15.3.1 Innate Releasing Mechanisms (IRMs)

• What is the adaptive value of sign stimuli in IRMs?

  Identifies rivals or threats
• IRMs are triggered by specific environmental cues
• IRM activation enables an aggressive response.
• What is the function of IRM activation?

  Initiates FAP
• The fixed action pattern ensures defense of territory and resources.
• The red belly of male stickleback fish is a sign stimulus that triggers aggression
• What are three types of innate behaviors?

  IRMs, reflexes, instincts
• Match the type of innate behavior with its description:

  IRMs ↔️ Genetic neural circuits triggered by sign stimuli

  Reflexes ↔️ Simple, involuntary responses to stimuli

  Instincts ↔️ Complex, genetically determined behavior patterns
• What triggers reflexes?

  Direct interaction with stimuli
• IRMs involve a complete sequence of behavior
• Instincts can be influenced by learning and environment.
• What is an example of an IRM in male stickleback fish?

  Attacking red-bellied rivals
• Reflexes are highly predictable and inflexible
• What is an example of a reflex?

  Knee jerk reflex
• Unlike stickleback fish, humans have complex social and cultural factors influencing aggression
• What are innate releasing mechanisms (IRMs)?

  Genetic neural circuits
• Innate Releasing Mechanisms (IRMs) are triggered by specific environmental stimuli called sign stimuli
• Male stickleback fish display aggressive behavior towards other males due to the red belly sign stimulus
• What is a fixed action pattern (FAP)?

  Stereotyped sequence of behaviors
• When a sign stimulus activates an IRM, it triggers a fixed action pattern (FAP), which is a pre-programmed, stereotyped sequence of behaviors
• Match the components of IRMs with their descriptions:

  Genetic neural circuits ↔️ Pre-programmed neural pathways

  Sign stimuli ↔️ Environmental cues that trigger IRMs

  Fixed action patterns ↔️ Stereotyped sequences of behavior
• What environmental cue triggers aggressive behavior in male stickleback fish during mating season?

  Red belly
• Innate Releasing Mechanisms (IRMs) are activated by environmental stimuli known as sign stimuli or releasers
• Genetic neural circuits in IRMs are pre-programmed pathways in the brain.
• What role do fixed action patterns (FAPs) play in IRMs?

  Stereotyped behavioral sequences
• Innate Releasing Mechanisms (IRMs) are triggered by environmental cues called sign stimuli, which then initiate a fixed action pattern
• Arrange the components of IRMs in the order they function:

  1️⃣ Genetic neural circuits

  2️⃣ Sign stimuli

  3️⃣ Fixed action patterns
• What triggers a fixed action pattern (FAP)?

  Innate releasing mechanism
• Sign stimuli are crucial environmental cues that activate IRMs, which then trigger a fixed action pattern
• The red belly of male stickleback fish acts as a sign stimulus to trigger aggressive behavior.
• What is the sequence of aggressive behavior initiated by the red belly of male stickleback fish?

  Attacking rival males
• What does IRM stand for in animal behavior studies?

  Innate Releasing Mechanism
• IRMs are triggered by specific environmental cues known as sign
• The red belly of a male stickleback fish is an example of a sign stimulus that triggers an IRM.
• What is the role of sign stimuli in activating IRMs?

  Activate genetic neural circuits
• Order the sequence of events from sign stimulus to fixed action pattern:

  1️⃣ Sign stimulus is detected

  2️⃣ IRM is activated

  3️⃣ FAP is initiated
• What does the red color of a male stickleback's belly specifically trigger?

  Aggression
• Sign stimuli are highly specific to certain stimuli.
• Why does the red belly of a male stickleback fish trigger aggression in other males?

  To ensure mating territory
• The red belly of a male stickleback fish is an example of a sign stimulus.