3.1 The Sun is the major source of energy for organisms and the ecosystems of which they are a part. Producers such as plants, algae, and cyanobacteria use the energy from sunlight to make organic matter from carbon dioxide and water. This establishes the beginning of energy flow through almost all food webs.

The AMOUNT of oxygen and carbon atoms released by photosynthesis are EXACTLY EQUAL to the atoms of these material contained in carbon-dioxide converted. In this way photosynthesis has conserved the mass or material, and in this way followed the law of conservation of mass.

The 2 primary sources of energy that power living systems are photosynthesis and chemosynthesis.

A food chain is a linear sequence of organisms through which nutrients and energy pass as one organism eats another. The levels in the food chain are producers, primary consumers, higher-level consumers, and finally decomposers. These levels are used to describe ecosystem structure and dynamics.

The energy flow takes place via the food chain and food web. During the process of energy flow in the ecosystem, plants being the producers absorb sunlight with the help of the chloroplasts and a part of it is transformed into chemical energy in the process of photosynthesis.

The ten percent law of energy transfer in a food chain is given by Raymond Lindemann. The ten percent law of energy transfer states that when the energy is transferred from one trophic level to another. Grass is present at producer level and forms the first stage of trophic level.

Ten PerCent Law – According to ten per cent law only 10 per cent of the energy entering a particular trophic level of organisms is available for transfer to the next higher trophic level. Example – Suppose 1000 Joules of light energy emitted by the sun falls on the plants.

Reymond Lindeman

The 10% rule states that between one trophic level to the next only 10% of the energy is passed on to the next. So if producers have 10,000 J of energy stored through photosynthesis, then only 1000 J is passed on to primary consumers.

Pyramid of biomass is usually inverted in a downward direction and sometimes takes other shapes. 2. Pyramid of numbers represents the number of organisms present in each trophic level.

The amount of energy at each trophic level decreases as it moves through an ecosystem. As little as 10 percent of the energy at any trophic level is transferred to the next level; the rest is lost largely through metabolic processes as heat.

Only small proportion of energy in the biomass of organisms in one trophic level will ever become part of the biomass of organisms in the next trophic level. As losses occur at each stage in the food chain, there is gradually less energy available to each successive trophic level.