Tag: zoology

Bioenergetics is a field in biochemistry, that concerns energy flow through living systems. This includes the study of different cellular processes, such as cellular respiration and the many other metabolic processes, that can lead to production and utilization of energy in forms such as ATP molecules.

The ten percent law for the transfer of energy from one trophic level to the next was introduced by Raymond Lindeman (1942). According to this law, during the transfer of energy from organic food from one trophic level to the next, only about ten percent of the energy from organic matter is stored as flesh. The remaining is lost during transfer, broken down in respiration, or lost to incomplete digestion by higher trophic levels.

Pyramids of numbers describes the relationship between organisms at successive trophic levels in terms of their number. In grassland, the producers, which are mainly grasses are always maximum in number as compared to the  primary consumers, the secondary consumers like snakes and lizards are lesser in number than the rabbits and mice. Finally, the top (tertiary) consumers like hawks or other birds are least in number. Thus, the pyramid becomes upright.

The physical components of the environment are also known as abiotic components. They include soil, water, air, climate, temperature and sunlight. It determines the type of habitat or living conditions of the living population. Thus the correct answer is option A.

According to the 10%  law, in a terrestrial ecosystem during the transfer of energy from one trophic level to the next, about ten percent of the energy in the form of organic matter is eaten and digested and stored as flesh. The remaining is lost during transfer in the form respiration or incomplete digestion. Thus the correct answer is option A.

Lindemann (1942) put forth ten percent law for the transfer of energy from one trophic level to the next. According to the law, during the transfer of organic food from one trophic level to the next, only about ten percent of the organic matter is stored as flesh. The remaining is lost during transfer or broken down in respiration.

Plants utilise sun energy for primary production and can store only 10% of the utilised energy as net production available for the herbivores. When the plants are consumed by animal, about 10% of the energy in the food is fixed into animal flesh which is available for next trophic level (carnivores). When a carnivore consumes that animal, only about 10% of energy is fixed in its flesh for the higher level.

So at each transfer 80 - 90% of potential energy is dissipated as heat (second law of thermodynamics) where only 10 - 20% of energy is available to the next trophic level.

Therefore, the correct answer is option A.

The flow of energy is always unidirectional. The energy passes from primary producers to primary consumers. From the primary consumers, the energy is passed to secondary consumers and then to tertiary consumers. Thus the energy pyramid is always upright.

Energy transfer along each trophic level of a food chain exhibit loss of 90% energy as heat and transfer of only 10% energy to the next trophic level. The energy is lost in metabolic activities. According to this, out of 400,000kJ energy of primary producers, 40000kJ will be transferred to primary consumers and 4000kJ will be transferred to the secondary consumer. Tertiary consumers will obtain only 400kJ energy from secondary consumers while top consumers will obtain as little as 40kJ energy. Correct answer is option C.