Transcript Chapter 35: Animal Behavior

Chapter 35: Animal Behavior
Section 1: Elements of Behavior
Behavior and Survival
• The behavior of an animal is just as
important to its survival and reproduction
as any of its physical characteristics
• For that reason, animal behaviors have
evolved in many different ways, just as
animal physical characteristics have
• Behavior is in an organism’s genetic makeup
• Behaviors can enhance an animal’s ability to
survive
Behavior and Survival
• There are some behaviors that animals must perform
automatically in order to survive
– “Know” how to hunt soon after they are born
– Dolphins must know in advance that they have to
hold their breath under water
• Other behaviors must be more flexible and capable of
being changed by experience
– Hummingbirds must learn to find food in different
kinds of flowers at different times of the year
Behavior and Survival
• A variety of automatic and flexible behaviors
exist in the animal kingdom
– Instinct
– Learning
Instincts
• Instincts are behaviors that can be called
inborn
• Instincts are built into an animal’s nervous
system and cannot be changed during the
animal’s lifetime, even by learned experiences
• Instinctive behaviors are genetically controlled
• Many instinctive behaviors consist of actions
that always continue in a certain order once
they have begun
Instincts
• Although some instinctive behaviors are
relatively simple, others can be very complex
– Web-building behavior in spiders
– Courtship behaviors in insects, fish, birds,
and mammals
Learning
• Learned behaviors are shaped by experience
• Learning is the way animals change their
behavior as a result of experience
• Learning is valuable to an animal because it
may enhance the animal’s chances of survival
and its chances of reproduction and passing on
its genes to another generation
Learning
• There are several different ways in which
animals learn
– Habituation
– Classical conditioning
– Operant conditioning
– Insight learning
Learning
• Habituation is a decrease in response to a stimulus that neither
rewards nor harms an animal
– One of the simplest ways in which animals learn
– EXAMPLE
• Very young ducks and geese are frightened of any shadow
that moves overhead
• Within a few days of hatching, however, the young birds
find that some shadows moving overhead – the shadows of
adult geese and ducks – mean nothing
• They soon habituate to these shadows and no longer try to
escape from them
Learning
• Classical conditioning occurs when an animal makes
a mental connection between a stimulus and some kid
of good or bad event
– Pavlov’s dogs
• Operant conditioning is sometimes called trial-anderror learning
– An animal learns to behave in a certain way in
order to receive a reward or avoid punishment
• EXAMPLE
– A predator learns not to eat a particular prey
in order to avoid an unpleasant experience
Learning
• In insight learning, an animal applies
something it has already learned to a new
situation – without a period of trial-and-error
– Rare among most animals
– Common only in primates
Instinct and Learning Combined
• Some behaviors cannot occur without some
learning on the part of the animal
• For example, newborn ducks and geese have a
built-in urge to follow their mother
• But this instinct to follow does not include a
picture of what their mother looks like
• This picture must be provided by experience in
a process called imprinting
– The newborn bird will follow the first large
slowly moving object it sees
Chapter 35: Animal Behavior
Section 2: Communication: Signals
for Survival
Communication: Signals for
Survival
• Any time animal behavior involves more than
one individual, some form of communication
is involved
• Communication is the passing of
information from one animal to another
• Animals use many varied techniques to
communicate with one another
Sensing the Natural World
• No two animal species sense the world in the
same way
• Each animal species has a unique way of
gathering and transmitting information
• Understanding the differences between our
sensory world and that of animals is important
in the study of animal behavior
• Today, many scientists study animals under
natural conditions
– Ethologists
Why Animals Communicate
• Animals communicate with one another for a
variety of reasons
– Courtship behavior
– Food
– Potential dangers
How Animals Communicate
• Animals communicate with other members of their species
and with other species
• The ways in which they communicate are limited only by
the kinds of stimuli their senses can detect
– Visual signals
• Movement and color
– Sound signals
– Chemical signals
• Well-developed sense of smell
• Produce special chemicals called pheromones that
transmit information
– Electrical signals
Language
• Some forms of animal communication are
more complicated than any of the signals just
described
– Animal “dances”
• Human language is the most complicated form
of communication
Chapter 35: Animal Behavior
Section 3: The Evolution of Behavior
The Evolution of Behavior
• The physical structures in organisms develop
according to a program contained in their DNA
• Different characteristics are coded in different
genes or groups of genes
• Variations in these genes lead to inheritable
variations in the characteristics of the animals
that carry them
The Evolution of Behavior
• Genes code for behaviors as well as for
physical characteristics
• Evidence for genetic control of behavior can
be demonstrated by crossing closely related
animals that show different behaviors
• The evolutionary fitness of an individual is
increased if it forms some type of social group
with others of its kind