Our Environment Test - 23

The Great Barrier Reef is home to numerous plants and animals, specially corals. The organisms form various food chains and web and all together, they form an ecosystem.

An ecosystem consists of the biological community of living organisms that occur in some particular area, interacting with each other and with the physical and chemical factors of that area. These factors are non-living or abiotic factors.  

• Abiotic components of an ecosystem consist of the physical aspects of the environment that determine what life forms can thrive. Examples of abiotic components are temperature, average humidity, topography and natural disturbances.
• Fungi, bacteria and chlorella are living organisms and can not be considered abiotic.

Organisms which feeds on both plants and animals is an omnivore. Dog is an omnivore as it feeds on milk, biscuits, meat, etc. Goats and rabbits are herbivores that feed on plants. Wolf is a carnivore that feeds on herbivores. 
Thus, the correct answer is option C. 

• Herbivores are at the second level of the food chain and mainly eat plants. Herbivores are considered primary consumers and are the first consumers in the food chain. 
• The honey bee is a herbivore and therefore lives purely on the nutrients from plants. 
• Deer is also a herbivores that eats plants and grasses. So, it belongs to the same trophic level as the honey bee, i.e., primary consumers.

• The food chain is comprised of different species which depend on each other for energy.
• The producers are the ones that convert solar energy into food and represent the first trophic level. 
• The producers are the autotrophs that can perform photosynthesis. Plants and algae are examples of producers. 
• The consumers feed on the producers. 
• An ecological food chain has three levels of consumers: primary, secondary, and tertiary.

Thus, the correct answer is option D.

Biodegradable is the waste which can be degraded by the activity of microbes. The leather is obtained from the skin of the animals which is degradable. Paper is made from the wood and contains the cellulose which can be degraded by the microbes producing cellulase. Cloth contains cellulosic fibres which can be broken down by the microbes.

Temporary ecosystem: it is short lived and man made or natural. Example include rain fed pond.

The ecosystem is responsible for the flow of energy as the autotrophs convert the light energy provided by the sun to chemical energy which is further consumed by heterotrophs. In this way energy transferred from plants to herbivores and from them to carnivores.