# In terms of ecology what is optimality? [closed]

I am studying animal science and I have been learning about reproductive theories however i cant seem to understand the theory of optimality

## closed as unclear what you're asking by fileunderwater, AliceD♦, kmm, James, The Last WordDec 15 '15 at 4:36

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• Can you give more context to your question? In biology, most references to optimality mean passing on your genes more successfully than others. However many proxies for this exist, such as gaining food, or investing energy in offspring. Usually these proxies are optimal in the context of a model which assumes some connection to the general problem of passing on your genes. – Hans Dec 7 '15 at 22:23
• What type of optimality are you referring to, i.e. what is optimalized? Fitness, energy use, foraging, life-history trade-offs etc? – fileunderwater Dec 14 '15 at 11:46

Optimality theory

Optimality theory is a concept of linguistic. See wiki > Optimality theory. This is probably not what you were referring to.

What is optimality

Optimality is the condition under which something is maximized! In behavioural ecology, this something is often fitness and the condition is often measured in terms of magnitude/intensity of a behaviour.

Optimality models

In ecology, we call optimality model any model that separate the benefits and costs (in terms of some measurement, often fitness) of a given phenotype (often behaviour). By weighing benefits and costs one can figure out what is the optimal phenotype. The principle is extremely simple. Such graphs are quite standard:

In the graph, the X-axis represents the magnitude of a phenotype (often a behaviour) and the Y-axis represents the benefit and cost of this behaviour (with the same scale) often in terms of fitness.

By definition, the fitness is maximized when $B-C$ is maximized. In other words, compute B-C and look for the maximum (through derivation) and you found the optimal phenotype (often behaviour). In the above graph, the optimal phenotype is a little bit left to the position of the B label.

Optimal foraging theory

Foraging behaviour has been subject to much investigations using optimality models. We refer to this body of knowledge as Optimal foraging theory.