Motor Mechanisms and Behavior Sensory and Motor Mechanisms

Motor Mechanisms and Behavior

Sensory and Motor Mechanisms l l Mechanoreceptors respond to physical stimuli, such as touch or vibration. Reception occurs when a receptor detects a stimulus. Perception occurs in the brain as the information is processed. Ex. When you view an optical illusion in which a figure seems to change, what changes is your perception of the object

Skeletal muscle l l For muscle function to occur, physical interaction of actin (thin filaments) and myosin (thick filaments) must occur. Muscle fibers - myofibrils – actin and myosin

Muscle contraction – sliding filament model l Sarcomere – basic contractile unit of skeletal muscle

Other types of muscle l Cardiac muscle – the heart l Smooth muscle – walls of hollow organs like blood vessels and digestive tract

Nature versus Nurture l l Behavior – action that can be observed and described. Genetic influence l l l Lovebirds, snakes, snails and human experiments Nervous and endocrine systems are both responsible for the coordination of body systems Studies support the idea that certain types of behavior have genetic basis

Nature versus Nurture l Environmental influences (nurture) l Learning: durable change in behavior brought about by experience. l l Laughing gull chicks pecking behavior Imprinting- sensitive period § l Associative learning – change in behavior that involves an association between two events § § l Song learning with white crowned sparrows Classical conditioning - Pavlov, 2 types of stimulus Operant conditioning – Skinner, stimulus/response Insight, imitation, and habituation

Behaviors l l Innate – developmentally fixed, unlearned Fixed Action Pattern: sequence of unlearned acts that is largely unchangeable and usually carried to completion once it is initiated. l Ex. Male sticklebacks and red bellies, triggered by a sign stimulus.

More behaviors l l l Migration – carried out by using environmental clues. Kinesis – a simple change in activity in response to a stimulus (pill bug lab) Circadian rhythms – those behaviors that occur on a daily cycle.

Signals l A stimulus that causes a change in the behavior of another individual and the basis for animal communication

Communication l l l Action by a sender that may influence the behavior of a receiver. Chemical – pheromones, anytime of day Auditory – fast, night or day, can be modified (length, pitch…) Language Visual – restricted to daytime Tactile – grooming, waggle dance of bees

Adaptive mating behavior l l Sexual selection – adaptive changes to secure a mate Fitness – ability to produce offspring Female choice – based on genes and survival or investment for offspring? Male competition – l l Cost (competition) benefit (mating) analyses This all applies to Humans too!

Sociobiology and animal behavior l Living in groups has a great reproductive benefit than cost l l l Ad: Avoid predators, rear offspring, find food Disad: access to food, shelter, sickness Behaviors are selected for the advantages they provide for survival and reproduction.

Altruism l Altruism – behavior that has potential to decrease reproductive success of altruist to benefit the reproductive success of another. l l l Ex. Blue jay giving an alarm call attracts attention to its location. Inclusive fitness – personal reproductive success and reproductive success of relatives Reciprocal altruism – making a minimal short term reproductive sacrifice in order to maximize future reproductive potential