Question

The efficiency of energy transfer between trophic levels is about _______ ? 

Select one: 

a. 10% 

b. 20% 

c. 30% 

d. 1%

Answer 1

9. a. 10%

Trophic level is the position of an organism occupies in a food chain . It refers to the food they eat and what organisms feed on them. Producers are always at the bottom of the food chain followed by primary consumers like herbivores, then comes the secondary consumers which feed on the herbivore, then comes the tertiary consumers, the carnivores which feeds on seconadary consumers. No other organisms usually eats the top trophic level tertiary consumers.

Transfer of energy as moving up from each trophic level is very small. Only 10% of the energy is transfered as moving up in each trophic level, because 90% is lost as heat. This is called 10% rule. For example, if you start with 1000 joules in producers, and a grass hopper eats the plant and only 10 joules will be transfered to grasshopper , and a bird eating the grasshopper will get transfered only 1joule and so on. Most of the energy is lost as heat.

The energy flow in an ecosystem follows the law of thermodyanamics. The first law states that energy can neither be created nor destroyed but it can be converted to one form to another. The second law states that this energy conversion is never completely efficient. As a result, most of energy is lost as heat.