Perception Behavior Perception Behavior How do you see
Perception & Behavior
Perception & Behavior How do you see, hear and feel? How has natural selection shaped our innate reflexes and learned behaviors?
E 1. 1 Definitions • Stimulus = change in the environment (internal or external) that is detected by a receptor and elicits a response • Reflex = a rapid unconscious response • Response = reaction to a stimulus
E 1. 2 Pain Reflex • Reflexes are the product of natural selection; pain allows for danger avoidance • Spinal cord – White matter: connects sections of CNS – Gray matter: environment for relay neurons • Relay neurons receive signal from the sensory neuron through synaptic transmission – Excitatory neurotransmitter muscles contract – Inhibitory neurotransmitter muscles relax
Instincts • Also known as Fixed Action Patterns (FAP) • FAPs are the result of natural selection • Examples – Migration of species to avoid harsh environmental conditions – Humans: yawning, crying, suckling
E 1. 3 Effects of natural selection • European blackcaps (Sylvia atricapilla) – Warblers which migrate between Spain (winter) and Germany (spring and summer) – Change in migration pattern from UK to Spain • UK blackcaps return to Germany 10 days earlier than Spanish blackcaps – Experimental evidence • Eggs taken from both populations of blackcaps. • UK blackcaps hatchlings fly to UK in the absence of parents to follow
E 1. 3 Effects of natural selection • Sockeye salmon – Introduced into Lake Washington in Washington State – Lake salmon: spawn on beaches and lay eggs in sand, heavy males to hide in lake – River salmon: bury eggs in river bottom, thin and narrow bodies to maneuver in fast current
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