Biol116 Lecture 6 (10/10/25) (In class)

Behavioral Ecology

• the study of the ecological and evolutionary basis of animal behavior

Evolution

• a process of change through time in the genetically determined characteristics of organisms being passed on to successive generations

• change in allele frequencies in a population over successive generations.

Natural Selection

• nonrandom process by which individuals with certain genotypes-phenotypes are favored to survive and reproduce over phenotypes in a particular environment

Natural selection requirement(s)

1. Variation in populations

2. The environment

3. Differences in survival and reproductive success

4. Heredity

Variation in populations

individuals are not exactly alike (different genotypes and phenotypes)

The envrironemnt (natural selection req)

Conditions and resources show variation, some become limiting factors.

Differences in survival and reproductive success (natural selection req)

only individuals with advantageous characteristics survive and then reproduce

Heredity (natural selection req)

Parents able to pass on some of their distinctive characteristics

Fitness

a measure of the genetic information contributed by an organism’s descendants to future generations

Behaviors influence ___

fitness

Behavior traits are often shaped by ___

natural selection

2 mains causes of behaviors

1. Proximate causes of behavior

2. Ultimate causes of behavior

Proximate (cause of behavior)

• an immediate underlying cause based on the operation of the internal mechanisms possessed by an individual

Ultimate (causes of behavior)

The evolutionary, historical reason why something is the way it is

Adaptation

• a hereditary trait that has spread or is spreading by natural selection

• has replaced or is replacing any alternative traits in the species

• A genetically determined characteristic that enhances the ability of organisms to cope with their environment. Provides a selective advantage and increases fitness

Optimal foraging theory

Animals will maximize the amount of energy gained per unit of feeding time, and minimize the risks involved

Difficult behaviors

• Infanticide in lions

• Slotting behavior (jumping in the air)

• Consider: are they communicating to something

Slotting behavior (In gazelles)

• Antipredator behavior

• Pursuit deterrence - predator breaks off pursuit

Sexual selection

Darwin proposed that the extravagant features of some males resulted from sexual selection

Direct benefit for mating

gifts of food, help in rearing young, access to a territory with good nesting sites, foods, etc.

Handicap hypothesis

a male that can support a costly ornament is likely to be a vigorous individual whose overall genetic quality is high

The sexy son hypothesis

The female receives indirect genetic benefits throughh her sons, who will themselves be attractive to females and produce many offspring 

Extra pair copulation

An individual that has a social bond with a mate also breeds with other individuals

Male guarding

males are there all the time by the female (scared of other male stealing)