Option E

1
Option E

• Keegan Murphy, John Rubenchik, Enkhjin
  Myagmarsuren, Michal Tesfemariam,

2
Define the terms stimulus, response and reflex in
the context of animal behaviour
3
Explain the role of receptors, sensory neurons,
relay neurons, motor neurons, synapses and
effectors in the response ofanimals to stimuli.
4
Draw and label a diagram of a reflex arc for a
pain withdrawal reflex.
-The central nervous system includes the brain
and the spinal cord. -The spinal cord acts
independently from the brain during reflex
actions. -The reflex is an automatic response to
specific stimuli. -The reflex response is a fast
involuntary reaction which increases the chance
of an animal avoiding damage and therefore
increasing chances of survival.
5
Explain how animal responses can be affected by
natural selection, using two examples.

• Animal behaviour is more than a single reflex but
  a complicated series of responses to the
  environment. Some populations of organisms have
  changed their behaviour in response to a change
  in the environment. 
• Variations in behaviour can occur in populations
  in the same way as variation in the
  characteristic, such as colour, of the animals.
  The characteristic of an animal is determined by
  genes just as behaviour can be determined by
  genes. 
• Variations in behaviour can be selected by the
  environment. Since a genetically programmed
  behaviour can have variations, one behaviour can
  work better than another in a changing
  environment. The variation will allow one group
  of organisms to survive and reproduce better in
  the new environment. 
• The theory of natural selection states that the
  organism best fitted for the environment is more
  likely to survive to reproduce. 

6
Outline the diversity of stimuli that can be
detected by human sensory receptors, including
mechanoreceptors, chemoreceptors, thermoreceptors
and photoreceptors

• mechanoreceptors
• membrane receptor proteins respond to mechanical
  deformation,
• which results in membrane depolarization
• leading to action potentials sent to brain,
• which interprets the sensation,
• e.g. Meissners corpuscle (light touch), Pacinian
  corpuscle (deep pressure), hair cells (hearing,
  balance), aortic baroreceptor (blood pressure)
• chemoreceptors
• membrane receptor proteins bind specific
  molecules
• which results in membrane depolarization
• leading to action potentials sent to brain,
• which interprets the sensation,
• e.g. olfactory neurons, gustatory cells of taste
  buds, aortic carotid bodies, hypothalamic
  glucoreceptors
• thermoreceptors
• membrane receptor proteins respond to
  temperature,
• which results in membrane depolarization
• leading to action potentials sent to brain,
• which interprets the sensation,
• e.g. free nerve endings in dermis detect warmth
  hypothalamic thermostat detects internal
  temperature
• photoreceptors

7
Label a diagram of the structure of the human eye.
8
Annotate diagrams of the human retina to show the
cell types and the direction in which light moves.
9
Compare rod and cone cells
10
Explain the processing of visual stimuli,
including edge enhancement and contralateral
processing.

• edge enhancement
• occurs within the retina
• two types of ganglion cell, each stimulated when
  light falls on a small circular area of retina
  called the receptive field
• on-center ganglion cells
• ganglion is stimulated if light falls on the
  center of the receptive field
• but this stimulation is reduced if light also
  falls on the periphery
• off-center ganglion cells
• light falling on the periphery of the receptive
  field stimulates the ganglion cell
• if light also fall on the center of the receptive
  field, stimulation is reduced
• both types of ganglion cell are therefore more
  stimulated if the edge of the light/dark is
  within the receptive field
• contralateral processing
• signal passes from photoreceptor to bipolar
  neuron to ganglion cell,
• which leave the eye bundled in the optic nerve,
• left and right optic nerves meet at the optic
  chiasm
• neurons carrying impulses from the half of the
  retina nearest the nose cross over to the
  opposite optic nerve
• thus, left optic nerve carries information from
  the right half of the field of vision, and vice
  versa
• allows brain to deduce distances and sizes

11
Label a diagram of the ear.
12
E.2.7 Sound perception

• How we perceive sound is a sequences of changes
  of energy from one form to another. Initially the
  incoming sound into the ear is in the form of a
  pressure wave in air which will ultimately be
  transformed into a nerve impulse, which as we
  know is a wave of sodium ions traveling down the
  axon.

13
E.3.1 Distinguish between innate and learned
behavior
14
E.3.2 Design experiments to investigate innate
behavior in invertibrates

• Innate behaviors can be measured as the animals
  respond to environmental stimuli
• Two basic kinds of movement are seen in
  invertebrate animals
• Taxis
• Kinesis

15
E.3.3 Analyse data from invertebrate behavior

• Chemotaxis response to chemicals in the
  environment experiments involving variation in
  pH, dissolved drugs, food, pesticides
• Phototaxis response to light experiments
  involving different wavelengths of light,
  intensities, and different types of bulb
• Gravitaxis response to gravity experiments
  with organism in container that is turned upside
  down or on a turntable
• Rheotaxis response to water current experiment
  involving animals with and against current
• Thigmotaxis response to touch experiment
  involving different types of material to touch an
  organism

16
E.3.4 Discuss how the process of learning can
improve the chance of survival

• Learning occurs most easily when it results in
  the animals survival
• Imprinting process by which young animals
  become attached to their mother within the first
  day or so after hatching or birth assures that
  the young stay close to their mother for
  protection and as a source of food

17
E.3.5 Outline Pavlovs experiment

• Classical conditioning can be used to modify a
  reflex response
• Russian physiologist Ivan Pavlov designed
  experiments to illustrate classical conditioning
• His subjects were dogs
• Salivation is a reflex response to the presence
  of food in the mouth
• Food is unconditional stimulus which elicits
  salivation which is unconditional response
• Neutral stimulation that Pavlov employed was the
  ringing of a bell
• He rang the bell (conditioned stimulus) just
  before the dog tasted the food
• After training, the could ring the bell (CS) and
  the dog would salivate (conditioned result)
• Dog had learned to salivate to the neutral
  stimulus

18
E.3.6 Role of inheritance -birdsong

• After hatching, there is a memorization phase in
  which the bird is silent but listening to the
  song of his species from adults (males)
• He attempts to match his template to the full
  adult song
• Phase if over within 100 days (sensitive period)
• 2nd phase is motor phase in which he practices
  singing, continuing to listen to his own song and
  match it to his fathers
• As he becomes sexually mature, his song will
  become perfected and he will begin to search for
  a mate
• Crude template is innate adult song is learned

19
E.4.1 State the presynaptic neurons
20
E.4.2 descision making in the CNS

• Neurones form synaptic junctions with the cell
  body of other neurones.
• A post synaptic neurone can have many
  pre-synaptic neurones forming synaptic junctions
  with it.
• Pre synaptic neurones depolarise (excitatory) or
  hyperpolarise (inhibitory) the post synaptic
  membrane locally.
• The sum of their effects takes place at the axon
  hillock

21
E.4.4 List three examples of excitatory and
three examples of inhibitory psychoactive drugs.

• excitatory psychoactive drugs
• nicotine
• cocaine
• amphetamines
• inhibitatory psychoactive drugs
• benzodiazepines
• alcohol
• tetrahydrocannabinol (THC)

22
E.4.5 Explain the effects of THC and cocaine in
terms of their action at synapses in the brain

• THC is an inhibitory psychoactive drug that
  decreases synaptic transmission
• cannabinoid synapses involve post-synaptic
  neuronal release of endo-cannabanoid NTs
• endo-cannabanoids bind to cannabinoid receptors
  on pre-synaptic neurons
• modifying the pre-synaptic neuronal release of
  NTs
• THC binds to cannabinoid receptors
• inhibiting the release of neurotransmitters from
  the pre-synaptic neurons such as GABA
• the reduction in GABA frees dopaminergic synapses
  from inhibition
• leading to increase in dopamine release in the
  pleasure pathway
• cannabinoid receptors are found in various brain
  locations
• cerebellum
• THC thus impairs motor functions
• hippocampus
• THC thus impairs short-term memory functions
• cerebral cortex
• THC thus affects higher order thinking

23
E.4.6 Discuss the causes of addiction, including
genetic predisposition, social factors and
dopamine secretion.

• genetic predisposition
• the tendency toward addiction is variable, with
  studies indicating that genetic factors have some
  influence
• alcoholism, especially, tends to run in families
• social factors
• a variety of social factors correlate positively
  with addiction
• cultural traditions
• peer pressure
• poverty
• social deprivation
• traumatic life experiences
• mental health problems
• dopamine secretion
• many addictive drugs are excitatory at
  dopaminergic synapses, also known as the reward
  pathway
• addiction is a result of dopaminergic synapses
  responding to regular use
• reduction in the number of dopamine receptors in
  post-synaptic neurons
• reduction in the release of dopamine from
  pre-synaptic neurons
• tolerance to a drug
• a result of decreased number of receptors
• leading to increased dosage to produce the
  desired effect

24
E.5.1 Label, on a diagram of the brain, the
medulla oblongata, cerebellum, hypothalamus,
pituitary gland and cerebral hemisphere
25
E.5.2 Outline the functions for each of the parts
of the human brain in.

• medulla oblongata controls automatic and
  homeostatic activities, such as
• swallowing
• digestion vomiting
• breathing
• heart activity
• cerebellum coordinates unconscious functions,
  such as
• body movements
• posture and balance
• hypothalamus maintains homeostasis, coordinating
  the nervous and endocrine systems
• regulates, appetite, thirst, body temperature,
  and sleep
• secretes hormones of the posterior pituitary
• secretes hormone releasing factors regulating the
  anterior pituitary
• pituitary gland
• posterior lobe stores and releases hypothalamic
  hormones
• anterior lobe produces, stores, and secretes many
  hormones regulating many body functions
• cerebral hemispheres
• act as integrating center for high complex
  functions, such as
• memory, learning, emotion, language, reasoning

26
E.5.3 Explain how animal experiments, lesions and
fMRI (functional magnetic resonance imaging)
scanning can be used in the identification of the
brain part involved in specific functions,
providing one specific example of each.

• animal experiments
• surgical procedures allow access to brain
• experiments performed on live animals so that
  brain is functioning
• effects of experiments observed during and/or
  after experiment
• specific example rats
• research into visual impairments such as
  strabismus (cross eye)
• induced by covering the eye with material or
  stitching the eye shut
• monitor visual development
• ethical issues related to suffering of animals,
  and sacrifice of animals
• lesions
• damage to specific brain regions
• injury by accident/war
• stroke
• tumor
• allow deduction of location of specific brain
  functions
• specific example stroke
• lesion in Broca's area in left cerebral
  hemisphere
• causes dysphasia, inability to speak
• but reading and writing are unaffected

27
E.5.4  Explain sympathetic and parasympathetic
control of the heart, movements of the iris, and
flow of blood to the gut.

• autonomic nervous system
• sympathetic
• fight-flight-excercise
• parasympathetic
• restorative, resting, digesting
• heart
• sympathetic
• heart rate accelerates, pumping more blood to
  muscles
• parasympathetic
• heart rate slows, body relaxes, less blood needed
  to muscles
• blood flow to gut
• sympathetic
• blood vessels constricted, decreasing blood flow
  to gut
• parasympathetic
• blood vessels dilated, increasing blood flow to
  gut

28
5.5 Explain the pupil reflex.

• pupil reflex when a bright light shines into one
  eye, the pupils of both eyes normally constrict
• retina detects light intensity
• impulses to brain in optic nerve
• brain stem/medulla controls the reflex
• sympathetic system causes dilation
• parasympathetic system causes constriction
• sympathetic neurons are in spinal nerve T1
• parasympathetic neurons are in cranial nerve III
• pre- and postganglionic fibers of symp/parasymp
• neurotransmitters of symp/parasymp
• polysynaptic reflex

29
Statement 5.6- Discuss the Use of the Pupil
Reflex in Testing for Brain Death

• If stimulation of the pupil with light fails to
  cause contraction then it is very likely that the
  CNS has sustained severe damage and brain death
  is possible.

30
Statement 5.7- Outline How Pain is Sensed and How
Endorphins and Enkephalins can Act as Painkillers.

• Pain receptors are located in the skin and on
  organs. Pain signals are sent along these nerve
  endings along nerve fibers on the spinal cord.
  The signals pass synapses to neurons that carry
  them up in an ascending tract to the stem or
  thalamus of the brain. The signals may pass on in
  other neurons to sensory areas of the cerebral
  cortex, causing conscious pain. --Endorphins and
  enkephalins act as painkillers by stopping the
  pain signal to the brain. Enkephalins block
  calcium channels in the membrane of the
  pre-synaptic neurons. They block the synaptic
  transmissions, so the message doesnt reach the
  brain. Endorphins are released from the pituitary
  gland to control pain. They are carried to the
  brain and bind to pain receptors and block the
  release of the neurotransmitter that is used to
  transmit pain signals to the brain.

31
Statement 6.1- Describe the Social Organization
of Honey Bee Colonies

• There are three castes of honey bees which have
  different tasks. The single queen bee of a colony
  has to lay eggs. The worker bees do jobs that
  maintain the colony. The drones do nothing to
  help the colony to survive. However, if they
  successfully mate with virgin queens, they spread
  the genes of the colony to new colonies. Workers
  eject drones from the colony at the end of the
  season during which virgin queens are available.

32
Statement 6.2- Outline How Natural Selection May
Act at the Level of the Colony in the Case of
Social Organisms.

• In the case of social animals, especially
  colonies, most of the individuals have very
  similar DNA so their genes are still getting
  passed down even if they aren't themselves
  reproducing. So these animals will sacrifice
  themselves for the greater good of their very
  close relatives.I.E. prairie dogs on the lookout
  for predators will make a loud noise warning
  everyone to get in their holes and by doing this
  he lets the predator know exactly where he is and
  will probably get eaten but he has saved a lot of
  the colony.Lions will give up trying to
  reproduce and just help their brother/nephew,
  whatever their relationship is to the dominant
  male, get as many ladies as possible and protect
  his young.From this evidence you can see that
  natural selection does not act on the population
  or the individual, rather the genes

33
Statement 6.3- Discuss the Role of Altruistic
Behavior in Social Organizations Using Two
Examples

• Wolves - In a pack of wolves, there is a dominant
  male and female which are the sole reproducers,
  and the other members of the pack hunt and bring
  back food for the breeding pair.
• Naked Mole Rats - There exist breeding males and
  females, the diggers (who dig tunnels and provide
  food) and protectors who offer their lives when
  facing a predator. The concept is that the
  sacrifices will indirectly pass on their genes by
  protecting the mating pair.

34
Statement 6.4- Outline Two Examples of How
Foraging Behavior Optimizes Food Intake,
Including Bluegill Fish Foraging for Daphnia

• Spirit Bear
• Spirit bears are omnivores whose diet includes
  plants, insects, living animals and carcasses.
  During the salmon spawning season, spirit bears
  gorge themselves on salmon because the salmon
  provide the maximum calorie supply. When salmon
  are not available, 80 of their diet consists of
  plant material because meat is harder to find.
• After catching a salmon spirit bears usually
  carry their fish away from the stream where they
  can feed in seclusion. If the fish is a female
  they begin feeding on the belly, which contains
  fat-rich eggs. They also feed on the brains and
  certain organs, which are also fat-rich.
• The bears preference of feeding in seclusion
  reduces the chances of losing a meal to a rival
  bear or wasting time fighting the rival. And
  their preference for high-fat organs ensures that
  their bellies fill up with organs with the
  highest energy content.
• The spirit bears food preferences match foraging
  theory. Over evolutionary time, natural selection
  has favored bears that prefer fatty meat because
  they were able to consume more calories than
  bears that ate less fatty meat. In bleak years,
  when competition for food was fierce, bears
  eating fatty foods would have survived better
  than individuals consuming lower energy food
  items.

35
Statement 6.4- Outline Two Examples of How
Foraging Behavior Optimizes Food Intake,
Including Bluegill Fish Foraging for Daphnia
(cont.)

• When environmental conditions change, generalist
  feeders have an advantage over specialist feeders
  because they can adjust their feeding behavior to
  optimize their chances of survival.
• A good example of this comes from studies on the
  bluegill sunfish, which feeds on small
  invertebrates like Daphnia.
• When Daphnia is abundant the sunfish can afford
  to be choosy, and as such they feed exclusively
  on larger prey items. However, when prey is
  scarce they must eat whatever food items they can
  find.
• The graphs indicate that average prey size
  increases as prey density increases.

36
Statement 6.5- Explain How Mate Selection Can
Lead to Exaggerated Traits.

• Evolutionary success means successfully passing
  on your genes to future generations. In some
  species evolutionary success has led to the
  evolution of differences between males and
  females, a phenomenon called sexual dimorphism.
• In some species, males have evolved conspicuous
  or exagerated traits that advertise their
  reproductive worth. The spectacularly colorful
  tail feathers of peacocks provide a good example
  of this.
• Some studies suggest that peahens choose to have
  sex with the most colorful peacocks available,
  and that males with parasites are less brightly
  colored. The researchers suggest that this color
  preference of peahens causes them to breed with
  the strongest, healthiest and least-parasitized
  males.
• However, more recent research has disputed a link
  between feather color and parasitism. These
  studies suggest that peacocks select males with
  the loudest vocalizations. So its possible that
  a peacock's color does not indicate health. If
  this is so then colorful peacock feathers could
  be an example ofrunaway evolution.
• In runaway evolution one female develops a whim
  for a particular male trait that she then passes
  on to future generations of females. These
  females start choosing males with the desired
  trait, which causes that trait to become
  exagerated in males over time.
• Thus runaway evolution can lead to to exaggerated
  traits that dont really help the species as a
  whole. The peacock's tail, for example, requires
  a great deal of energy to grow and maintain, it
  reduces the bird's agility, and it increases the
  animals visibility to predators. Yet it has
  evolved, indicating that the advantage of having
  a longer tail, in terms of getting sex, outweighs
  the disadvantages.

37
Statement 6.6- State That Animals Show Rhythmical
Variations in Activity

• Animals show a rhythmic variation in activity as
  the year passes. Many different animals show
  their rhythmic variation in the form of
  hibernation when, annually, the animals decrease
  in activity drastically during the winter months
  of the year

38
Statement 6.7- Outline Two Examples Illustrating
the Adaptive Value of Rhythmical Behavior
Patterns.

• Krill
• Krill are shrimp-like marine invertebrates. They
  are important sources of food for certain whales,
  sharks, seals and penguins.
• Krill typically follow a diurnal vertical
  migration. They spend the day at greater depths
  and rise during the night towards the surface.
  The deeper they go, the darker the water becomes,
  and this makes it more difficult for predators to
  eat them.
• The diurnal migrations of krill depend on
  accurate monitoring of daylight, which is
  achieved by their circadian system.
• Insect-eating Bats
• The circadian "clock" in mammals is located in a
  part of the hypothalamus called the SCN. The SCN
  receives information about daylight from special
  photoreceptors in the retina.
• The SCN sends a message to the pineal gland, a
  tiny structure in the brain, which secretes the
  hormone melatonin. Melatonin causes mammals to
  feel sleepy. In humans, secretion of melatonin
  peaks at night.
• In bats, melatonin peaks in the daytime, which is
  why they are more active at night? Being active
  at night is a benefit to bats because they feed
  on moths, which mainly fly at night. Thus the
  circadian rhythm of bats helps them to hunt and
  feed when their prey is most abundant.