Animal Behavior Chapter 51

YOU MUST KNOW How behaviors are the result of natural selection How innate and learned behaviors increase survival and reproductive fitness How organisms use communication to increase fitness The role of altruism and inclusive fitness in kin selection

Sensory Input & Behavior A. Behavior – what an animal does and how it does it 1. Results from genetic and environmental factors 2. The nervous system’s response to a stimulus (internal or external) , carried out by the muscular or the hormonal system

B. Innate behaviors – fixed, unlearned, inherited 1. Fixed action pattern (FAP) – sequence of unlearned behaviors, unchangeable, carried to completion, triggered by “sign stimuli” ***Goose will complete even if egg is removed

C. Behavior helps an animal Obtain food Find a partner for sexual reproduction Maintain homeostasis https://www.youtube.com/watch?v=oYmzdvMoUUA

In male stickleback fish, the stimulus for attack behavior is the red underside of an intruder When presented with unrealistic models, as long as some red is present, the attack behavior occurs

D. Kinesis & Taxis 1. Kinesis – change of behavior in response to stimuli, generally random, often an increase in rate of movement 2. Taxis – automatic movement towards stimulus

E. Migration – complex, regular, long-distance change in location 1. Stimulus may be visual cues, magnetic fields, position of stars or sun, rhythms, etc. 2. Rhythms – circadian (daily), circannual (yearly), seasonal, lunar

F. Signal – stimulus that causes a change in the behavior of another individual and is the basis of animal communication 1. Pheromones – chemicals emitted 2. Visual signals – warnings, attractants, imitations 3. Auditory – bird songs, warnings

According to early ethologist Niko Tinbergen, four questions should be asked about behavior: What stimulus elicits the behavior, and what physiological mechanisms mediate the response? How does the animal’s experience during growth and development influence the response mechanisms? How does the behavior aid survival and reproduction? What is the behavior’s evolutionary history?

When a minnow or catfish is injured, an alarm substance in the fish’s skin disperses in the water, inducing a fright response among fish in the area (a) Minnows before alarm (b) Minnows after alarm

Learning A. Links experience and behavior B. Learned behaviors – behaviors modified based on specific experiences C. Imprinting – combination of learned and innate components limited to a sensitive period of life, generally irreversible

Associative learning – ability of many animals to associate a feature of the environment with another feature – associates certain stimuli or behaviors with reward or punishment

1. Classical conditioning - a type of associative learning in which an arbitrary stimulus is associated with a reward or punishment For example, a dog that repeatedly hears a bell before being fed will salivate in anticipation at the bell’s sound

2. Operant conditioning is a type of associative learning in which an animal learns to associate one of its behaviors with a reward or punishment “trial-and-error” learning For example, a predator may learn to avoid a specific type of prey associated with a painful experience

E. Cognition is a process of knowing that may include awareness, reasoning, recollection, and judgment Problem solving is the process of devising a strategy to overcome an obstacle Some animals learn to solve problems by observing other individuals https://www.youtube.com/watch?v=fPz6uvIbWZE https://www.youtube.com/watch?v=0N1yAyOGRGU

Behavior and Natural Selection A. Behaviors give selective advantages/disadvantages B. Optimal foraging model – finding balance between having nutrition and cost of obtaining food

Case Study: Variation in Prey Selection The natural diet of western garter snakes varies by population Coastal populations feed mostly on banana slugs, while inland populations rarely eat banana slugs Studies have shown that the differences in diet are genetic The two populations differ in their ability to detect and respond to specific odor molecules produced by the banana slugs

Mating systems – generally determined by needs of young 1. Promiscuous – no strong pair-bonds 2. Monogamous – one male, one female 3. Polygamous – one individual mates with several What are the needs of the young?