Chapter 51
Behavioral Ecology
I. Proximate and Ultimate Behavior
Elements of behavior
Proximate vs. Ultimate
Ethology
– Fixed-Action Patterns (FAP)
Sign stimulus
– Imprinting
Sensitive period
Figure 51-03
LE 51-4
BEHAVIOR: A male stickleback fish attacks other male
sticklebacks that invade its nesting territory.
PROXIMATE CAUSE: The red belly of the intruding male acts as
a sign stimulus that releases aggression in a male stickleback.
ULTIMATE CAUSE: By chasing away other male sticklebacks,
a male decreases the chance that eggs laid in his nesting
territory will be fertilized by another male.
LE 51-5
BEHAVIOR: Young geese follow and imprint on their mother.
PROXIMATE CAUSE: During an early, critical developmental
stage, the young geese observe their mother moving away
from them and calling.
ULTIMATE CAUSE: On average, geese that follow and
imprint on their mother receive more care and learn
necessary skills, and thus have a greater chance of
surviving than those that do not follow their mother.
Figure 51-06
II. Genetic Component
Directed movement
– Kinesis
– Taxis
– Migration
Animal signals and communication
– Chemical
– Auditory
– Visual
LE 51-7a
Dry open
area
Moist site
under leaf
Kinesis increases the chance that a sow bug will encounter and stay
in a moist environment.
LE 51-7b
Direction
of river
current
Positive rheotaxis keeps trout facing into the current, the direction
from which most food comes.
Figure 51-08
LE 51-9
Minnows are widely dispersed in an
aquarium before an alarm substance
is introduced.
Within seconds of the alarm
substance being introduced, minnows
aggregate near the bottom of the
aquarium and reduce their movement.
Mating and Parenting
– Prarie voles
– AVP – arginine-vasopressin
Table 51-1
III. Environmental Influence
Diet and mate selection
Social learning and aggressive behavior
Learning
– Habituation
– Spatial learning
– Cognitive maps
– Associative learning
Classical conditioning
Operant conditioning
Figure 51-16
IV. Behavior and Natural Selection
Variations exist
Natural selection favors behaviors that
increase fitness
– Foraging
– Mating behaviors and mate choice
LE 51-22
125
60
Average number of drops
50
100
40
Average number of drops
30
75
Total flight height
20
Drop height
preferred
by crows = 5.23 m
10
50
25
0
2
3
5
7
Height of drop (m)
15
LE 51-25
Since monogamous species, such as these trumpeter
swans, are often monomorphic, males and females are
difficult to distinguish using external characteristics only.
Among polygynous species, such as elk, the male (left)
is often highly ornamented.
In polyandrous species, such as these Wilson’s phalaropes,
females (top) are generally more ornamented than males.
LE 51-28
Experimental Groups
Both parents
ornamented
Males
ornamented
Control Group
Females
ornamented
Parents not
ornamented
Results
Females reared by
ornamented parents
or ornamented fathers
preferred ornamented
males as mates.
Females reared by
ornamented mothers or
nonornamented parents
showed no preference
for either ornamented or
nonornamented males.
Males reared by all experimental groups showed
no preference for either ornamented or
nonornamented female mates.
Figure 51-30
V. Inclusive fitness
Altruism
Inclusive fitness
– Hamilton’s rule and kin selection
– Reciprocal altruism
Figure 51-37