Question

1. the tendency of an ecosystem to return to a certain state after a disturbance is called (1) diversity (2) resistance (3) stability (4) sterility 8. as a result of human activities that have occurred over the last 50 years, biodiversity has generally (1) increased (2) decreased (3) remained constant (4) fallen to zero 9. which ecosystem has a better chance of surviving when environmental conditions change over a long period of time? (1) one with a high level of biodiversity (2) one with animals and bacteria but no plants (3) one with plants and animals but no bacteria (4) one with very little biodiversity unlike a desert, a tropical rain forest typically has (1) low biodiversity (2) high biodiversity (3) a small variety of organisms (4) a small number of organisms 10. in a certain ecosystem, rattlesnakes are predators of prairie dogs. if the prairie dog population started to increase, how would the ecosystem most likely regain stability? (1) the rattlesnake population would start to decrease. (2) the prairie dog population would increase rapidly. (3) the rattlesnake population would start to increase. (4) the prairie dog population would begin to prey on the rattlesnakes. 11. which statement concerning ecosystems is correct? (1) stable ecosystems that are changed by a natural disaster will slowly recover and may become stable again. (2) an ecosystem that is high in biodiversity is unlikely to recover from a natural disaster that changes the ecosystem. (3) a decrease in biodiversity will make an ecosystem more likely to recover from a natural disaster. (4) stable ecosystems that are changed by a natural disaster are unlikely to recover or become stable again. base your answers to questions 12 and 13 on the information in the table below, which lists events that occurred in four different ecosystems. | ecosystem | ecological events | |---|---| | a | a severe ice storm occurs during the winter, damaging trees and shrubs. | | b | a drought causes most of the leaves to fall from the trees during a single summer. | | c | a volcanic eruption on a small island covers most of the island with lava. the lava then cools and hardens into rock. | | d | a fire burns through a large grassy area, destroying most of the plant life in the area. | 12. which ecosystem would probably require the most time for succession to restore it to its previous condition? (1) ecosystem a (2) ecosystem b (3) ecosystem c (4) 13. which ecosystem would probably the least time for succession to restore it to its previous condition? (1) ecosystem a (2) ecosystem b (3) ecosystem c (4)

Explanation:

• Question 7: Ecosystem stability refers to the tendency to return to a certain state after a disturbance.
• Question 8: Human activities over the last 50 years have generally decreased biodiversity.
• Question 9: Ecosystems with high - level biodiversity have a better chance of surviving environmental changes.
• Question 10: If prairie dog predators increase, rattlesnake population (predators of prairie dogs) would decrease to regain ecosystem stability.
• Question 11: Stable ecosystems changed by natural disasters will slowly recover and may become stable again.
• Question 12: A volcanic eruption (ecosystem C) covers the area with lava and hardens into rock, requiring the most time for succession to restore.
• Question 13: A drought causing leaves to fall (ecosystem B) is a less severe disturbance and would probably require the least time for succession to restore.

Answer:

1. (3) stability
2. (2) decreased
3. (1) one with a high level of biodiversity
4. (1) The rattlesnake population would start to decrease.
5. (1) Stable ecosystems that are changed by a natural disaster will slowly recover and may become stable again.
6. (3) ecosystem C
7. (2) ecosystem B