BIOL1003 Study Guide - Quiz Guide: Odometer, Courtship Display, Meadow Vole
Behavioural Ecology
An evolutionary approach to animal behaviour
Tinbergen’s Four Questions
1. Development
How does behaviour develop during an animal’s lifetime?
Learning and growth
E.g. role of genes and environment during development in hare colour
2. Mechanism
What are the physiological and other direct causes of behaviour?
Senses and physiology
E.g. does day length or temperature affect colour change?
3. Adaptive function (or survival value)
How does a behaviour help an animal survive or reproduce, and why
has it evolved?
Contribution to survival and reproduction
E.g. does colour affect survival?
4. Evolutionary history
How has current behaviour changed from ancestors?
Changes from ancestors
E.g. colour of ancestors
Inheritance of behaviour
Ways to test if behaviour can be inherited:
oSimilarity between parents and offspring
Similarity between parents and offspring that is not due to learning
or the environment shows that behaviour is heritable
E.g. blackcaps raised in captivity show the same pattern of migratory
behaviour as their parents
oCross-breeding experiments
Genetic crosses between populations with different behaviour can
reveal the mechanisms of inheritance
E.g. cross-breeding in the blackcap leads to an intermediate
behaviour that is probably due to polygenic inheritance
E.g. cross-breeding reveals simple inheritance of hygienic behaviour
in honeybees
oArtificial selection experiments
If some of the variation in behaviour among individuals in a
population is heritable, it should be possible to artificially select for
different behavioural traits
E.g. field crickets can be selected to sing more or less than the
parental population
E.g. behavioural (and morphological) variation among different
breeds of dogs
oMolecular biology
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In some cases, it is possible to track down the particular gene
responsible for differences in behaviour, and even use molecular
genetic methods to transfer genes from one species to another
E.g. inserting the “social” vasopressin receptor gene from Prairie
voles makes the solitary Meadow vole more social
Evolutionary history of behaviour
The heritability of behaviour means that it is valid to ask questions about both the
adaptive value and evolution of behaviour
Behaviour doesn’t fossilise, so it is usually not possible to follow its evolutionary
history directly in the fossil record, but comparison among species can suggest
possible sequences of behavioural evolution
E.g. the bizarre courtship behaviour of the balloon fly could have evolved in small
steps, like the differences among species within the living empidid fly family
Making Decisions
Making decisions
Decisions can affect an animal’s chances of survival and reproduction
We assess whether animals make adaptive decisions
Three methods to study adaptive questions about behaviour:
oObservation
oExperiment
oOptimality modelling
Not that animals can make conscious decisions, but natural selection has resulted in
behaviours that help an animal survive and reproduce
Provisioning of young by Siberian Jays
Have well-hidden nests, but parents visiting a nest with food for young can give away
its location to predators
Parents therefore should visit less when there are more predators around
Eggers found that jays fed at the greatest rate very early in the morning before most
predators became active
This feeding pattern was absent in areas without predators, and could be prompted
by playbacks of predators’ calls, suggesting that jays indeed time feeds to avoid
being spotted by predators
Jays face the dilemma that reducing the risk of predation increases the risk of
starvation, hence an intermediate rate of feeding would be the best
Optimal decisions
Eggers did not make quantitative predictions about the best rate of feeding, because
he did not have precise measures of how parental visit rate affected the nestlings’
predation risk, growth and subsequent survival
Other studies, particularly of foraging behaviour have made quantitative predictions
about animal behaviour
find more resources at oneclass.com
find more resources at oneclass.com
Document Summary
E. g. role of genes and environment during development in hare colour: mechanism. E. g. does day length or temperature affect colour change: adaptive function (or survival value) E. g. does colour affect survival: evolutionary history. Ways to test if behaviour can be inherited: similarity between parents and offspring. Similarity between parents and offspring that is not due to learning or the environment shows that behaviour is heritable. E. g. blackcaps raised in captivity show the same pattern of migratory behaviour as their parents: cross-breeding experiments. Genetic crosses between populations with different behaviour can reveal the mechanisms of inheritance. E. g. cross-breeding in the blackcap leads to an intermediate behaviour that is probably due to polygenic inheritance. E. g. cross-breeding reveals simple inheritance of hygienic behaviour in honeybees: artificial selection experiments. If some of the variation in behaviour among individuals in a population is heritable, it should be possible to artificially select for different behavioural traits.
