The reason for the decreasing energy flow in the ecosystem is:

Answer: The reason for the decreasing energy level of d is that the life activities of each trophic level of the organism consume a part of the energy, and a part of the energy cannot be used by the next trophic level and is finally used by the decomposer.

Answer]: The energy in animal feces is the energy that has not been assimilated and belongs to the energy fixed at the previous trophic level, so the energy in the elephant feces is the energy that has not been assimilated and belongs to the energy fixed at the previous trophic level; The dung beetle uses elephant feces as food, so the energy obtained by the dung beetle does not come from the elephant, but the elephant's upper trophic level, that is, about 0kj, a error in the energy assimilated by the elephant can flow into the human dung beetle's body. The producer is the first trophic level, and the rabbit is the primary consumer belongs to the second trophic level, and the wolf preys on the rabbit, indicating that the wolf is the second fan rock level consumer belongs to the third trophic level, b is false.

Green plants (producers) use light energy through photosynthesis to convert carbon dioxide and water into organic matter that stores energy, and release oxygen, so that the carbon elements and energy of the inorganic environment enter the biological community, c correct. The energy flow of the ecosystem is characterized by one-way transfer, decreasing step by step The transfer efficiency between trophic levels is 10% to 20% (energy flow does not include energy flowing to decomposers), d error.

Answer]: The energy in animal feces is not assimilated and belongs to the energy fixed at the previous trophic level, so the energy in the elephant feces is the energy that has not been assimilated and belongs to the energy fixed at the previous trophic level; Dung beetles feed on elephant dung, so the energy obtained by dung beetles does not come from elephants, but from the elephant's upper trophic level, that is, about 0kj,a error in the energy assimilated by elephants that can flow into the body of human dung beetles. The producer is the first trophic level, and the rabbit is the primary consumer belongs to the second trophic level, and the wolf preys on the rabbit, indicating that the wolf is the secondary consumer and belongs to the third trophic level, b is false.

Green plants (producers) use light energy through photosynthesis to convert carbon dioxide and water into energy-storing organic matter, and release oxygen, so that the carbon ephemera and energy of the inorganic environment enter the biome, c correct. The energy flow of the ecosystem is characterized by one-way transmission, decreasing step by step The transfer efficiency between trophic levels is 10% to 20% (energy flow does not include energy flowing to decomposers), d error.

The source of energy in an ecosystem is sunlight, and the total amount of solar energy fixed by the producer is the total amount of energy flowing through the ecosystem, and this energy flows along the food chain, and the energy flow is characterized by unidirectional, decreasing, and non-cyclic energy transfer to the next trophic level with an efficiency of about 10 20 percent

So the answer is: the food chain; Reduce

The structure and function of the ecosystem of the eight biologicals of Beijing Normal University - the material cycle is accompanied by the flow of energy.

Answer]: C Knowledge Points] This question tests the flow of energy in the Datancha ecosystem.

Answer] c. Analysis] The reason for the unidirectional flow of energy in the ecosystem is the irreversible relationship between food. The causes of the decline are related to respiratory consumption and inadequate resource utilization.

All kinds of ecosystems on the earth need solar energy, and any closed ecosystem cannot complete the flow of energy and the material cycle if it does not obtain imitation energy from outside the system. Therefore, C.

Problem Solving Ideas: The energy flow of the ecosystem is characterized by one-way transmission and decreasing step by step, and the transfer efficiency between trophic levels is 10%-20% The energy in animal feces is not assimilated and belongs to the fixed energy of the previous trophic level

a. Since elephant dung is the energy that the elephant does not absorb after digestion, it does not belong to the energy of elephant assimilation, but the energy of the previous trophic level, so a dung beetle that eats elephant dung dung cannot obtain energy from the energy of elephant assimilation, and the energy obtained from elephant feces should belong to the previous trophic level of the elephant, a is wrong;

b. The food chain starts from the producer, so the organisms of the first trophic level must be the producers, and the rabbit should belong to the second trophic level, so when the wolf preys on the rabbit and assimilates into its own organic matter, the energy flows from the second trophic level to the third trophic level, b is false;

c. Green plants (producers) use light energy through photosynthesis to convert carbon dioxide and water into organic matter that stores energy, and release oxygen, so that energy and carbon elements enter the biological community, c correct;

d. The material of the ecosystem can be recycled, while the energy is transmitted in a single fiber and is not recycled, d is wrong

Therefore, c 2, of the following descriptions of ecosystem energy flows, the correct one is ( ).

a A dung beetle that feeds exclusively on elephant dung can obtain up to 20 per cent of the energy assimilated by elephants

b When a wolf preys on a rabbit and assimilates it into its own organic matter, energy flows from the first trophic level to the second trophic level.

c Producers synthesize organic matter through photosynthesis, and energy flows from the abiotic environment into the biome.

d The energy of the ecosystem is recycled along with the matter.

The process of input, transfer, transformation, and dissipation of energy in an ecosystem is called the energy flow of an ecosystem.

1. Energy input: The starting point of the energy flow sorghum hail in the ecosystem is the beginning of solar energy fixed by the producers (mainly plants) through photosynthesis. The channels through which energy flows are the food chain and the food web.

2. Energy transfer: In the energy flow of the ecosystem, energy changes in the form of solar light energy and chemical energy and thermal energy loss in organic matter in living organisms. Energy flows in the form of chemical energy in organic matter (food) in the trophic levels of the food chain.

3. Energy conversion: refers to the transfer and conversion of energy within the ecosystem and between the ecosystem and the outside world in the process of interaction.

3. Energy loss: The main way of energy loss in the energy flow of the ecosystem is through the cellular respiration of the organisms at each trophic level in the food chain and the cellular respiration of the decomposers, which are mainly lost in the form of heat.

Extended scumbag information:

Unidirectional flow: refers to the energy flow of the ecosystem can only flow from the first trophic level to the second trophic level, and then to the subsequent trophic levels. Generally, it cannot flow in reverse.

This is determined by the trophic structure formed by the long-term evolution of organisms. For example, a wolf preys on a sheep, but a sheep cannot prey on a wolf.

Step-down means that the energy input to one trophic level cannot flow 100% into the next trophic level, and the energy decreases step by step as it flows along the food chain. The average efficiency of energy transfer along the food web is 10% to 20%, i.e. only 10% of the energy in one trophic level is used by the next trophic level.

The energy pyramid refers to the energy value obtained by each trophic level in a unit time, which is drawn into a pyramid shape according to the trophic level from low to high, which is called the energy pyramid. From the energy pyramid, it can be seen that in the ecosystem, the more trophic levels, the more energy is lost in the process of energy flow; The higher the trophic level, the less energy you get.

In the food chain, there are generally no more than 5 trophic levels, which are determined by the law of energy flow.