Animal Behavior Chapter 36. I.Science of Animal Behavior A. Ethology Ethology—study of animal...
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Transcript of Animal Behavior Chapter 36. I.Science of Animal Behavior A. Ethology Ethology—study of animal...
Animal Behavior
Chapter 36
I. Science of Animal BehaviorA. Ethology
• Ethology—study of animal behavior in its natural habitat
• Behavior is the way an animal acts in response to a stimulation; usually involve finding food, interacting in social groups,
avoiding predators, and reproducing• Idea that behaviors can be isolated and
measured to trace their evolution• Proximate causation—physiological reasons
for animal behavior• Ultimate causation-selective adaptations are
the reasons for certain animal behaviors• Interested in tracing behavior across species
B. Sociobiology
• Study of social behavior• E.O. Wilson father of sociobiology
• Reciprocal communication between individuals in a group of the same species that
is cooperative and permits the group to become organized
• Differing levels of complexity• individuals that act as 1 large individual,like
Portuguese man-o-war• Social insects like bees, ants, termites
• Groups like elephants, dolphins, primates• humans
C. Behavioral Ecology
• Individual behavior that maximizes reproductive success
• Mate choice, foraging, parenting are all studied
II. Principles of EthologyA. Stereotypical Behavior
• Konrad Lorenz & Niko Tinbergen were pioneers
• Automatic programmed responses to a stimulus in the environment that may mimic
intelligent behavior (usually most effective in the wild); these are instincts
• Releaser—any stimulus that triggers a certain behavior
• Sign stimulus—one specific part of the stimulus that the animal responds to
• Examples—parent’s call releasing the freeze response in a chick; male stickleback
becoming aggressive in presence of other male’s red coloration
B. Control of Behavior1. Innate
• Predictable stereotyped behaviors that are inherited
• Independent of learning but does depend on interactions during development
• Important for survival, especially in animals that do not have parental care
• Reflexes are simplest type and usually protective; instinctive behavior is more
complex series of actions• Longer lived animals may also develop
additional social and learned behaviors since have time to acquire them
2. Genetics
• Inheritance of innate behavior depends on many interacting genes
• Some, however, like honeybee hygiene, are just 1 gene; bees that were recessive for 1
gene, uncapped cells that contained decaying larvae; those that were recessive
for another gene carried out the decayed larvae
• Sometimes crossing purebred dominants and recessives for certain traits creates
hybrids that have confused behavior
3. Learned• Learning is modification of behavior through
experience• Habituation—animal learns to ignore a stimulus
(perceived as harmless or unrewarding) and does not react to it; repeated stimulation
diminishes the release of neurotransmitters from sensory neurons to motor neurons
resulting in no reaction• Conditioning—animal connects a certain
stimulus with a certain behavior; used in training animals usually with a reward
• Sensitization—a noxious stimulus is added to an initial stimulus resulting in a response; later
only initial stimulus need be given to have same result
• More complex learning involves the formation of new neural pathways and connections as
well as changes in existing circuits
3. Learning Con’t
• An animal can only learn to do what it is physically capable of doing
• Imprinting—young animal exposed to object during critical window of development; bond
then lasts for life; ”mother”; learning bird songs
• Trial-and-error learning or operant learning—animal relates its past experience to new
stimulus• Communication—the sharing of information
that results in a behavior change• Language—using symbols to represent ideas
III. Social BehaviorA. Examples
• Response of one animal of a species to another of the same species
• Males fighting over female; breeding may sometimes be the only social interaction
• Monogamy—relationship for life• Mother mammals and birds usually form
bond with young until weaned or fledged• Social aggregations for feeding, warmth,
protection
B. Advantages
• Passive and active defense since safer in group than alone
• More animals in a group, less likely will be eaten• Brings together males and females for breeding;
contact may also bring about necessary endocrinal changes needed for breeding
• Survival of young increases• Hunting, protection from weather, division of
labor, potential for learning and transmitting useful information
C. Disadvantages
• If depend on camouflage for protection, better off dispersed
• Large predators need great quantities of food
• Habitat may not support large numbers of individuals in a certain area
D. Aggression & Dominance
• Social species must cooperate, but not at expense of own interests such a food, mates, shelter
• Aggression—offensive physical action or threat to force others to abandon something
• Agonistic behavior—any activity related to fighting
• Most dangerous weapons used only on prey not on own species, relying on ritualized displays to
avoid injury or death• Ritualized display—behavior that has been
modified through evolution to make it effective in communication; may be used to gain access to
food, mates, or territory; loser runs away or signals defeat by subordination ritual
• Dominance hierarchy—establishes a “pecking” order; weaker members typically die in times of
scarce resources
E. Territoriality
• Territory—fixed area from which intruders of same species are excluded
• May be an alternate behavior to dominance• Ensures food supply
• Provides protected area for mating and rearing young
• Sometimes costs of maintaining a territory outweighs benefits
• Birds tend to form territories; mammals typically have home ranges
F. Mating Systems
• Monogamy--1 male and 1 female mating at a time• Polygamy—general term for any system that has
multiple partners• Polygyny—1 male mates with more than 1
female; male may hold critical resources to attract several mates (resource defense); females
may aggregate making them easily defensible (female defense); female may pick male from
group of males based on display (male dominance)
• Polyandry—1 female mates with more than 1 male
G. Altruistic Behavior & Kin Selection
• Inclusive fitness—relative number of individual’s alleles that are passed on to
future offspring or that of related individuals• Some insect workers, that are haplodiploid,
give up reproduction and aid the queen in reproducing; they are 75% related to sister-
queen’s offspring, rather than only 50% if mated and had own offspring
• In these systems, it is important to be able to distinguish kin from non-kin
IV. Animal CommunicationA. Chemical Signals
• One animal influences the behavior of another though sounds, scents, touch, and movement
• A signal conveys one message and can not be rearranged to construct new kinds of information (in contrast to language)
• Chemical signals evolve easily since there is selection for better detectors
• Pheromones are chemical signals used to attract mates
• Female moths emit pheromones; males use antennae that detect it and then locate female
B. Displays1. Bees
• Communicate location of food through the Waggle Dance
• Figure eight pattern done in comb of hive• Waggle in middle part of the 8 indicates direction of food source relative to the sun
• The speed of the waggle is inversely proportional to the distance the food is from
the hive• If food is close to hive, a found dance is used
instead• Dancing less common when food is plentiful;
more intense when food is scarce
2. Other Organisms
• Courtship dances of birds repeat many displayed behaviors so that a commitment
to courtship is ensured
C. Language
• Animal cognition—mental function, perception, thinking, and memory
• Studies try to detect extent to which animals are self aware and levels of reasoning
• Humans have a hard time determining this in other animals
• Chimps have learned 132 words in ASL• Parrots can vocalize like humans which aids in measuring cognition; can identify shapes,
colors, and numbers