Multiple Choice Questions
Biology: Ecology and Ecosystem Dynamics
Topic: Ecology and Ecosystem Dynamics
Grade: 10
Question 1:
Which of the following best defines an ecosystem?
a) A community of organisms and their physical environment
b) A group of organisms of the same species living together in a specific area
c) A network of food chains interconnected within a community
d) A collection of all the populations in a specific area
Answer: a) A community of organisms and their physical environment
Explanation: An ecosystem refers to a community of organisms and their physical environment, where they interact with each other and the non-living components of their surroundings. For example, a forest ecosystem consists of various organisms such as trees, animals, insects, and microorganisms, as well as the soil, air, and water that make up the physical environment. The interactions between these organisms and their environment determine the dynamics of the ecosystem.
Example 1: In a pond ecosystem, the community of organisms includes fish, aquatic plants, algae, insects, and bacteria, while the physical environment includes water, sunlight, rocks, and sediments. The fish depend on the algae and insects for food, and the algae depend on sunlight for photosynthesis.
Example 2: In a desert ecosystem, the community of organisms includes cacti, reptiles, insects, and birds, while the physical environment includes sand, rocks, and limited water. The cacti have adaptations to conserve water and provide shelter for other organisms, and the reptiles rely on the cacti for shade and protection.
Question 2:
Which of the following is an abiotic factor in an ecosystem?
a) Plants
b) Temperature
c) Predators
d) Decomposers
Answer: b) Temperature
Explanation: Abiotic factors refer to the non-living components of an ecosystem that influence the organisms within it. Temperature is an example of an abiotic factor as it affects the metabolic rates and behavior of organisms. For instance, extreme heat or cold can limit the survival and reproduction of certain species. Other examples of abiotic factors include sunlight, water availability, soil composition, and pH levels.
Example 1: In a coral reef ecosystem, high water temperatures can cause coral bleaching, which is the loss of symbiotic algae that provide food for the corals. This can lead to the decline of the entire reef ecosystem.
Example 2: In a forest ecosystem, temperature variations throughout the year influence the timing of flowering and fruiting in plants, which in turn affects the availability of food for animals.