PBSI 311 EXAM 2 CHEAT CODE NOTES

Communication

Transmission of a signal from sender → receiver that changes receiver behavior

Signal

Trait evolved specifically to convey information

Incidental cues

Not evolved for communication

Examples of signals

Color, sound, movement, chemicals (pheromones), electrical discharge

Auditory signals

Example: birdsong; Advantage: works in dark; Disadvantage: energy expensive

Chemical signals

Example: pheromones; Advantage: long lasting; Disadvantage: slow

Visual

Example: coloration; Advantage: fast; Disadvantage: needs light

Tactile

Example: grooming; Advantage: precise; Disadvantage: short distance

Vibrational

Example: spider web vibration; Advantage: substrate travel; Disadvantage: limited range

Electrical

Example: electric fish; Advantage: murky water; Disadvantage: short range

Why does communication evolve?

Because receivers evolved.

What do efficient receptors allow receivers to do?

Extract useful information.

Why does the sender evolve signals?

To benefit itself and reduce signal cost.

What ability does the receiver evolve?

To maximize benefit and detect dishonesty.

What is the relationship between sender and receiver in communication evolution?

It is a coevolution between sender and receiver.

What do signals tend to be in shared interest situations?

Honest

What do signals tend to evolve into in conflicting interest situations?

Dishonesty

What is an example of an honest signal?

Alarm calls

What are examples of dishonest signals?

Satellite males, false alarm snort, begging exaggeration by offspring

What does the handicap principle state?

Signals are honest because they are costly.

What is an example of a costly signal?

Peacock tail

What is auto-communication?

Communication with self.

What are examples of auto-communication?

Echolocation, territorial scent marking.

What risk arises when auto-communication becomes public?

Eavesdropping risk.

Eavesdropping

Third party intercepts signal

Co-option

Trait originally evolved for another purpose now used for signaling

Ritualization

Signal becomes exaggerated + clearer

Stereotypy

Reduced variation → clearer meaning

Redundancy

Multiple signals convey same message

Frequency

Pitch

Amplitude

Loudness

Decibel scale

+10 dB = 10× intensity; BUT humans perceive as only 2× louder

Sound Distance Rule

Low frequency (infrasound) → long distance; High frequency (ultrasound) → short distance

Ultrasound Features

Used by bats, rats, mice; reflects well, low energy, good for echolocation, doesn't linger

example of a Tymbal

Cicadas

Stridulation

Crickets, grasshoppers

Larynx

Mammals, frogs

example of a Syrinx

Birds

Chemical Signal

Pheromone = chemical signal within species

Small Molecules

Airborne, evaporate fast

Large Polar Molecules

Persistent, stick to surfaces, last longer

Tactile Signals

Used when animals close together for aggression, affiliation, grooming

Vibrational Signals

Detected using tympanum membrane

Visual Signals

Fast, cheap, don't linger; need light, blocked by obstacles

Bioluminescence Example

Most deep sea animals: blue-green light; Loosejaw fish: red light

Electrical Signals

Used in muddy water fish, sharks for communication, navigation, prey detection

Multimodal Signals

Multiple signal types together; Example: bee waggle dance

Sexual Selection Signal Rule

Mate preference → stronger signals evolve

Supernormal Stimulus

Exaggerated stimulus preferred over natural version

Game Theory + Communication

Animals behave strategically; Sender wants benefit, low cost; Receiver wants accurate information

Interspecific Signaling

Between species; Types: Attractive, Repellent, Inadvertent, Mutualistic

Kinesis

Movement change based on stimulus intensity; NOT directional

Taxis

Directional movement toward stimulus

Path Integration

Return home using distance + direction tracking

Cognitive Map

Mental representation of environment; Requires hippocampus

Homing Strategies

Far from home: path integration; Near home: landmarks, odors, snapshot memory

Profit

Energy / (Handling + Search)

Shortcut rule

Eat highest profit prey

Prediction 1

If high-profit prey available, ignore low-profit prey

Prediction 2

Eat low-profit prey ONLY when high-profit prey scarce

Prediction 3

Decision depends ONLY on encounter rate of BEST prey, NOT worst prey

PATCH CHOICE MODEL

Leave when patch value drops below environment average

Travel time effect

Short travel time: leave sooner; Long travel time: stay longer

Central-place prediction

Longer distance: carry more food; stay longer

RISK-SENSITIVE FORAGING MODEL

Hungry animals are risk-prone; Well-fed animals are risk-averse

Herbivore

Plants

Frugivore

Eat Fruit

Folivore

Eat leaves

Carnivore

Eat Animals

Insectivore

Eats insects

Omnivore

Plants + animals

Saprophage

eat Dead material

Parasite

Host tissue

Hematophagous

Eats Blood

Grazers

Eat grass (e.g., cattle); Advantage: nutrient-rich

Browsers

Eat leaves + bark (e.g., deer); Advantage: available in snow

Folivores vs Frugivores

Folivores: low energy food, slow movement, long intestine; Frugivores: high energy food, active, short intestine

Cellulose digestion

Animals cannot digest cellulose alone; need gut microbes (e.g., leafcutter ants)

Sodium limitation fact

Plants low in sodium; Herbivores seek salt licks and mineral puddles

Predator strategies

Active pursuit, Sit-and-wait, Mimicry/luring (e.g., frogs tongues, chameleons tongues, orb-weaver spiders)

Parasite life cycle types

Simple: one host; Complex: two hosts minimum (Intermediate host, Final host)

Behavior manipulation example

Toxoplasma gondii: rats attracted to cats

Search patterns

Straight line: sample environment widely; Spiral: intensive search; Levy walk: mixed pattern

Self-defense strategies

Avoid detection, Deterrence, Evasion, Fighting back

Crypsis types

Countershading, background matching, disruptive coloration, object mimicry, chemical crypsis

Countershading

Dark top, light bottom; removes shadow effect

Background matching

Blend with environment (General, Specific)

Disruptive coloration

Breaks outline (e.g., zebra stripes)

Mimicry types

Batesian mimicry: harmless species mimics harmful species; Muellerian mimicry: two harmful species resemble each other

Aposematism

Warning coloration indicating poison, venom, danger; Honest signal (e.g., blue-ringed octopus)

Startle display

Sudden exposure of bright colors (e.g., eyespots on wings)

Diversion

Redirect predator attack (e.g., killdeer broken-wing display)

Threat display

Look larger, show teeth, hiss, spread wings

Predator imminence model

As predator gets closer, behavior escalates through stages: Risk environment, Predator detected, Predator attacking

Evasion strategies

Rapid flight, Zig-zagging, Erratic turning, Flash behavior, Autotomy, Group escape

Autotomy

Self-amputation (e.g., lizard tail drop)

Pursuit deterrence signals

Signal predator detected (e.g., stotting, tail-flagging deer, snorting antelope)

Group defense benefits

Dilution effect, Confusion effect, Predator saturation (e.g., periodical cicadas)

Mobbing

Group attacks predator (e.g., birds harassing hawk)

Tonic immobility

Play dead (e.g., opossum)