Chapter 51 2011 2012

Chapter 51

Behavioral Ecology

PowerPoint Lectures for
Biology, Seventh Edition
Neil Campbell and Jane Reece

Lectures by Chris Romero
Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings

What You Must Know:

• The difference between kinesis and taxis
• Various forms of animal communication.
• The role of altruism and inclusive fitness in kin
selection.


• Behavioral ecology extends observations of
animal behavior by studying how such behavior is
controlled and how it develops, evolves, and
contributes to survival and reproductive success


Concept 51.1: Behavioral ecologists distinguish
between proximate and ultimate causes of behavior

• Behavior is what an animal does and how it does
it
– It is the result of genetic and environmental
factors
– It is essential for survival and reproduction
– It is subject to natural selection over time
• Natural selection: those best adapted to
their environment will survive, reproduce
and pass on their traits to the next
population..


Proximate and Ultimate Questions
• Ethology is the study of animal behavior.
• There are two ways to analyze animal behavior:
1. Proximate, or “how,” questions focus on:
– Environmental stimuli that trigger a behavior
– Genetic, physiological, and anatomical mechanisms
underlying a behavior
– Example: a female bird chooses to mate with a male
bird who sings the best song
2. Ultimate, or “why,” questions focus on evolutionary
significance of a behavior
– Why is that behavior important to survival,
reproduction and passing on traits
– Example: Females who select the best singing males,
have males who sing well

Innate Behaviors:

• Innate behaviors are developmentally fixed.
– They are unlearned behaviors
• You do not have to learn them- you
automatically do them without thinking
• Instincts
• Reflexes
– Example:
• Newly hatched sea turtles go into the ocean


Innate Behaviors/Instincts:

• Fixed Action Pattern
• Kinesis
• Taxis
• Migration
• Circadian rhythms
• Signals
• Waggle dance


Innate Behaviors:

• A fixed action pattern (FAP) is a sequence of
unlearned, innate behaviors that is unchangeable
• Once initiated, it is usually carried to
completion
• Unchangeable
• A FAP is triggered by an external sensory
stimulus known as a sign stimulus
• Example: Nicholas Tinbergen
– male stickleback fish, attack red objects.
– Sign stimulus: red object
– FAP: the attack


•It does not matter the
shape of the fish or
object.
•When male sticklebacks
are presented with an
object with RED, they
attack.
•They do not attack the
fish that looks like a
stickleback, but does not
have any red on it.


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.

Innate Behavior:

• Undirected Movement:
– Kinesis is a simple change in activity in
response to a stimulus.
– Examples:
– Turn on a light and cockroaches randomly
scatter
– **sow (pill) bugs become more active in dry
areas and less active in humid areas
• End up spending more time in damp areas


LE 51-7a

Kinesis

Moist site
Dry open
under leaf
area

Kinesis increases the chance that a sow bug will encounter and stay
in a moist environment.

Innate Behavior:

• Directed Movement:
– A taxis is an automatic movement toward or
away from a stimulus.
• Positive taxis- movement towards the
stimulus
• Negative taxis- movement away from the
stimulus
• Phototaxis- movement in response to light
• Chemotaxis- movement in response to
chemicals
• Hydrotaxis
• Thermo taxis, etc.

Taxis Example:

• Many stream fish exhibit positive rheotaxis
– In response to a current
– they automatically swim in an upstream
direction
– prevents them from being swept away
– keeps them facing the direction from which
food will come


LE 51-7b

Direction
of river
current

Positive rheotaxis keeps trout facing into the current, the direction
from which most food comes.

Innate Behaviors:

• Migration: is a complex behavior seen in a wide
variety of animals.
– Navigation may be by detection of the Earth’s
magnetic field over visual cues


Migration- studies supporting it is innate

• Birds placed in funnel cages left marks indicating
the direction they were trying to migrate

Blackcaps placed in a funnel cage left marks indicating
the direction in which they were trying to migrate.

Innate Behaviors:

• Circadian rhythms: are those that occur on a daily
cycle (24 hours)
– Other rhythms that occur over longer periods
of time may be triggered by:
• Variations in day lengths
• Lunar cycles
– Examples:
• Active/rest cycles


Innate Behaviors:

• A signal is a behavior that causes a change in the
behavior of another individual and is the basis for
animal communication.
• Examples:
• Chemical signals:
– Pheromones: are chemical signals that are
emitted by members of one species that affect
other members of the species.
• Visual signals: such as warning flash- when a deer
lifts its tail- white is seen to warn other deer of
danger
• Auditory signals: bird singing, mating calls, etc.

Chemical Communication Example

• When a minnow or catfish is injured, an alarm
substance in the fish’s skin disperses in the water,
inducing a fright response among fish in the area

Minnows are widely dispersed in Within seconds of the alarm
an aquarium before an alarm substance being introduced,
substance is introduced. minnows aggregate near the
bottom of the aquarium and
reduce their movement.

Innate Behaviors:

• The waggle dance of the honeybee as described
by Karl von Frisch
– The behavior in which the location and
distance of a food source is communicated to
the members of a hive by a foraging worker.


51.2 Learning establishes specific links between
experience and behavior

• Learning is the modification of behavior based on
specific experiences.
– Imprinting
– Habituation
– Spatial learning
– Associative learning
– Classical conditioning
– Operant conditioning
– Cognition


Imprinting

• Imprinting is a behavior that includes learning and
innate components
– Is generally irreversible
– It is distinguished from other learning by a
sensitive period
– A sensitive period is a limited developmental
phase that is the only time when certain
behaviors can be learned


Imprinting Example

• Young geese following their mother
– Konrad Lorenz showed that when baby geese
spent the first few hours of their life with him,
they imprinted on him as their parent

Video: Ducklings


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.

Learned Behavior:

• Habituation: the loss of responsiveness to stimuli
that convey little or no information.
– Simple form of learning
– Example: nagging sibling
– A hydra contracts when disturbed by a slight
touch, but it stops responding if repeatedly
disturbed without further consequences


Learned Behavior:

• A cognitive map is an internal representation of
spatial relationships among objects in an animal’s
surroundings.
– Spatial learning
Nest

No nest
Nest


Learned Behaviors:

• Associative learning is the ability of many animals
to associate one feature of their environment with
another feature.
– Classical conditioning
– Operant conditioning


Learned Behaviors:
• Classical conditioning : a change in responding that occurs
when two stimuli are regularly paired in close succession:
the response originally given to the second stimulus comes
to be given to the first
– Pavlov
– Pair an unconditioned stimulus (food) to cause a
response (salivation) to a conditioned stimulus (tuning
fork) to create the same response (salivation)
– The conditioned stimulus (tuning fork) would not cause
the response (salivation) on its own, it must be FIRST
paired with the unconditioned stimulus (tuning fork)
and then can be removed.
– This results in the dog salivating (response) to the
tuning fork (conditioned response)


Classical Conditioning


Learned Behaviors:

• Operant conditioning occurs as an animals learns
to associate one of its behaviors with a reward or
punishment.
– Rewards: increase the behavior
– Punishments: decrease the behavior
– Skinner
– Trial-and-error learning


Learned Behaviors:

• Cognition is the ability of an animal’s nervous
system to perceive, store, process and use
information from sensory receptors.
– Problem solving
– Perception
– Pattern recognition
– Memory
– Language
– Art


Concept 51.3: Both Genetic makeup and environment
contribute to the development of behaviors.

• Twin studies in humans indicate that both
environment and genetics contribute significantly
to behaviors.
– Personality, temperament, attitude, social
behavior, etc.
• Behavior can be directed by genes.
– For example, a single gene appears to control
courtship rituals in fruit flies.


Concept 51.4: Behavioral traits can evolve by
natural selection
• Because genes influence behavior, natural
selection can result in evolution of behavioral traits
in populations
– Those best adapted to their environment,
survive, reproduce and pass on their traits
(genes).
• As generations continue, those traits will be
more common among the population
• Fitness: refers to how well the organism is
adapted to its environment

Foraging Behavior:
• Foraging behavior not
only includes eating,
but also mechanisms
used in searching for,
recognizing and
capturing food.
• The optimal foraging
model proposes that it
is a compromise
between the benefits
of nutrition and the
cost of obtaining food.

Mating systems

• Vary between species.
• The needs of the young are important in the
development of this behavior:
– Promiscuous- no strong pair-bonds
– Monogamous- one male/one female
– Polygamous- one individual mating with
several others.
• Ornamental males


LE 51-25b

Among polygynous species, such as elk, the male (left) is
often highly ornamented.

Agonistic Behavior

• Are often ritualized contents that determine which
competitor gains access to a resource, such as
food or mates.


Concept 51.5: Inclusive fitness can account for the
evolution of altruistic behavior
• Altruism occurs when animals behave in ways that
reduce their individual fitness, but increase the
fitness of other individuals in the population.
– selflessness
• Example: a blue jay giving an alarm call attracts
attention to its location.
• Example: In naked mole rat populations,
nonreproductive individuals may sacrifice their
lives protecting the reproductive individuals from
predators

• Inclusive fitness: is the total effect an individual
has on proliferating (passing on) its genes by
producing its own offspring and by providing aid
that enables other close relative to produce
offspring.
– The natural selection that favors this kind of
altruistic behavior by enhancing reproductive
success of relatives is called kin selection.


Chapter 51 2011 2012

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