social behaviors Flashcards
social behaviors
interactions with members of one’s own species, including mates, offspring, other relatives, and unrelated individuals
predator detection/evasion (group benefits)
a group may be able to fend off predators better than an individual
dilution effect (group benefits)
the reduced, or diluted, probability of predation to a single animal when it is in a group
-probability of death = 1/group size
vigilance-group size effect (group benefits)
more individuals watching for predators allows each individual to spend less time watching and more time feeding
food location (group benefits)
many individuals teaching for food may be able to find rare food more easily
-probability of prey capture may increase in a group
mate finding (group benefits)
being social makes it easier to find potential mates because large groups attract the attention of the opposite sex
lek
the location of an animal aggregation to put on a display to attract the opposite sex
predation (group cost)
groups of animals are more conspicuous to predators
disease transmission (group cost)
the risk of parasites increases in groups
-high densities can increase the rate at which diseases spread
competition (group cost)
larger groups are better able to locate food, but that food must be shared among all members
aggression (group cost)
living in groups can lead to aggression among members
balancing costs and benefits
optimal group size
-not too big or too small
territoriality common
mobile species, limited resources
territoriality uncommon
high population density, unpredictable resources
-benefits of group living
dominance hierarchy
a social ranking among individuals in a group, typically determined through contests such as fighting or other contests of skill and strength
-occurs when defending a territory is impractical
-saves energy by decreasing duration of subsequent contests
donor
the individual who directs a behavior toward another individual as a part of a social interaction
recipient
the individual who receives the behavior of a donor in a social interaction
cooperation
donor = increased fitness
recipient = increased fitness
(herd of lions kill prey)
selfishness
donor = increased fitness
recipient = decreased fitness
(competition for food)
altruism
donor = decreased fitness
recipient = increased fitness
(between relatives)
spitefulness
donor = reduced fitness
recipient = reduced fitness
(does not occur in natural populations)
altruism does not lead to direct fitness
fitness an individual gains by passing on copies of its genes to its offspring
indirect fitness
the fitness that an individual gains by helping relatives pass on copies of their genes
inclusive fitness
the sum of direct fitness and indirect fitness
direct selection
selection that favors direct fitness
indirect selection (kin selection)
selection favoring indirect fitness
coefficient of relatedness
the probability of an individual and its relative carrying copies of the same genes from a recent common ancestor
eusocial animal characteristics (4)
- several adults living together in a group
- overlapping generations of parents and offspring living together in the same group
- cooperation in nest building and brood care
- reproductive dominance by one or a few individuals, and the presence of sterile individuals
caste
individuals within a social group sharing a specialized form of behavior
queen
the dominant, egg-laying female in eusocial insect societies
-typically mate once during their lives
-sons are made by laying unfertilized eggs and daughters are made by laying fertilized eggs (haplodiploid system)
haplodiploid
a sex determination system in which one sex is haploid and other sex is diploid
offspring remain sexually immature until
the king or queen dies
in mole rats why are offspring not willingly subordinate
the dominant female harasses offspring, which increases stress, reduces levels of sex hormones, and makes them less motivated to breed
eusociality has independently evolved many times, how can it evolve
if the cost of leaving a colony is high due to a low likelihood of surviving
