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biological functions

Friday 11 July 2003


Definition: A biological function is the reason some object or process occurred in a system that evolved through natural selection. That reason is typically that it achieves some result, such as that chlorophyll helps to capture the energy of sunlight in photosynthesis.

Hence, the organism that contains it is more likely to survive and reproduce, in other words the function increases the organism’s fitness.

A characteristic that assists in evolution is called an adaptation ; other characteristics may be non-functional spandrels, though these in turn may later be co-opted by evolution to serve new functions.

In physiology, a function is an activity or process carried out by a biological system in an organism, such as sensation or locomotion in an animal.

The concept of function as opposed to form or struture (respectively Aristotle’s ergon and morphê) was central in biological explanations in classical antiquity, and in more modern times formed part of the Cuvier–Geoffroy debate.

In the philosophy of biology, talk of function inevitably suggests some kind of teleological purpose ( teleology , teleonomy ), even though natural selection operates without any goal for the future. All the same, biologists often use teleological language as a shorthand for function.

See also : physiological functions


- molecular functions
- cellular functions
- tissular functions
- organ functions
- system functions
- systemic functions

The structures have a function .

- molecular functions

- cellular functions (cells )
- tissular functions (tissues )
- organ functions (organs )
- system functions (systems )
- systemic functions (body / organism )

In pathological conditions, a function can be abnormal (functional anomalies).


- A function may have anomalies or disorders leading to a disease. This disease can express through lesions, lesionnal syndromes, functional signs, clinical signs and biological anomalies (phenomenons ).

See also

- processes

- structures