2. LEARNING OBJECTIVES
• Describe how behavior can improve survival.
• Describe how behavior can improve
reproductive success.
• Describe the benefits and drawbacks of
living in a group.
• Compare and contrast the behavioral
adaptations of solitary and social animals.
• Explain why male cuttlefish mimic females of
the species.
7. How can natural selection cause
evolution of behaviors?
VIDEO: This is how your brain grows
8. Examples of proximate and ultimate
explanations of behavior
Section 36.1
This figure summarizes some examples of proximate and
ultimate explanations of behavior.
Figure 36.27
Fruit Fly Courtship Mole Rat Nest Building Ground Squirrel Alarm
Call
Cuttlefish Female
Mimicry
Proximate
cause
(explains how
behavior
occurs)
The fru gene guides
development of motor
neurons involved in
courtship.
Mole rats detect magnetic
field lines and build nests
(long underground tunnels)
from north to south.
Adult females use neural signals
and muscles to produce a
distinctive alarm call when they
see a predator.
Small males use neural
signals
and muscles to change their
color and pull in their arms,
appearing more like females.
Ultimate cause
(explains why
behavior is
adaptive)
Courtship with a female of
the same species leads
to copulation and prevents
mating with other species.
Mole rats can orient
themselves toward or
away from the nest exit
without visual stimuli.
The alarm call signals danger
to nearby ground squirrels, many
of which are related to the calling
female.
Large males guard females.
Small males that mimic
females
can slip past the guard and
mate with the female.
12. An example of a fixed action pattern
Section 36.2
A classic example of a fixed action
pattern comes from research done by
Niko Tinbergen, one of the founders
of modern ethology.
Tinbergen found that any object that
was red on the bottom was a stimulus
for an aggressive response in
stickleback fishes, even if the object
did not resemble a fish.
Since rival males have red undersides,
being aggressive toward anything that
resembles a rival male is adaptive.
Figure 36.2
Stimulus
Simple models with red
undersides
Accurate model without red
Response
Models are attacked
Model is ignored
13. Fixed action patterns are genetically
determined and inherited
Section 36.2
Fruit fly copulation is another example of a fixed
action pattern. Scientists have determined that a
gene called fruitless is responsible for developing the
motor responses of this behavior.
Figure 36.3
1. Orienting:
male detects
female
2. Tapping:
male taps
female’s
abdomen
3. Singing:
male
vibrates
wing
4. Licking:
male licks
female’s
abdomen
5. Attemptin
g
copulatio
n
6. Copulatio
n: male
mates with
female
(b): Courtesy of Professor Daisuke Yamamoto, Tohoku University/JST-ERATO project
15. Genes and the environment interact to
determine behavior
Section 36.2
Learning plays an important role
in song development among
young birds. Birds that never hear
their normal song will develop an
abnormal song.
If a bird is exposed to a song of
another species, the result is no
better than if the birds heard no
song at all. A genetic template
therefore guides young birds to
learn the correct song.
Figure 36.6
17. Optimal foraging theory
Section 36.3
Optimal foraging theory
predicts that an animal’s food-
finding strategy should
maximize the amount of energy
collected per unit of time.
For example, crows that eat
snails must first break the
shell. The bird picks up the
snail, flies with it, and drops it
on a rock.
Figure 36.10
