Genes, environment Topic 9

Definition of evolution: descent with modification

1. Genes produce structures necessary for potential to learn

2. Once learned, behavior may become fixed or plastic (changeable)

3. May require prior experience with a stimulus

4. Behavior can vary with stimuli (external and internal) and across individuals

5. Stimulus initiates learned

In a variable environments, there should be selection for individuals that are good at learning

Habituation: Loss of responsiveness to unimportant stimuli

• not associated with a response

Associative learning: learning to associate a stimulus with a response

1. classical conditioning

   • associate a neutral signal given before a behavior (reflex)

   • train to associate cue with negative or positive reward

2. observational learning

   • learning by watching others and copying

Innate behavior- controlled by a gene

controlled by fos8 gene in mice, nurturing behavior in mice

Innate behavior is highly adaptive if

• have little opportunity to learn

• may learn wrong behavior

• mistakes would be costly- dangerous

Fixed action pattern: a fixed sequence of behaviors that

• is performed the same way every time

• continues to completion (must start over if interrupted)

Key stimulus- also called sign stimulus

• stimulus that triggers a behavior

• often just a subset of stimuli

Evolution of behaviors

Imprinting- form of learning by which young of some species associate an aspect of some stimulus with their care-giver

• includes both a fixed and learned component

• irreversible learned information

• usually only occurs during critical period

• needs stimulus from environment

Animal movement: kinesis

kinesis- movement of an animal in response to the intensity of a stimulus, where:

• the rate of movement or frequency of turning is altered due to the intensity of the stimulus

• the direction of individual movements is random (non-directional)

Taxis- movement of an animal in response to a stimulus gradient where

• the direction of movement is non-random relative to the stimulus

  • positive taxis: towards the stimulus

  • negative taxis: away from the stimulus

Orientation: use of compass direction to determine the direction of movement (follow a bearing or hearing) (innate behavior, they are just following this signal/piece of their environment)

• sun compass

• star compass

• magnetic compass

Piloting: movement relative to landmarks

• requires prior experience

Navigation: movement that involves both orientation and piloting

Kinesis- random scramble