Chapter 8 Social Relations

MARTENS

Behavioral Ecology

Studies the relationships between organisms and the environment that are mediated by behavior, the ecological factors that drive behavioral adaptations

Sociobiology

The scientific study of biological aspects of social behavior in organisms. Meaning some behaviors are partly inherited and can be affected by natural selection

Ethnology

Study of animal behavior with a focus on behavior under natural conditions and viewing behavior as an evolutionary adaptive trait

Is female choice and choosing mate either Intersexual Selection or Intrasexual Selection

Intersexual Selection

Evolutionary Fitness

How well a species is able to reproduce in its environment

How is evolutionary Fitness measured?

By an organisms ability to survive and reproduce, which determines the size of its genetic contribution to the next generation

Sexual Reproduction Females

Produce larger, and more energy costly gametes, invest longer time and energy in rearing offspring

Sexual Reproduction Males

Produce smaller, and less costly gametes, usually does not rear offspring

Sexual Selection

A form of natural selection in which individuals with certain inherited characteristics are more likely than others to obtain mates

Intrasexual selection

Competition for mates between same-sex individuals, winner gets access to mate

Intersexual selection

Member of one sex chooses mate based on preference

Is direct combat and sperm competition either Intersexual Selection or Intrasexual Selection

Intrasexual Selection

Sperm competition

Competition between the ejaculates of different males to fertilize the ova of a particular female

Adaptations for Sperm Competition

Larger teste, larger sperm storage organs, larger accessory glands; this produces seminal fluid in which the sperm are transported

What is the deciding factor for female guppies to mate?

Female guppies will mate with brightly colored males

What is the tradeoff for brightly colored males?

Tradeoff between higher mating success and vulnerability to predators

What happened in Endler’s Experimental Tests?

Performed natural selection study to test color patterns in guppies, field experiments in Trinidad and Tobago. When free from predator - spots on male guppies increased

What were the results of Endler’s tests?

Decreased color in male guppies meant that predators fed more on colorful mates, but increased color in nonpredatory environments gave colorful males the mating advantages.

How do male scorpionflies attract females?

Offers a dead arthropods as a food source, thus larger males have a greater reproductive success

What is sociality?

Relationships among individuals change when they begin living in groups and cooperating with each other. This leads to a restriction of reproductive opportunites

What are some examples of sociality?

Mutual grooming, defense of the group, cooperative care of young.

Two examples of caste division of labor.

Leaf cutter ants - division of labor based on size

Naked moles rates - Only one female with multiple males, others are nonreproductive workers and large workers defend colony, while smaller workers do everything else.

What is Inclusive Fitness?

Improve survival and reproductive rates of family members

Kin selection

When an animal engages in self-sacrificial behavior that benefits the genetic fitness of its relatives