Lecture 1: Introduction to Animal Behavior
January 6, 2003
I.
II.
III.
IV.
Lecture outline
A.
Introduction to course (schedule, policies, etc…)
B.
Four categories of questions addressed in animal behavior studies
C.
Origins of animal behavior as a field of study
D.
The Ethological approach
1.
Review: Principles of Evolution
2.
Ethological methods
3.
Key concepts in ethology
Four categories of questions (Niko Tinbergen, 1963); anglerfish example
A.
What are the mechanisms that cause a behavior?
B.
How does a particular behavior develop (within the individual’s lifetime)?
C.
What is its survival value? (current)
1.
What’s the “working hypothesis”? Is it necessarily true?
D.
Why did it evolve? (past)
Origins of Animal behavior as a field of study:
A.
Ethology
1.
Evolutionary perspective
2.
Primarily field-based
3.
Wide range of animals studied
B.
Psychology
1.
Mechanistic/Developmental perspective
2.
Primarily lab-based
3.
Focused primarily on mammals
The Ethological Approach
A.
Principles of evolution
1.
Evolution: Change in the frequency of alleles /genotypes in the
population over time (>1 generation)
2.
Adaptation: A phenotypic trait that helps an individual
survive/reproduce
3.
Genotype vs. phenotype: How are they related? What is the
difference?
4.
Natural selection: Differential reproduction of genotypes leads to
persistence of those genotypes that enable an individual to
survive/reproduce most effectively.
a)
Example: Change in antibiotic resistance of the
tuberculosis bacterium.
5.
Only traits that are variable and inheritable are subject to
natural selection.
a)
Example: Rabbit camouflage
6.
Where does variability come from?
7.
Maintenance of non-adaptive traits
a)
Pleiotropy: Multiple effects of a single gene
b)
B.
C.
Linkage: Gene for non-adaptive trait located near gene for
highly adaptive trait.
c)
Gene flow: Populations in different environments move
between habitats, may interbreed
d)
Ex: Funnel-web spiders
e)
Time lag: Non-adaptive traits are being selected against,
but are not yet completely gone
f)
OR: Maybe the traits are neither variable or
inheritable!
Ethological methods
1.
Comparative approach
a)
Overall concept: Behavioral differences among related
species are due to environmental differences

Example: Comparisons of ground-nesting and cliffnesting gull species (Esther Cullen, 1957)

NOTE: More details of this study in Signs and
Signals video
b)
Benefits of this approach

Be able to explain…
c)
Limitations of this approach

Be able to explain…
2.
Experimental approach
a)
Overall concept: manipulate variables in field or lab and
observe/measure consequences.
b)
Examples: “Classical” experiments in Signs and Signals
video Wednesday (studies by Karl von Frisch, Niko
Tinbergen and Konrad Lorenz)
c)
Benefits of this approach

Be able to explain…
d)
Limitations of this approach

Be able to explain…
Key concepts in ethology
1.
Fixed action patterns
a)
Can be initiated by environmental stimulus, but proceed to
completion

Ex: grayleg goose egg-rolling behavior
b)
Occur in unalterable (stereotyped) sequence

Minor alterations may occur
c)
Are not learned (are innate)
d)
Can be triggered inappropriately

Ex: stickleback response to unrealistic models, etc.
e)
Performed by all appropriate members of a species
2.
Sign stimuli and releasers
a)
Function: Serve to trigger the FAP

Examples…
b)
Supernormal stimuli
c)

Examples…
Mimicry

Examples…
Study questions
1. Be able to list and provide examples of the four categories of questions studied in
animal behavior. Also, given a particular question, you should be able to figure out
the “type” of question. NOTE: Lab 1 explores this in more detail.
2. Provide a definition of the term “evolution” as defined by biologists.
3. What is an “adaptation”?
4. What is “genotype”? What is “phenotype”? How are they related?
5. How is “natural selection” related to evolution? Be able to explain and provide a
clear example of natural selection.
6. What must be true of traits if they are to be affected by natural selection?
7. Where does variability come from?
8. Sometimes, traits that appear to be non-adaptive persist in populations. Provide four
explanations as to how these non-adaptive traits can persist in populations (assume
they are variable and inheritable...)
9. From what two fields of study did the field of Animal Behavior originate? Compare
these two fields of study. NOTE: You will be able to do this more thoroughly after
the first several lectures.
10. Compare the “comparative” vs. “experimental” approaches used to study ethology,
being sure to examine overall methods, benefits, and limitations.
11. What are the key characterstics of fixed action patterns?
12. What is a sign stimulus? Provide and example.
13. What is a supernormal stimulus? Provide an example.
14. How do mimics take advantage of sign stimuli?