chapter 15- Our environment Question Answer

1. What is the trophic level? Give an example of a food chain and indicate the different trophic levels that make it up. 

Explanation:

Levels of the food chain that provide food or energy are called trophic levels. Example: goats, goats and humans In a food web, the lowest trophic level is grass. The second trophic level is represented by goats.The third level of the food chain is people.


2. What is the role of decomposers in an ecosystem? 

Explanation:

Decomposers play the following role in ecosystems: by breaking down dead plants and animals, they act as environmental cleansers. They help in the circulation of nutrients. By leaving the dead to rot, they make room for new life in the biosphere.They help recycle ingredients back into water, soil and air for use by growers such as crops.


3. Why are some substances biodegradable and others not?

Explanation:

 Some compounds are biodegradable while others are not due to the specific role played by microorganisms such as bacteria and decomposers such as saprophytes. Only natural products, such as paper, wood, etc., can decompose there, unlike manufactured products, such as plastics


4. Therefore, some substances are biodegradable and others are not. 

Explanation:

 Biodegradable materials affect the environment in the following ways: They break down easily and help keep the environment clean. With the help of decomposers, they can quickly complete geochemical cycles.


5. Name two ways in which non-biodegradable substances affect the environment.

Explanation:

Non-biodegradable materials have the following effects on the environment: they pollute the air, soil and water.They can endanger humans by causing biomagnification in the food chain.


6. What would happen if we killed all organisms at a trophic level?

Explanation:

If all the organisms of a trophic level are eliminated, the ecology will be unbalanced, because the organisms of a higher level will not have food. Higher animals die as a result, greatly accelerating the growth of lower trophic animals. All of these factors have an impact on the overall balance of the ecosystem.


7.  If organisms from all trophic levels are removed, does this have different effects on different trophic levels? Can these organisms be removed from any trophic level without causing damage to the ecosystem?

Explanation:

Of course, the effect of destroying each trophic level creature will vary by trophic level. For example, if all producers are eliminated, primary consumers may die or migrate, disrupting trophic levels. The same applies at all levels.Thus, any level of organism removal that disrupts a food chain could disrupt an entire ecosystem. The lower animals are absolutely necessary for the survival of the higher animals.


8.  What is biofortification? Does this level of intensification vary according to the levels of the ecosystem?

Explanation:

 The gradual increase in the concentration of non-biodegradable pollutants in the food chain is called biomagnification.All other trophic levels in the ecosystem are affected by successive levels of increasing concentrations which may differ from the initial level. 


9. What are the problems caused by the non-biodegradable waste we generate? 

Explanation:

Non-biodegradable waste has the problem that microbes cannot break down the material. As the volume increases, spillage becomes a problem. Non-biodegradable wastes, such as heavy metals, can enter higher trophic levels in the food chain.They can enter groundwater, which disturbs the pH of the soil and makes it infertile. 


10. What is ozone and how does it affect an ecosystem?

Explanation:

Ozone (O3) is a molecule made up of three oxygen atoms and is an isotope of oxygen. Ozone plays an important role at higher atmospheric altitudes. It protects the Earth's surface from the sun's ultraviolet (UV) rays.Consider the food chain illustrated in the diagram below: 


11. Which of the following groups contains only biodegradable elements? 

  1. grass, flowers and leather 

  2. (b) grass, wood and plastic Â

  3. © bark, cake and lime juice 

  4. (d) cake, wood and grass 

Explanation:

 Â© bark, cake and lime juice and (d) cake, wood and grass 


12. Which of the following constitutes a food chain?

(a) Grass, wheat and mango 

(b) Grass, goat and man Â

© Goat, cow and elephant 

(d) Grass, fish and goat 

Explanation:

(b) Grass, goat and man 


13. Which of the following is eco-friendly? environment exercise? (a) wear cloth bags when shopping (b) turn off unnecessary lights and fans © walk to school instead of your mom putting you on her scooter (d) all of the above 

Explanation:

 (d) all of the above 


14. Determine the source of energy moving through the food chain? (a) Carbon dioxide (b) Glucose © Oxygen (d) Sunlight

Explanation:

All living things get their energy directly or indirectly from sunlight reaching the Earth's surface.