Biology

1. Biology PODs Ecology

2. Scientists found that, over a period of 200 years, a mountain pond was transformed into a meadow. During that time, several communities of organisms were replaced by different communities. Which of these best explains why new communities were able to replace older communities? A The original species became extinct. B Species in the older community died from old age. C The abiotic characteristics of the habitat changed. D Diseases that killed the older organisms disappeared.

3. Answer C The abiotic characteristics of the habitat changed.

4. After a volcanic eruption has covered an area with lava, which of the following is the most likely order of succession in the repopulation of the area? A lichens ?grasses ?shrubs ?trees B mosses ?grasses ?lichens ?trees C grasses ?trees ?mosses ?lichens D shrubs ?grasses ?trees ?lichens

5. Answer A lichens ?grasses ?shrubs ?trees

6. When the Mount St. Helens volcano erupted, the blast covered much of the surrounding area with ash. Based on the diagram above, which list shows the sequence of secondary succession that followed that eruption? A X, Y, Z, W B Z, X, Y, W C W, Y, X, Z D Z, Y, W, X

7. Answer B Z, X, Y, W

8. In a pond, the primary producer is a green alga, Spirogyra; the primary consumer is the crustacean, Daphnia; the secondary consumer is a small fish, the bluegill; and the tertiary consumer is a larger fish, the smallmouth bass. What changes can be expected in the pond if the Daphnia are killed with pesticides? A The Spirogyra population will probably die. B The bluegill population will probably increase. C The Daphnia population will eat something else. D The smallmouth bass population will die.

9. Answer D The smallmouth bass population will die.

10. For the food chain shown, which of the following changes would have the most severe consequences? A) a drastic decrease in rainfall, causing drought B) the poaching of predatory hawks by game hunters C) the introduction of a second predator that eats field mice D) a parasitic infestation that reduces the cricket population

11. Rabbits introduced into Australia over 100 years ago have become a serious pest to farmers. Rabbit populations increased so much that they displaced many native species of plant eaters. What is the most logical explanation for their increased numbers? A Rabbits have a high death rate. B There are few effective predators. C Additional rabbit species have been introduced. D There is an increase in rabbit competitors.

12. Answer B There are few effective predators.

13. The graph shows the birth rate and death rate for a population during the 1900s. From 1900 to 2000, the population has A increased. B decreased. C stayed the same. D increased until 1930, then decreased.

14. Answer A increased.

15. Complete burning of plant material returns carbon primarily to the A herbivores. B water. C vegetation. D atmosphere.

16. Answer D atmosphere.

17. Which of these organisms are most helpful in preventing Earth from being covered with the bodies of dead organisms? A herbivores B producers C parasites and viruses D fungi and bacteria

18. Answer D fungi and bacteria

19. Which of these organisms would most likely be found at the top of an energy pyramid? A clams B sardines C sharks D kelp

20. Answer C sharks

21. Which of these organisms would most likely be found at the bottom of a biomass pyramid? A giant squids B sand sharks C sea cucumbers D green algae

22. Answer D green algae

23. Thrips are insects that feed on the pollen and flowers of certain plants. The size of a thrip population depends on the number of flowers available. Which graph best represents changes in a population of thrips if winter was longer than usual and the summer was too cool and dry for many flowers to bloom?

24. Answer

25. Which phrase is an example of autotrophic nutrition? (1) a cow eating grass in a field (2) a mushroom digesting a dead log (3) an apple tree making its own food (4) a tapeworm feeding in the body of a dog

26. Answer (3) an apple tree making its own food

27. By studying the chemicals in rare plants that grow only in rain forests, scientists hope to discover new life-saving medicines. Chances of finding such new medicines are reduced by (1) predation by carnivores (2) homeostasis in organisms (3) recycling of materials in food webs (4) loss of species due to human activities

28. Answer (4) loss of species due to human activities

30. Answer (2) ecological succession

31. Which process initially provides the link between an abiotic factor and the energy needs of an entire ecosystem? (1) respiration (3) decomposition (2) photosynthesis (4) predation

32. Answer (2) photosynthesis

33. Which organisms directly help to reduce overpopulation in a deer herd? (1) parasites and predators (2) parasites and scavengers (3) decomposers and predators (4) decomposers and consumers

34. Answer (1) parasites and predators

35. Depletion of nonrenewable resources is often a result of (1) environmental laws (2) human population growth (3) reforestation (4) recycling

36. Answer (2) human population growth

37. Competition for biotic resources can be illustrated by organisms fighting for a limited amount of (1) air to breathe (3) mates for breeding (2) water to drink (4) space for nesting

38. Answer (3) mates for breeding

39. A diagram frequently used in ecological studies is shown This diagram can be used to represent the (1) dependency of animal survival on physical conditions in an ecosystem (2) loss of energy from various groups of organisms in an ecosystem (3) competition among species in an ecosystem (4) mechanisms that maintain homeostasis in the plants in an ecosystem

40. Certain organisms are able to store energy from the Sun in energy-rich compounds. Which event best illustrates this activity? (1) A fox captures and eats a young rabbit. (2) A caterpillar is eaten by a blackbird. (3) Lettuce produces organic substances. (4) Bacteria change organic material into simple nutrients.

41. Answer (3) Lettuce produces organic substances.

42. Researchers have reported that the number of different species of fish found in certain areas of the ocean has been greatly reduced over the past 50 years. This situation is an example of (1) a loss of biodiversity (2) an increase in ecological succession (3) a lack of differentiation (4) an increased carrying capacity

43. Answer (1) a loss of biodiversity

44. Two species of animals with a similar appearance live in the same habitat but do not compete for food. This is because they most likely (1) reproduce at different times of the year (2) are the same size (3) occupy different ecological niches (4) are active at night

45. Answer (3) occupy different ecological niches

46. During its annual migration, the red knot, a medium-size shorebird, flies the entire length of North and South America. During one critical stop to feed on the eggs of horseshoe crabs, the birds nearly double their body mass. The relationship between the red knot and the horseshoe crab is that of (1) parasite�host (2) consumer�producer (3) scavenger�producer (4) predator�prey

47. Answer (4) predator�prey

48. Which method of protecting members of an endangered species is most ecologically sound? (1) protecting the habitats where these animals live from human development (2) capturing these animals and putting them in wildlife parks (3) feeding and constructing shelters for these organisms (4) passing laws that encourage hunting of the predators of these species

49. Answer (1) protecting the habitats where these animals live from human development

50. In a particular ecosystem, squirrels make up a large portion of the diet of coyotes. A fatal disease in the squirrel population begins to reduce their population over a period of months. Which graph best represents the expected changes in population size of the coyotes and the squirrels?

51. Answer

52. Changes in a deer population are shown in the graph Which statement best explains section X? (1) The population has reached the carrying capacity of its environment. (2) Energy is used for interbreeding between members of different species. (3) A predator recycles the remains of dead organisms. (4) Competition does not occur between members of different species in the same habitat.

53. Answer (1) The population has reached the carrying capacity of its environment.

55. Answer (4) Community D modified the environment, making it more suitable for community E.

57. answers 42 (4) frog, snake, and hawk 43 (1) mouse