Ecosystems Quiz - ICSE Class 8 Science

Free practice quiz: Ecosystems (ICSE Class 8 Science). 52 multiple-choice questions with answers and explanations. Play online, no sign-up needed.

This ICSE Class 8 Science practice quiz has 52 multiple-choice questions on Ecosystems, and 52 of them come with an explanation. Try the 5 sample questions below (tap an option to check yourself), then play the full quiz online. No sign-up needed.

Sample questions

1. Which of the following best describes a producer in an ecosystem?

   1. An organism that consumes other organisms for energy.
   2. An organism that converts light energy into chemical energy.
   3. An organism that breaks down dead organic matter.
   4. An organism that occupies the highest trophic level.
   Show answer

   Answer: B. An organism that converts light energy into chemical energy.

   Producers, such as plants and algae, are autotrophs that produce their own food through photosynthesis, converting light energy into chemical energy in the form of organic compounds. Consumers eat other organisms, decomposers break down dead matter, and apex predators are at the top of the food chain.

2. What is the primary function of scavengers in an ecosystem?

   1. To convert light energy into chemical energy
   2. To consume living organisms
   3. To feed on dead or decaying organisms
   4. To break down organic matter into inorganic nutrients
   Show answer

   Answer: C. To feed on dead or decaying organisms

   Scavengers, like vultures and hyenas, play a role in cleaning up the environment by consuming the carcasses of dead animals. While decomposers also break down dead matter, scavengers are typically larger animals that consume larger pieces of dead organic material.

3. What is the term for the organisms that consume dead or decaying organic matter in an ecosystem?

   1. Producers
   2. Primary consumers
   3. Secondary consumers
   4. Decomposers
   Show answer

   Answer: D. Decomposers

   Decomposers, such as bacteria and fungi, break down dead organisms and waste products, returning essential nutrients to the ecosystem.

4. The process of denitrification in the nitrogen cycle results in:

   1. Conversion of ammonia to nitrates
   2. Release of nitrogen gas back into the atmosphere
   3. Absorption of nitrogen by plants
   4. Formation of organic nitrogen compounds
   Show answer

   Answer: B. Release of nitrogen gas back into the atmosphere

   Denitrification is carried out by denitrifying bacteria, which convert nitrates (NO3-) in the soil back into atmospheric nitrogen gas (N2), completing the nitrogen cycle.

5. Which process in the nitrogen cycle converts nitrates back into atmospheric nitrogen?

   1. Nitrification
   2. Assimilation
   3. Denitrification
   4. Ammonification
   Show answer

   Answer: C. Denitrification

   Denitrification is the microbial process of reducing nitrate or nitrite to gaseous nitrogen (N2 or N2O), thereby returning nitrogen to the atmosphere.

More questions in this quiz

Answers and explanations are in the full quiz.

1. In a food chain, what is the primary source of energy for most ecosystems on Earth?
2. Which of the following describes a symbiotic relationship where one organism benefits and the other is harmed?
3. What term refers to all the living organisms in a particular area?
4. An increase in the population of which organism would likely lead to a decrease in the population of grass?
5. Which biogeochemical cycle involves the process of transpiration?
6. What is the role of decomposers in an ecosystem?
7. Which term describes the total number of individuals of a single species living in a specific area?
8. If a forest ecosystem experiences a severe drought, what is a likely immediate effect on the plant life?
9. Which organism is typically a secondary consumer in a terrestrial food chain?
10. Which of the following is an example of abiotic factor in an ecosystem?
11. The process by which carbon is exchanged between the atmosphere, oceans, land, and living organisms is known as the:
12. What is the term for the natural environment where an organism lives?
13. Which factor would most likely cause a rapid decline in a prey population within an ecosystem?
14. In a pond ecosystem, what would be an example of a producer?
15. What is the term for the role and position a species has in its environment, including how it meets its needs for food and shelter, and how it interacts with other species?
16. Which of the following cycles involves nitrogen fixation by bacteria?
17. When two species benefit from their interaction, the symbiotic relationship is called:
18. Which of the following is a biotic factor that influences an ecosystem?
19. In a food web, what is the trophic level occupied by organisms that eat only producers?
20. Which of the following is a characteristic of a successful invasive species?
21. What is the primary role of respiration in the carbon cycle?
22. If the population of a predator decreases significantly, what is a likely consequence for its prey population?
23. Which process is responsible for converting atmospheric nitrogen into usable forms for plants, such as ammonia?
24. What is the term for the total number of organisms of all species in a given area?
25. Which of the following is an example of commensalism?
26. What is the primary source of energy for the deep-sea hydrothermal vent ecosystem?
27. If a forest ecosystem experiences an increase in rainfall, what might be a consequence for the producers?
28. Which trophic level includes organisms that obtain energy by consuming dead or waste organic matter?
29. Which of the following is an example of a tertiary consumer in a grassland ecosystem?
30. What is the term for a group of individuals of the same species living and interacting in the same area?
31. Which relationship is characterized by one organism benefiting and the other being harmed?
32. The process by which plants release water vapor into the atmosphere is called:
33. What is the main role of decomposers like bacteria and fungi in an ecosystem?
34. Which term describes the unique role and position of a species within its ecosystem, including its interactions with other organisms and the environment?
35. If a disease drastically reduces the population of rabbits in a forest, what is a likely indirect effect on the fox population?
36. Which of the following is an abiotic factor?
37. What is the primary way that energy flows through an ecosystem?
38. In a forest ecosystem, a bear eating berries and then spreading their seeds is an example of:
39. What is the consequence of eutrophication in a lake ecosystem?
40. Which of the following are considered consumers in an ecosystem?
41. The gradual change in the species structure of an ecosystem over time is known as:
42. What is the main role of the phosphorus cycle in an ecosystem?
43. Which of the following is a population that is likely to be negatively impacted by biomagnification?
44. What is the correct order of trophic levels in most ecosystems, starting from the bottom?
45. Which term refers to the variety of life in a particular habitat or ecosystem?
46. Which of the following is a predator-prey relationship?
47. Which of the following is NOT a part of the carbon cycle?

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