Download communication

OPTION – COMMUNICATION
Humans are social animals and, as such, are in constant communication with others. Many animals
have an extensive range of communication strategies that include both visual and vocal signals.
Learning these signals relies heavily on the involvement of all the sensory organs as well as the
brain.
While the full range of senses can be involved in communication, the relative importance of each of
the sense differs from animal to animal. This module focuses on the two senses that are important
for many vertebrate and invertebrate animals – sight and hearing.
Human cultural development exploded with the development of speech and concurrent increasing
complexity of communication. For some people, however, communication signals are not identified
effectively because of faults in the sending, receiving or deciphering of some of the signals. With
increasing advances in technology, assistance for people with difficulties in communicating
continues to improve.
Identify the role of receptors in detecting stimuli.
Things to consider:
 What does identify mean?
 What is a receptor?
 Be succinct
The roles of receptors are to detect stimuli within the surrounding environment. Once a stimulus has
been detected by the organism it will respond. For example if the thermoreceptors on your skin
detect cold air you will begin to shiver to maintain your body heat.
Receptors are also classified on the basis of their function, they are as follows:
Chemoreceptors: detect chemicals.
Electromagnetic receptors: change in electromagnetic field, E.G. light receptors in eye.
Mechanoreceptors: detect mechanical features such as pressure, touch, stretch.
Pain receptors: detect pain.
Thermoreceptors: detect change in temperature.
Explain that the response to a stimulus involves:
- stimulus
- receptor
- messenger
- effector
- response
Things to consider:
 What does explain mean?
 Be succinct.
A stimulus is something that produces a response in the organism. For example if you were
suddenly exposed to bright light (stimulus) the photo - receptors in the eye (receptor) send a
message to the central nervous system (CNS - messenger) which then in turn sends a message to the
muscles in the eye (effector) for the muscles to contract which then elicits the response of blinking
(response). This process applies to all stimulus/response actions.
Identify data sources, gather and process information from secondary sources to identify the range
of senses involved in communication.
Things to consider:
 What does identify, gather and process mean?
 What are the main senses used in communicating?
 Underline key words, be succinct
There are five main senses which are involved in communication, which are seeing, hearing, touch,
taste and smell.
Seeing (OCCULAR): or sight involves the use of an eye. An eye contains many structures which
allow certain amounts of light as well as different electromagnetic waves to pass in and out of the
eye. The organism reacts to these changes by relaying a message via the optic nerve to the brain to
either allow more or less light/electromagnetic waves into the eye.
Hearing (AUDITORY): involves the use of ears. The ear contains many structures which allow
certain frequencies of noise to enter the ear and to be deciphered by the brain.
Touch (SOMATOSENSORY SYSTEM): involves the use of mechanoreceptors, pain receptors and
thermoreceptors. These receptors are usually found on the skin of the organism and enable the
organism to enjoy certain stimulus and to avoid certain stimulus.
Taste (GUSTATION): refers to the ability of being able to taste foods and chemicals entering the
mouth. Taste involves the use of chemoreceptors which detect chemicals within the food. There is
said to be 4 aspects of taste; sweet, sour, salty, bitter.
Smell (OLFACTION): smell is the ability of an organism to perceive odours or smells.
Chemoreceptors are found in the nose which has the ability of detecting these smells.
Describe the anatomy and function of the human eye, including the:
- conjunctiva
- cornea
- sclera
- choroid
- retina
- iris
- lens
- aqueous and vitreous humor
- ciliary body
- optic nerve
Things to consider:
- What does describe mean?
- Ensure you can label the diagram without using your textbook.
- Include the function of each highlighted structure.
PART OF
EYE
Conjunctiva
Cornea
Sclera
Choroid
Retina
STRUCTURE
A delicate membrane that covers the surface of
the eye and the inside of the eyelids.
The front part of the eyeball which is transparent
and quite thick.
Continuous with the cornea but not transparent,
it forms the tough, white outer back part of the
eyeball.
The choroid lies on the inside of the sclera. It is a
thin black layer which contains many blood
vessels.
The innermost layer of the eye. It lines the back
of the eyeball with a network of photoreceptors
and nerve fibres.
FUNCTION
Protects the front part of the eye.
Refracts light rays as they pass through it.
Protects the eye and helps maintain eye shape.
The pigment absorbs stray light preventing stray
images.
Receives the light images and translates this into
electrical impulses which are sent to the brain
and deciphered.
Iris
Lens
Aqueous
and
Vitreous
Humor
Ciliary
Body
Optic Nerve
The coloured part at the front of the eye
containing many fibrous muscles.
A transparent biconvex protein disc behind the
pupil.
Aqueous humor a vitreous substance fills the
front chamber of the eye. Vitreous humor a jelly
– like substance fills the back chamber of the
eye.
Connects the choroid with the lens. It contains
suspensory ligaments as well as ciliary muscles.
Connects the eyeball to the brain. Where the
optic nerve connects to the brain is known as the
blind spot as no image can be made or processed
due to the lack of photoreceptors.
(HEINEMANN BIOLOGY 2nd EDITION)
Regulates the amount of light entering the eye.
Refracts and bends light rays towards the retina.
Keeps the eyeball in shape as well as refracts
light towards the retina.
Holds the lens in place as well as altering the
shape of the lens depending on the distance of an
object.
Carries nerve impulses to the visual cortex of the
brain so images can be translated.
Identify the limited range of wavelengths of the electromagnetic spectrum detected by humans and
compare this range with those of other vertebrates and invertebrates.
Things to consider:
- What does identify and compare mean?
- Ensure you include other vertebrates AND invertebrates.
The electromagnetic spectrum is a range of energy forms which all travel at the speed of light.
However these energy forms vary in wavelength and frequency. Humans detect visible light which
ranges from 400nm to 700nm. This means that humans can only see objects within this wavelength.
In comparison snakes use infrared light to detect prey and to avoid predators. Infrared light falls
between 750nm to 1mm. Bees use ultraviolet light to detect petals on plants. This leads the bees to a
food source (nectar). U.V. light ranges from 10nm to 400nm.
Use available evidence to suggest reasons for the differences in range of electromagnetic radiation
detected by humans and other animals.
Things to consider:
- Understand what the question is asking before you answer.
- Be succinct
- This question is almost a discussion so provide points for and/or against the differences in
range of electromagnetic radiation.
There are many different reasons as to why humans detect a different range of the electromagnetic
spectrum in comparison to that of other animals. The reasons are as follows:
 Many organisms live in different niches. These niches produce different obstacles for the
organism. Each organism needs to detect predator and prey within their environment to survive.
This may come in the form of a different electromagnetic field.
 For example electric eels emit an electric field within their environment. Any disturbance to this
environment such as that by prey is detected by the eel. Subsequently the prey is consumed.
Eels use this form of electromagnetic radiation as vision within a water environment is quite
poor.
 The platypus has electromagnetic receptors in its bill. This helps the platypus to detect prey
which produces an electric field. Platypuses use these receptors as vision within a water
environment is quite poor.
 Snakes use infrared light to detect predators and prey. This is due to the fact that snakes are
largely found on the ground and in the underbrush of bushland. Snakes rarely use normal vision
due to the lack of periphery on the ground.
 Bees use ultraviolet light in detecting the nectar on flowering plants. This form of
electromagnetic radiation is an advantage as the bee is able to quickly and efficiently detect a
food source.
 Humans use two single lens eyes to detect visible light. Humans have many photoreceptor cells
of different pigment which detect the various colours of the spectrum. This form of
electromagnetic radiation enables humans to produce sharp images of various objects.
 It is evident that depending on the organism and its environment organisms have adapted
various electromagnetic fields to detect predators and prey.
Identify the conditions under which refraction of light occurs.
Things to consider:
- What does identify mean?
- Be succinct
- Understand key concepts before writing an answer.
Light refraction occurs when a light wave travels from a higher density to a lower density or a lower
density to a higher density. An example of refraction is light waves travelling from air to water.
Identify the cornea, aqueous humor, lens and vitreous humor as refractive media.
Things to consider:
- What does identify mean?
- What is refraction?
- Keep your answer simple.
Refraction occurs in the eyeball where light waves are bent towards the retina to from an image.
This refraction occurs with the use of refractive media. The refractive media in the eye include:
- cornea
- aqueous humor
- lens
- vitreous humor
Identify accommodation as the focusing on objects at different distances, describe its achievement
through the change in curvature of the lens and explain its importance.
Things to consider:
- What does identify, describe and explain mean?
- Underline key words.
- Ensure you answer all aspects of the dot point.
- Be succinct
Accommodation is the process by which the lens changes shape according to the distance of an
object of which it is focusing on. This process is possible due to the lens altering its curvature. If an
object is less than six meters away the ciliary body will contract causing the lens to bulge. This in
turn will cause the lens to refract the light at a greater angle. The effect of this is a greater sharper
image. In contrast if you were to look at an image one hundred meters away the ciliary body
relaxes, this cause the lens to elongate, this causes the lens to refract the light at a smaller angle. The
effect of this process allows for a sharper image. Therefore accommodation allows humans to focus
on objects at varying distances.
Compare the change in the refractive power of the lens from rest to maximum accommodation.
Things to consider:
 What does compare mean?
 What is refractive power?
 What is accommodation?



DISTANT OBJECT
Light reaches eye in parallel rays.
Lens is quite flat/elongated and at resting
state. Ciliary muscles relax.
Low refractive power. This means that there
is very little to low levels of refraction
occurring.



CLOSE OBJECT
Light reaches eye as diverging rays.
Lens becomes convex, that is bulging out.
This is due to the ciliary muscle contracting.
High refractive power. This means that there
is a high level of refraction occurring.
Analyse information from secondary sources to describe changes in the shapes of the eye's lens
when focusing on near and far objects.
Things to consider:
 What does analyse mean?
 What does describe mean?
 Use diagrams to illustrate your answer.
Accommodation is the process by which the lens changes shape and curvature due to the distance of
an object the person is looking at. In general a distant object causes the ciliary muscles to relax.
This in turn causes the lens to elongate. The refraction index is low. This is due to the fact that if we
focus on a distant object the light rays are coming in parallel lines. This means that the refractive
media within the eye do not have to work as hard to refract the light to produce an image. When we
refer to a close object the eye has to work harder in order to refract the light rays. Light rays at a
close object are generally diverging, meaning they are splitting in an outwards direction. This
causes the ciliary muscles to contract in turn causing the lens to bulge and refract the light at a
higher index. An example of accommodation taking place when focusing on a distant and close
object is illustrated below: (NOTE THE SIZE OF THE LENS. THIN = FAR OBJECT, THICK =
CLOSE OBJECT.)
http://upload.wikimedia.org/wikipedia/commons/thumb/8/81/Focus_in_an_eye.svg/325pxFocus_in_an_eye.svg.png
Distinguish between myopia and hyperopia and outline how technologies can be used to correct
these conditions.
Things to consider:
 What does distinguish mean?
 What does outline mean?
 Be succinct. Ensure you know the technologies used.
Myopia commonly known as short sightedness, usually results from an elongated eyeball. Close
objects can be viewed with no difficulty due to accommodation by the lens. However distant objects
appear to be blurred due to the light rays being refracted in front of the retina. To correct this
condition a concave lens is used either as spectacles or contact lenses. As you can see below the top
diagram indicates myopia, as the light is focused before the retina. Through the use of the concave
lens, which diverges the light rays, the focal point hits the right spot on the retina. (Fovea)
Figure 1: Myopia – illustrating refraction and the effect the concave lens has on the focal point.
http://upload.wikimedia.org/wikipedia/commons/1/13/Myopia.png
FIGURE 2: A TYPICAL IMAGE SEEN BY A PERSON SUFFERING FROM MYOPIA
http://www.psych.ucalgary.ca/PACE/VALab/AVDE-Website/Assets/Barn%20Scene%20Myopia.jpg
Hyperopia is commonly known as long sightedness. The condition occurs from either a short
eyeball or poor accommodation ability by the lens. Distant objects can be viewed easily where as
close objects appear blurry. This is due to the fact that the focal point for close objects is behind the
retina, indicated below in figure 3. To correct this convergent or convex lenses are used in the form
of spectacles or contact lenses, see figure 3.
Figure 3: Hyperopia - illustrating refraction and the effect the convex lens has on the focal point.
http://upload.wikimedia.org/wikipedia/commons/thumb/6/60/Hypermetropia.png/250pxHypermetropia.png
FIGURE 4: A TYPICAL IMAGE SEEN BY A PERSON SUFFERING FROM HYPEROPIA
http://www.bausch.com/en_US/images/concern_full_img/farsightedness.jpg
Other technologies that are used to correct myopia and hyperopia include radial keratotomy and
photo – refractive keratectomy. Both of these technologies involve a surgical procedure which
reshapes the cornea in order to alter the refractive power. In radial keratotomy fine surgical
instruments shave small amounts of corneal tissue off the eye while in photo – refractive
keratectomy a computer controlled laser is used to remove thin slices of corneal tissue.
Plan, choose equipment or resources and perform a first – hand investigation of a mammalian eye
to gather first hand data to relate structures to its function.
Things to consider:
- What does plan, choose equipment and resources mean? Ensure you write an experimental
procedure similar to the one on page 502 of the text book.
- The experimental procedure, results, discussion and conclusion needs to be handed up to me
by the end of the lesson.
MODELLING ACCOMMODATION USING CONVEX LENSES
Plan, choose equipment or resources and perform a first hand investigation to model the process of
accommodation by passing rays of light through convex lenses of different focal lengths.
Things to consider:
- The dot point says to plan so you need to complete a detailed write up of this experiment.
- Ensure you learn the detailed method as you could be asked to reproduce the method in the
HSC exam.
- Refer to page 503 of your text book.
AIM:
To model the process of accommodation by passing rays of light through convex lenses of different
thicknesses.
MATERIALS/EQUIPMENT:
 One thin convex lens, one thick convex lens.
 A lens holder.
 A sheet of white cardboard or paper clipped on to a solid support; this acts as a screen where the
object is focused.
 A metre ruler.
 A small lamp.
METHOD:
1. Darken the room and set up the thin lens in the holder as shown in figure 12.1. (Page 503 of
text book)
2. Move the lens forwards and backwards to find a position that produces a clear focused
image of the light source on the screen.
3. Describe the image and measure and record the distance of the image from the lens.
4. Keep the lens holder the same distance from the screen and change the lens to the thick lens.
5. Observe the screen and note the appearance of the image. Record it.
6. Move the light source until the image is focused again.
7. Measure and record the distance from the light source to the lens.
8. Answer the questions.
RESULTS:
LENS THICKNESS


DISTANCE OF FOCAL
POINT (cm)
Thin
28
Thick
13
The image is a clear/white dot on the white screen. Some of the spectrum can be seen.
When changing the lens from thin to thick the image became unfocused, larger in size and
blurred.
DISCUSSION/QUESTIONS: (Page 503 of text book)
1. In this experiment the lens represents the lens in our eye, the distance from the lens to the
screen represents the focal length and the screen represents our retina.
2. a.) The image on the screen was a small round white dot. As it was a perfect circle it did not
matter if it was inverted.
b.) If we had an image in front of the light it would have produced a shadow, which could
have been our object. If this occurred the shadow should have appeared upside down on the
screen of paper. This relates to our eye as when we first look at an image it is shown upside
down on our retina. Our brain turns the image the right way around.
3. A thin lens gives a clear focus on a far object. This is illustrated by the results as the lens was
28cm away from the screen, compared to the thick lens which was 13cm. This indicates that a
thinner lens accommodates best when focusing on a distant object.
4. A thick lens gives a clear focus on a near object. This is illustrated by the results as the lens was
13cm away from the screen, compared to the thin lens which was 28cm. This indicates that a thick
lens accommodates best when focusing on a near object.
5. Through this experiment links can be drawn between the results and how the human eye works.
Through accommodation the human eye is able to see distant and near objects with precision. This
is largely due to that fact that the lens is able to change shape or accommodate according to the
distance of the object it is looking at. When we look at a distant object our ciliary muscles relax and
lens becomes thinner, this was also illustrated by the experiment and our results. When we look at
near objects the ciliary muscles contract causing the lens to bulge and become more convex, this
was also illustrated by our results.
6. This model differs from the eye in the following ways. The focal length in the human eye will be
a lot shorter. The size of the lens is controlled by ciliary muscles in the eye. The human eye contains
other refractive media such as the cornea, aqueous humor and vitreous humor which also affects the
amount of refraction.
7. This model is similar to what happens in the eye in the way the lens refracts the light to a central
point. In this experiment the light was refracted to one point on the screen while in the human eye
light is refracted to the retina.
8. Models help to explain key concepts in science on a larger scale. Their disadvantage is that they
can not include all relevant data and concepts.
CONCLUSION:
In this experiment we were able to model the concept of accommodation. This was evident in the
refraction taken out by the different sized lenses and their focal lengths on the screens.
Process and analyse information from secondary sources to describe cataracts and the technology
that can be used to prevent blindness from cataracts and discuss implications of this technology for
society.
Things to consider:
- What does analyse, describe and discuss mean?
- Break the question up, firstly describe what cataracts are, secondly describe the technology
and thirdly discuss how this technology affects society.
BACKGROUND:
A normal human adult lens should be transparent to allow light to flow through to the retina. The
transparency is due to structural and biochemical factors. The lens consists of many folded fibres
called crystallins. The way these fibres are arranged makes the lens transparent. Lens fibres are
capable of producing energy for the lens. Like all fibres and tissue, lens fibres need to be replaced
making the lens become thicker and less elastic over time.
When the lens thickens or becomes cloudy the vision of the person decreases. This condition is
known as cataracts. It is believed that the cause of cataracts is the insufficient nutrients in the lens
fibres due to the density of these fibres. The crystallin proteins are then oxidised which then in turn
causes the fibres to clump together producing a cloudy thickened lens.
Cataracts can come in many forms including age – related cataracts (old age), radiation – induced
cataracts (U.V. light) and infectious cataracts (rubella virus causing cataracts). The simple type of
technology used in preventing these types of cataracts is the use of sunglasses to prevent U.V. light
damaging the lens and an adequate diet high in anti – oxidants which destroy free radicals. However
in some circumstances the cataracts are well developed causing blindness to the patient. In this case
a surgical procedure known as phakoemulsification must take place. During this procedure a small
chisel – like instrument is inserted into the lens. The content of the lens is sucked out while the lens
cavity is filled with a fluid to prevent damage to the cavity and loss of vitreous humor which will
cause the retina to detach from the eyeball. A contact lens is then placed in the lens cavity. This is
performed by folding the contact lens and inserting it into the eye via a straw. Once inside the cavity
the lens unfolds and remains there for the rest of the patient’s life restoring their vision. The contact
lens is known as an interocular lens (IOL) which resists U.V. light and is accepted by the body due
to its plastic nature.
Phakoemulsification is a surgical technique which has greatly implicated society. The procedure
itself takes very little time, is performed under a local anaesthetic and can be performed almost
anywhere around the world. Phakoemulsification has revolutionised how doctors treat cataracts as it
prevents unnecessary blindness especially third – world countries. Phakoemulsification is a safe,
precise and successful technique available to thousands of people in developed and developing
countries. The late Fred Hollows, who was responsible for restoring sight to many people in third
world countries, set up a factory which made interocular lenses for only 10 cents. This made the
process even affordable for the poor. It is through phakoemulsification, a huge advance in
technology, cataracts are easily and successfully treated.
Figure 1: Person suffering from cataracts
http://www.ehponline.org/docs/2005/113-3/eye.jpg
Figure 2: Simple process of phakoemulsification
http://www.med.umich.edu/1libr/aha/phacoext.gif
Explain how the production of two different images of a view can result in depth perception.
Things to consider:
- What does explain mean?
- What is depth perception?
- Be succinct.
The ability to judge the distance of an object from our eyes is called depth perception. Depth
perception relies on many factors. Firstly as humans we have binocular vision meaning we see
through two eyes. The eyes are separated horizontally which enables humans to have stereoscopic
vision (3D). So when we look at an object with both eyes two different images are formed on both
retinas. This is due to the fact that the object we are looking at is at a different distance compared
from one eye to the next. The brain interprets these two images produced by both eyes and fuses the
images together to ascertain a general perception about the depth of the object.
Experience is an important factor relating to depth perception. Through our life we learn how tall
certain objects are, this also helps us to perceive the depth of an object because we also know that
distant objects appear to be small. So when we look at an object the size of the image on the retina
is interpreted as being close or distant depending on the size of the object.
Identify photoreceptor cells as those containing light sensitive pigments and explain that these cells
convert light images into electrochemical signals that the brain can interpret.
Things to consider:
- What does identify mean?
- What does explain mean?
- What are photoreceptors?
- Relate to brain and electrochemical signals.
Photoreceptor cells are special types of neurons which are sensitive to light. In a human eye there
are two types of photoreceptors rods which contain the light sensitive pigment rhodopsin and cones
which contain the light sensitive pigment photopsin.
These photo-sensitive pigments are responsible for changing light signals into electrochemical
signals which are interpreted by the brain as a certain image. When light enters the eye it is focused
onto the retina. Rods and cones are not in the first layer of the retina. The light or collection of light
known as photons pass through the layer of the ganglion cells, then the bipolar cells and then finally
reach the rods and cones. In the rods the rhodopsin absorbs the light causing the retinal part of the
molecule to change shape. This change in the rhodopsin molecule causes a change in the opsin
molecule which then activates a relay molecule known as transducin. This results in less inhibitory
neurotransmitter being released between the synapses between the rods and bipolar cells and the
bipolar cells and ganglion cells, (enables messages to pass through). The electrochemical signal is
passed through the rods to the bipolar cells, then from the bipolar cells to the ganglion cells, then
from the ganglion cells to the optic nerve which delivers the electrochemical signal to the brain for
interpretation.
Describe the difference in distribution, structure and function of the photoreceptor cells in the
human eye.
Things to consider:
- What does describe mean?
- Differences only
- What are photoreceptor cells?
CONES
DISTRIBUTION
 6 Million cones in the
human eye.
 Cones are largely
concentrated around the
fovea where most of the
daylight is focused.
RODS
DISTRIBUTION
 125 Million rods in the
human eye.
 They are largely
concentrated around the
surface of the whole retina.

STRUCTURE
Elongated cells with a
synaptic terminal and an
outer terminal containing
discs. Similar to the basic
structure of a nerve cell.





STRUCTURE
Elongated cells with a
synaptic terminal and an
outer terminal containing
discs. Similar to the basic
structure of a nerve cell.


FUNCTION
Provide sharp images.
Not sensitive to light.
Images are NOT sharp
during night time due to the
lack of light.
Can distinguish colour.
FUNCTION
Rods are very sensitive to
light.
Responsible for night
vision seeing black and
white.
Outline the role of rhodopsin in rods.
Things to consider:
- What does outline mean?
- What is rhodopsin?
- You can use point form for this answer.






Rhodopsin is a light absorbing pigment found in the rods of the human eye.
Composed of a derivative of vitamin A called retinal bonded to a protein called opsin.
Retinal part of the rhodopsin molecule is responsible for the initial absorption of light.
Different opsin molecules affect the light – absorbing ability of the retinal.
Rhodopsin is sensitive to lower wavelengths in the visible spectrum, (blue – green).
Rhodopsin is more active during duller light or darkness.
Identify that there are three types of cones, each containing a separate pigment sensitive to either
blue, red or green light.
Things to consider:
- What does identify mean?
- Keep your answer simple, be succinct.
There are three types of cones found in the human eye which are all sensitive to different
wavelengths of the visible spectrum. This is due to the type of opsin molecule which best absorbs
that certain colour. The opsin molecule and its absorbing wavelength are as follows:
- Blue region, maximum of 420 nanometres.
- Green region, maximum of 530 nanometres.
- Red region, maximum of 560 nanometres.
These cones are responsible for all the colours of the spectrum which we see.
Explain that colour blindness in humans results from the lack of one or more of the colour sensitive
pigments in the cones.
Things to consider:
- What does explain mean?
- What are colour sensitive pigments?
- Be succinct.
Colour blindness, a sex – linked condition often occurring in males, is the deficiency in
distinguishing between certain colours. There are three types of colour blindness. The most
common is referred to as red – green colour blindness. With this condition individuals either lack
the red pigment or green pigment in their cones. This results in the other two cones, which are
present, seeing all the colours of the visible spectrum. However as a result the individual is easily
confused when distinguishing between red and green or they can not see red or green properly.
The second rarer type of colour blindness is blue – yellow colour blindness. These individuals lack
the blue pigment in their cones. This results in confusion between blue and yellow, or the colours of
blue and yellow are difficult to see.
The third and extremely rare condition of colour blindness is the total absence of cones. These
individuals have no cones which means they have no colour – sensitive pigments. This results in the
individual only seeing in black and white.
Process and analyse information from secondary sources to compare and describe the nature and
functioning of photoreceptor cells in mammals, insects and in one other animal.
Things to consider:
- What does compare and describe mean?
- Understand what the question is asking.
- Ensure you use a mammal example, an insect example and another animal example.
- Pages 479 – 481
MAMMAL (Human)




Evolved single – lens eyes
to see.
Each eye contains a retina
which is composed of many
differing cells. In particular
photoreceptor cells known
as rods and cones.
Rods and cones contain
visual pigments that absorb
light.
This in turn causes the light
signal to be changed by the
photoreceptors into an
electrical impulse which is
eventually interpreted by
the brain.
INSECT (Fly)





Evolved a compound eye
which contains thousands
of light detecting units
called ommatidium.
Each ommatidium contains
a lens which focuses the
light on the light absorbing
pigments.
The cells are arranged in a
stack formation called a
rhabdom.
Each photoreceptor alters
the light signal to an
electrochemical signal
which is interpreted by the
brain.
Insects see different
coloured dots through each
ommatidium. A change in
shade or colour could mean
that there is a predator
present.
OTHER ANIMAL (Planarian
Worm)
 Evolved an eye cup which
holds many photoreceptor
cells.
 These photoreceptors are
stimulated by light and send
a nerve impulse to the brain
for interpretation.
 The planarian worm has
two eye cups. When the
brain registers the strength
and direction of the light
the worm moves to an area
of lower light intensity.
 The resulting darkness
helps the worm steer clear
of predators.
Process and analyse information from secondary sources to describe and analyse the use of colour
for communication in animals and relate this to the occurrence of colour vision in animals.
Things to consider:
- What does process, analyse and describe mean?
- Understand what the question is asking.
- Be succinct
- Refer to page 479.
The animal kingdom heavily relies on vision as a means of communication. In particular is the use
of colour vision. Each organism varies in its capabilities of seeing certain objects. In order to have
colour vision an organism must have cones, a photoreceptor found in the retina of the eye. Bees are
an example of an organism which uses colour vision as a means of communication. Bees can see
the ultraviolet end of the spectrum which enables the bees to see certain patterns on flowers. This
results in the bee distinguishing between which plants to access its food from.
Many members of the five classes of animals; amphibians, fish, reptiles, birds and mammals can
see using colour vision. This adaptation enables the organism to communicate within its
environment, aid in reproduction as well as reproductive behaviour and eat certain foods which they
are attracted to due to the colour of the food. For example many primates can detect the ripeness of
the food they eat based on the colour of the food.
Nocturnal animals do not rely on colour vision. Nocturnal animals are largely active during the
night and hence have a larger number of rods in their eye structure. This enables the nocturnal
organism to see sharper images during the night time.
Birds use colour vision as a means of communicating with other birds and detecting food. Birds are
strongly attracted to the colour red. To enable birds to see the red colour more readily they have a
higher concentration of red pigment photoreceptors in their eye. The result of this is that birds can
see red more readily then any other colour resulting in finding food at a much more efficient rate.
Ultimately colour vision is a useful tool for all organisms in communicating within their own
environment.
Explain why sound is a useful and versatile form of communication.
Things to consider:
- What does explain mean?
- What is communication?
- Be succinct
Sound is a useful and versatile form of communication as it is used by many organisms for
socialising, mating behaviours, feeding patterns, the avoidance of prey and overall an effective
communication tool.
Sound is an advantageous form of communication. Sound does not need light in order to be heard.
Sound can travel through solids, liquids and gases. This means that sound can be used in dense
environments. For example birds could call out to warn other animals of approaching predators.
Sound is used to send and receive messages. Humans and other mammals use vocal chords, fish use
swim bladders and insects such as cicadas use a tympanal membrane to produce a “chirping” noise.
Sound by organisms is detected by the ear.
Explain that sound is produced by vibrating objects and that the frequency of the sound is the same
as the frequency of the vibration of the source of the sound.
Things to consider:
- What does explain mean?
- What is frequency, how is it measured?
- Be succinct
Sound is always produced by a vibrating object. For example when humans speak their vocal
chords vibrate in order to produce the sound. In birds their vocal chords vibrate to produce a
squawking noise. These vibrations produced by different organisms result in the same frequency of
vibrations in the medium for which the sound is travelling through. For example if I say the word
“biology,” at 80 Hertz (Hz) this will result in the word “biology,” being transferred through the
medium (air) at 80Hz.
Another example in the text book states that if a tuning fork vibrates at 256Hz it sets the air
particles through which it is travelling at 256Hz also.
Outline the structure of the human larynx and the associated structures that assist the production of
sound.
Things to consider:
- What does outline mean?
- What is the larynx?
- Be succinct
The larynx is a complex structure located at the front of the throat - neck. The larynx is part of the
trachea a passageway surrounded by rings of cartilage which is connected to the oral cavity and the
lungs. The major function of the larynx is to produce sound. Sound is produced through many
different structures which make up the larynx. The larynx is made up of nine different cartilages.
The vocal chords are connected to some of these cartilages and extend across the tracheal opening.
These vocal chords are made up of elastic fibres. As air rushes up from the lungs the vocal chords
vibrate which results in the production of sound. The vocal chords and larynx surround a narrow
opening of the trachea called the glottis.
Speech involves the passage of air passing through the glottis. The pitch of the sound is altered by
the length and tension of the vocal chords as well as the degree of the opening of the glottis. High
pitched noises are due to the following structural characteristics; tense short vocal chords, vocal
chords that vibrate at a fast rate and the glottis forming a narrow passage for air to pass through.
Low pitched noises are due to the opposite; relaxed long vocal chords that vibrate at a slow rate
with the glottis forming a large passage for air to pass through.
Louder noises are produced by the amount of air being forced through the and across the vocal
chords.
Gather and process information from secondary sources to outline and compare some of the
structures used by animals other than humans to produce sound.
Things to consider:
- What does gather process, outline and compare mean?
- Understand what the question is asking before you answer the question.
- Underline key words
- Be succinct.
A comparison showing various organisms and the means of their sound production is outlined
below:




FROGS
Male frogs produce a
croaking noise for various
forms of communication,
for reproduction or the
marking or territory by
various males.
The croak is generated by
vocal sacs and their mouth
cavity.
Sound is produced by
forcing air out of the lungs
across the vocal chords
causing them to vibrate.
Muscles in the surrounding
trunk area contract to expel
the large amounts of air to
produce a croaking noise.
Croaking is species –
specific meaning that each
individual species produces
a croak at a different
frequency compared to that
of different male frogs.


REPTILES
Reptiles produce sound for
various forms of
communication such as for
reproduction or warning off
other predators.
Sound is produced similar
to that of the frog.
Depending on the size and
shape of the vocal chords
air is expelled from the
lungs to produce a sound.
For example a snake will
“hiss” to scare off
predators, a gecko will
“chirp” to call other geckos
and a crocodile can produce
a variety of sounds
including “roar,” “hiss,”
and “bark.”





BIRDS
Birds produce various calls
or songs to warn others of
predators or for calling a
mate.
To produce these calls birds
have a special structure
known as a syrinx.
The syrinx is generally
located at the base of the
trachea.
The rings of cartilage the
surround the bronchi and
trachea are modified in the
syrinx. They have partially
become muscular in nature
which results in the “bird
call.”
Different vibrations of the
membranes and the amount
of air expelled causes
different sounds produced
by different birds.
Plan and perform a first hand investigation to gather data to identify the relationship between
wavelength, frequency and pitch of a sound.
Things to consider:
- What does plan mean? You will have to recall how you performed this experiment.
- Ensure you understand the process of the experiment.
- Be succinct.
- What are wavelength, frequency and pitch?
-
Fill in results table.
Answer questions 1 – 5 page 504.
Answer questions 1 – 4 page 505.
Where necessary write a conclusion to these experiments.
Outline and compare the detection of vibrations by insects, fish and mammals.
Things to consider:
- What does outline mean?
- What does compare mean?
- What would be a good way of recording this information?
- Be succinct
Sound is produced by the vibration of certain structures within an organism. These vibrations are
received by other organisms using various sound detecting structures. A comparison of how
different organisms detect sound is outlined below:


INSECTS
Insects such as mosquitoes
have tiny hairs on their
body (mainly on the
antennae) which detects
sound emitted by the
female mosquito beating
her wings. This form of
communication brings the
two insects closer for
mating.
Other insects such as
grasshoppers contain a
tympanic membrane. This
membrane is stretched over
an air chamber which in
turn vibrates when sound is
produced. This produces a
response in the insect.



FISH
To detect vibrations within 
their ecosystem fish use
their lateral line. The lateral
line is used to detect the
fish’s movement through
the water, the direction and
flow of the current,
pressure waves from other
objects such as predator and
prey and in the detection of
low frequency sound.
The lateral line works
similar to that of the

mammalian ear. (Sound
detected, bends hair cells,
nerve impulse sent to the
brain.)
Fish also have an inner ear
which detects high pitched
sound.
MAMMALS
To detect vibrations within
their ecosystem mammals
use a structure known as
the ear. The vibration of air
particles causes the
membranes, bones, fluid
and hair cells to vibrate
within the inner ear. This in
turn causes a nerve impulse
to be sent to the brain and
the sound or message is
interpreted.
Organisms such as bats,
whales and dolphins use
echolocation to determine
the distance and size of an
approaching object.
Describe the anatomy and function of the human ear including:
- pinna
- tympanic membrane
- ear ossicles
- oval window
- round window
- cochlea
- organ of Corti
- auditory nerve
ALSO
Gather process and analyse information from secondary sources on the structure of a mammalian
ear to relate structures to functions.
Things to consider:
- What does describe, gather, process and analyse mean?
- What would be the best way to illustrate this answer? Table (Structure/function)?
- Be succinct.
STRUCTURE
Pinna
Tympanic Membrane
(eardrum)
Ear Ossicles
Oval Window
Round Window
Cochlea
Organ of Corti
Auditory Nerve
DESCRIPTION
The outer cartilage of the ear.
FUNCTION
Round in shape which causes
sound to enter the ear.
A thin type of membrane
The tympanic membrane or
located in the outer ear. Also
eardrum separates the outer ear
known as the eardrum.
from the inner ear. The
membrane vibrates in the
presence of a sound which
initiates the process of hearing.
The ear ossicles consist of three The ear ossicles vibrate at the
small bones, located in the
same frequency as the ear drum
middle ear known as the
in the presence of a noise.
malleus (hammer), incus
These vibrations are passed on
(anvil) and the stapes (stirrup). to the inner ear.
The oval window is a
This membrane passes the
membrane which separates the frequency from the middle ear
middle ear from the inner ear.
to the inner ear into the
cochlea. (Same vibration.)
The round window is a
Similar tot eh oval window this
membrane similar to that of the membrane passes the frequency
oval window which adjoins the from the inner ear to the
inner ear and the cochlea.
cochlea. (Same vibration.)
Main part of the inner ear
The cochlea contains 3
involved in the hearing process. chambers. These chambers
It is a coil like structure.
contain fluids which vibrate at
the original frequency.
The cochlea duct contains the
Organ of corti contains hair
organ of corti which contains
cells which eventually convert
the receptor cells responsible
the vibrations into electrical
for detection of sound.
signals which connect to the
auditory nerve.
The auditory nerve is a bundle Responsible for the
of sensory neurones located
transmission of electrical
next to the cochlea.
impulses to be interpreted by
the brain as sound.
Outline the role of the Eustachian tube.
Things to consider:
- What does outline mean?
- Where is and what is the Eustachian tube?
- Be succinct.
Our body is unique as everything in some manner is connected. The tube that connects the middle
ear to the nose and throat is known as the Eustachian tube. By connecting to an air filled space such
as the nose and throat the Eustachian tube is able to equalise the pressure between the eardrum and
the middle ear. Equalising the pressure often happens when a person swallows or opens their mouth
wide enough in time to equalise the pressure.
Outline the path of a sound wave through the external, middle and inner ear and identify the energy
transformations that occur.
Things to consider:
- What does outline and identify mean?
- Figure 9.7.2 on page 485 will be very useful in answering this dot point.
- Ensure you include the energy transformations that occur.
The following is an outline illustrating the hearing process.
1. Sound is emitted causing the air to vibrate.
2. These vibrations in the air travel to the outer ear and strike the eardrum (tympanic
membrane).
3. The eardrum begins to vibrate at the same initial frequency.
4. Sound energy is then transferred from the eardrum to the ear ossicles. The three ear ossicles
vibrate and transfer these vibrations to the oval window.
5. When the oval window is pushed in by the ear ossicles a pressure wave is produced through
the fluids in the cochlea.
6. As the pressure wave passes through the cochlea fluid it reaches the round window whereby
the round window is pushed in the opposite acting as a pressure release valve.
7. The pressure wave also acts on the cochlea duct, the basilar membrane, the tectorial
membrane and eventually the organ of corti as a whole.
8. The “push” from the pressure wave causes the hair cells in the organ of corti to bend. This in
turn causes the hair cells to release neurotransmitter into the synapses, between the hair cells
and the neurones which carry the message to the auditory nerve.
9. An action potential is created by these hair cells and the message is delivered to the cerebral
cortex for interpretation.
Basically the energy transformations that occur in the hearing process are sound waves into pressure
waves which are eventually converted into nerve (electrical) impulses and are interpreted by the
brain.
Describe the relationship between the distribution of hair cells in the organ of corti and the
detection of sounds of different frequencies.
Things to consider:
- What does describe mean?
- Underline key words.
- Understand what the question is asking before you write an answer.
The distribution of hair cells in the organ of corti cause different interpretation of sound. Firstly we
know that when sound enters the ear at a certain frequency it will cause the eardrum and ossicles to
vibrate at that frequency. Once the vibration has been passed through the ear and it reaches the
cochlea as a pressure wave an ingenious set of hairs in the organ of corti determine the frequency of
the original sound. This originally begins in the basilar membrane. The fibres in the basilar
membrane are of different lengths. Each of these different length fibres vibrate at a certain
frequency. Hair cells run along the basilar membrane so that when a certain fibre is triggered by a
certain frequency that group of hair cells will begin to bend. Thus different frequencies of sound
will activate different areas of the basilar membrane in turn causing different groups of hair cells to
bend.
If we observe the cochlea like a piano the hair cells are arranged according to the level of the
frequency they detect. Low frequencies are detected at the apex of the membrane while high
frequencies are detected at the base.
The hair cells, neurones, the auditory nerve and the brain all work in tandem to determine the
frequency of the noise. Different neurones are produced when the hair cells bend causing the nerve
impulses to travel to different areas of the cerebral cortex resulting in the interpretation of different
frequencies of noise by the brain.
Therefore hair cells are arranged to detect different frequencies of noise working in tandem with the
brain to interpret these frequencies.
Outline the role of the sound shadow cast by the head in the location of sound.
Things to consider:
- What does outline mean?
- What is a sound shadow?
- Be succinct.
The ears are placed on either side of the human head. If a noise or sound is coming from the right it
reaches the right ear first. For the sound to reach the left ear it must travel around the head or
through the head to reach the left ear. The head absorbs high frequencies much more easily then low
frequencies causing a sound shadow to be cast over the ear furthest away from the sound source.
The sound shadow in turn enables humans to determine the direction of the sound.
Process information from secondary sources to outline the range of frequencies detected by humans
as sound and compare this range with two other mammals, discussing possible reasons for the
differences identified.
Things to consider:
- What does process, outline, compare and discuss mean?
- Best way to represent this information? Table?
- Ensure you can identify the frequency at which humans hear best.






HUMANS
The range of sound that can
be detected by humans is
about 0.02 kHz – 20 kHz or
20 – 20000 Hz.
The range that humans are
most sensitive at is
approximately 2 – 4 kHz or
2000 – 4000 Hz.
Humans are capable of very
finely discriminating
between different
frequencies and intensities.
This means that humans
can accurately identify the
differences and loudness of
sounds.
This adaptation is believed
to be handed down by the
primates whereby humans
developed dialogue and the
ability to distinguish
between a moderate
frequency range.
This adaptation has also
enabled humans to detect
different frequencies and
the direction of the sound.





DOLPHINS
The range of sound that
dolphins can detect lies
between about 1 kHz – 100
kHz.
The range that dolphins are
most sensitive at lies
between 20 – 80 kHz.
The lower range
frequencies represent what
a dolphin “usually” hears,
while the high range of
frequency is used in the
process of echolocation.
Echolocation is used to
determine the distance,
size, speed, shape and
texture of an approaching
object.
This is a valuable asset for
the dolphin as it enables it
to survive within its
environment.



KANGAROO RAT
The range of sound that a
kangaroo rat can detect lies
between about 0.03 kHz –
50 kHz.
The range that the kangaroo
rat is most sensitive at lies
at about 1 kHz.
Kangaroo rats are most
sensitive at low frequency
sounds as it enables them to
detect predators which emit
low frequency sounds such
as the slithering of a snake
or the wings beating of an
owl.
Process information from secondary sources to evaluate a hearing aid and a cochlear implant in
terms of:
- The position and type of energy transfer occurring.
- Conditions under which the technology will assist hearing.
- Limitations of each technology.
Things to consider:
- Important dot point as it is secondary source. Could be a 6 – 7 marker in the HSC.
- What does process and evaluate mean?
- Ensure you answer the question properly.
Position on
the body.
HEARING AID
A hearing aid can be attached to the body
in a variety of ways. Firstly the behind
the ear (BTE) hearing aid consists of a
hard plastic case worn behind the ear and
is connected to a plastic ear mould which
sits inside the outer ear. The second type
of hearing aid is the “in the ear,” (ITE)
hearing aid. This hearing aid as it
suggests is a tiny mould which sits
directly in the ear canal.
The third type of hearing aid is a canal
hearing aid and as the name suggests this
small type of hearing aid sits in the ear
canal.
Type of
energy
transfer.
The type of energy transfer that takes
place in a hearing aid includes:
A sound is produced in the external
environment. This sound reaches the
hearing aid. The hearing aid uses this
sound and converts it into an electrical
signal. This electrical signal is then
turned into amplified sound in which the
person wearing the hearing aid can hear.
Conditions
under which
the
technology
The purpose of a hearing aid is to make
sound louder and audible for a person
who is suffering from hearing loss. A
hearing aid can work in quiet as well as
COCHLEAR IMPLANT
The cochlear implant as the name
suggests has to be implanted into the
patient’s ear. There are external parts to
the cochlear implant as well as internal
parts. The external parts consist of a
microphone which sits behind the users
ear, a thin chord which connects the
microphone to the speech processor, a
speech processor which deciphers noise
which is a small device usually in the
users pocket or attached to their waste
and the transmitting coil which usually
is attached to the behind to ear on the
users scalp. The internal parts consist of
receiver/stimulator which sits just
inside the skin and on top of the skull
and the electrode array which is
implanted into the cochlear.
The type of energy transfer that takes
place in a cochlear implant is as
follows: sounds are detected by the
microphone which amplifies the sound.
The sound waves are sent to the speech
processor which converts the sound
into an electrical signal. The electrical
signals are sent to a transmitter which
turns the electrical signals into radio
waves. The transmitter sends these
radio waves to the receiver/stimulator
which converts the radio waves into
electrical signals. These electrical
signals go to the electrodes fitted to the
cochlear and excite the auditory nerve.
The brain receives these electrical
impulses via the brain and interprets
them as sound.
The cochlear implant works
considerably differently from a hearing
aid. A cochlear implant is implanted
into a patient if they suffer from
will assist
hearing.
Limitations.
noisy areas. Ultimately the use of a
deafness. Depending on the patient a
hearing aid is to amplify sound, and it can cochlear implant can be very helpful.
be used in all conditions.
Usual sound is picked up by the person
with the implant; however some sounds
are hard to distinguish in a noisy
environment.
 Hearing aids can be somewhat
 Surgery and the cost of a cochlear
expensive to buy and maintain
implant may be somewhat
depending on the patients economic
expensive depending on the
status.
patient’s economic status.
 Hearing aids can be uncomfortable to  The device as a whole can be
wear.
uncomfortable.
 The voice of the person using the
 A person who has not developed
device may seem a lot louder to them
speech will be at a far greater
then usual.
disadvantage then a patient who
becomes deaf at a later date in their
 Hearing aid users may get feedback
life.
from their device such as a whistling
noise.
 Sound in noisy areas can be
somewhat hard to distinguish.
 Hearing aid may pick up background
noise which may give the patient
 Sound can be unclear.
some difficulty in distinguishing
 Full hearing potential is not reached
between people and sounds within a
with a cochlear implant.
room or area.
 Some hearing aid users may get a
buzzing noise when they use a mobile
phone.
http://www.nidcd.nih.gov/health/hearing/coch.asp
http://www.nidcd.nih.gov/health/hearing/hearingaid.asp
http://www.science.org.au/nova/029/029box01.htm
COCHLEAR IMPLANT
Identify that a nerve is a bundle of neuronal fibres.
Things to consider:
- What does identify mean?
- Understand the difference between the words nerve and neurones.
As the question states a nerve is a bundle of nerve fibres also known as neurons. These neurons all
have specific structures including:
- Nucleus to control the function of the neuron.
- Dendrites to provide a larger surface area for the collection of nerve signals.
- Cell body to provide nutrients as well as maintain metabolism in the neuron.
- Axons to convey signals along the neuron. Axons can be covered in myelin sheath, which is
made by Schwann cells. The myelin sheath insulates the axon. In between each Schwann
cell is a gap called the node of ranvier. This gap allows fast and efficient signalling through
the nerve.
- Synapse or synaptic knob is a gap between neuron to neuron.
http://training.seer.cancer.gov/module_anatomy/images/illu_neuron.jpg
Identify neurones as nerve cells that are the transmitters of signals by electro – chemical changes in
their membranes.
Things to consider:
- What does identify mean?
- Understand what the question is asking before you answer it.
Neurons are transmitters of electrical signals. However when the electrical signal reaches the axon
terminals it somehow has to jump across the synapse from one neuron to the next neuron. How does
it do this? This action is performed through the use of neurotransmitters (chemical).
Neurotransmitters are released from the axon branches into the synaptic space. Once in the synapse
the neurotransmitter will travel to the dendrites of the next neuron. There the neurotransmitter will
stimulate the dendrites membrane to become permeable to sodium ions. This therefore initiates a
nerve impulse (action potential) in the next neuron and hence the message is passed on.
Define the term threshold and explain why not all stimuli generate an action potential.
Things to consider:
- What does define and explain mean?
- Two parts to your answer. Ensure you answer both.
The threshold is the value that must be reached usually in the vicinity of -50mV, -55mV. This value
is reached depending on the strength of the stimulus acting on the neuronal membrane. If these
values are reached an action potential will occur.
The stronger the stimulus the more likely it will change the membrane potential towards the
threshold value. Once the threshold is reached the action potential occurs. Action potential occurs in
an all or nothing phase which means if the threshold is reached it will occur and if the threshold is
not reached it will not occur.
Some stimulus however will not cause the membrane to become permeable to sodium ions
therefore causing the threshold not to be reached in turn causing no action potential.
Identify those areas of the cerebrum involved in the perception and interpretation of light and
sound.
Things to consider:
- What does identify mean?
- Ensure you can identify these areas if given a brain model.
LIGHT (VISUAL AREA)
SOUND (AUDITORY AREA)
 Interpretation and perception of light
 Interpretation and perception of sound
(vision) is located in one of the largest
(auditory) is located in the temporal lobe.
sensory areas of the brain which is the
(Above the ear.)
occipital lobe. (Back of the brain)
 Two parts – the primary auditory cortex,
through the natural function of the ear
 Two parts – the primary visual cortex which
synthesises images from both the left and
interprets different electrical impulses and
right eye to gain an overall image. The visual
converts them into sound. The auditory
association area of the brain associates with
association area which recognises sounds or
images we have seen before, for example
voices from previous experience.
someone you have met before or a “familiar
face.”
http://sehati.org/neurosurgicalprocedures/images/craniotomy/craniotomy1.jpg
Explain, using specific examples, the importance of correct interpretation of sensory signals by the
brain for coordination of animal behaviour.
Things to consider:
- What does explain mean?
- What is coordination?
- Relate findings to the actual brain and its structures.
It is very important for all organisms to interpret stimulus in a way that enables them to respond in
an appropriate way in order to survive. For example if we look at human beings. Our behaviour is
coordinated as a result of the signals coming to our brain and our correct interpretation of these
signals. For example if we were to cross a road and as we were crossing we did not notice a truck
coming towards us at a high speed. Many signals enter the brain and are integrated into one
conclusion – get out of the way. These sensory signals enable humans to respond to their
environment in a coordinated way which leads to survival of the species.
Another example is the migratory patterns of birds and whales. It has been shown through various
studies that birds and whales can perceive, store, process and use the information obtained by vision
and hearing to behave in a manner that is advantageous for them. Whales and birds rely on the
storage of certain data to enable them to migrate accordingly every year. This unique ability
illustrates that by interpreting these sensory signals, storing these signals and reusing these signals
birds and whales are capable of coordinating in their behaviour in such a way that enables them to
find exact locations hundreds to thousands of kilometres away.
Perform a first hand investigation using stained prepared slides and/or electron micrographs to
gather information about the structure of neurones and nerves.
Things to consider:
- This is an experiment using a light microscope. Recall how to draw a field of view. Ensure
you include a title, total magnification and relevant labels to what you are viewing.
- Refer to the diagram of a neuron on page 489 of the text book to assist you in how you label
your neuron(s)
- Refer to page 510 of the text book, which outlines the experimental procedure.
- Answer questions 1 – 4 on page 510 and conclude your experiment.
Perform a first hand investigation to examine an appropriate mammalian brain or model of a
human brain to gather information to distinguish the cerebrum, cerebellum, and medulla oblongata
and locate the regions involved in speech, sight and sound perception.
Things to consider:
- Ensure you make a good observation of the brain. In the HSC they could possibly give you a
diagram of the brain and you have to indicate the areas involved in speech, sight and sound
perception.
- For revision of this experiment please refer to the experimental procedure, diagrams and
pictures on pages 508 – 510.
Present information from secondary sources to graphically represent a typical action potential.
Things to consider:
- What does present mean?
- Ensure you can explain the parts of the graph.
http://gargoyle.arcadia.edu/psychology/blustein/neuro/Lecture_Notes/Week_1/Week_2/Action_Pote
ntial.jpg
STEP 3 = FULL ACTION POTENTIAL