1. In a cold, waterlogged bog, the rate of decomposition is very slow. Which of the following is a direct consequence of this slow decomposition?
- A. Rapid recycling of nutrients and carbon in the ecosystem.
- B. An accumulation of dead organic matter, such as peat.
- C. Exceptionally high levels of atmospheric carbon dioxide above the bog.
- D. An increase in the population of large herbivores.
2. The removal of decomposers from an ecosystem is described as 'breaking the chain' in the carbon cycle. This is because their absence directly interrupts the:
- A. flow of energy from the sun to producers.
- B. transfer of carbon from producers to consumers.
- C. return of carbon from dead matter to the atmosphere.
- D. conversion of atmospheric oxygen into carbon dioxide.
3. Why would the elimination of decomposers eventually impact herbivores in an ecosystem?
- A. Herbivores would run out of oxygen for respiration.
- B. The population of producers, which herbivores eat, would likely decline.
- C. Decomposers would no longer be available as a food source for herbivores.
- D. Predators would increase in number due to the lack of decomposition.
4. What is the primary role of decomposers, such as bacteria and fungi, in the carbon cycle?
- A. They convert sunlight into chemical energy for the ecosystem.
- B. They release carbon dioxide by breaking down dead organic matter.
- C. They fix atmospheric nitrogen for use by plants.
- D. They are the main source of food for all carnivores.
5. A widespread fungal disease eliminates most decomposers in a forest ecosystem. What would be the most immediate effect on the carbon cycle in that area?
- A. The rate of photosynthesis in plants would dramatically increase.
- B. Herbivores would have an unlimited supply of food.
- C. The amount of carbon dioxide available for producers would decrease.
- D. The amount of oxygen in the atmosphere would increase.
6. A gardener notices that the leaves and vegetable scraps in their compost bin are not breaking down. A soil test reveals an absence of microbial life. What is the most likely cause of this problem?
- A. The compost bin is receiving too much sunlight.
- B. There are not enough decomposers like bacteria and fungi.
- C. There are too many earthworms in the compost.
- D. The vegetable scraps are not the right type for composting.
7. Which of the following pairs of organisms are primary examples of decomposers?
- A. Lions and tigers
- B. Squirrels and rabbits
- C. Bacteria and fungi
- D. Grass and trees
8. Decomposers are critical for which essential ecological process?
- A. Photosynthesis
- B. Pollination
- C. Matter cycling
- D. Water evaporation
9. What is the primary role of decomposers like bacteria and fungi in an ecosystem?
- A. To provide a food source for primary consumers.
- B. To convert sunlight into chemical energy through photosynthesis.
- C. To break down dead organic matter and recycle nutrients back into the environment.
- D. To regulate the population of producers by consuming them.
10. If the decomposer population in a forest ecosystem were to collapse, what would be the most immediate effect?
- A. An increase in the number of large predators.
- B. A rapid growth of all plant life in the area.
- C. The number of herbivores would suddenly increase.
- D. Dead organic material like fallen leaves and animals would accumulate.