Am too shy to put this on public :/ so this is a private video. Just let me know who are those that i have missed out alright. Hee, have fun studying!

1. TTC Biology
Seminar 2012
JaySze Yong
WELCOME!

2. Let’s start!
It’s not about how many times have you studied, but how much
did you understand
Syllabus of the day:
Transport
Dynamic Ecosystem
Endangered Ecosystem

3. ☺ Transport
The system and its components:
Blood
Circulatory
system
Pump Blood vessels

4. Question!
But why do we need a circulatory system?
Because…
 Multicellular organisms have small TSA/V ratio(long
distances between body cells and environment.
 Impermeable skin
These lead to inefficiency in substances exchange.

5. Circulatory Systems
Open Circulatory System
Closed Circulatory System
☺ Movie time!

6. ☀ Open Circulatory
System
Found in INSECTS, prawns, snails and etc.
Aorta
Haemocoel
Haemolymph flows out of circulatory
Dorsal Ostia
system into body cavities. Vessel
Dorsal
Diaphragm
Haemolymph reaches the body cells DIRECTLY.

7. Start pumping!
heart haemolymph heart haemolymph
flow into flows back
contracts haemocoel relaxes into the heart

8. ☀ Closed Circulatory
System
Found in ALL vertebrates (e.g. humans/fishes) and some
invertebrates(earthworms)
Blood flows within the blood circulatory system WITHOUT
moving into body cavities

9. Has a two- Has a three- Has a four-
chambered heart, chambered heart, chambered heart,
single and closed double, closed double, closed
circulatory circulatory system circulatory system
system

10. 2 types of closed circulation
 Pulmonary Circulation ( heartlungheart)
 Blood flows from the right ventricle to the lungs via pulmonary
artery and return to the left atrium via pulmonary vein.
 Systemic Circulation ( heartrest of bodyheart)
 Blood flows from the left ventricle to the body tissues via aorta and
return to the right atrium via vena cava.

11. Heart
The PUMP!
 Four chambers : two atria and two ventricles
 Made up of MYOGENIC cardiac muscles
 Located in the thoracic cavity
 Connected to the lungs

13. Sequence of Heart Pumping
1) The contractions of
the heart are
initiated by the
sinoatrial(SA) node.
SA node 2) SA node generates
electrical impulses
which make atria
contract to pump
blood into ventricles.
Purkinje
AV node
Fiber
Electrical signals reach
the atrioventricular
Electrical impulses node(AV) node, Bundle
Bundle of
spread to the ventricles of His, Purkinje fibres.
His
and causes ventricles to
contract and pump
blood out of heart.

14. Question!
What is meant by the term MYOGENIC?
It means the ability to contract and relax without stimulation of nervous
system.
Describe the sequence of heart pumping!
Everything in previous slide! 
What is the function of valves?
Ensure one way flow of blood/ prevent back flow.
Why left ventricle is thicker than right ventricle?
Left ventricle needs to pump blood at higher pressure through the body.

15. Overall flow of blood
 Deoxygenated blood!
Vena cava  Right atrium  Right ventricle 
Pulmonary Arteries  Lungs
 Oxygenated blood!
Lungs  Pulmonary veins  Left Atrium  Left Ventricle
 Aorta  Body Cells
☺ Movie time!

16. We the • Arteries
containers!
Blood vessels
• Capillaries
• Veins

17. Let’s compare!

18. Question!
Explain two characteristics of capillaries which allow
efficient substances exchange.
State THREE differences between arteries, capillaries
and veins.

19. Blood
Hmm…what is in a drop of blood? Let’s see..

20. ! A yellowish
fluid
containing
soluble
substances
! Formed
elements
containing RBC,
WBC, Platelets

21. Red blood cells
*Erythrocytes
• Red in colour
• Biconcave disc shape
• Elastic
• Contain haemoglobin for respiratory gases transportation
• Manufactured in bone marrow, destroyed in spleen and liver
• Lose nucleus upon maturity

22. Question!
 Why RBC need all those characteristics?
WHY.. BECAUSE..
Biconcave disc shape? Increase surface area for rapid
substances exchange.
Lose nucleus upon maturity? Accommodate more
haemoglobin to transport
oxygen.
Elastic membrane? Easily squeeze through small
capillary membrane.
Blood is red? Red pigments are present in
haemoglobin.
RBC can act as binding site of Oxygen can bind with Iron
oxygen? atom in the haem group.

23. White blood cells
*Leucocytes
• Nucleus present
• Irregular in shape
• Important in body defense mechanisms against
disease
• Manufactured at bone marrow and spleen
• TWO BASIC TYPES : GRANULOCYTES
AGRANULOCYTES

24. Types of WBC
Granulocytes
• Multi lobed nucleus
• Rich in granules
• Short live span (often few days)
Members:

25. Agranulocytes
• No granules
• Compact nucleus
Members:

26. Platelets
• Cell tiny fragments of large cell in bone marrow
• Involved in blood clotting mechanism
• Short life-span (few days)
• Irregular shape

27. Let’s compare!

28. Blood clotting mechanism
Platelets adhere to
damaged wall of Platelets release Platelet plug
blood vessels clotting factors. formed
Thrombokinase
(activator)
released
Blood clot dries
off to form scab.
Fibrinogen - Fibrin by
Thrombin
Fibrin forms threads
network over the wound Prothrombin -
trapping RBC and form Thrombin
blood clot.
in the presence of
calcium ion +
Thrombokinase + Vit K

29. Why blood clotting is so
important?
• Prevent excessive loss of blood
• Maintain blood pressure
• Main circulation of blood in a closed system
• Prevent entry of microorganisms and foreign particles
into the body
• Form scab and helps in healing wounds

30. Cardiovascular disorders

31. Blood pressure regulation
• Increase in blood pressure
 Baroreceptor stimulated
 Increase stimulation of cardiovascular centre
 Increase discharge of parasympathetic nerve
 reduce heart rate
 reduce contractility of heart
 vasodilation of blood vessels
→ Blood pressure drops back to normal

32. • Decrease in blood pressure
 Baroreceptor less stimulated
 Decrease stimulation of cardiovascular centre
 Increase discharge of sympathetic nerve
 increase heart rate
 increase contractility of heart
 vasoconstriction of blood vessels
 Blood pressure rise back to normal

33. Lymphatic system
What is a lymphatic system?
✐ Lymphatic system is a network of lymph vessels
running alongside the veins
✐ Lymph is found inside lymph vessels
✐ Lymph composition = interstitial fluid composition but
maybe lymph has more fats

34. Why need a lymphatic system?
☃ Interstitial fluid formed in the
interstitial space must be
returned into the circulation
☃ 90% returns to the venule ends
☃ 10% can only return into the
circulation by lymphatic system

35. How is interstitial fluid formed?
• Changes in the diameter of lumen between arterioles and
capillaries
• High hydrostatic pressure at the arteriole ends
• Forces blood contents into interstitial space forming interstitial fluid
* Interstitial fluid composition is almost the same as blood contents
EXCEPT WITHOUT
• Erythrocytes
• Platelets
• Plasma proteins

37. Sequence of lymphatic pathway
interstitial spaces
back into the heart
lymphatic capillaries
(circulatory system
thoracic duct flow
to left subclavin
vein right lymphatic vessel
lymphatic duct flow
to right subclaviab
duct
In between, lymph thoracic duct right
lymphatic duct
nodes are present for
filtration of lymph
contents

38. Lymphatic vessels return the lymph to the heart via two
ducts:
Right lymphatic duct drains lymph from the right arm, the
right side of the head and the thorax and opens into the
right subclavian vein near the heart.
Thoracic duct receives lymph from left side head, neck,
chest, upper limb and the rest of the body into the left
subclavian vein near the heart.

39. Lymphatic flow Hmm…How do lymph
flow back to the
heart? What aids its
movement?
Present of valves in lymphatic system which prevent the
back flow of lymph.
Contraction of skeletal muscles around the lymphatic
channels which milk the lymph towards the heart.
Peristaltic contraction of intestinal organs
Changes in body cavities pressure during respiration
# What happens if tissue fluid is not returned
completely?
• Oedema

40. Defense mechanism
First line Second line Third line
defense defense defense
First line defense
• Physical and chemical barriers
• Non-specific defense (do not distinguish, destroy all kind of
pathogen bacteria)
• Inborn (natural built in)
• Do not involve circulatory system lymphatic system
• Examples : Skin, Mucus membrane, Saliva, Tears, Gastric acid
• Prevent entrance of pathogens into circulatory system and body
tissues.

41. Second line defense
• Non specific defense
• Eliminate bacteria or ANY TYPE of pathogens by phagocytosis
(meal time! *eat up everything)
• Involve circulatory system
• Phagocytosis carried out by phagocytes
#iNFO! The makan members are all M-E-N of white blood cells
M: Macrophages E: Eosinophils N: Neutrophils

42. Phagocytosis is a process where an organism or a
specific type of cell surrounds, engulfs and ingests
a pathogen.

43. Third line defense
• VERY SPECIFIC DEFENSE (Recognises pathogens - produces specific
antibodies to destroy them)
• Involve immune, circulatory, lymphatic system *produces lymphocytes
• Involves the interaction between antigen and antibody
• What’s an antigen? “Name tag” of all cells – Membrane surface protein found in
every cell but differ in type in each individual
• Antigen STIMULATES the production of antibody in the body
• What’s an antibody? The “killer” – Protein produced on the surface of
LYMPHOCYTES
• Antibody have specific binding site(antigen receptors) that bind with specific
antigen
#To fight against PERSISTENT infections

44. After pathogens killed by antibodies, phagocytosis carried out by
MACROPHAGES.
• Mechanisms of action:
Agglutination Neutralisation
Antibodies cause Antibodies
pathogens to clump neutralise toxins
together, making produced by
them easy for bacteria by binding
phagocytes to to toxin molecule.
destroy.
Opsonisation Lysis
Antibodies bind to Antibodies bind to
antigens to act as antigens and cause
markers so that the antigens to
antigens can be rupture.
recognised and
destroyed by
phagocytes.
#All by which the specific antibodies bind to specific antigens of pathogens

45. Types of immunity
Immunity – The ability of human body to resist infection.
Active immunity Passive immunity
Body produces own antibodies to Body obtains antibodies directly
fight against infection when from outside source
infected Short term immunity – Antibodies die
Requires the present of antigens off, or removed from body as foreign
(infection) protein
Long term immunity

46. Active immunity
• Natural active : Lymphocytes activated
by antigens to produce antibodies
naturally when infection attacks. (You
fall sick - recover)
 Example? If you have throat
infection, lymphocytes in your body
actively produce antibodies to
combat it
• Artificial active : Antigens are injected
on purpose to artificially stimulate
lymphocytes to produce
antibodies(Vaccination) (Without
falling sick)
Vaccine is a preparation of
 Example? All vaccine injections – weakened, dead or non-virulent
Hepatitis B, Cervical cancer forms of pathogen that is harmless
vaccination to the person who receives it.

47. Passive immunity
• Natural passive :
• Baby in the uterus
• Breastfed babies
• Obtained antibodies naturally from mother
across placenta/when babies breastfeed.
• Artificial passive :
 Antibodies extracted from other
infividual/animal are injected as a
serum into body of person who has no
immunity
 Immediate, temporary
 Example? Antivenom injection given to
treat snake bites

48. Let’s compare!
Graph A Graph B
Which type of immunity are they?

49. AIDS
What’s AIDS? Acquired Immune Deficiency Sydrome
caused by HIV (Human Immunodeficency Virus)
How does it occur?
 Attacks a specific type of lymphocyte
 Leading to failure of defense activation(Other
infections/cancers take advantage to come in!)
 Vulnerability to minor infections which can cause dead

50. Mode of transmission
 Direct transmission
 Body fluids (blood,
semen, vaginal
AIDS is NOT secretion, joint fluids ,
TRANSMITTED spinal cord fluid)
#by insect bites
 Indirect transmission
#through the air –
sneezing  Contaminated blood
#by hugging, touching, products, needles
handshaking  Vertical transmission
#by living in the same
house  From mother to baby
#by sharing food and through placenta
water
#by sharing cups,
glasses, plates

51. Prevention of AIDS
☀ Screen blood products for HIV
☀ Sex education program
☀ Safe sex (wear condom)
☀ Avoid needle sharing (tattoos,
drugs, body piercing practices)
☀ Avoid multiple sex partners
☀ Avoid free sex
☀ Avoid exposure to blood
products and bodily fluids

52. ☺Chapter 8 revision
time!
! What are the interactions between living things (biotic
components)?
 Symbiosis
 Saprophytism
 Prey-predator
 Competition
Memorise TWO EXAMPLES at least for each! 

53. Symbiosis
Commensalism – Benefits one species(commensal)
but neither benefits nor harms the other species(host)
Examples : Epiphytes(Plants) , Epizoic(Animals)
Parasitism – Parasite benefits, but the host is harmed
Examples : Endoparasites , Ectoparasites
Mutualism – Both species gain benefit
Examples : Lichen, Sea anemone and hermit crab

54. Saprophytism
Living organism obtain food from dead and decaying
organic matter.
☂ Examples of saprophytes(plants) : Bread mould,
Mushrooms, Fungus
☂ Examples of saprozoites(animals) : Protozoa in frog
intestine

55. Prey-predator
 weaker animal (prey) is hunted eaten by another
stronger animal (predator)
 Examples : Snake(predator) hunts and eats a
rat(prey)

56. Colonisation and succession
Colonisation : occurs in newly formed area where no life has existed previously
Succession : gradual continuous process in which one community changes the
environment so that it is replaced by another community

57. Adaptations of Mangrove Swamps
Problems faced Adaptations
Soft muddy soil strong · Long, extensive cable roots
coastal winds pose support · Ex. Avicennia sp. Sonneratia sp.
problems · Prop roots @ aerial roots
· Ex. Rhizophora sp.
· Buttress roots
· Ex. Bruguiera sp.
· These roots anchor the plants
onto the muddy soil
Waterlogged conditions of · Breathing roots (pneumatophores) which grow
the soil reduce the amount vertically upwards have numerous pore for
of O2 leading to anaerobic gaseous exchange during low tides
environment · Ex. Avicennia sp. Sonneratia sp.
· Lenticels are present on the bark of the plants for
gaseous exchange to occur
Direct exposure to the sun · Leaves are covered by a thick layer of cuticle to
leads to a high rate of reduce transpiration during hot days
transpiration · Leaves are thick succulent to store H2O
High salinity of sea H2O · Cell sap of root cells of mangrove plants has a
causes the surrounding higher osmotic pressure than surrounding soil H2O
H2O in the soil hypertonic · This enables diffusion of salty H2O into root cells
compare to cell sap of root · Excessive mineral salts will be then excreted
cells through hydathodes in the form of crystalline salt
Seeds which fall onto the · Mangrove plants show viviparity where the seeds
ground die because they germinate while still attached on mother plant
are submerged in the soft · This increase the chance of survival as the
waterlogged soil seedlings can float horizontally on the H2O
subsequently get washed up on the sand or
mudflats where they start to grow
· During low tide, the seedlings fall vertically bind
to the mud that prevent them from carry away by
H2O current

58. ☼ Zonation of Mangrove Swamps
Seaward zone
(exposed to high tides twice daily)
 Avicennia sp. Sonneratia sp.
Middle zone
 Rhizophora sp.
Inland zone
(less frequent covered by sea H2O receives freshwater from
ground)
 Bruguiera sp.

59. Colonisation and succession in
Mangrove Swamps
Pioneer species!
Avicennia sp. and
Sonneratia sp.
 Extensive root systems
trap collect
sediments
 Soil becomes more
compact firm
 The condition favours
the growth of
Rhizophora sp.
Successor species: Rhizophora sp Successore species: Bruguiera sp.
 Replaces pioneer species  Replaces Rhizophora sp.
 Prop root system traps silt mud, creating  Buttress root system form loops to trap more silt
firmer soil structure mud
 Ground becomes higher less submerged by  As more sediments are deposited, shore extend
sea H2) further to the sea is like terrestrial ground
 The condition now favours the growth of  Terrestrial plants (nipah palm Pandarus sp.) begin
Bruguiera sp. to replace Bruguiera sp.
Gradual transition succession from a mangrove
swamp to a terrestrial forest eventually to a
tropical rainforest which is climax community takes
a long time

60. Colonisation and succession in a
pond
Pioneer species: submerged plants (Hydrilla sp., Cabomba sp.,
Elodea sp., phytoplankton algae. )
 Fibrous roots penetrate deep into the soil to absorb nutrients bind sand
particles together
 Able to photosynthesise
 When pioneer species die decompose, organic nutrients are released into
the pond being converted into humus at the pond base
 Humus soil eroded from the sides of the pond are deposited on the base
of the pond, making the pond shallower
 The conditions become unfavourable for submerged plants but more
suitable for floating plants.

61. Succession by the aquatic floating plants (Lemna sp., Eichornia sp., Nelumbium sp.)
 Float freely on the surface of H2O
 Reproduce by vegetative propagation spread to cover a large area of H2O surface,
preventing sunlight from reaching the submerged plants
 Submerged plants die due to unable to photosynthesise the decomposed remains of the
submerged plants add more organic matter on the base of the pond
 At the same time, erosion at the pond edge results in more sediments being deposited on the
base of the pond
 Pond becomes more more shallow which makes it unsuitable for floating plants
 Submerged plants are subsequently replaced by emergent plants which can live in H2O lands.
Successor species: Emergent plants (sedges, cattails)
 Rhizomes grow horizontally
 Extensive roots bind soil particles together penetrate deeply to absorb more mineral
salts
 Grow from the edge of the pond towards the middle of the pond as the pond becomes
more shallow
 When these plants die, decomposed remains add to the sediments on the base of pond
further reduce the depth of the pond
 The condition of the pond becomes more favourable for land plants.

62. At the end….
Successor species : Land plants (Ageratum conyzoides, Euphoria hirta,
Oldentandia dichotoma, shrubs, bushes, woody plants)
 As time passes, the land becomes drier land plants become more numerous
 Primary forest emerges turns into tropical rainforest
which is known as climax community

63. ☺ Population ecology
Few formulas!
Percentage frequency =
X100%
Density =
X 100%
Percentage coverage =
X 100%
Population size = For capture,
X 100% mark, release
and recapture
technique!

64. Maintains the
The Nitrogen Cycle nitrogen balance
in water, soil and
atmosphere!

65. ☺Chapter 9 revision
time!
! What is meant by eutrophication?
Eutrophication is the process whereby a body of
water (e.g. pond or lake) becomes rich in dissolved
nutrients (nitrates or phosphates) either naturally or
due to human activities.

66. Eutrophication
Algae boom is the increase of
rate of growth of algae and blue
green bacteria.
Causes of eutrophication:
☃ Overuse of fertiliser
☃ Run-off of manure from farms
☃ Discharge of untreated and
treated sewage
☃ Erosion from cultivated land

67. Describe Eutrophication
1. Eutrophication is the artificial enrichment of an aquatic system with nutrients,
causing the excessive growth of aquatic plant life.
2. Excess nutrients from agricultural run-off cause the rapid growth of algae, which
is algae boom.
3. Algae use a lot of oxygen and block sunlight penetration.
4. Photosynthesis decreases and further depletes oxygen in the lake.
5. Algae and some aquatic plants die.
6. Dead matter is decomposed by bacteria.
7. Aerobic bacteria use up oxygen, deplete oxygen content in the water.
8. B.O.D high, dissolved oxygen low.
9. Aquatic animals die.

68. Describe how CFCs destroy the
ozone layer
1. UV radiation strikes a CFC molecule  causes a chlorine
atom to break away.
2. The chlorine atom collides with an ozone molecule 
steals an oxygen atom to form chlorine monoxide and
leaves a molecule of oxygen.
3. When a free atom of oxygen collides with the chlorine
monoxide  the two oxygen atoms form a molecule of
oxygen. The chlorine atom is thus released and free to
destroy more ozone molecules.

69. What is greenhouse effect?
1. Solar energy from the sun enters the atmosphere.
2. Some energy is reflected back to space.
3. Earth’s surface is heated by the sun.
4. Earth radiates the heat back towards space.
5. However, greenhouse gases in the atmosphere trap some
of the heat and cause global warming.
6. Greenhouse gases are produced by burning fossil fuels.

71. Formation of acid rain
Caused by oxidation process :
• SO2 (Sulphur Dioxide) + ½02 + H20  H2S04 (Sulphuric Acid)
• 2NO2 (Nitrogen Dioxide) + ½O2 + H20  2HNO3 (Nitric Acid)
1. Acidic gases(Sulphur Dioxide and Oxides of Nitrogen) released by factories
2. Gases carried by the wind.
3. Gases dissolved in rainwater to form acid rain.
4. Acid rain kills plant life, pollutes rivers and streams, and corrodes stonework.