Animal Behavior (Exam 1)

Natural Selection Conditions

Variation, Differential Reproductive Success, Heredity

Proximate vs Ultimate

Proximate = How (Mechanistic & Developmental)

Ultimate = Why (Evolutionary & Adaptive)

Bird Song Example

Environmental Adaptation & Sexual Selection

Nutritional Stress Hypothesis

Brain structures controlling bird singing develop early in life, when birds are likely to experience developmental stress from undernutrition

Only individuals that can cope well w/ stress fully develop brain structures and will have high-quality songs

Mechanism for Song Learning in Birds

HVC & LMAN

Central Dogma

Translation (DNA) → Transcription (RNA) → Proteins

Behavioral Ontogeny

The development of individual organisms

Bee Study - Epigenetic Modifications

Alterations to genome that do NOT change DNA sequence that can affect behavior and development

Bee Study - DNA Methylation

Study where Dnmt3 enzyme (which controls DNA Methylation) was silenced in bees

Results were more queen bees developed

Voles - Evolutionary Development

Prairie Voles = monogamous, Montane Voles = polygynous

In prairie voles, Vasopressin hormone binds to V1A receptor and this triggers cellular activity, telling the vole to be monogamous and care for young

In montane voles, V1A receptors are on different parts of brain, so they do not have inclination to be monogamous

Voles Study

extra avpr1a gene (which encodes for V1a receptor proteins) was inserted into montane males

It resulted in an increase in time they spent with female partners

Established causal link btw gene and social behavior

Developmental Constraints Hypothesis

Structures and processes of an organisms developmental system that limit range of possible phenotypes (poor early life conditions negatively affect behavior, physiology, and fitness)

Ex. If a female baboon is born in a dry year, she will have lessened fertility; if baboon is born under conditions when food is limited, this negatively affects fitness

Predictive Adaptive Response Hypothesis

Organisms developmental trajectory is shaped in a way to optimize health and fitness

Ex. Risk of predation increases production of stress hormone, causing organism to run away

Behavioral Plasticity

Reversible changes in behavioral phenotype in response to changes in environment

Ex. Octopus changing its color based on environment

Behavioral Polyphenism

Clear, distinct changes in phenotype between organisms with same genome based on environment (Not always reversible)

Ex. Cichlid males

Cichlid Non-Developmental Polyphenism

Social Status determines phenotype

GnRH nerve cells increase activity of egr-1, which encodes for GnRH, and regulates reproduction and increases hormone production

Behavioral Polymorphism

Genetically pre-determined phenotypes and traits

Supergene - Behavioral Polymorphism

Region of DNA containing linked genes that influence a behavioral phenotype]

Ex. Male Ruffs can be either independent type (common, brown plumage, territorial, non-supergene), satellite type (white plumage, non-territorial, supergene), or faeder type (female-impersonator, non-territorial, supergene)

Fixed Action Pattern

Actions/behaviors triggered by stimulus

Ex. Young gulls pecking behavior for feeding (stimulus = shape and contrasting dot); goose putting egg under body (stimulus = egg-like size); bee-mating behavior (stimulus = female bee like size/shape)

Moths Avoiding Bats

Moths have tympanic membrane in ear that vibrates when a high-frequency pitch is heard. It has A1 and A2 receptors on it that are connected to interneurons in the thoracic ganglia, whose action potentials reach the motor neurons and the moth starts to fly away.

Stimulus → Receptor → Nervous system → Response

UV Radiation

Used to escape predators

Bees use it to locate nectar on flowers

Monarch Butterflies use it to navigate (also use polarized light to keep them on track aka regulates circadian clock)

Muscular Responses in Invertebrates - Central Pattern Generator

Sea slugs bending to escape predators

1) Dorsal Ramp Interneurons (DRIs) receive signal from sensory receptors and from Tr1 (other interneurons)

2) DRIs interact w neurons (DSIs, C2, VSIs)

3) Messages sent to flexible interneurons (DFN-A, DFN-B, VFN)
*activity in DSI turns on C2, which begins to send excitation messages to DFN (makes U) and inhibit VFN. then reverses

Muscular Responses in Vertebrates - Plainfin Midshipman Fish

1) Vocal Prepacemaker Nucleus (VPP) encodes call duration

2) Vocal Pacemaker Nucleus (VPN) ecodes call frequency

3) Vocal Motor Nucleus (VMN) relays outputs to vocal muscles

*males contract and relax muscles to sing and attract mates

Circadian Clock Genes

1) PER

2) tau/dbt (turned on when PER is at peak)

3) TIM

*PER & TIM peak at dawn, lowest at dusk

Glucocorticoids

Class of hormones that allow animals to respond rapidly to stressors

*Acute stress = temporary (GOOD)

*Chronic stress = long-term (BAD)

Activational Effect

Temporary influence

Organizational Effect

Effects to nervous system that can cause permanent changes to behavior