BIO 1306 Exam 4 Study Guide: Sensory Systems, Muscle Physiology, and Animal Behavior

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Chapter 50: Sensory Systems and Muscle Physiology

Ear Structures and the Path of Sound Waves

The human ear is divided into three main regions: outer, middle, and inner ear. Each structure plays a specific role in the transmission of sound waves from the environment to the brain.

Pinna: The external part of the ear that collects sound waves (Outer ear).
Auditory Canal: Channels sound waves toward the tympanic membrane (Outer ear).
Tympanic Membrane (Eardrum): Vibrates in response to sound waves (Middle ear).
Malleus, Incus, Stapes: Three ossicles that amplify and transmit vibrations (Middle ear).
Oval Window: Membrane that receives vibrations from stapes (Inner ear).
Cochlea: Spiral-shaped organ where vibrations are converted to neural signals (Inner ear).
Round Window: Allows for movement of fluid within the cochlea (Inner ear).
Hair Cells: Sensory cells in cochlea that transduce mechanical vibrations into electrical signals (Inner ear).
Auditory Nerve: Carries electrical signals to the brain (Inner ear).
Eustachian Tube: Equalizes pressure between middle ear and environment (Middle ear).

Example: Sound waves travel from the pinna through the auditory canal, vibrate the tympanic membrane, are amplified by ossicles, and finally stimulate hair cells in the cochlea, which send signals via the auditory nerve.

Slow vs. Fast Twitch Muscle Fibers

Muscle fibers are specialized for different types of activity based on their structure and function.

Slow Twitch (Type I): Rich in mitochondria, adapted for endurance and continuous contraction; fatigue-resistant.
Fast Twitch (Type II): Fewer mitochondria, adapted for rapid, powerful contractions; fatigue quickly.
Structural Differences: Slow twitch fibers have more myoglobin and capillaries; fast twitch fibers have larger diameter and more glycolytic enzymes.
Functional Differences: Slow twitch for aerobic activities (e.g., marathon running); fast twitch for anaerobic activities (e.g., sprinting).

Types of Muscles

Skeletal Muscle: Voluntary, striated, attached to bones.
Cardiac Muscle: Involuntary, striated, found in the heart.
Smooth Muscle: Involuntary, non-striated, found in walls of internal organs.

Depolarization vs. Hyperpolarization

These terms describe changes in the membrane potential of cells, especially neurons and muscle cells.

Depolarization: Membrane potential becomes less negative (closer to zero); often triggers action potentials.
Hyperpolarization: Membrane potential becomes more negative; inhibits action potentials.
Key Difference: Depolarization increases excitability; hyperpolarization decreases it.

Five Basic Tastes Recognized by Humans

Sweet
Sour
Salty
Bitter
Umami (savory)

Taste and Smell Receptors

Taste Receptors: Located on taste buds; detect chemicals dissolved in saliva.
Smell Receptors: Located in the olfactory epithelium; detect airborne chemicals.
Olfactory Bulb: Brain structure that processes smell information.

Relationship: Taste and smell are closely linked; loss of smell can diminish taste perception.

Chapter 51: Animal Behavior

Niko Tinbergen’s Four Questions

To understand animal behavior, Tinbergen proposed four key questions:

How? (Proximate causation): Mechanisms and development of behavior.
Why? (Ultimate causation): Evolutionary significance and function.

Example: Proximate: How do birds learn songs? Ultimate: Why do birds sing?

Fixed Action Patterns (FAPs) vs. Cognitive Decisions

Fixed Action Pattern: Innate, stereotyped behavior triggered by a specific stimulus (sign stimulus).
Cognitive Decision: Flexible, learned behavior based on information processing.
Example FAP: Egg-rolling in geese.
Example Cognitive: Tool use in primates.

Migration and Biological Rhythms

Migration: Regular, long-distance movement of animals; guided by migration cues (e.g., sun, stars, magnetic field).
Circannual Rhythm: Yearly biological cycle (e.g., hibernation, breeding).
Biological Rhythms: Regular cycles in physiology or behavior (e.g., circadian rhythm).

Signals, Communication, Culture, and Stimulus-Response Chains

Signal: Behavior or feature that conveys information.
Communication: Transmission and reception of signals.
Culture: Learned behaviors shared within a population.
Stimulus-Response Chain: Sequence of behaviors triggered by specific stimuli.

Types of Learning

Visual Learning: Learning by observing visual cues.
Chemical Learning: Learning via chemical signals (pheromones).
Tactile Learning: Learning through touch.
Auditory Learning: Learning by hearing sounds.

Cross-Fostering Studies

Cross-fostering involves raising young of one species by adults of another to study environmental influences on behavior.

California Mice: More aggressive, parental.
White-footed Mice: Less aggressive, less parental.
Main Conclusion: Behavior can be shaped by environment as well as genetics.

Drosophila Foraging Behavior Study

Studies on fruit flies (*Drosophila*) show genetic variation in foraging behavior, with "rovers" and "sitters" exhibiting different strategies.

Optimal Foraging Model

Animals maximize benefits and minimize costs when foraging.

Cost: Energy, risk, time.
Benefit: Nutritional gain.

Example: Birds choose prey that offers the most energy for the least effort.

Imprinting and Sensitive Period

Imprinting: Rapid, irreversible learning during a sensitive period early in life.
Sensitive Period: Specific time when imprinting can occur.

Innate Behavior

Innate behaviors are genetically programmed and do not require learning.

Definition of Learning

Learning is a change in behavior based on experience.

Key Factors: Environment and genetics.

Types of Learning

Spatial Learning: Using environmental cues to navigate.
Associative Learning: Linking two stimuli or events.
Classical Conditioning: Associating a neutral stimulus with a meaningful one.
Social Learning: Learning by observing others.

Reciprocal Altruism vs. Kin Selection

Reciprocal Altruism: Helping others with expectation of future help.
Kin Selection: Helping relatives to increase genetic fitness.
Difference: Kin selection is based on genetic relatedness; reciprocal altruism is based on repeated interactions.

Hamilton’s Rule

Hamilton's rule predicts when altruistic behavior will be favored by natural selection:

Formula:

r: Coefficient of relatedness
B: Benefit to recipient
C: Cost to altruist

Example: If the benefit to a sibling is high and the cost to the actor is low, altruism is favored.

Certainty of Paternity

Internal Fertilization: Lower certainty; often more maternal care.
External Fertilization: Higher certainty; often more paternal care.
Costs and Benefits: Internal: protection, but less certainty. External: less protection, more certainty.

Game Theory and California Lizards

Game theory models behavioral strategies in competitive situations. California lizards exhibit different mating strategies that can be analyzed using game theory.

Sexual Selection Nuances

Imprinting: Early experiences influence mate choice.
Mate-choice Copying: Individuals copy mate choices of others.
Intersexual Selection: Selection between sexes (e.g., female choice).
Intrasexual Selection: Competition within one sex (e.g., male-male competition).

Sociobiology and Human Behavior

Sociobiology: Study of social behavior from an evolutionary perspective.
Human Behavior: Shaped by both genetic and environmental factors.

Additional info:

For detailed mechanisms of muscle contraction, see Chapter 50 worksheets.
For specific examples of animal behavior studies, refer to class notes and PowerPoint slides as indicated.