Review
- Behavior: reaction of living things to stimuli (either from the physical environment or other living things)
- Behaviors may be encoded in DNA or learned; group behaviors or individual
- Behavior used to maintain homeostasis, find mates and nutrients
- Proximate causation: how a behavior occurs or is modified
- Ultimate causation: why a behavior occurs in the context of natural selection
- Do it to increase fitness → find mates or survive
Kinds of Animal Behavior
- Instinct: behaviour that is innate/inherited (genetically controlled)
- Ex: in mammals, care for offspring by the female parent is innate
- Fixed Action Patterns (FAPs) innate behaviors that follow a regular, fixed pattern
- Initiated by specific stimulus and usually carried out to completion
- Sign stimulus: external cue thats acts as a trigger for the behavior
- Ex: if goose sees egg outside nest will roll back to nest → egg is stimulus → anything that looks like the egg will be treated same
- Male stickleback fish defend territory against other males → red belly of a male is a stimulus for aggressive behaviour → any object with red initiates aggressive FAP
- Imprinting: an innate program for acquiring a specific behaviour only if have correct stimuli experienced during critical/sensitive period (limited time interval during life of an animal) → irreversible
- Ex: geese goslings will accept any moving object as mothers, salmon imprint odors associated with birthplace so that they can return
- Learning
- Learning: the modification of behavior as a result of specific experiences
- Capacity for learning depends on nervous system organization established during development following instructions encoded in the genome
- Associative Learning (association) occurs when animal recognizes (learns) that two or more events are connected
- One form called classical conditioning when an animal performs a behavior in response to substitute stimulus rather than normal stimulus
- Ex: dogs salivate when presented with food → bell rung before giving food → dogs salivate in response to bell ringing alone; associated ringing of bell (substitute stimulus) with presentation of food (normal stimulus)
- Trial-and-error learning (operant conditioning): form of associative learning when an animal connects its own behavior with environmental response.
- If response is desirable (positive reinforcement) animal will repeat behavior
- If response is undesirable, animal will avoid behavior
- Learning acquired by association can be forgotten or reversed if performed behavior does not result in expected response
- Extinction: loss of acquired behavior
- Spatial learning: form of associative learning when an animal associates attributes of a location (landmarks) with reward it gains by going back there
- Ex: wasps were able to associate nearby markers (pine cones) with location of nests; removed markers and couldn’t identify
- Habituation: learned behavior that allows animal to disregard meaningless stimuli
- Sea anemones tentacles can ignore nonfood items after repeated attempts to grab food
- Observational learning: when animals copy behaviors of another animal
- One monkey learned that could more easily clean potatoes in water and soon all monkeys did same
- Cognition and Problem Solving
- Cognition: the process of knowing that involves awareness, reasoning, recollection, and judgment
- Problem solving: the cognitive ability to overcome obstacles
- Insight: when an animal, exposed to new situation with no experience, performs behavior with desirable outcome
- Ex: monkey will stack boxes to climb and access previously unreachable bananas
- Signaling behavior: response and communication between organisms that can change behavior and reproductive success
- Organisms exchange info in response to internal and external signals
- Cooperative behavior increases fitness of individuals and survival of the population
Notes
- Some behaviors that appear learned may be innate but need maturation
- Ex: birds appear to learn to fly by trial and error or observational learning but birds raised in isolation will fly on first try if are physically capable
- Inherited behaviors and learning capabilities have evolved because increase individual fitness
- Innate behaviors improve fitness by providing dependable mechanic for animal to respond to expected behavior
- Associative learning allows individuals to benefit from unexpected events
- Once form association can respond appropriately next time
- Habituation allows them to ignore repetitive events which have learned (from experience) are inconsequential → can focus on more important events
- Observational learning and insight allows animals to learn new behaviors in response to unexpected events without receiving reinforcement
- Game Theory: The fitness of a particular behavior is influenced by other behavioral phenotypes in a population
General Animal Behaviors
- Animal always encountering different situations so respond to each in way that maximizes survival and reproductive success (fitness)
Survival responses: when encounters dangerous situation
- Fight-Flight response: animal encounters situation where must either fight or run
- Response is triggered by stress and stimulates nervous system to produce adrenaline → prepares body by dilating blood vessels, increasing heart rate, and increasing release of sugar from liver into blood
- Avoidance response: when animal avoids encountering a stressful situation → associative learning bcuz recognizes that is stressful
- Ex: avoid predator habitats, unfamiliar objects, scents, or sound
- Alarm response: triggered when animal detects threat so warns group
- Ex: monkeys emit distinctive alarms for intruders, with special calls for snakes, birds and leopards
Foraging Behaviors:
- Optimal foraging model: natural selection should favor a foraging behavior that maximizes the benefits (food eaten) & minimizes the costs (energy extended and risk) + behaviors that increases survival of populations
- Flower color and flower scent are signals that animals use to locate flowers (and that plants use to attract them)
- Often vision and olfactory abilities of animals have coevolved with flower color and scents
- Flowers provide animals protein (from pollen) and carbs (sugar in nectar) ←→ animals disperse pollen
- Ex: bees attracted to blue or yellow flowers with sweet smell
- Flowers provide animals protein (from pollen) and carbs (sugar in nectar) ←→ animals disperse pollen
- Fruit color: a signal that animal uses to locate fruit and know if are ripe/edible or toxic
- Sometimes fruit color is warning that is poisonous; chemical signals provide cues that is edible
- Food toxic to one animal may be nutritious for another and many animals have evolved metabolic pathways to detoxify plant materials
- Ex: monarch butterflies use milkweeds to make themselves toxic
- Body scents: signals presence of predators
- Ex: zebras increase vigilance when detect body odor
- Herds, flocks, and schools provide advantages when foraging
- Concealment: most individuals hidden from view
- Vigilance: more ppl watching
- Defense: can shield or mob attack
- Packs: corner and attack large prey
- Search Images: look for abbreviated forms of of object to find favored or plentiful food
Social Behavior
May live in group or alone; always make contact to reproduce
- Agonistic behavior (aggression and submission) originates from competition for food, mates, or territory
- Parental Care: innate behavior in response to producing offspring
- Paternal behavior exists because it has been reinforced over generations by natural selection
- Dominance Hierarchies: indicate power and status among individuals in group → minimize fighting
- Pecking order
- Territoriality: possession and defense of territory → ensure enough food and safety
- Eusocial (truly social) consists of members divided into castes
- One caste will forage, other will feed and care
- Altruistic behavior: seemingly unselfish behavior that appear to reduce fitness of an individual
- Often occurs when animal risks safety in the face of another to help another individual (of same species) rear its young
- This behavior increases inclusive fitness: fitness of individual plus fitness of relatives (share % DNA)
- Evolution of these behaviors occurs by kin selection: form of natural selection that increases inclusive fitness
- Altruistic behavior can be maintained by evolution because furthers survival of population
- Ground squirrels give alarm calls that warns other squirrels of predators but risks own safety by revealing presence
- These squirrels live in groups of closely related females so is example of kin selection
- Bees live in colonies made of queen and female daughters (worker bees) → only queen reproduces so fitness of workers is zero
- Kin selection favors sterile workers in haplodiploid society because all sister bees share 75% genes and fitness of worker bees (by how much genes contributes to the next gen) is greater if it promotes production of sisters by nurturing queens rather than by themselves.
- Reciprocal Altruism: exchange of aid between unrelated individuals
- Do it bcuz think they will receive something in return in future
Animal Movement
- Animals can respond to external stimuli by moving → allows them to seek food, shelter, safety, or mates
- Kinesis: undirected change in speed of an animal’s movement in response to stimulus
- Animal slows down in favorable environment (stay longer) & speed up in unfavorable
- Ex: animal will suddenly scurry about in response to light, touch, or air temp
- Taxis: directed movement in response to stimulus; either toward or away from stimulus
- Phototaxis: movement in response to light; Chemotaxis: movement in response to chemicals
- Ex: bacteria move toward oxygen or nutrients (positive chemotaxis) or away from taxis
- Moths move toward light at night, sharks move toward when food odors reach them by diffusion or bulk flow (ocean current)
- Migration: long-distance, seasonal movement of animals; response to seasonal availability of food or degradation of environmental conditions
- Ex: migrating birds use sun or stars (celestial cues) or magnetic field of earth