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A biogenic substance is a product made by or of life forms. The term encompasses constituents, secretions, and metabolites of plants or animals. In context of molecular biology, biogenic substances are referred to as biomolecules.
- Coal and oil are possible examples of constituents which may have undergone changes over geologic time periods.
- Chalk and limestone are examples of secretions (marine animal shells) which are of geologic age.
- grass and wood are biogenic constituents of contemporary origin.
- Pearls, silk and ambergris are examples of secretions of contemporary origin.
- Biogenic neurotransmitters.
An abiogenic substance or process does not result from the present or past activity of living organisms. Abiogenic products may, e.g., be minerals, other inorganic compounds, as well as simple organic compounds (e.g. extraterrestrial methane, see also abiogenesis).