Transcript Adaptiveness of Behavior

Chapter 43
I.
What are the Causes of Behavior?
A. two levels of causation
1. proximate causation
a. immediate basis of behavior (“how”)
b. includes learned behaviors; anatomy and physiology
2. ultimate causation
a. evolutionary basis of behavior (“why”)
b. includes innate and instinctive behaviors
B. behavioral ecology
1. impact of behavior on an organism’s life
2. uses both kinds of causation and many variables are involved
3. habitat selection
a. why do animals live where they do?
b. how is habitat chosen – genetics or learning?
4. foraging behavior
a. why do animals forage where they do?
b. generalists vs. specialists
• opportunists vs. extreme specialists
c. efficiency of foraging
• maximize gain and minimize expenditure
Fig. 43.13
Foraging for food
II.
Biological Clocks
A.
B.
III.
innate mechanisms that allow an org. to perceive lapse & flow of time
biorhythms (cycles)
1. behaviors associated with biol. clocks
2. annual
a. yearly cycles, usually based on the seasons
b. most fundamental life activities are annual cycles
3. lunar
a. based on phases of moon causing the tides
b. Important for intertidal organisms
4. circadian
a. daily, day-night cycles
b. diurnal vs. nocturnal vs. crepuscular
c. can be influenced by photoperiod (day-length)
5. organ, physiological, hormonal, cellular cycles
Orientation and Navigation
A.
navigation
1. directional sense that allows orgs. to make way back to territory
2. compass sense (general direction) vs. map sense (specific location)
•
often coupled to biol. clocks  time-direction mechanism
B. orientation
•
navigation around env. obstacles
C. migration
1.
2.
3.
4.
5.
6.
7.
seasonal movement of a sp. from one geographic location to another
vast distances
between breeding & non-breeding (wintering) grounds
high E and risk
occurs in many species
some sp. only migrate if conditions are very harsh
navigation cues
a.
b.
c.
d.
e.
f.
sun (day migrators)
stars (night migrators)
General Cues
earth's magnetic field
geographical cues (mountains, rivers, etc.)
memory, experience (learning), biorhythms
group cohesion (ind. working together)
Specific Cues
8. migration is triggered by:
1.
2.
physiological cues (esp., changing hormone levels)
changing photoperiod and env. temperature
•
migratory sp. get “restless” just prior to migration
9. combination of genetics and experience
Fig. 43.6
Starling migratory
experiment, showing
the combined effect of
genetics and learning
IV.
Animal Communication
A. any behavior produced by one org. and received by another  response
B. enhances survival and reproduction  reproductive enabling device
C. direct vs. indirect
•
enhancing one’s own reproductive success vs. enhancing success of offspring
D. modes of communication
1. each has advantages and disadvantages
2. visual
a. color, posture, shape, movement
b. graded displays
Fig. 43.9 Male baboon
displaying a full visual
threat display.
Fig. 43.10
Fireflies using visual
communication. Each
number represents the
male flash pattern of a
different species. The
patterns are a behavioral
reproductive isolating
mechanism.
3. vocal
a.
b.
c.
The
repertoire of
a songbird
frequency, amplitude, duration
seismic communication
•
produced in some way other
than vocal apparatus
vocal repertoire
•
sp. full range of vocal comm.
Fig. 43.8 Vocal communication in vervet
monkeys. The monkeys give different
alarm calls according to whether a troop
member sights an eagle or leopard.
4. chemical
a.
b.
c.
pheromones
most basic of all comm. forms
can produce stereotyped behaviors
•
always performed in same way
5. tactile
•
V.
touch or very close proximity
Social Behavior
A.
B.
behavior of orgs. in groups
agonistic behavior
1.
behaviors used to resolve conflict
2.
intraspecific vs. interspecific
3.
territoriality
•
behaviors associated
with defending territory
C.
fighting
•
usually ritualized
o
not to death
Fig. 43.15
Ritualized competition
among elk
Fig. 43.7 Chemical communication with
a pheromone. A male cheetah spraying
urine to mark his territory.
C.
cooperation
•
D.
species or individuals work together for mutual benefit
mating behavior
1. may include sexual dimorphism
•
2.
visual and/or behavioral differences between males and females
often involves species-specific courtship rituals and displays
•
males advertise/display for females  females choose mates
o
female-choice
Fig. 43.14
Sexual dimorphism in
Hamadryas baboons.
The male is silver-white
and twice the size of the
brown females.
Female warblers prefer males with large song repertoires.
3.
4.
several modes of communication used
social dominance hierarchies often play a role
•
males compete among themselves for dominance and position
o
winners have greatest access to females  mate with females

male competition
Female choice and
male dominance
among baboons.
E. symbiosis
1. two or more species living closely together
2. mutualism
• both organisms benefit from relationship
3. commensalism
• one organism benefits, the other is unaffected
4. parasitism
a. one organism benefits, the other is harmed
b. host vs. parasite
c. endoparasites vs. ectoparasites
F. altruism
1. any action that benefits another individual at one’s own expense
2. kin selection
• tendency to help relatives at one’s own expense
3. reciprocal altruism
• “I’ll scratch your back, if you scratch mine”
VI. Sociobiology (E.O. Wilson)
A. applies evolutionary principles to study of social behavior
B. adaptive basis for animals to live together in groups
1. group foraging
2. group protection (“selfish herd” effect)
3. increased vigilance
4. reproductive coordination