50.1 An Introductional to Behavioral Ecology

• The eminent evolutionary biologist Ernst Mayr wrote an influential paper on “cause and effect in biology" in 1961.

  • He clearly identified two types of biological causation:

    • Proximate (or mechanistic) causation explains how actions occur in terms of the genetic, neurological, hormonal, and skeletal-muscular mechanisms involved.

    • Ultimate (or evolutionary) causation explains why actions occur based on their evolutionary consequences and history. Behavior is just like any other phenotype in that it can evolve by natural selection.

• Innate behavior is inherited-meaning that it is passed genetically from parents to offspring.

• Learning is an enduring change in behavior at results from a specific experience in an individual’s life.

• Animals take in information from the environment and, based on that information, respond in a certain way.

  • But each behavior has different costs and benefits， resulting in fitness trade-offs, and inescapable compromises between two traits that cannot be optimized simultaneously.

• Behavioral ecologists use a framework borrowed from economics called cost-benefit analysis to understand and quantify the behavioral choices that animals make.

  • Costs and benefits are measured in terms of their impact on fitness-their success in producing viable, fertile offspring.

50.2 Choosing What, How, and When to Eat

• When animals seek food, they are foraging.

• The hypothesis that animals maximize their feeding efficiency is called optimal foraging.

• Evolutionary game theory is a mathematical modeling approach to predicting the outcome of natural selection on behaviors when multiple “players” are interacting.

50.3 Choosing a Mate

• Bald eagles, like many birds, engage in monogamy by forming lasting pair bonds between one female and one male.

  • In contrast, many cuttlefish engage in promiscuity, where each individual may have multiple mates.

  • Polygamy lies in between, called either polygyny (“many-females”) or polyandry (“manymales”) depending on whether one male is mating with many females (as in red deer) or one female is mating with many males (as the queen bee does in some honeybee species).

• Mate choice typically involves a chooser and a courter and some kind of signal, an information-containing behavior or characteristic.

• It is socially polygynous; each male (the courter) typically defends a feeding area, or territory, sufficient to support two to six females (the choosers).

• A type of selection called sexual selection favors individuals possessing aits that increase their ability to obtain mates.

• There are two types of sexual selection.

  • When an individual of one sex chooses an individual of another sex as a mate, intersexual selection is said to occur.

  • When two individuals of the same sex compete with one another for mates, intrαsexual selection is taking place.

50.4 Choosing Where To Go

• In ecology, migration is defined as the long-distance movement of a population associated with a change of seasons.

• The circadian clock that exists in organisms maintains a 24-hour rh hm of chemical activity.

50.5 Communicating with Others

• In biology, communication is defined as any process in which a signal from one individual modifies the behavior of a recipient individual.

  • It creates a stimulus that elicits a response.

50.6 Cooperating with Others

• Altruism is behavior that has a fitness cost to the individual exhibiting the behavior and a fitness benefit to the recipient of the behavior.

• Hamilton’s rule is important because it shows that individuals can pass on their alleles to the next generation not only by having their own offspring but also by helping close relatives produce more offspring.

  • Direct fitness is derived from an individual’s own offspring. Parents can increase their direct fitness by spending resources to ensure the welfare of their offspring. This behavior is called parental care

  • Indirect fitness is derived from helping relatives produce more offspring than they could produce on their own. For example, a grandmother can increase her indirect fitness by caring for her daughter’s child so that her daughter will have more resources available to have a second child.

  • The combination of direct and indirect fitness components is called inclusive fitness.

• Biologists use the term kin selection to refer to natural selection that acts through benefits to relatives at the expense of the individual.

• In these societies, workers sacrifice most or all of their direct reproduction to help rear the queen’s offspring; this phenomenon is called eusociality.

• The leading hypothesis to explain altruism among nonrelatives is called reciprocal altruism-an exchange of fitness benefits that are separated in time.

  • Reciprocal altruists help individuals who have either helped them in the past or are likely to help them in the future.