Upload
bartholomew-floyd
View
216
Download
0
Embed Size (px)
Citation preview
Animal Behavior
What is behavioral ecology? Behavioral ecology studies how
behavior is controlled and how it develops, evolves, and contributes to survival
Behavior is everything an animal does and how it does it
Ethology is the scientific study of how animals behave, especially in natural environments
Understanding Behavior Questions that must be asked to understand
any behavior: What is the mechanistic basis of the
behavior (chemical, anatomical, and physiological mechanisms)?
How does development of the animal, from zygote to mature individual, influence behavior?
What is the evolutionary history of the behavior?
How does the behavior contribute to survival and reproduction (fitness)?
Fixed Action Patterns One type of behavior studied by ethologists is the fixed
action pattern (FAP) An FAP is a sequence of unlearned behavioral acts that is
essentially unchangeable and, once started, is usually carried to completion Triggered by a sign stimulus (some external sensory
stimuli that triggers the behavior Example: Aggressive behavior in male stickleback fish in
response to the red underside of an intruder fish
The following models were used to induce aggressive behavior. The realistic model did nothing, but the shapes with red bottoms caused aggressive behavior
Imprinting Imprinting is a type of
behavior that includes both learning and innate components and is irreversible There is a limited phase in an
animal’s development which is the only time when certain behaviors can be learned (sensitive period)
Incubator-hatched goslings imprinted on scientist (Konrad Lorenz) during first few hours of life and followed him
Nature vs. Nurture? In biology, it’s not an either/or scenario Genes and the environment both influence
behavior Some behaviors can be altered based on the
environment (still set behavior, but the behavior changes based on changing external conditions)
Other behaviors are virtually identical in a population . . . regardless of external stimuli
Innate behavior is behavior that is developmentally fixed, regardless of the environment
Directed MovementsAnimal movements can have
substantial genetic influence (directed movements)Examples:
KinesisTaxisMigration
Directed MovementsKinesis: a simple change in
activity or turning rate in response to a stimulusExample: pillbugs live best in
moist conditions; they move around more in dry areas and less in moist/humid areasMore movement increases
likelihood they will encounter a moist area
Directed MovementsTaxis = a more or less
automatic, oriented movement toward or away from a stimulusExample: fish swimming
against the currentMigration
Animal Signals & Communication
Many interactions between organisms are a result of sending and receiving information that alters behavior
A signal is a behavior that causes a change in another animal’s behavior
Communication involves the transmission of, reception of, and response to signals between animals
Types of Communication Chemical Communication:
Pheromones – chemically emitted odors that may attract organisms from several kilometers away. Particularly important in reproduction behavior
Auditory Communication: Bird songs and insect songs are also
important in reproductionDrosophila males produce a
characteristic “song” by beating their wings
Environment & Genetics Environmental factors,
such as the quality of the diet, the nature of social interactions, and opportunities for learning can influence the development of behaviors in every group of animals Example: Variations in diet
led to rejection of mates in Drosophila
Learning (start here) Learning is the modification of behavior based on
specific experiences Learning has a large range of expression
From simple imprinting to “learn” to recognize a parent to extremely complex . . . i.e. AP Biology
Habituation: loss of responsiveness to stimuli that convey little or no information If you poke a hydra, it will contract into itself.
Yet, if you keep poking the hydra (not very nice), eventually it will ignore the stimuli if it is not harmed
Evolutionarily it is believed this prevents organisms from wasting energy on stimuli that are not pertinent to survival or reproduction
Learning Spatial Learning: the modification of
behavior based on experience with the spatial structure of the environment, including the location of nest sites, hazards, food, and prospective matesExample: Organisms being able to recognize
landmarksThis is a much more sophisticated form of
learning because it involves “learning” stimulus that may vary in an environment
Learning By putting together several landmarks in a spatial
learning scheme, organisms could traverse to a variety of different environmental locations
Another possibility is the use of cognitive maps, an internal representation of the surrounding environment with spatial relations to each other (a mental map) Sometimes it is difficult to determine if an
organism is using spatial learning or relying on a cognitive map
Associative Learning
Another type of learning has to do with an organism learning behaviors based on experiential factors
Associative learning is the ability of many animals to associate one feature of the environment with another Example: Associating eating one type of
insect with a bad taste
Types of Associative Learning Classical Conditioning
an arbitrary stimulus is associated with a reward or punishmentExample: Pavlov’s Experiment
Operant Conditioning “trial-and-error learning”
Example: Mouse eating distasteful caterpillar OR a coyote getting a face full of quills from a porcupine
Cognition & Problem Solving Some behaviors show more sophisticated levels
of learning Cognition is the ability of an animal’s nervous
system to perceive, store, process, and use information gathered by sensory receptors Cognitive ethology studies how an animal’s
nervous system and behavior interactExample: chimpanzees cracking open oil
palm nuts by observing an experienced chimpanzee performing the task
Natural Selection & Behaviorism The genetic components of behavior evolve
through natural selection Natural selection favors behaviors that increase
survival and reproductive success Foraging behavior – Balance between
benefits of nutrition and cost of finding food (predation, energy, etc.)Cost-benefit analysis
Mating systems and parental careMost animals are promiscuous (no strong pair-
bonding relationship)MonogamousPolygamous (usually single male with many
females)
Reasons for mating systems Finding mates, caring for young, and passing on
genetic traits are strong determining factors in mate selection
Monogamy is important in birds. It takes a lot of work to feed and care for young that are relatively helpless. Both male and female are needed to provide for young, so they stick together
Polygamy occurs when the young can care for themselves at a young age. Males seek to maximize reproductive success
There are many other factors that influence behavior
Sexual selection Reminder:
Intersexual selection: one sex chooses a mate based on some characteristic of the other sex (female usually makes the selection and males vie for selection)
Intrasexual selection: competition of one sex for mates (males fight each other to “win” a female)
Evolutionary impact A lot of male behaviors, or anatomical features, may be
due to intersexual selection Females choose traits and those traits become
selected forPeacock feathers, birdsong, long eyestalks in male
stalk-eyed flies Male behaviors, or anatomical features, may also be
due to intrasexual selection Agonisitic behaviors are ritualized competitions that
teach males to fight for mates
Altruism & Inclusive Fitness
Most social behaviors are selfish
Altruism = when an animal behaves in a way that reduces its individual fitness but increases the fitness of the other individuals in the population Example: squirrels alarm
call, worker bees Helps close relatives (children,
siblings, etc.), thereby increasing the individual’s genetic representation in the next generation (saving close relatives) – “inclusive fitness”
Reciprocal Altruism Sometimes animals will behave
altruistically to other animals that are not related
This behavior can be adaptive if it aids the animal in the future, reciprocal altruism Reciprocal altruism is rare in animals Limited largely to same species that live in
a social group, but not always related (chimpanzees)
Social Learning In addition to genetic and environmental
influences, learning can be influenced by social contact Social learning is learning from
observing the behaviors of others Social learning forms the roots of culture Mistakenly, we believe social learning
only occurs in humans. It may also occur in animal populations
Social Learning Example: Mate choice copying
Female guppies have been seen to mate with males that have been successful in attracting other females
Example: Alarm calls Monkeys learn different calls to symbolize different
predators (leopards, eagles, snakes) When young these calls are inaccurate (any bird may
be given the “eagle” call Yet, as they mature and “learn” to discriminate
species, their calls become more accurate
What about us? Biology is not limited to the study of just
animal behaviors Some scientists study how evolutionary
theory applies to human culture, sociobiology This field is highly controversial
Could be used to justify status quo human societies (caste systems)
Risk of oversimplification