2. AP Biology
Why study behavior?
Evolutionary perspective…
part of phenotype
acted upon by natural selection
lead to greater fitness?
lead to greater survival?
lead to greater reproductive success?
3. AP Biology
What questions can we ask?
Proximate causes
immediate stimulus & mechanism
“how” & “what” questions
Ultimate causes
evolutionary significance
how does behavior
contribute to survival
& reproduction
adaptive value
“why” questions
male songbird
→ what triggers singing?
→ how does he sing?
→ why does he sing?
male songbird
→ what triggers singing?
→ how does he sing?
→ why does he sing?
→ how does daylength influence breeding?
→ why do cranes breed in spring?
→ how does daylength influence breeding?
→ why do cranes breed in spring?
Courtship behavior in cranes
→ what…how… & why questions
Courtship behavior in cranes
→ what…how… & why questions
4. AP Biology
The heart of Ethology…….
1. What is the basis of the behavior,
including chemical, anatomical and
physiological mechanisms?
2. How does development of the animal,
from zygote to mature individual, influence
the behavior?
3. What is the evolutionary history of the
behavior?
4. How does the behavior contribute to
survival and reproduction?
Developed by Tinbergen in 1963
5. AP Biology
What is behavior?
Behavior
everything an animal does & how it does it
response to stimuli in its environment
innate behaviors
automatic, fixed, “built-in”, no “learning curve”
despite different environments,
all individuals exhibit the behavior
ex. early survival, reproduction, kinesis, taxis
learned behaviors
modified by experience
variable, changeable
flexible with changing environment
6. AP Biology
attack on red belly stimulus
court on swollen belly stimulus
Innate behaviors
Fixed action patterns (FAP)
Sequence of unlearned acts
that are triggered by a
sign stimulus.
Usually carried out to
completion
male sticklebacks exhibit
aggressive territoriality
7. AP Biology
Complex Innate behaviors
Use of environmental cues to carry out behavior
Migration, Hibernation, Estivation, Courtship
“migratory restlessness” seen in birds bred & raised in captivity
navigate by sun, stars, Earth magnetic fields
Monarch
migration
Sandpiper
ancient
fly-ways
Bobolink Golden plover
8. AP Biology
Innate: Directed movements
Taxis
Response movement toward (positive taxis) or
away from (negative taxis) a stimulus
phototaxis
chemotaxis
Kinesis
Random movement in
response to a stimulus
ex: stopping, starting, or
turning.
ex: sowbug activity
increases when conditions
are dry.
9. AP Biology
Learning: Imprinting
Young animals go through a “critical
period” whereafter they follow the
organisms present during the period.
Konrad Lorenz
10. AP Biology
Learning: Associative
learning to associate
a stimulus with a
consequence
operant conditioning
trial & error learning
associate behavior with
reward or punishment
ex: learning what to eat
classical conditioning
Pavlovian conditioning
associate a “neutral
stimulus” with a
“significant stimulus”
11. AP Biology
Operant conditioning
Skinner box
mouse learns to associate behavior
(pressing lever) with reward (food pellet)
Basic animal
training with
rewards for
behaviors.
12. AP Biology
Learning: Habituation
Loss of response to
stimulus
“cry-wolf” effect
decrease in response to
repeated occurrences of
stimulus
enables animals to
disregard unimportant
stimuli
ex: falling leaves not
triggering fear response in
baby birds; animals
standing next to hwy
13. AP Biology
Learning: Spatial
Establishment of
memories that reflect the
physical structure of the
environment.
Squirrels using physical
markers to find buried
food.
Wasps using physical
markers to find their
nest.
14. AP Biologysea otter
Learning: Problem-solving/Cognition
Involves reasoning,
awareness, recollection and
judgment
tool use
crow
Insight learning
15. AP Biology
Social behaviors
Interactions between individuals that develop
into evolutionary adaptations
communication / language
agonistic behaviors
dominance hierarchy
cooperation
altruistic behavior
17. AP Biology
Communication by song
Bird song
species identification & mating ritual
mixed learned & innate
critical learning period
Insect song
mating ritual & song
innate, genetically
controlled
Red-winged blackbird
18. AP Biology
Social behaviors
Agonistic behaviors
threatening & submissive rituals
symbolic, usually no harm done
ex: territoriality, competitor aggression
20. AP Biology
Social behaviors
Pack of African dogs
hunting wildebeest
cooperatively
White pelicans “herding”
school of fish
Cooperation
working together in coordination
21. AP Biology
Social interaction requires communication
Pheromones
chemical signal that stimulates a
response from other individuals
alarm pheromones
sex pheromones
22. AP Biology
Pheromones
Spider using moth sex
pheromones, as allomones,
to lure its prey
The female lion lures male by spreading sex
pheromones, but also by posture & movements
Female mosquito use CO2
concentrations to locate victims
marking territory
23. AP Biology
Behaviors should increase fitness!
Foraging behavior – cost and benefits
Mating systems – monogamy vs.
polygamy
Certainty of paternity
Agonistic behavior
Game theory – California lizard species
Orange outcompetes blue
Blue outcompetes yellow
Yellow outcompetes orange
24. AP Biology
Social behaviors
Altruistic behavior
reduces individual fitness but
increases fitness of recipient
kin selection
increasing survival of close relatives passes
these genes on to the next generation
How can this be of adaptive value? Belding ground squirrel
25. AP Biology
“Picture a hot dog that's been left in a microwave a little
too long…add some buck teeth at one end, and you've got a
fairly good idea of what a Naked Mole Rat looks like.”
Colonial mammals are altruistic!
Naked mole rats
underground colony, tunnels
queen, breeding males, non-breeding workers
hairless, blind
26. AP Biology
Make sure you can…
Provide proximate and ultimate
explanations for behaviors
Compare innate and learned behaviors
and provide examples of each
Describe how a particular behavior can
evolve
Explain how particular behaviors
contribute to an organism’s fitness
Explain how altruistic behaviors can
evolve in a population
Proximate cause questions
Male songbirds sing during the breeding season as a response to a high level of testosterone which binds to hormone receptors in the brain & triggers the production of song.
Ultimate cause questions
The male sings to defend territory from other males & to attract a female with which to reproduce. This is the evolutionary explanation for the male’s vocalization.
Proximate cause questions
The red–crowned cranes, like many animals, breed in spring and early summer. A proximate question about the timing of breeding by this species might be, “How does day length influence breeding by red–crowned cranes”? A reasonable hypothesis for the proximate cause of this behavior is that breeding is triggered by the effect of increased day length on an animal’s production of and responses to particular hormones. Indeed, experiments with various animals demonstrate that lengthening daily exposure to light produces neural and hormonal changes that induce behavior associated with reproduction, such as singing and nest building in birds.
Ultimate cause questions
In contrast to proximate questions, ultimate questions address the evolutionary significance of a behavior. Ultimate questions take such forms as, Why did natural selection favor this behavior and not a different one? Hypotheses addressing “why” questions propose that the behavior increases fitness in some particular way. A reasonable hypothesis for why the red–crowned crane reproduces in spring and early summer is that breeding is most productive at that time of year. For instance, at that time, parent birds can find ample food for rapidly growing offspring, providing an advantage in reproductive success compared to birds that breed in other seasons.
Bird migration, a behavior that is largely under genetic control. Each spring, migrating western sandpipers (Calidris mauri), such as those shown here, migrate from their wintering grounds, which may be as far south as Peru, to their breeding grounds in Alaska. In the autumn, they return to the wintering grounds.
The sow bugs become more active in dry areas and less active in humid areas. Though sow bugs do not move toward or away from specific conditions, their increased movement under dry conditions increases the chance that they will leave a dry area and encounter a moist area. And since they slow down in a moist area, they tend to stay there once they encounter it.
In contrast to a kinesis, a taxis is a more or less automatic, oriented movement toward (a positive taxis) or away from (a negative taxis) some stimulus. For example, many stream fish, such as trout, exhibit positive rheotaxis (from the Greek rheos, current); they automatically swim or orient themselves in an upstream direction (toward the current). This taxis keeps the fish from being swept away and keeps them facing the direction from which food will come.
But how do the young know on whom—or what—to imprint? How do young geese know that they should follow the mother goose? The tendency to respond is innate in the birds; the outside world provides the imprinting stimulus, something to which the response will be directed. Experiments with many species of waterfowl indicate that they have no innate recognition of “mother.” They respond to and identify with the first object they encounter that has certain key characteristics. In classic experiments done in the 1930s, Konrad Lorenz showed that the most important imprinting stimulus in graylag geese is movement of an object away from the young. When incubator–hatched goslings spent their first few hours with Lorenz rather than with a goose, they imprinted on him, and from then on, they steadfastly followed him and showed no recognition of their biological mother or other adults of their own species. Again, there are both proximate and ultimate explanations
View Waggle Dance AVI file: waggledance180x135.avi
View Lifewire territoriality video: “lizards cost of defending-lifewire.swf”
Review setting up a behavior experiment:
The luring function of sex pheromones is a perfect way for predators to get heir prey without having to work too hard. The spider Mastophora hutchinsoni spreads sex pheromones of moths, using them as allomones. This way he can lure about enough moths to sustain. When the moths fly in, convinced they are about to mate, the spider shoots a sticky ball on wire towards them. As they stick to the ball, he drags them in and eats them.
