PBSI 311 First Exam Flash Cards

Behavior

a tool allowing animals to manipulate and adapt to their environment (includes: movement, social interaction, cognition, learning), provides flexibility as a pattern of activity responding to changing extern or internal conditions, internally coordinated and externally visible

Ethology

The study of non-human animal behavior, incorporating techniques and insights from multiple disciplines (ecology, evolution, genetics, molecular biology)

Niko Tinberg

One of the founders of the modern study of animal behavior, ethology grounded in his 4 central questions 1963 developed by him, studied behavior in birds bees and fish

Mechanism (Birdsong example)

What is the internal mechanism producing the behavior? Several brain structures ae known to be necessary for motivation and generation of birdsong

Survival value/Utility (Birdsong example)

What is the usefulness of the behavior in terms of survival and reproduction? Song is important for territoriality and mate selection

Development (Ontogeny)

How does the behavior develop (genetics/physiology)? Proper singing depends on learning from other birds in the species

Evolution (Phylogeny)

How did the behavior evolve from an ancestral state? Songs have evolved differently in some species

Levels of analysis for forming hypotheses: Proximate causes

Immediate causes, “how is the animal doing the behavior?” mechanism and development

Levels of analysis for forming hypotheses: Ultimate causes

Evolutionary forces, “why is the animal doing the behavior?” survival value and evolution

Vision: Mechanism

Lens focuses light onto retina, photoreceptors convert light into neural signals sent to brain areas specialized for motion, color, shape etc.

Vision: Utility

helps to detect food, avoid predators and move efficiently in complex environments

Vision: Development

Experience dependent wiring of visuals system during early critical period

Vision: Evolution

Vertebrate eyes formed with retinal neurons in front of photoreceptors, creating a blind spot. Cephalopods evolved camera-like eyes without a blind spot

Sleep: Mechanism

involves neurotransmitters and hormones, circadian rhythms, sleep pressure

Sleep: Utility

Energy restoration, metabolic regulation, brain plasticity, detoxification of cell waste, risk avoidance

Sleep: Development

Sleep architecture changes across lifespan; REM sleep is critical for early neural development

Sleep: Evolution

Sleep-like states in invertebrates and vertebrates; REM evolved independently in different mammals and birds

George Romanes

Founded comparative psychology, coined “Anthropomorphism”

C.L. Morgan

Questioned George Romane’s approach, introduction to comparative psychology

Comparative Psychology

Focus on proximate questions (how animals learn), laboratory experiments under controlled conditions, emphasize similarity across species

Edward Thorndike

Studied learning using cats, introduced scientific method to animal psychology

John Watson

Founded behaviorism, studied what can be observed: behavior not emotions, viewed reinforcement as primary driver of behavior modification

B.F. Skinner

Pioneered operant conditioning, animal learning based on experience in rats/pigeons, influenced by Pavlov and classical conditioning

Ethology

Focus on ultimate questions, studying behavior in the wild, emphasized differentiation of species

Karl von Frish

Studied sensory biology of honeybees, discovered bee perception of UV, polarization of light and color, led to decoding the honeybee dance

Konrad Lorenz

Studied instinctive behaviors, such as imprinting in goslings

Modern updates: Comparative psychology and Classical ecology

Comparative psychology no longer emphasized, cognitive psychology and behavioral neuroscience favored in animal research, Classical ethology now known as behavioral ecology

Darwin’s three conditions required by evolution

1. Variation exists among individuals in a population in terms of traits

2. Traits are at least partly inherited (genes passed from parents to offspring)

3. Traits cause differences in fitness (survival and Reproduction)

Genetic variation

Refers to differences in genetic traits within a population (qualitative), necessary for evolution, if all animals are identical, no animal will have genetic advantages/disadvantages

What causes genetic variation?

Mutation- Random change in DNA; some are beneficial, some are detrimental, some have no impact on fitness
Gene Flow- When new organisms move into a population, bringing new genes with them
Genetic Recombination- From meiosis; each individual gamete (egg/sperm cell) has unique genetic mix from parent
S*xual Reproduction- Genetic mixing between two individuals

Gene frequency

Refers to the proportion of a specific allele in a population (quantitative), what causes a change in gene frequencies

Mutation

Infrequent and random

Genetic Drift

“Accidental” shift based on a random event (bad luck)

Migration (Gene flow)

Organisms move into a population, with Mutation, genetic drift, and migration any change is random

Natural Selection

Traits are inherited that promote survival and reproduction, only mechanism that can cause an increase in the frequency of an adaptation

Killer Bee Example

Scientist imported bees from SE Africa to breed new hybrids, bees accidentally released and spread across western hemisphere. Result was gene flow increased genetic variation, natural selection increased the gene frequency

3 Requirements for Evolution by Natural Selection: Variation

There must be variation in the population (if all animals are identical, natural selection cannot act)

3 Requirements for Evolution by Natural Selection: Inheritance

Variation must be transmitted to the next generation (if there is no mode of inheritance [genes] for the trait, then natural selection cannot act on the trait

3 Requirements for Evolution by Natural Selection: Increased Fitness

Variation must impact fitness (Survival and reproduction) or reproductive success (# of fertile offspring produced), if there is no increase in fitness for the trait, then natural selection cannot act on the trait

Why does behavioral variation exist?

Genetic composition, behaviors develop from both genetic and environmental effects, behavioral traits can differ based on other characteristics, fitness of a trait depends on its frequency in a population relative to other traits

Speciation

The evolutionary process that results in the formation of two or more genetically independent groups that can no longer interbreed (Caused by: geographic barriers, resource shifts, mate choice, genetic change [mutations produce individuals that cannot mate with other members of the population])

Ecotype

Population within a species genetically adapted for a specific environment

Subspecies

Subgroup with more distinct differences based on natural selection

Breed

Subgroup based on artificial selection (Created by breeding for a trait)

Phylogeny

Branching structure showing the relationship between species, to choose a tree a set of traits must be chosen (structural, developmental, molecular, behavioral), phylogenies constantly being updated based on new information, anything alive today has been subject to natural selection for as long as any other organism

Behavioral Genetics

The study of genes that influence behavior, allows separation of genetic and environmental effects on behavior so we can identify selective forces that shape behavior and how behavior responds to forces across generations, most behavioral traits involve interactions of many genes

Genetics

As a field comes from distinct traditions and scientific cultures (Domestications, Phylogeny, Quantitative and biometrical genetics, molecular genetics) that can be used to better understand the influence of genes on behavior

Domestication (Artificial selection)

Domestication as a practice for 10,000 years, resulted in dogs showing broad range of artificially selected behaviors, e.g. Domesticated silver fox, foxes showing dog-like tendencies and a curly tail)

Cladogram

An evolutionary tree showing a well-defined hypothesis about evolutionary relationships (phylogeny). A widely distributed population can lead to more behavioral variation.

Classical Genetics

Developed by Gregor Mendel, used to study simple behavioral traits (such as mutations impacting coordination in the fruit fly), but not complex

Quantitative genetics

studies traits that vary continuously (height) and are influenced by a combination of genes. this includes complex behavioral characteristics such as aggressiveness, play behavior in mammals, and intelligence. used to study population-level variation.

Heritability

quantifies how much trait variation within a population can be attributed to genetic variation (as opposed to environmental), different from inheritance (passing genes from parent to child), heritability is a population-level statistic

Chance the Bull example

Chance was a gentle bull, so scientists cloned Second Chance who ended up becoming aggressive, phenotype (traits are outwardly displayed) comes from genotype (genetics) + the environment

Evolutionary Change

How gene frequencies change over generations, uses models to describe and a predict effects of genetic forces on behavioral traits (mutation, genetic drift, migration, natural selection, artificial selection)

Molecular genetics-uses tools to map and manipulate genes

Map gene sequence (DNA) location on chromosome to identify candidate genes for a behavior, map gene expression (RNA) and how expression is regulated, manipulate genes or gene expression (CRISPR to change DNA)

Contemporary Behavioral Genetics

Seeks to understand how multiple interacting genes can shape patterns of behavior, proximate causes of behavior, ultimate causes of behavior (how evolution and long-term selective pressure have shaped behavior where in the evolutionary process a trait first appeared)

Neural System

The body’s communication network (neurons, circuits) that allows animals to sense, process, and respond to environmental stimuli

Central Nervous System (CNS)

Brain, central nerve cord (or spinal cord in vertebrates)

Peripheral Nervous System (PNS)

Nerves that connect the CNS to the body (muscles, organs)

Neuron (The basic unit of the nervous system) and components

Cell body, axon (carries signal from soma to other neurons), dendrites

Glia

Cells that provide metabolic and/or mechanical support, astrocytes, microglia, oligodendrocytes (CNS) and Schwann cells (PNS) provide insulation to axons

Neurons communicate via…

Electrical signals (action potentials), chemical signals (Neurotransmitters released into the synapse and influence other neurons)

Resting Potential

At rest, the inside of the cell is electrically negative as compared to the outside of the cell (-70 mV)

Action Potential

How neurons “fire” to communicate; during the action potential, the electrical potential reverses and the inside of the cell becomes positive (+40 mV) very briefly

Electrical Signals: Propagation of the action potential

An action potential originates in the initial segment of the axon, just after the axon hillock, the action potential is then actively propagated along the axon as it travels toward the terminals

Axon Diameter and Axon Myelination (insulation)

Larger diameter = faster speed due to lower resistance, myelination increases speed and conduction for all vertebrates insulation provided by myelin sheath

Neurotransmitters

chemical messengers released by neurons to communicate with other neurons or muscle (Acetylcholine), released by action potential arriving at axon terminal, neurotransmitters then cross synapse, bind to receptors on the next neuron, after binding are inactivated via metabolism and uptake out of the synapse

Common Neurotransmitters found across animal species

Acetylcholine, Biogenic Amines (Serotonin, dopamine, octopamine, norepinephrine), amino acids (Glutamate, GABA)

Cephalization

The concentration of CNS in an anterior head (especially sensory components & response coordination),

Compartmentalization

Separate but interconnected structures for functions, seen in complex brains, seen in many organisms that involved independently

Umwelt

Understanding the species-specific perception and priorities of the organism we are studying (e.g. the ticks locating hosts is their entire world)

The three major groups of animals with a highly sophisticated brain

Vertebrates (within Chordate phylum), Cephalopods (within Mollusks phylum), Insects (within Arthropods phylum)

Vertebrae brains

Cerebral hemispheres (learning and cognition, more developed in birds and mammals), cerebellum (coordinates physical movement), hypothalamus (direct physiological functions, secretes neurohormones), medulla (controls cardiac and respiratory systems)

Mollusks

Have ganglia associated with the mouth, foot, and gut

Cephalopods

Squid and octopi have complex brains, active predators capable of sophisticated movements, color changes and learning, central brain and mini brain in each arm

Insect brains

Nervous system reflects the segmented body plan of all arthropods, fusion of anterior ganglia with distinct areas devoted to vision, antennae and memory

Hormones

Chemical messengers secreted by glands in the endocrine system (including pineal and pituitary glands), hormones travel through bloodstream to influence distant organs and tissues, can regulate long-term and short-term changes to behavior

Types of chemical communication: Synaptic

Neurotransmitters move across synaptic cleft

Types of chemical communication: Endocrine

Hormones released into bloodstream to selectively affect distant target tissues

Types of chemical communication: Pheromone

Chemicals released outside the body to affect other individuals of the same species

Types of chemical communication: Allomone

Chemicals released outside the body to affect individuals of other species

Peptide Hormone

Short string of amino acids, fast acting bind to cell surface (Oxytocin, Vasopressin, Insulin, Growth hormone)

Amine Hormone

Modified version of a single amino acid (Epinephrine, melatonin)

Steroid Hormone

Derived from cholesterol, long-lasting usually enter cells and act directly on gene expression (Testosterone, estrogen, cortisol, Ecdysone)

Terpenoid Hormones

JH (insects)

What causes hormone release?

Internal cues, environmental stressors, seasonal cues, social interactions

HPG Axis

Hypothalamus produces gonadotropin-releasing hormones, Pituitary releases FSH and LH, gonads (ovaries/testes) release estrogen or testosterone

Testosterone

Largely responsible for physical and behavioral traits in males

Organizational effects

During development, testosterone released in utero can even affect neighboring embryos activation effects: seasonal mating behavior and aggression

Activation effects

In seasonal mating, males, testes typically enlarge see increased intermale competition, courtship displays and willingness to copulate

JH (juvenile hormone)

Released by the CA and affects: maturation and reproduction, behavior, caste differences in eusocial insects, Ecdysone (steroid hormone, arthropod growth and development, exoskeleton molting, egg production

Transduction

Conversion of energy from one mode to another, receptor cells transduce external energy to internal signals (action potentials in nervous system)

Vertebrates- Chemo sensors

Tongue, Olfactory epithelium (smell), vomeronasal organ (pheremones)

Color (light wavelength) perception based on:

Number of color photoreceptors (cones), cone sensitivity, cone tuning (narrow/broad)

Polarization of light

Many animals can detect the polarization of light, cuttlefish have most acute polarization

Vision: Acuity (detail)

Based on the density of receptors in the fovea (center of retina: receives light from center of visual field), hawks have greatest acuity

Vision: Flicker Fusion

Motion processing speed, cats and hawks have highest processing speed

Ultrasonic hearing

High frequency, low energy, requires thinner hearing membrane for detection, used in echolocation (in bats) and social contexts, echolocation relies on the reflection of sound off the surface of a denser medium

Infrasonic

Low frequency, high energy, travels well in the ground/water, requires large receiver, used in long distance communication in large species

Heat Sensitive receptors

Respond to heat, called TRP receptors