Lec01 - Animal Behaviour.docx
2 animal behaviour
What is animal behavior?
What do genes and environment interact?
What are major types of behavior?
How to animals communicate with one another?
How does behavior influence survival and reproduction?
Why do animal societies evolve?
How does behavior influence populations / communities
3 what is animal behavior
Humans have always studied animal behavior – informally
Animal behavior – informs behavioral ecology = study of how organisms make decisions that
influence their survival and reproductive success
Study of how animals decide
o Where to carry out activities
o Select resources
o Respond to predators and competitors
o Interact with conspecifics
= other members of their species
4 animal behavior = ethology
Study of animal behavior in natural environments from an evolutionary prospective
In natural environments
What are the questions that must be answered to understand any behavior?
o What is the mechanistic basis of the behavior, including chemical, anatomical,
o How does development of an animal influence behavior?
o What does the evolutionary history of the behavior?
o How does behavior contribute to survival and reproduction (fitness)?
5 how do genes and environment interact
Genes do not encode behavior
Gene products (e.g. enzymes) can affect behavior by starting a series of gene-environment
interactions that underlie development of behavioral mechanisms
Experimental methods to determine how genes and environment influence behavior:
o Deprivation experiments
Young animals are reared with no experiences related to behavior
o Genetic experiments
Genome is altered by interbreeding; by comparing individuals that differ by only
one gene; or by knocking out or inserting specific genes
6 what are the major types of behavior?
Biologists study the ways both genes and the environment influence the development of
Nature-vs-nurture issue is not about whether genes or environment influence behavior – how
are both involved?
Types of behavior:
o Instinctive behavior
Genetically programmed response
Complete and functional on first use
o Learned behavior
Dependent upon experiences during development
7 instinctive behaviors
Is innate behavior
Often highly stereotyped
Variation may reflect underlying genetic differences
o Directed movements
o Fixed action pattern
8 instinctive behaviors – kinesis
Involves a simple change in activity or turning rate in response to a stimulus
E.g. pill bugs
9 instinctive behaviors – taxis
Is a more or less automatic, oriented movement toward or away from a
10 instinctive behaviors – fixed action pattern
Fixed Action Pattern (FAP)
o Some behaviors – expressed only in certain conditions, where an object, event, or
condition is required to elicit a behavior
releaser or sign stimulus
o sequence of unlearned, innate behaviors that is unchangeable
o usually carried to completion once initiated
o triggered by an external sensory stimulus
11 examples of fixed action pattern
stereotypic behaviors can be adjusted by spatial cues in the environment:
o spider adjusts web to fit geometry of nearby structures
o digger wasps learn location of their nest by remembering features around it
e.g. use landmarks
12 examples of fixed action pattern
in male stickleback fish
o sign stimulus for attack behavior is red underside of intruder
o even when presented with unrealistic models with some red present on the underside,
attack behavior occurs
o The red belly of the intruding male acts as a sign stimulus that releases aggression in a
o By chasing away other male sticklebacks, a male decreases chance that eggs laid in his
nesting territory will be fertilized by another competing male
13 examples of fixed action pattern
In herring gulls
o Sign stimulus for pecking behavior of chicks is a red spot on lower beak of parent
o The red spot on parent’s beak acts as a sign stimulus that triggers pecking behavior of
chick to get food
o Ensures chicks get fed and survive until the can feed on their own
14 learned behaviors
Is modification of behavior
Based on specific prior experiences
Range from very simple to very complex