Principles of Animal Behavior Notes
Principles of Animal Behavior
Chapter 1: Principles of Animal Behavior
This chapter introduces the field of ethology, the study of animal behavior, highlighting its historical roots and modern approaches. It emphasizes the importance of understanding behavior through various lenses, including natural selection, individual learning, and cultural transmission.
Types of Questions and Levels of Analysis
Ethologists explore animal behavior through four primary types of questions, as outlined by Niko Tinbergen:
Mechanism: What are the stimuli that trigger a behavior? What neurobiological and hormonal changes are associated with the behavior?
Development: How does behavior change as an organism develops? How do developmental factors influence behavior later in life?
Survival Value: How does the behavior contribute to an animal's survival and reproductive success?
Evolutionary History: How does the behavior vary across species, reflecting their evolutionary history? When did the behavior first appear in the species' lineage?
These questions can be approached through two main types of analysis:
Proximate Analysis: Focuses on the immediate causes of behavior, including mechanisms and development.
Ultimate Analysis: Focuses on the evolutionary forces that have shaped the behavior over time, including survival value and evolutionary history.
What Is Behavior?
Defining behavior is complex. A useful definition is: Coordinated responses of whole living organisms to internal and/or external stimuli. This definition distinguishes between organism-level responses (behavior) and organ-level responses (not typically considered behavior).
Three Foundations
Three core concepts form the foundation for studying animal behavior:
Natural Selection: Traits that enhance an animal's reproductive success become more common over generations.
Individual Learning: Animals modify their behavior based on personal experiences.
Cultural Transmission: Animals learn from others through social learning, allowing for rapid spread of information.
Natural Selection
Natural selection operates on behavioral traits. An example is the evolution of flatwing males in Hawaiian crickets. Normally, male crickets sing to attract mates, but this also attracts parasitic flies. On Kauai, a mutation led to the development of flatwings, which cannot sing, avoiding parasites. These males use a "satellite" strategy, staying near singing males to mate with attracted females. This trait was favored with the mutation, and has an advantage of survival and mating.
Another example is xenophobia in common mole rats. Xenophobia (fear of strangers) is stronger in populations facing resource scarcity. Arid-environment mole rats are more aggressive towards strangers of the same sex due to intense competition for limited resources. However, this aggression is tempered in male-female interactions, as strangers can be potential mates.
Individual Learning
Individual learning involves changes in behavior based on experience. For example, female birds might learn to prefer mates that father successful offspring.
Dukas and Bernays's experiment on grasshoppers demonstrates the fitness consequences of learning. Grasshoppers that learned to associate specific cues with a balanced diet had higher growth rates ( percent) than those that learned at random, which translates to greater reproductive success overall.
Cultural Transmission
Cultural transmission occurs when animals learn through social learning. Galef's work on rats shows that they can learn about new food sources by interacting with rats that have recently foraged. Observer rats are more likely to eat food that their tutors have eaten due to olfactory cues (use of smell).
Cultural transmission can have both within- and between-generation effects, influencing behavior across multiple generations.
Conceptual, Theoretical, and Empirical Approaches
Ethology employs conceptual, theoretical, and empirical approaches.
Conceptual Approaches: Integrate disparate ideas in new ways, such as Hamilton's kin selection.
Hamilton expanded natural selection theory to include the concept of inclusive fitness, which includes both direct fitness (number of offspring) and indirect fitness (impact on the reproductive success of relatives). An individual's inclusive fitness is the sum of its direct and indirect fitness.
Theoretical Approaches: Develop mathematical models to explain behavior, like optimality theory.
Optimality theory seeks the best solution to a problem, given constraints. Foraging models, for instance, identify optimal prey choices to maximize energy intake, where represents the total search time, represents the energy provided by a prey type, represents the time it takes to handle the prey, and represents the rate at which prey are encountered.
Empirical Approaches: Use observational and experimental studies.
Observational studies record animal behavior without manipulation. Experimental studies manipulate variables to determine causality.
Interview with Dr. E.O. Wilson
E.O. Wilson discusses the development and legacy of sociobiology. He emphasizes the importance of understanding animal societies as populations with characteristics determined by genetics and ecology. Sociobiology aims to create a cause-and-effect link between natural and social sciences.
Wilson credits Darwin for the concept that instincts evolved by natural selection. He also notes key discoveries in sign stimuli, ritualization, communication, neurobiology, endocrinology, and kin selection.
Wilson advises that animal behavior is fundamental to many biology disciplines. He suggests that social sciences need biology as a foundation. Wilson predicts future advances will link genes to behavior via proteomes, sensors, and neuron circuits.
Summary
The study of animal behavior is ethology. Three important aspects exist for an integrative view: natural selection, learning, and cultural transmission. Tinbergen suggests four types of questions: causes, development, effect on survival and reproduction, and evolution. Ethologists go about their work by applying proximate and ultimate perspectives. Work in ethology can be conceptual, theoretical, or empirical.