Chapter 51: Animal Behavior

Nurture or Nature?

Nurture or Nature?

I. Evolution: Process by Which “Fit” Genes are passed to next generation.

Evolution drives biology, including

behavior.

Behaviors are favored if they increase survival AND chance of passing on genes!

II. Influences on Behavior

A. Genes: Example, Bird song

II. Influences on Behavior

A. Genes

Fixed Action Pattern: Inborn (genetic)response to a environmental cue; operates independent of feedback.

II. Influences on Behavior

B. Hormones: A chemical released by one cell that affects other cells.

Pheromones: A hormone released by one organism that influences another organism of the same species.

C. LearningIII. Types of Learning

A. Imprinting:

III. Types of Learning

A. Imprinting: Time-dependent learning in response to a sign stimuli. Usually early in life.

• Must involve time.• Ducks, geese at birth.• Human language?

III. Types of Learning

B. Habituation – Learning that certain stimuli have no effect, thus eliminating a response to such stimuli.

• Loss of a natural response.

III. Types of Learning

C. Classical Conditioning: Linking of involuntary, unconditioned response to a previously meaningless trigger. Learner

responds to environment; trigger doesn’t depend on behavior.

• Classic experiment: Pavlov’s dog• Stimulus precedes action

III. Types of Learning

D. Operant Conditioning: Linking of voluntary action with consequence/stimuli. Learner operates on environment; stimuli depends upon behavior.

• Toad eating a wasp (once)• Trial-n-Error Learning

III. Types of Learning

E. Spatial/Latent Learning – Many animals are able to navigate familiar territory by memorizing landmarks.

III. Types of Learning

F. Insight Learning or Cognition– "Higher" learning, associated with problem solving and reasoning.

• Only in some birds and mammals.

IV. Social Behaviors

Why?

IV. Social Behaviors

A. Altrustic Behavior vs. Selfish Genes

1. Altrustic: Caring for others, even to the point of sacrificing one’s life.

2. Selfish: Infanticide example in gorillas. Often falsely implied in ‘survival of the fittest.’

IV. Social Behavior

B. Theory of Kin Selection

Altruistic Behavior may help pass on genes through relatives.

IV. Social Fitness

C. Inclusive Fitness: Sum of number of alleles/genes directly passed on as offspring and number of alleles/genes passed on by kin (relatives).

D. Why Biological Altruism?

Social Group Benefits:

1. Care for young,

2. Cooperative hunting,

3. Care for old/weak,

4. Cooperative efforts (bee hive),

5. Specialization.

Fig. 47.23, p. 849