What is the 10% law in ecology?

Lindeman's 10% law (1942) states that only 10% of the energy at one trophic level is available to the next higher trophic level. The remaining 90% is lost as heat (respiration), excretion, and unused biomass. This is why food chains are limited to 4–5 levels — there is very little energy left at higher levels. It also explains why eating lower on the food chain (vegetables vs meat) is more energy-efficient and can feed more people.

What is biomagnification and how does it affect humans?

Biomagnification (biological magnification) is the progressive increase in concentration of toxic chemicals at successive trophic levels of a food chain. Non-degradable chemicals like DDT, mercury, and PCBs accumulate in fat tissues of organisms. As predators eat many prey animals, the chemical concentrates. Top predators (including humans) end up with the highest concentrations. Humans are affected through eating contaminated fish, meat, and dairy. DDT biomagnification caused the decline of bald eagles in the USA.

What causes ozone depletion and what is the Montreal Protocol?

Ozone depletion is caused mainly by chlorofluorocarbons (CFCs) — synthetic chemicals used in refrigerants, aerosol sprays, and foam packaging. CFCs reach the stratosphere and are broken down by UV radiation, releasing chlorine atoms. Each chlorine atom can destroy thousands of ozone molecules (Cl + O₃ → ClO + O₂). The Montreal Protocol (1987) is an international treaty where nations agreed to phase out the production of CFCs and other ozone-depleting substances. It is considered one of the most successful environmental agreements.

Food Chains and Ecosystems

Our Environment • Class 10 Science • NCERT • CBSE

An ecosystem consists of biotic (living) and abiotic (non-living) components. A food chain shows the transfer of energy through: Producer → Primary consumer → Secondary consumer → Tertiary consumer. Only 10% of energy passes to the next trophic level. Ozone (O₃) in the stratosphere protects Earth from UV radiation; it is depleted by CFCs.

Key Formulas

10% energy law: only 10% energy transfers between trophic levels

Frequently Asked Questions

What is the 10% law in ecology?: Lindeman's 10% law (1942) states that only 10% of the energy at one trophic level is available to the next higher trophic level. The remaining 90% is lost as heat (respiration), excretion, and unused biomass. This is why food chains are limited to 4–5 levels — there is very little energy left at higher levels. It also explains why eating lower on the food chain (vegetables vs meat) is more energy-efficient and can feed more people.
What is biomagnification and how does it affect humans?: Biomagnification (biological magnification) is the progressive increase in concentration of toxic chemicals at successive trophic levels of a food chain. Non-degradable chemicals like DDT, mercury, and PCBs accumulate in fat tissues of organisms. As predators eat many prey animals, the chemical concentrates. Top predators (including humans) end up with the highest concentrations. Humans are affected through eating contaminated fish, meat, and dairy. DDT biomagnification caused the decline of bald eagles in the USA.
What causes ozone depletion and what is the Montreal Protocol?: Ozone depletion is caused mainly by chlorofluorocarbons (CFCs) — synthetic chemicals used in refrigerants, aerosol sprays, and foam packaging. CFCs reach the stratosphere and are broken down by UV radiation, releasing chlorine atoms. Each chlorine atom can destroy thousands of ozone molecules (Cl + O₃ → ClO + O₂). The Montreal Protocol (1987) is an international treaty where nations agreed to phase out the production of CFCs and other ozone-depleting substances. It is considered one of the most successful environmental agreements.

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