In terms of ecology what is optimality?

Question

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

Answer 1

Optimality is the basic assumption that animals make decisions and choose behaviors that will benefit them and best adapt them to their environment. In other words, a species tends to evolve traits and behaviors through natural selection that will ultimately optimize fitness.

However, there are always trade-offs involved when an animal selects one possible behavior over another. Every animal has a limited amount of brain power and size, so every skill and talent has an opportunity cost, causing the animal to choose the behavior that optimizes their fitness. 

In the context of reproductive optimality for a particular organism, we need to consider (1) ecological factors such as food availability and predation that affect an organism's probability of survival and reproduction and (2) the fact that there are limited resources and trade-offs involved. To determine the optimal values to maximize reproductive success, we must ask ourselves:

1. What extrinsic factors affect survival and reproduction? (ie: environment)
2. What life-history traits occur at the expense of others? (ie: ‘trade-offs’--how large an organism grow? How many times should it reproduce? How many offspring should it produce and what size should they be? How long should the animal live?) 

The theory of optimality suggests that animals tend to assess costs and benefits so that they choose reproductive strategies that will maximize fitness.

Optimality example: The Cognitive Trade-Off Hypothesis

Let’s say there are two traits in primates (1) Superior ability to use language and (2) Superior short-term memory. While both of these traits are very useful, you can only optimize one of these traits at the expense of the other due to having a finite amount of energy. Humans, a primate, have optimized Trait (1) Superior ability to use language at the expense of Trait (2) Superior short-term memory. This is because the forces of natural selection caused humans to optimize our ability to use language over having superior short-term memory. According to The Cognitive Trade-Off Hypothesis, this happened because language is an excellent mechanism for collaboration and altruism in humans and brings better benefits than having superior short-term memory. Chimpanzees, on the other hand, are a primate who evolved superior short-term memory rather than the ability to use language. This is because chimpanzees live in the wild where they must make rapid and complex decisions such as navigating branches to feed, or deciding what to do in a situation where they are being threatened. 



Conclusion: Language use is the optimal trait for humans, and short-term memory is the optimal trait for chimpanzees. Although both traits are useful, limited energy made it so that each species was only able to evolve the trait most optimal for their survival.

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