Exam 3

Describe the three major roles of the nervous system in vertebrate animals

Sensory input, sensory integration and motor response. PNS receives sensory input from internal and external stimuli, CNS integrates the information and sends commands to PNS for motor response.

Describe the role of the CNS and PNS in a vertebrate

CNS - is the brain and spinal cord, the brain is processing center, role is to integrate information brought in from the PNS process the information and send out commands to body.

PNS - made up of the sensory and motor neurons that make up our body, detects signals from environment and sends that information to CNS, signal goes to spinal cord then is sent to specific brain region with sensory signal, the cns processes and sends out command to motor neurons.

Describe the structure and function of the two main types of cells that comprise the nervous system

Two types of cells -
Neurons are excitable cells that send and receive information in the form of action potentials.

Glial cells are neuronal cells that are characterized by not being excitable, they do not produce action potentials and help maintain healthy neurons and provide support for the excitable cells.

Explain what the three different types of neurons are and what their roles are in the nervous system.

Sensory neurons - detect signals from internal and external environments via sensory receptors, chemical detects chemicals from the environment, taste and smell, mechanical receptors are sensory hairs that send signals when they are physically manipulated, touch and hearing, photo receptors - respond to different wavelengths of light, vision, known as afferent neurons because they send information to CNS. (afferent)

Motor neurons - located in the motor cortex of the brian brainstem and spinal cord, they send information from the brain to periphery, they are called efferent neurons because they send neurons from CNS to muscles tissues and glads of the body. (efferent)

Interneurons - interconnections between neurons, they have many dendrites that extend from cell body, found primarily in the brain and spinal cord they send signals between neurons that make up the different brian regions and between sensory and motor neurons.

Explain what reflexes are and how they are controlled by the nervous system

Simple circuits in the nervous system that allow for fast responses to environmental stimuli that could be potentially harmful to an organism, allow for response without the need for processing in the brain. Reflex form reflex arc between the PNS and CNS, the pathway of the reflex arc takes the signal from the PNS to the CNS and them motor neurons bypassing integration of the signal in the brian.

Describe the electrical properties of a neuron

Neurons are polarized meaning they have different charge inside compared to outside the cell. The way they send signals is through changing the electrical properties within the cell, intracellular is more negative, while extracellular is more positive.

Explain what a membrane potential is and how it is established

The membrane potential is the difference in electrical charge across membrane, its established by the electrochemical gradient set up by the inside of the cell being negatively charged while the outside is positively charged, concentrations differences of Na,K and CL is the main contributor of membrane potential of nerve cells.

Describe what a resting potential is and how it is established and maintained

When a nerve cell is at rest and not producing an action potential its said to be a resting potential, its typically around -70 mV, to achieve this resting potential cells have to regulate ion concentrations inside the cell, their is chemical gradient with higher concentration of K ions inside than outside and low centration of Na inside compared to outside, Sets up passive movement of ions down their concentration, Na wants to move into the cell and K wants to move out, K ions can move out quite easily through leak channels but Na needs specialized channels controlled by voltage gate, only opens when membrane potential becomes positive. Resting potential is maintained by Na/K pump

Describe the driving forces involved in the movement of ions and what ions are involved in establishing a membrane potential

nerve cells depend on the operation of NA/K pump to transport against the concentration gradient, moves 3 NA out and 2 in to keep the cell out of equilibrium and make the electrochemical gradient needed for nervous system to operate, if cell is at electrochemical equilibrium it cannot continue to send signals. For a neuron at rest the resting membrane potential is typically -70mV, the equilibrium potential for NA is +60 mV, the different stets ups driving force to move NA+ across the cell membrane, in this case NA will move into the cell to achieve equilibrium potential by creating more positive intracellular environment, occurs when a voltage channel activates allowing for Na to move down its electrical and chemical gradient.

Explain what channels are involved in the transport of ions across the membrane of a neuron.

Leak channels - help potassium establish neuron resting potential.

Voltage gated channels - open when membrane potential reaches positive voltage and allows NA to move down its electrical and chemical gradient help establish resting potential.

Sodium potassium pump - uses atp to transport ions against concentration gradient 3 Na out and 2 K in, maintains membrane potential. Ligang gated channels - open only when neurotransmitter binds to them.

Describe how an action potential is started and transmitted down an axon, what channels are involved, what channels are open at each phase and how it is a one way signal.

Action potential are produced when graded potential is large enough to reach threshold, threshold potential is the voltage at which an action potential will be triggered, usually around -55 mv, starts at the axon hillock near the cell body of neuron, voltage gated Na channels open and Na enters the cell, this depolarizes or makes its more positive once initiated Na channels are close and will not open until resting potential is reestablished. Voltage gated K channels remain open which allows for the flow of K out of the cell which starts hyperpolarization or making the membrane potential more negative bring it down to the resting potential of the cell, they are one way signal due to the refractory period of voltage gated channels.

Describe the different types of synapses that a neuron can have and how they function

Synapse are connection between the axon terminal of a nerve sell and the surface of muscle cell or gland or dendrites of another nerve cell.

Electrical synapses - conduct electrical signals through gap junctions from presynaptic neuron to postsynaptic cell, used in if coordination of signaling between cells is needed.

Chemical synapses - use neurotransmitters to excite the cell it is connected to. opens voltage gated calcium when action potential is reached, neurotransmitter is released in the space between the two cells called the synaptic cleft.

Describe the sympathetic and parasympathetic nervous systems

Sympathetic - controls fight or flight response, gets your body ready to react in stressful or emergency situations, inhibits areas of the body that are not needed for rapid responses and increase areas of the body that are needed for fighting or running away.

Parasympathetic - promotes calming and a return to normal rest and digestive functions, it brings the body back to restful state, slows your heart rate and constricts bronchi in the lungs.

Explain the evolutionary significance for changes in brain structure and size

The vertebrate brain is divided into 3 regions that play different roles -
forebrain is for complex processing, midbrain is for sensory input, hindbrain controls involuntary activities, evolution shaped the size of brain areas depending on which region is most important for the survival of the organism, ex. Forebrain is most developed in humans.

Be able to analyze how damage in a brain region could affect life skills.

Frontal lobe - decision making, motor, Broca’s area forming speech.

Parietal lobe - integration of sensory information, sense of touch.

Occipital lobe - visual stimuli and recognition.

Temporal lobe - hearing and wernicke's area comprehending language. Damage to Broca's area causes people to not be bale to speak but understand language, damage to Wernicke's area causes people to not understand but still speak.

Discuss how different neurological diseases affect an individual

Alzheimer's disease - causes mental deterioration ( dementia) and confusion and memory loss

. Parkinson's disease - affects the motor control in individuals, lack of dopamine in brain results in muscle tremors flexed postures and shuffling gait.

CTE - people with multiple concussions forms tau tangles in brain cortext and accumulate around blood vessels, leads to memory loss depression suicidal thoughts explosive or agressive behavior.

Discuss addiction pathway and how different drugs can be addictive.

Dopamine is a neurotransmitter released in the brain when pleasure is experienced, certain drugs stimulate reward centers by signaling release of dopamine, preventing dopamine from being degraded or taken back into neuron that released it, other drugs enhance the activity of serotonin. Pain medications mimic body's natural pain reducing chemicals known as endorphins, these bind to opioid receptors to block pain signals ex. Morphine and heroin, some stimulate dopamine and bind to opioid receptors. Nicotine activates acetylcholine receptors which releases adrenaline and dopamine in the body

Define what sensory receptors are and determine how they send information to the CNS for processing

Sensory receptors are neurons in the PNS that detect stimuli from external and internal environment of an animal, they turn stimulus energy from environment into neuronal signal.

Explain what the sensory pathway is and describe the path information takes from signal to response.

Sensory pathways are the route that signals take from PNS to CNS back out to PNS usually have 4 steps. Reception - detecting the stimulus. Transduction - converting to receptor potential. Transmission - sending as action potential. Perception - processing and action.

Apply your knowledge of sensory receptors to explain how sensory adaptation occurs

Sensory adaptation - the reduction in the responsiveness of sensory receptors to continuous stimulation, sensory adaptation happens every day our skin becomes adapted to the pressure our clothes put on the skin which enables us to ignore the feeling of those materials and only react to something that is more intrusive.

Describe the different types of sensory receptors and explain how each one receives, transduces and transmits sensory information.

Mechanoreceptors are sensory receptors cells that respond to physical manipulation - they transduce signals due to physical deformation at the dendrite region of the sensory cell, many use mechanoreceptors use microscopic hairs, when the hair cell is physically moved it create a receptor potential at the dendrite, if stimulus is strong enough it reaches threshold and action potential is produced sending the signal to somatosensory cortex, sense of touch balance and hearing all use mechanoreceptors with hair cells to transduce and transmit stimuli to our brain.

Chemoreceptors - use chemical stimuli throughout the body, have dendrites that are in close proximity to the surface which chemicals will bind to receptors on dendrites which stimulate receptor potential, detects smell and taste.

Electromagnetic receptors - allow animals to detect different forms of electromagnetic energy or light energy.

Thermoreceptors - detect heat and cold temperature, belong to a special group of receptors called Transient receptor potential Channels, TRP channels are sensitive to different temperature ranges and will produce a receptor potential when that temperature is reached, Opens Ca channels resulting in receptor potential and sensation of hot.

Pain receptors (nociceptors) - sensory receptors that detect pain signals when an animal's tissues are damaged due to extreme pressure, temperature and even chemicals. Initiates defensive response in animal.

Explain how Hair cells respond to sound waves, how different sound Frequencies are detected and where Auditory information is processed.

The stapes will vibrate the oval window that is connected to cochlea which is filled with fluid that vibrated and send pressure through the vestibular canal which vibrates hair cells and puts pressure on them causing them to bend and depolarize the hair cells. Within the cochlea there is organ called organ of corti where the hair cells are located. Ear can detect different pitches/frequency due to basical membrane being different thicknesses as it runs through the middle of cochlea.

Describe the vertebrate visual system and how visual processing begins.

Starts with light entering the eye through the pupil once light has entered the pupil it focused on the retina by stretching of the lens, retina is where the photoreceptor cells are housed where signal transduction occurs, when photoreceptors cells in the retina are excited transduction occurs.

Explain how the different photoreceptors operate in the vertebrate eye. Which ones are used for color and which ones are used for dim light.

Two types of photoreceptors.
Rods - are more sensitive to light and are the main photoreceptor under low light conditions.
Cones - sensitive to different wavelengths of light and provide color vision.

Describe how photoreceptors respond to light to produce an image and how contrast is discerned.

Photoreceptor cells consist of photopigments that collect the photons of light that come into the eye, photopigments consist of retinal and opsin, one type is called rhodopsin, when light hits the photopigment it causes the retinal in the photopigment to change shape which sets of the chemical messenger system to stimulate an action potential, when light hits retinal it changes from cis retinal to trans retinal. In the dark photoreceptors release glutamate which inhibits the action potentials, in light photoreceptor is hyperpolarized which decreases or stops the release of glutamate which allows more action potentials.

Contrast is created with lateral inhibition, when a rod or cone stimulates a horizontal cell which inhibits more distant photoreceptors, make receiving light appear lighter and dark even darling which enhances contrast.

Describe the different types of sensory receptors involved in taste and where they are located.

Taste receptors have 5 different taste profiles salty, sweet, bitter, sour and umami, located on the tongue and mouth and organized in structure that project out on the tongue called papillae. Sweet umami and bitter are detected vis G-Coupled Protein Receptors (GCPR’s). Sour is detected by TRP receptor. Salty is detected by Na channel receptor proteins.

Explain the difference between taste and smell.

Taste is called gustation - reliant on substances called tastants and needs to have physical contact with tastant. Smell is called olfaction - its dependent on the detection of chemical molecules called odorants, does not need direct interaction with the object being detected.

Describe what it means to have different "Flavors"

Flavors are combination of gustatory and olfactory senses, complex flavors we experience is due to olfaction not taste, this is why when we have a cold we can't taste anything

Determine the proximate or ultimate causes of behavior

Proximate causes - how the behavior occurs, focuses on mechanisms triggers and development. Ultimate causes - why the animal behavior, explains adaptive significance and the effect on reproductive success.

Describe what Innate behaviors are and how they can be an evolutionary advantage

Innate behaviors - instinctive behaviors that are genetically programmed, will exhibit the same behavior regardless of their environment, fixed action pattern is a behavior that once initiated the behavior continues until its completion, evolved because they increased the survivorship of offspring and increased fitness of organism doing the behavior.

Describe the characteristics of Learned behaviors; Why do they have huge variation within a species

Learned behaviors - are behaviors that are developed based on an individuals experiences they have throughout life, huge amount of variation as no two individuals experience the same things.

Describe and give examples of the different types of learned behaviors: conditioning, cognitive learning, prepared learning, social learning and imprinting.

Conditioning - the behavior of an individual is modified through an association,
classical conditioning is an involuntary response that becomes associated with stimulus that did not originally elicit the response ex. Pavlov's dog bell rang every time food is given, now when the bell rings even without food the dog salivates,
operant conditioning is where the animal's behavior is reinforced by a reward or a punishment ex. Blue jay eats monarch butterfly gets sick learns not to eat.
Cognitive learning - involves the ability to problem solve with a conscious effort and thought ex. Bees recognize color and patterns to pick food.

Prepared learning - behaviors that organisms are genetically primed or predisposed to learn quickly because the skill was vital to their ancestors’ ex. Humans and monkeys are genetically primed to develop phobias of snakes or spiders.

Social learning - learning through the observation of others and forms the roots of culture ex. Chimpanzees learn how to crack open nuts with tools by watching others in their social group.

Imprinting - occurs during a period of developments as infants, establishment of long lasting behavioral response ex. Gosling follow individual that they see moving away from them.

Describe the different types of communication that animals use

Communication is the transmission and reception of signals between animals which can alter the behavior of an individual, signals are stimuli transmitted from another, 3 types are most common chemical, auditory, and visual. but their is also tactile

Describe the different types of communication and how they are used

Chemical communication - involves taste and smell, taste for short, smell used for long distances, pheromones are substances used in chemical communication can be long lasting effective at low concentrations detected miles away, used to mark territories, attract mates, avoid predation, direction of food sources.

Auditory communication - use of sound waves to communicate to others, humans primarily use auditory and visual so this is familiar to us, can be used to establish territory attract mates capture prey and navigate nocturnal environments (echolocation).

Visual communication - visual signals help animals identify potential mates or potential rivals and attract mates, can be used to solidify and establish mating relationships.

Tactile communication - communication via sense of touch, establish and maintain social bonds (grooming), convey information about the location of food (bee waggle dance) communicate dominance (the licking and mouthing of canines).

Explain what altruism is and discuss whether or not "true" altruism actually exists

Altruism - act of performing a costly behavior that benefits someone else. Most acts of altruisms are directed at relatives and can be explained by kin selection, coefficient of relatedness (r) probability that two individuals will share a copy of a particular gene, the higher coefficient the more likely you are to act altruistically (Hamilton's rule).

Describe what Kin selection is and explain the conditions necessary for Kin selection to occur

Kin selection - evolutionary process that explains why animals exhibit altruistic behavior, occurs when the benefits to the relative are greater than the cost to the individual performing the altruistic or self sacrificing act. Ex. bending ground squirrels will produce whistle like call to warn members if predator is nearby, mostly older females as they have more relatives. Usually acting in their own gene’s best interest, benefits outweigh the cost, alarm calls attract the predator to the caller.

Discuss what inclusive fitness is and how this relates to Kin selection.

Direct fitness - passing on genes to next generation through personal reproduction. Indirect fitness - helping relatives survive and reproduce ensuring shared genes are passed on. Inclusive fitness - the sum of passing on genes by reproducing and helping genetic relatives survive and reproduce.

Determine if an individual should act altruistically or selfishly.

An altruistic gene is favored by natural selection when r x B > c. R being relatedness, B being the benefit, C being the cost.

Discuss what conditions need to be in place for reciprocal altruism to occur

Reciprocal altruisms - when apparent acts of altruism can occur between non related individuals, the cost to the donor is offset by the likelihood of a return benefit down the road. Needs to be repeated interaction between individuals, benefits need to be greater than the cost to the donor, needs to be ability to recognize and punish cheaters.

Explain and give examples of female strategies for choosing a mate

4 different types.
Courtship rituals - requires male to perform a courtship dance before she will mate with him. Gifts up front - a female hanging fly will not mate with a male unless he brings her a large offering of food.
Control of valuable resources - female arctic squirrel is attracted to a male squirrel that controls the best territory.
Good looks - a female peacock is attracted to a male with the most beautiful tail feathers.

Describe the different mating rituals and competition strategies employed by the different sexes

Male competition for mates -
direct competition often fighting between males to gain access to females.
Indirect competition - uses displays or contest to judge who is better. Agonistic behaviors - ritualized fights between males, reduces fight intensity, establishes dominance hierarchies, reduces duration of fights and mortal injury.

Dominance Hierarchies - often males form and females form dominance hierarchies to keep social order, individuals in the group know their role and perform their tasks, alpha males have priority in gaining resources such as food and mates, Alpha females have access to food resources first, subordinates often do not get to mate or try sneaky copulations in order to reproduce.

Describe how internal fertilization reduces the certainty a male is the father and what strategies can he use to ensure his paternity.

Internal fertilization - happens inside so paternity certainty is low, he can use several strategies. Provide parental care to the developing young, guard their mate during copulation and after, can use copulatory plug to ensure that no other males have access to the females internal eggs. Infanticide - males will kill the infants of other males when they take over a territory or harem.

Explain the difference between the different types of mating systems: Monogamy versus Polygamy

Polygamy - individuals attract multiple mates while others attract none. Monogamy - breeding pairs that are faithful to each other for either a season or for life.

Describe the factors that lead to Monogamy and polygamy

Resource availability - abundant resources have more promiscuous systems, limited resources have high fidelity. Predation risk - ability to hide from predators will lend to smaller groups, if its more difficult to hide they tend to group together in larger groups or polygamy.

Explain how these Sexual Dimorphism and monomorphism can be used to identify the mating system in place for a particular species.

Sexual dimorphism - differences between the appearance of two sexes (tend to be poly) ex. Male is bigger and more showy. Sexual monomorphism - no distinguishable differences between the sexes (tend to be monogamous).

Explain what biotic and abiotic factors are and apply these concepts to how ecosystems are structured

Biotic factors - interactions between living organisms within an environment. Abiotic factors - interactions between living organisms and non living components of their ecosystem or habitat, ex. Physical features of a habitat such as the temperature water flow, rain and wind, soil composition or topography of an area, influence evolutionary adaptations, the availability of food, capture and sense food finding mates and nesting sites.

Explain what demography is and the methods used to determine population densities

Demography - the study of different components that make up a population. Population density - the number of individuals of a specific species in a given geographic location, quantified using quadrats and line transects for counting sessile organism, pitfall traps sweep nets, sien nets, mark recapture, used for motile animals.

Explain how availability of resources determines distribution patterns of species

3 types of patterns that tells us about social interactions and competition for available resources. Clumped dispersal patterns - tend to be where resources are more accessible, where environmental conditions favor growth and reproduction, associated with mating behavior. Uniform dispersal - associated with direct interactions between individuals, high competition for resources. Random dispersal - unpredictable spacing, chemical and physical resources are constant throughout the habitat, no territoriality or associated mating behavior.

Describe the ecological events that influence population growth within different habitats or regions of the globe

North africa and middle east are the fastest growing but also the driest, several events that impact population growth. Number of births and deaths, number of immigration and emigration.

Calculate population growth rates of a given population

Take birth rate and subtract death rate. Birth rate = number of births / number in the population. Death rate = number of deaths / number in the population. Growth rate = r.

Apply population growth rate to determine the growth patterns of a population

If r (rate) is = to 0 the population will be at equilibrium and not increase or decrease. If greater than 0 population will increase, if lower the population will decrease.

Describe what carrying capacity is and explain how it affects growth rates of populations

Carrying capacity (K) - is the limit of the environment to carry the population, environment limits the size and growth of population based on available resources, as population nears K the growth rate (r) will decline and become zero as k is reached.

Compare and contrast density dependent and density independent growth factors

Density dependent factors - factors that influence population growth based on the size and density of the population, associated with carrying capacity as population grows larger these factors have a bigger impact. Ex. higher competition between individuals for food habitats for living sleeping and breeding.

Density independent factors - can occur at any point in population growth curve, decrease the number of offspring, increase death rates due to bad luck, have to do with weather or geological events, freezing, wildfires, hurricanes, volcanic eruptions.

Describe the different types of life history strategies and explain how they are associated with the different survivorship curves

Type 1 curve - long lived, loss of young is low, adults have few offspring but high parental care, old is more prone to sickness and predation, high survivorship, most large mammals (humans). Type 2 - equal chance of dying at any time during their life, young tend to mature to sexual maturity in the first year of life, have parental care for young.
Type 3 survivorship curve - juveniles die very early or are eaten - low survivability, no parental care, adults can survive fairly long time if offspring survives early pressure.

Two life history strategies. K selected species - fairly stable populations that have been selected for adaptation for living at or near carrying capacity (K).
R selected species - have high population growth rate, have traits that have been selected for maximum reproductive success.

Compare and contrast r-selected and k-selected strategies.

K selected - have few young high parental care reproduce later in life. R selected - maximize the rate of per capita growth, live well below the carrying capacity, mass reproducers only once no parental care, insects small mammals, some fish.

Discuss human population growth and apply the concept of carrying capacity to humans

Human population growth is declining due to disease increase in contraceptives, weather we have carrying capacity is debated as we are always striving to find ways to develop technology to allow us to prosper, some limiting resources for human population growth are fresh water, extremely important to protec