra mussels. If the plankton population was insufficient, the mussel population could not be able to grow. • B. What is happening to the quantity of plankton at point B? • A lack of sufficient food could be the factor preventing the mussel population from increasing beyond that level

6. Stopping to Think 2 (E-71) • A. What is the carrying capacity of ZM in Lake Ness? How did you determine this? • The carrying capacity is approximately 2000 organisms per square meter. • This is obtained by sketching an imaginary line from the plateau of the curve, parallel to the x-axis, until it intersects with the y-axes • B. List some factors that might affect this carrying capacity. • Oxygen availability • Nutrient and food availability • Competition for resources • Predation • Sunlight • Other environmental factors

7. Stopping to Think 3 (E-72) • A. CC of ZM between years 13-25? • About 1000 mussels per square meter • B. 3 NON-Livingfactors with an explanation. • Human pollution, change in temperature, pH, wind or precipitation • C. 3 Living factors with an explanation. • Decline in food, introduction of a ZM predator, increase in a population of competing species or new competing apecies • D. Do you think the ZM population will return to what it was between years 5-10? Explain!

8. Stopping to Think 4 (E-73) • Is this a good experiment to test the hypothesis that the factory was affecting the zebra mussel population? Why or why not? • This experiment does not resolve the question of whether the factory is responsible for the change in the carrying capacity of the ZM. • It does provide information about whether the factory has affected the quality of the water in a way that will directly affect the growth of the mussels.

9. Analysis # 1-3 (E- 73) • Complete Analysis Q 1 • For full credit: • Answer all three parts. (a, b, c) • Use numbers of owls and years. • Explain your thinking for parts b and c. • Complete Question 2: Anticipation Guide: # 9 and 10 in the after column. • Question 3 refers to the “Miracle Fish” Activity 72!

10. Question1 • For the first 7-8 years, the owl population increased. Then population leveled off and stayed about the same for a period of at least five years around Year 10. At that time, the carrying capacity was almost 25 owls. But then the population decreased. The carrying capacity went down to about 10 owls. This is where the population stayed between years 30 and 40. • The change could have been a predator appeared on the scene or that the population of the voles and mice the owls feed on was reduced by drought, fire, habitat loss, or other factors. Or a new species could’ve been introduced and competed with the owl for food. Or maybe a change in temperature, pollution, or rainfall made it difficult for the owls to survive.

11. Question 3 • You can’t determine carrying capacity with this graph because the graph doesn’t provide information about the total population of Nile perch in the lake. • Instead it provides information about the number of Nile perch caught. • One could assume that the population was continuing to increase. However, it is difficult to know if the increase in the number of Nile Perch caught is due to better fishing techniques or to an increase in the population. • Additional information would be necessary to determine the reason or combination of reasons.