Animal Behavior - Exam 2

What are the three main mechanisms that organize and prioritize behavior?

1. Neural Command Centers

2. Biological Clocks or Biorhythms

3. Hormones

What is a neural command center?

A neural cluster with primary responsibility for the control of a particular behavioral activity.

Neural Clusters can: (2 things)

1. Communicate with one another

2. Suppress one another in a hierarchical fashion to prioritize behaviors

Neural Command Center Praying Mantis Example: Observations (2 of them)

1. Cutting link between protocerebral ganglion (brain) and rest of body results in walking and grasping (a conflict of behaviors)

2. Cutting link between subesophageal ganglion and rest of body results in no movement

Neural Command Center Praying Mantis Example: Interpretations (2 of them)

1. Subesophageal ganglion sends out commands for various behaviors to the body

2. Protocerebral ganglion inhibits most behaviors so that only the appropriate behavior is permitted

Explain how this relates to observations

Neural Command Center Blowfly Example: Observations (3 of them)

1. Sensors on legs activate feeding response when stimulated by sugar

2. When crop is full, feeding stops

3. Cutting a nerve between foregut and brain causes fly to feed until its gut explodes

Neural Command Center Blowfly Example: Interpretations (2 of them)

1. Food in full crop backs up into the foregut

2. stretch receptors in the full foregut sends signals to the brain inhibiting the feeding response

Explain how this relates to observations

What is a biological clock or “biorhythm”?

An internal physiological mechanism that enables an organism to time its biological processes and activities.

Give two examples of biorhythms and their supporting details

1. Cricket calling

   a) Males only call at night when females are active

   b) Males kept under constant light still call when it should be night

2. Ground Squirrel Hibernation

   a) Squirrels hibernate each winter

   b) Squirrels blinded and kept in constant darkness, at constant temperature, with plentiful food, still hibernate.

What are the 5 types of biorhythms?

1. Circadian

2. Circannual

3. Tidal

4. Lunar/semilunar

5. Ultradian

Circadian Rhythms

Daily cycles

Examples:

1. Human sleep/activity, body temperature

2. Moth, fruit fly emergence as adult (early in morning, air still and moist)

Circannual Rhythms

Yearly cycles

Examples:

1. reproduction

2. migration/hibernation

3. molting/shedding

Tidal Rhythms

12.4 hour cycles, based on the tide cause by the moon and earth’s rotation

Examples:

1. crabs feeding in tidal zone, not stranded out of burrows when tide comes in

2. Oysters opening valves to feed

Lunar/semilunar Rhythms

29.4/14.7 day cycle based on the cycle of the moon.

Examples:

1. Kangaroo rat activity (avoidance of full moon)

2. Grunion spawning every 14 days

3. Midge mating and egg laying

Ultradian Rhythms / Epicycles

Short cycles

Examples:

1. Euglena feeding activity - every 6-8 minutes

2. Vole Activity - every 2 hours

Are biorhythms under exogenous or endogenous control?

Endogenous

Define entrainment

A process in which a biological clock is set or reset by synchronization with the period of an exogenous, environmental stimulus.

Define Biological Clock

Internal timing mechanism involving both an internal self-sustaining pacemaker and an external environmental synchronizer.

List 5 entrainment cues (synchronizers)

1. Photoperiod

2. Temperature

3. Food

4. Tidal and Lunar cycles

5. Social Cues

Be able to give examples of each

Where can a biological clock be found?

1. Individual cells can have a clock

2. Something synchronizes the clocks

What are 2 ways biological clocks are synchronized?

1. Light penetration

2. A “Master” clock

What are the three variations of the location of master clocks and photoreceptors that entrain master clocks?

1. Clock and photoreceptors in eyes

2. Clock and photoreceptors in brain

3. Clock in brain and receptors in eyes

Be able to give examples of each (page 26)

What are the three advantages of an endogenous biological clock?

1. Allows for anticipation of environmental change that can be prepared for

2. Allows behavior to be synchronized with an environmental factor that cannot be directly sensed by the animal

3. Provides a continuous measure of time that allows orientation that compensates for the passage of time

Be able to provide examples of each (page 27)

Define Hormones

Chemicals produced by special glands or cells that circulate in the blood and cause changes in other parts of the body.

Describe the hormones in the Ringed Dove reproductive cycle

• increasing daylength and ????????? Watch lecture

Define the relationship between hormones and the nervous system

• Hormones operate in tandem with the nervous system

• Hormones operate over longer time frames than the nervous system

Organizational hormone effects

Hormonal effects during a critical developmental period produce permanent changes

Activational hormone effects

Hormones act as a trigger of behaviors

Hormone variation

Hormone effects vary among species and sexes

Examples:

• progesterone:

  • regulates incubation in ring doves

  • regulates infanticide in mice

• Testosterone

  • Triggers courtship/mating in many species

  • Does not in red-sided garter snake (warming temps instead)

• Estrogen (in Zebra finch)

  • Male - brain development for song

  • Female - reproductive cycle

What is an associated reproductive pattern?

When hormones synchronize the reproductive physiology of the animal with its reproductive behavior.

Sex hormones that trigger gamete production also regulate reproductive behavior, such as territoriality and mating.

What is a “dissociated reproductive pattern”?

A lack of synchronization between the reproductive physiology of the animal and its reproductive behavior.

Example of the red-sided garter snake:

• found in northern US and southern Canada

• hibernate together and mate when they emerge

• testosterone peaks in the fall; sperm produced and stored over the winter (physiology)

• emergence and mating (behavior) triggered in spring by warmth, when testosterone levels are low

Gamete production and mating are not associated

Define adaptation

A hereditary trait favored by natural selection

• has better cost:benefit ratio than alternatives

• gives higher fitness to individual

Define fitness

a measure of the reproductive or genetic success of an individual

Fitness benefit

increases an individual’s fitness

Fitness cost

Decreases an individual’s fitness

What are the two proposed origins of “adaptations”?

1. Evolutionary traits from random mutations (adaptation)

2. Design by God (functional design)

What are four constraints on adaptations?

1. Mutations in a macroevolutionary paradigm might not occur as needed: selection has to “wait”

2. In pleiotropy, while a gene might be benefiting one trait, that same gene might cause a suboptimal effect on another trait

3. A coevolutionary arms race might keep either a predator or a prey one step ahead of the other, preventing an optimal stability from being reached

4. The Fall means that the biological world is not perfect

Hypothesis formation in the Adaptationist Approach

Hypotheses of adaptation/designs are developed using a cost:benefit approach

• there are potential benefits to the behavior

• there are potential costs

• the benefits > costs?

What is a primary focus of hypothesis testing for adaptations?

Confirmation of benefit predictions

Be able to give examples (page 30)

What are the two ways the comparative method can be applied?

1. Similar species under different conditions showing a divergent pattern

   1. Different species under similar conditions showing a convergent pattern

Divergent and convergent patterns can also reflect what?

Design strategies of a Creator, versus a pattern produced by evolution

What is the optimality theory?

A comparison of costs to benefits

What is optimal in terms of the Adaptationist Approach?

Better than other traits in terms of fitness benefits to costs. (not easy to measure)

Give examples of easy and not easy to measure (page 30)

What is the game theory?

This is a theory of adaptations where costs and benefits vary depending on the actions of other individuals in competitive situations.

What is a “Darwinian Puzzle”?

When an animal has traits whose benefits are not obvious; Cost seems to outweigh benefits.

What are the four feeding behaviors?

1. Finding food

2. Selecting food

3. Capturing/collecting food

4. Consuming food

What are five ways animals increase efficiency in finding food?

1. Search Image

2. Resource (niche) Partitioning

3. Territoriality

4. Traps

5. Deceit (aggressive mimicry)

Search image

Learning mechanism that improves a predator’s efficiency in recognizing desirable prey

Give an example (page 32)

Resource (niche) partition

Dividing resources to avoid competition

Give an example (Page 32)

Territoriality

Defense of a resource

Give examples (page 32)

Traps

Makes it easier to find the food

Example (page 32)

Give examples of deceit/aggressive mimicry

1. Death adder tail

2. angling fish, turtles

3. bola spider

4. predatory/mimicking firefly

What kinds of cues for finding food are there?

1. Direct cues (stimuli)

2. Indirect cues from companions

Optimal foraging theory

Food choice maximizes the cost:benefit ratio

Give two examples of Optimal foraging theory

1. Oystercatchers and mussel selection

2. Chickadees and sunflower seed selection

What are 3 advantages of social hunting?

1. More success/ efficiency

2. Larger prey taken

3. Prey more easily protected

What is an important consideration when animals are collecting food?

The number of items per trip

What are two elements of consuming food to consider?

1. Food preparation

2. Where to consume food

What are four ways animals respond to (avoid) predation?

1. Decreasing detection

2. Making an attack less likely

3. Making capture less likely

4. Making consumption less likely

What are ways an animal can decrease detection?

1. Cryptic behavior

2. Risk-sensitive behavior

3. Distraction displays

What are examples of cryptic behavior? (4 of them)

1. Camouflage/ mimicry and habitat selection

2. Disruptive color patterns

3. Counter shading

4. Freezing

Disruptive color patterns

Patterns that break up animals’ outline, making detection more difficult

Counter shading

White below/ dark above (less contrast with environment)

Freezing

Remaining motionless (less visible from above or below

Risk-sensitive behavior

The adjustment of behavior to take into account variable levels of predation (or other) risk

Distraction displays

parental display to lure predator from young

What are four ways to make an attack less likely?

1. Protection (physical)

2. Advertising Unprofitability

3. Batesian mimicry

4. Associating with an undesirable species

What are examples of advertising unprofitability? (3 of them)

1. Aposematic (warning) coloration

2. Mullerian (Think multiple) mimicry

3. Stotting

Aposematic coloration

Coloring on an animal that warns predators of toxicity

Mullerian mimicry

Several undesirable species converge in coloration for protection

Stotting

Solitary Thomson’s gazelles jump stiffly prior to cheetah attack.

Batesian mimicry

A desirable species mimics an undesirable species for protection.

What are two ways animals make capture less likely?

1. Solitary behaviors

2. Social behaviors

What are solitary behaviors that make capture less likely?

1. Rapid escape

2. Eyespots

   1. Startle reaction

   2. Miss directed attack

What are 5 ways social behaviors make capture less likely?

1. Vigilance effect

2. Him-first effect

3. Dilution effect

4. Confusion effect

5. mobbing

Vigilance effect

Predator detected sooner in a large group

Him-first effect

1. Odds of being targeted decrease with group size

2. Dominants can take advantage of safer foraging/nesting sites

Dilution effect

predators restricted to taking advantages of a smaller proportion of prey as group size increases because of satiation

Confusion effect

Prey’s rush for safety confuses predator

Mobbing

a group distractive defense

What are three ways animals make consumption by predators less likely?

1. adhesives

2. Toxins

3. Attraction of competing predators

What are the four variations proposed as a transition to the Honey Bee dance?

1. No direction or distance, just arousal of hive by running and buzzing, with flower odor providing only clue to food source

2. Location indicated by a pheromone trail and arousal of hive with buzz

3. Both direction and distance communicated

   • Distance = length of pulses of sound

   • Direction = orientation of zigzag outside hive

4. More complex direction and distance information

   • Distance = duration of waggle dance

   • Direction = deviation from vertical angle from sun