Transcript Chp 51 Animal Behavior

Behavior
Chapter 51
Behavior is what an animal does and how it
does it




Behavior is influenced by innate (present at
birth) and learned factors.
Behavioral ecology emphasizes evolutionary
hypotheses.
Optimal behavior = A behavior that maximizes
individual fitness.
Optimal behavior is a valid concept if behavior
is genetically influenced and subject to natural
selection.
A behavior has both an ultimate and a
proximate cause


Ultimate causation =
The evolutionary reason
for the existence of a
behavior.
Proximate causation =
The immediate cause
and/or mechanism
underlying a behavior.
Innate behaviors
Fixed-action pattern = A
highly stereotyped,
innate, behavior.
 Sign stimulus = An
external sensory
stimulus which triggers
a fixed-action pattern.

Learning is modification of behavior



While European ethologists were discovering
innate behaviors in nature, American
psychologists were finding learning abilities in
lab animals.
Nature versus nurture = The debate over
whether instinct or learning is of primary
importance in animal behavior.
Modern biologists feel that behavior is a result of
genetic and environmental factors.
Changing behavior




Habituation = Learning to
ignore irrelevant stimuli or
stimuli that do not provide
proper feedback.
Imprinting is a form of learning
closely associated with innate
behavior. (Konrad Lorenz)
Imprinting stimulus = An object
in the environment to which the
response is directed.
Critical period = A limited time
during which imprinting can
occur.
Conditioning


Classical conditioning = A
process in which an animal
learns to respond to an external
stimulus which does not normally
elicit that response.
Operant conditioning = A process
where an animal learns to
associate one of its behaviors
with a reward or punishment and
then tends to repeat or avoid that
behavior.
Rhythmic behaviors




Animals repeat behaviors at
regular intervals (daily,
seasonally).
Circadian (daily) rhythms are
regulated by environmental cues.
Light is the most common
external cue (nocturnal/diurnal).
Breeding and hibernation are
partially based on physiological
and hormonal changes linked to
external factors such as day
length.
Environmental cues guide animal
movement



Animals use a variety of cues
to guide them in their
movements.
Kinesis = A randomly directed
change in activity rate in
response to an environmental
stimulus.
Taxis = An oriented
movement toward or away
from a stimulus. (chemotaxis,
phototaxis, geotaxis)
Social behavior




Social behavior = Interaction
between two or more animals.
(Signals include physical movement
and chemicals.)
Agonistic behavior = A contest of
threat displays which continues until
a participant submits and yields
access to a resource (e.g. mate,
food, territory).
Ritual = Symbolic behavior that
minimizes the possibility of serious
injury to the antagonists.
Territoriality = defense of areas
typically used for feeding, mating,
rearing young etc.
Mating Systems





Promiscuous = A mating system with no
strong pair-bonds or lasting relationships.
Monogamous = A mating system where one
male mates with one female.
Polygamous = A mating system where an
individual of one sex mates with several of
the other.
• Polygyny is a mating sub-system where
one male mates with multiple females.
• Polyandry is a mating sub-system where
one female mates with multiple males.
Mating Systems (cont)


Certainty of paternity is relatively low in
species with internal fertilization because
mating and birth (or egg laying) are
separated over time. Exclusive male parental
care is rare in birds or mammals.
Certainty of paternity is higher when egg
laying and mating occur together, as in
external fertilization. Parental care, when
present, in fishes and amphibians is as likely
to be by males as by females.
Fitness and altruistic behavior



Altruistic behavior = A
behavior that reduces an
individual's personal welfare
but benefits others.
Inclusive fitness = The
reproductive fitness of an
individual as measured by its
offspring and assistance to
the reproductive efforts of
close relatives.
Kin selection = The
mechanism of increasing
inclusive fitness.