Chapter 8 dynamic ecosystem Form 4 Biology

Chapter 8 Dynamic EcosystemOng Yee Sing

2017

Chapter index

• 8.1 The Abiotic and Biotic Components of the Environment

• 8.2 Colonisation and Succession in an Ecosystem

• 8.3 Population Ecology

• 8.4 Biodiversity

• 8.5 The Impact of Microorganisms on Life

• 8.6 Appreciating Biodiversity

8.1 The Abiotic and Biotic Components of the Environment

Components of Ecosystem

Altitude

Slope Gradient

Aspect

Microclimate

土壤

地形

方面

Abiotic factors• pH value

• a drastic change in pH of the soil and water may kill the organisms

• Temperature • affects the physiological activities of organisms

• most of organisms cannot tolerate extremes temperatures

• Light intensity• affects the distribution and growth of

organisms

• the sun is the source of energy for plants

• most animal need sunlight but some show adaptation to live in the dark

• Humidity • is the amount of water vapour in the air

• plant and animal that live in wet or dry climate have special adaptation

The amount of light

which different levels of

a forest may receive

varies.

Hydrangea flower color is influenced by soil pH. In soil with low pH, aluminum ions

(Al3+) are more available for uptake by plants, altering the flower pigments to reflect

more blue as myrtillin (red pigment) forms complexes with metal ion.

Abiotic factors• Water

• some organisms are able to survive under condition where there is a limited supply of water such as camel and cactus

• Microclimate • Refers to local climate in a small area• humidity, temperature and light intensity

affect the microclimates

• Topography • physical feature of the land • influence local climate and soil

development• higher altitude: lower atmospheric pressure

and temperature • steeper slope cause a faster drainage and

run-off (thinner soil) • gentle-slope areas receive more sunlight

compared to valley• aspect (direction of the slope) influences

the microclimate intensively • Facing the direction of wind – more rain• Facing south – more sunlight

Slope effect, a vegetational

result of aspect, in evidence

in the coastal sage scrub

community of

southern California's Santa

Monica Mtns. The slope on

the left side is north-facing,

thus moister and dominated

by Ceanothus sp.. The

south-facing slope on the

right side is much drier

(receiving more direct sun),

and is more sparsely

vegetated with the more

drought tolerant Artemisia

californica and Yucca

whipplei.

The presence of

concrete paths, brick

walls and ponds will act

as heat sinks, absorbing

the sun's heat during the

day and slowly releasing

it at night. They can offer

good protection against

frost on cool nights to

prevent frost.

Quiz

• An ecosystem possesses _________.

A. only living components

B. only non-living components

C. both living and non-living components

Food chain and food web

• Food chain食物链 is a series of organisms through which energy is transferred in the form of food.

• Food web食物网are interconnected food chains.

Trophic level

• Trophic level营养级别represents each stages in the food chain.

Pyramid of numbers

• Trophic level can be shown as a pyramid of numbers.

• Pyramid of numbers数字金字塔shows the population of each organism in a food chain can be shown in a sort of stacked bar chart.

Energy flow• When the energy is

transferred to the next trophic level, a lot of energy is lost (through undigested matter, excretory products, lost as heat during respiration)• 90% : energy is lost

• 10% : transfer from one trophic level to the next

Quiz

• Energy flows through an ecosystem because when one form of energy is transformed into another form, and there is always a loss of some energy as heat.

A. True

B. False

Quiz

• When numerous food chains link to each other in an ecosystem, it is known as a(n) _________.

A. food pyramid

B. food web

C. food cluster

D. feeding guild

E. energy pyramid

Quiz

• All organisms that feed at each link in a food chain comprise a/an ______.

• trophic level

• biomass

• food pyramid

• energy pyramid

• calorie

Quiz

• A pyramid of energy shows that there is an increasing amount of energy available at each successive trophic level.

A. True

B. False

Quiz

• It is generally stated that only about ______ % of the energy available at one trophic level is incorporated into the tissues of animals at the next level.

A. 10

B. 20

C. 30

D. 40

E. 80

INTERACTION BETWEEN ORGANISMS

Symbiosis Saprophytism Prey-predator Competition

Commensalism Mutualism Parasitism

Intraspecific Interspecific

Symbiosis共生生物

Commensalism

• ( + , 0 )

• example

- clown fish &

sea anemones

- pigeon orchid

Mutualism

• ( + , + )

• example

- lichens

- root nodules

Parasitism

• ( + , - )

• example

- flea

- tapeworm

+ : benefits

0 : neither benefit

nor harm

- : harm

Epiphytes(plant)

Epizoics(animal)

Ectoparasite Endoparasite

Interaction in which there is a close and permanent relationship between two specific organisms

片利共生 互利共生 寄生

附生植物 附生动物 内寄生外寄生

Saprophytism

• A type of interaction in which living organisms obtain food from dead and decaying organic matter

• Enzymes are secreted onto the food and digestion occurs outside the cell

• Example : • saprophyte (plant) : fungus

• saprozoite (animal) : earthworm, maggot

腐生

Prey-predator(+ ,- )• Predator

• kills other animal for food• larger and fewer in number than

its prey• the number of predator affects

the size of prey population

• Prey• the animal that kill by the

predator• must be able to protect itself from

being killed

• Example : owls & snakes, frogs & snakes

捕食

Competition • An interaction between organisms which

live together in a habitat and compete for the same resources (light, water, space and nutrients) that are in limited supply.

• Species that lost in the competition either migrate to other areas or die.

• Intraspecific competition: between individuals of the same species e.g. plantlets from a Bryophyllum sp. leaf

• Interspecific competition: between individuals of different species e.g.Paramecium aurelia & Paramecium caudatum

plantlets from a Bryophyllum sp. leaf The niche of Paramecium aurelia and Paramecium

caudatum overlap very much. Therefore, it brings to the extinction of the failing competitor, Paramecium caudatum.

Quiz

• Which of the following statements is true?

A. Symbiosis refers to different organisms living together.

B. Members of a symbiotic relationship cannot live without each other.

C. Symbiosis refers to different organisms living together and benefiting from each other.

D. A parasite is not in a symbiosis with its host.

Quiz

• An association in which one population of organisms benefits while the other is neither harmed nor helped is called a(n) _____ association.

A. parasitic

B. commensalistic

C. mutualistic

D. prey-predator

Quiz

• Which of the following associations is characterized by one organism attaching or engulfing the other?

A. predation.

B. commensalism.

C. mutualism.

D. competition.

Quiz

• Which of the following associations is characterized by some degree of coexistence whereby one organism benefits at the expense of the other?

A. predation.

B. commensalism.

C. parasitism.

D. mutualism.

Quiz

• What is the relationship between Hieracium pilosellaand Plantagolanceolata?• Interspecific

competition

• What are the relationships between mycorrhizae with Hieraciumpilosella and Plantago lanceolata?• mutualism

Mix population

non-mycorrhiza

mycorrhizal

8.2 Colonisationand Succession in an Ecosystem

Ecosystem生态系统

• A dynamic system formed by the interaction of living organisms and their non-living environment

• Example : Mangrove, swamp, desert, marine forest

Some example of ecosystems.

Components of an ecosystem

Term Description

Habitat栖息地 A habitat is the natural environment in which an organism lives and obtains its basic resources such as food and shelter.

Biosphere生物圈 A biosphere is the global ecological system integrating all living beings and their relationships, including their interaction with the elements of the lithosphere, geosphere, hydrosphere, & atmosphere.

Biome生物群系 A biome is a a large naturally occurring community of flora and fauna occupying a major habitat, e.g., forest or tundra.

Community群落 A community consists of different populations of plants and animalsliving and interacting in the habitat of an ecosystem.

Population族群 A population consists of organisms of the same species living in thesame habitat at the same time.

Species物种 A species is a group of organisms which can interbreed to producefertile offspring.

Niche生态位• Niche is the function of an organism

in the habitat

• Organisms can live in the same habitat but they occupy different niches.

• A niche comprises:• its habitat• its activity patterns (interactions with

others, the range of temperature, the spaces it occupies, period of activity)

• resources it consume

• Example: a caterpillar and aphid live in the same habitat but occupy different niche (caterpillar eats the leaf but aphid sucks sap from the leaf).

Each species utilizes a different aspect of the tree's habitat to reduce competition with other species. This allows multiple species to extract resources from the same location.

Colonisation移植 and succession演替

• Colonisation takes place in newly formed areas where no life previously existed.

• Succession is the gradual process through which one community changesits environment so that it is replaced by another community.

Colonisation

The process of succession

Succession also occurs in animals

Pioneer species先锋物种• The first species of organisms to

colonise a new habitat is called the pioneer species.

• Special adaptation of pioneer species • hardy plant • have good dense root system (bind sand

particles and hold water + humus)• have short life cycle• when they die, their remains add to

humus content

• Examples : grasses, ferns & sedges

Pioneer plants on a lava flow.

Lichen on rocks.Abandoned Mamut Copper Mine in Sabah.

Successor species后继物种• Succession leads to a final and stable

community which is in equilibrium with its environment and is known as climax community顶极群落

• Successor species : a series of plant that replaced the pioneer species (herbaceous plant)

• Successor : • grow bigger than pioneer thus reduced

the amount of sunlight available • have small wind- dispersable seeds (able

to spread and grow rapidly)• can change the structure and quality of

soil for larger plant to grow • Example: herbaceous shrubs

Ragweed

Shrubby fields

Dominant species优势种• Dominant species grow faster and

dominate the slower growing pioneer and successor species.

• Dominant species turn modify the environment which allows larger tree to grow

• The larger trees provide shade and the shrubs cannot compete and are replaced by forest floor species.

• Ecological succession leads to a relatively stable community which is a climax community.

• Example: tropical rain forest

Pine as a dominant species.

Pine-Oak-Hickory Forest as a climax community,

Example: mangrove swamp• Found in tropical and subtropical regions

where freshwater meets salt water.

• Characteristics :

1) Soft & muddy soil

2) High concentration of salt

3) Low level of oxygen

4) Exposed to high intensities of sunlight and strong wind

• 4 species of mangrove :

1) Avicennia sp.

2) Sonneratia sp.

3) Rhizophora sp.

4) Brugeria sp.

• The mangrove plants are well adapted to the harsh conditions of these regions.

Distribution of Mangrove Trees in the Banks of Rivermouth

Colonisation and succession in mangrove swampsCOLONISATION

• The pioneer species : Avicennia sp. and Sonneratia sp.

• The extensive roots system of Avicennia sp. and Sonneratia sp. collect sediments & organic matter

• As times passes, the soil become more compact & firm

SUCCESSION

• Rhizophora sp. replaces the pioneer species

• The arcing roots of Rhizophora sp. trap silt and mud, creating a firmer soil structure.

• As times passes, the ground becomes higher & the soil becomes drier

• Bruguiera sp. replaces Rhizophora sp.

• The buttress roots of Bruguiera sp. form loops which protrude from the soil to trap more silt and mud. The soil structure changes.

• Over time, terrestrial plants (Nypa fruticans & Pandanus sp.) replace Bruguiera sp.

• As times passes, the tropical plants replace the terrestrial plants to form climax community.

Pioneer species

Adaptations :

• pnematophores

• aerenchyma tissue

• viviparous seedlings

Successor species

Adaptations:

• props roots

Successor species

Adaptations :

• buttress roots

• viviparous seedlings

• hydatodes

• thick & succulent leaves

• waxy cuticles

Props roots

Excretion of crystalline

salt from hydathodesViviparity

Pneumatophores

Cable roots

Adaptation of mangrove plantsPROBLEMS ADAPTATIONS

Soft, muddy soil

Strong coastal wind

Avicennia sp. : underground cable roots (long & branch)

Rhizophora sp. : prop roots (aerial roots)- for anchor & aeration

Waterlogged conditions of soil (↓ amount of O2)

Avicennia sp. : breathing roots (pneumatophores), grow vertically upwards

Gaseous exchange through lenticels (on the bark)

Direct exposure to the sun

(↑ rate of transpiration)

Leaves are covered by a thick layer of cuticle

Leaves are thick & succulent (able to store water)

High salinity of the sea water

(soil hypertonic compared to the cell sap of the root cells)

The cell sap in the roots cells has a higher osmotic pressure(hypertonic) than the soil.

The excess salt is excreted as crystalline salt from hydatodes(pores on the lower epidermis)

Seeds which fall onto the ground die (submerged in the soft & waterlogged)

Viviparity : seeds are able to germinate while still attached to the mother plant

Processes of Colonisation and Succession in a Pond

Shallowing of a pond

1. Pioneer stage

• When pioneer plants die and decompose, the organic matter settle to the bottom of the pond and make the pond shallower.

• This produce suitable conditions for aquatic floating plants.

2. Succession by aquatic floating plants

• Floating plants cover the surface of the pond and prevent light from entering the pond.

• Pioneer plants cannot perform photosynthesis and die. These dead plants will sink to the bottom and increase the organic matter layer of the bottom.

3. Succession by amphibious plants

• Dead aquatic floating plants and erodedsoil from the pond banks will raise the pond floor and make the pond too shallow for aquatic plants to float.

• The aquatic plants are succeeded by amphibious plants.

4. Succession by herbaceous plants

• The continued deposition of organic matter enables grass to gradually replace amphibious plants.

5. Succession by woody plants

• The death of amphibious plants caused continued deposition of organic matter and evaporation of pond water will make the pond very shallow and eventually dry it up.

• Finally land plants and other woodyplants will replace the amphibious plants and form a jungle.

6. Climax community

• The succession will stop when a level of balance is achieved.

Quiz

• Which of the following describes a population?

A. The function of an organism or the role it plays in an ecosystem

B. The natural environment in which an organism lives

C. A group of organisms of the same species living in the same habitat at the same time

D. A natural collection of plant and animal species living within a habitat in an ecosystem

Quiz

Which gives the correct sequence of plants involved in the process ofsuccession in a disused pond?

A. Emergent plants floating plants land plants submerged plants

B. Floating plants submerged plants land plants emergent plants

C. Submerged plants floating plants emergent plants land plants

D. Land plants emergent plants floating plants submerged plant

Quiz

Over many years a forest can be found on an initially barren piece ofland left behind by a volcanic eruption. What is the correct sequence ofecological processes that have taken place?

A. Colonisation, succession, climax community

B. Colonisation, climax community, succession

C. Succession, colonisation, climax communiity

D. Succession, climax community, colonisation

Quiz

Phytoplankton, zooplankton and algae are often among the firstspecies to establish themselves in a mining pond. As time passes,submerged and floating plants will grow, followed by amphibiousplants, grasses, small shrubs, bushes and eventually trees.

This is an example of

A. colonisation

B. competition

C. evolution

D. succession

Quiz

• During primary succession, lichen or algae would be considered __?

A. pioneer species

B. volunteer species

C. founder species

D. conqueror species

8.3 Population Ecology

Population ecology种群生态学• Population ecology: a branch of ecology

that studies the structure and dynamics of populations

• Population density: the number of organisms per unit area of the habitat

• Population density is affected by abiotic, biotic, birth rate, death rate immigration and emigration.

• Direct counting allow us to know the exact number of the organisms in a population.

• Sampling techniques allow us to use a small sample to estimate the total population size of the organisms.

Direct counting

Sampling

Sampling technique

• Sampling technique: estimate the total population size of the organisms

• Type of sampling technique:

1. quadrat sampling technique样方抽样技术

2. the capture, mark, release & recapture technique記號再捕捉法

Quadrat sampling technique

Mark and recapture technique

Quadrat sampling technique

• Generally used to estimating the size of plant populations.

• Made from a metal or a wooden frame to forms a square of a known area.

• The quadrat is placed randomly in the ecosystem.

Function of the quadrat sampling technique• Frequency: the number of times a particular species is found present

when a quadrat is thrown a certain number of times

Frequency : Number of quadrats containing the species Number of quadrats

• Density: the mean number of individuals of a species per unit area

Density : Total number of individuals of a species in all quadrats Number of quadrats X quadrat area

• Percentage coverage : an indication of how much area of the quadrat is occupied by a species.

Percentage coverage : Aerial coverage of all quadrats (m2)Number of quadrats X quadrat area

X 100%

Capture, mark, release and recapture technique • Used to estimate the

populations of mobile animals• The method :1. A specific animal sample is

captured 2. The animal is marked (a ring,

a tag or waterproof colouredink/paint).

3. The marked animals are released into the general population

4. After suitable period of time, a second sample are recaptured

5. The number of marked animal is recorded

Formula to calculate population size

Population size : (no. of individuals in the 1st sample) X (no. of individuals in the 2nd sample)

no. of marked individuals recaptured

Quiz

• The quadrat sampling technique can be used in the study of the populations of

A. birds

B. earthworms

C. grasshoppers

D. rabbits

Quiz

• Which of the following steps need to be taken to improve the accuracy of the capture, mark, release and recapture technique ?

A. Put a bigger mark.

B. Capture more animals.

C. Capture the bigger animals.

D. Do recapture after one month.

Quiz

• The following information is about the capture, mark, release and recapture technique.

P – Mark the captured animals.

Q – A second sample is captured.

R – Release the marked animals.

S – An initial sample is captured.

Which of the following is the correct sequence of the capture, mark, release and recapture technique?

A. PRSQ

B. PSRQ

C. SPRQ

D. SRQP

The table shows the results obtained from an investigation into thedistribution of mimosa plants on a school field.

Table 1

The percentage frequency of the mimosa plants is

A. 25%

B. 36%

C. 66%

D. 80%

Quadrat 1 2 3 4 5 6 7 8 9 10

Number of plants

5 2 0 1 8 2 0 3 4 5

Quiz

8.4 Biodiversity

Biodiversity and classification

• Biodiversity is the diverse species of plants and animals interacting with one another on Earth.

• Taxonomy is a branch of biology concerned with identifying, describing and naming organisms.

• Organism are classified into 5 major kingdoms :

1) Monera

2) Protista

3) Fungi

4) Plantae

5) Animalia

Five kingdom classification

Kingdom Characteristics Example

Monera原核生物界 • prokaryotic organisms (unicellular organisms)• no distinct nuclear membrane• cell wall is present but lack of both membrane-bound nuclei and organelles• no tissues formation• photosynthetic and non-photosynthetic

• bacteria• cynobacteria

Protista原生生物界 • have a nuclear and membrane-bound organelles• may be unicellular or multicellular (algae and protozoa)• they can either be heterotrophic or autotrophic or even both• the cell are not specialised to perform specific functions in the organisms • some have both plant and animal characteristic

• Amoeba• Paramecium • Spirogyra • Chlamydomonas

Fungi真菌界 • heterotrophic multicellular but some are unicellular• the cell walls contain chitin• the main bodies consists of network of thread-like hyphae called mycelium• do not have chlorophyll• produce spores for reproduction• saprophytic but some are parasitic

• mold (Mucor)• mushrooms • yeast

Plantae植物界 • include all land plants• have a chlorophyll and carry out photosynthesis• multicellular• cells are specialise into tissues

• mosses• fern • flowering plant• non-flowering plant

Animalia动物界 • multicellular, heterotrophic and eukaryotes• do not have cell wall• mobile• do not have chlorophyll

• invertebrate• fish• reptiles• bird • mammals

The Hierarchy in the Classification of Organisms 生物分类

• Living organisms are classified according to certain basic features.

• Note:• Phylum (sg.), phyla (pl.)

• Genus (sg.), genera (pl.)

• Species (sg.), species (pl.)

域，界，門，綱，目，科，属，种

Linnaeus Binomial System二名法

• The Linnaeus Binomial System of classification uses two words to name every species of organisms found.• the first word in the name refers to the genus

• the second word is the specific name

• The characteristics of the system are as follows:• both names are Latin words.

• the name of the genus is written first and the first letter should be in upper case.

• the name of the species is written in lower case.

• both names are in italics if typed or underlined if written

Scientific names of some local organisms

Common name

Scientific name

Paddy Oryza sativaDurian Durio zibethinus

Oil palm Elaeis guineensisRambutan Nephelium lappacium

Sugar cane

Saccharum officinarum

Chicken Gallus domesticusToad Bufo melanosticusFrog Rana erythraeu

The importance of biodiversity

Shelter

Clean drinking water

Economic resources

Clean air

Sources of food

Sources of medicine

Importance of Biodiversity

8.5 The impact of microorganisms on life

Microorganisms

• Microorganisms are tiny organisms that can only seen clearly under the microscope

• Microorganism are classified into 5 major types :

1) Virus

2) Bacteria

3) Algae

4) Protozoa

5) Fungi

Name Characteristics Examples

Bacteria • unicellular prokaryotic organisms• have a cell walls made of a polymer called peptidoglycan• certain bacteria form spores under unfavourable conditions• in spherical (coccus), rod (bacillus) or spiral (spirilium) shape

• Lactobacillus sp.• Staphylococcus

sp.

Algae • photosynthetic eukaryotic plant-like organisms in the kingdom protista• have a chlorophyll and chloroplast• cell walls are made of cellulose• do not have leaves, stems or roots

• phytoplankton • Spirogyra sp.

Fungi • heterotrophic multicellular or unicellular• do not have chlorophyll• have a cell walls made up of chitin• sapophytic

• Mucor sp.• yeast

Protozoa • unicellular organism• have nucleus, cytoplasm and plasma membrane• have flagella, cilia or pseudopodia to move

• Euglena sp. Paramecium sp.

• Amoeba sp.

Viruses • is not a living cell because it cannot survive or reproduce on its own outside the host

• is composed of DNA and RNA, surrounded by a protein coat• can be crystallised

• T4 bacteriophage • tobacco mosaic

virus

The effect of abiotic components on the activity of microorganisms

• Concentration of nutrient• all microorganisms except viruses

need nutrient and water for reproduction and growth.

• without nutrient and water, microorganisms will die or form spores

• Light intensity• microorganisms prefer place which

are dark or have a low light intensity• a high intensity of sunlight and

ultraviolet rays can kill microorganisms

• however, algae and photosynthetic bacteria need light to photosynthesis

• Temperature• most microorganisms are inactive at low

temperatures• optimum temperature for most

microorganisms is between 35 ⁰C and 40 ⁰C

• beyond 60 ⁰C the growth of microorganisms is inhibited

• microorganisms and their spores can only be destroyed when they are sterilized at a temperature of about 121 ⁰C

• pH• most bacteria -pH around 7.4• moulds, yeast and protozoa - pH 4.5 and

5.0

The role of useful microorganisms in the ecosystem• Digestion:

• in stomach, intestine or caecum of herbivors have bacteria that produce cellulases enzymes to digest cellulose

• Termite have a Trichonympha sp. (flagellated protozoan) to digest cellulose from the wood

• Human have bacteria in the colon that synthesise vitamin B12 and K

• Medicine • fungi – produce antibiotic (prevent

the growth of bacteria)• Penicillium notatum produce

antibodies to treat gonorrhoea, syphilis, lung infection

• Streptomycine produce antibodies to treat tuberculosis (TB)

• dead bacteria or viruses – produce vaccine• BCG for TB

• Decomposition:• bacteria and saprophytic fungus

are microorganisms that feed on dead organic matter to get energy for their life processes.

• play an importance role in the natural cycles of the elements such as the carbon cycle and nitrogen cycle

• Nitrogen cycle• Nitrogen Fixation

• fix atmosphere nitrogen into nitrate NO3-

• Rhizobium sp. (in root nodule)• Nostoc sp. (cyanobacteria in the soil)

• Decomposition• decomposition of organic matter into

ammonia NH3• fungi

• Nitrification• Changes ammonia into nitrite, NO2

-

• Nitrosomonas sp.• Nitrococcus sp.

• Changes nitrite into nitrate, NO3-

• Nitrobacter sp.

• Denitrifying• changes nitrate into nitrogen

The role of useful microorganisms in the ecosystem

Nitrogen cycle

-)

, Nostoc

• Industry • production of alcohol – using yeast

through the fermentation process of sugar, starch or grains

• production of vinegar – the bacterium, Acetobacter, acts on alcohol to produce vinegar (ethanoic acid)

• Making bread – using yeast and sodium bicarbonate to produce carbon dioxide to rises the bread dough

• Production of butter – cream is made sour by the action of bacteria.

• production of fermented milk –tairu and yogurt using bacteria, Lactobacillus sp. and Streptococcus sp. and yeast

• production of vitamins – Vitamin B2 – yeast, Vitamin D – yeast and bacterium

• textile industry – bacteria are use to decomposed the soft plant tissues leaving the plant fibres

The role of useful microorganisms in the ecosystem

Pathogens, Vectors and Symptoms of Some Diseases

Disease Pathogens Vector Symptoms Method of infection

TB Bacteria - -Feeling tired

-Constant coughing

-Coughing out blood

Droplet infection, dust, food and drinks that are contaminated

Cholera Bacteria (Vibrio sp.) House fly -Vomiting

-Serious diarrhea

Water or food that is contaminated

Food poisoning

Bacteria, fungi House fly -Vomiting

-Diarrhoea

-Abdominal pains

-Fever

Water or food that is contaminated

Cold Virus - - Fever, Headache

- Muscle pain

Through the air

Ringworm Fungi - - Red spot on the skin

- Itchiness

Touch

Pathogens, Vectors and Symptoms of Some Diseases

Disease Pathogens Vector Symptoms Method of infection

Dengue Virus Mosquito, Aedes aegypti

- High fever

- Headache

- Rashes

- Pain at the joint

- Bleeding from the nose, gums and tooth sockets

Mosquito bite

Mumps Virus - - Fever

- Painful feeling when eating

-Difficulty opening the mouth

-Soft swelling in front and below the ears

Through the air

Malaria Protozoa (Plasmodium)

Mosquito - Fever

-Headache

- Muscle pain

-Shivering

Mosquito bite

Pathogens, Vectors and Symptoms of Some Diseases

Disease Pathogens Vector Symptoms Method of infection

AIDS Virus

(HIV 1 and HIV 2)

- - Fever

- Loss of body weight

-Tiredness

-Candidiasis around the mouth and throat

-Pneumonia

-Kaposis’s sarcoma

-Through sexual contact with a person infected with HIV

- Transfusion of blood from a HIV victim

-Sharing of injection needles

SARS Virus - -High fever

-Cry cough

-Shortness of breath or breathing difficulty

-Pneumonia

-Headache, muscular stiffness

-Loss of appetite

-Rash, diarrhoea

-Droplet infection touch

- Close contact with someone who has SARS

-Body secretion

Transmission of Disease

• The air • Droplet transmission

• Airborne transmission

• Touch

• Food

• Vectors

• Water

Controlling Pathogens

Methods of controlling pathogens

Antibiotics抗细菌药

Penicillin and streptomycin are chemicals produced by microorganisms which inhibit the growth or kill other microorganisms, especially bacteria

Vaccines疫苗

Are modified or weakened forms of bacteria or viruses. Is a suspension of dead bacteria or viruses which is inoculated into our body to induce the production of antibodies. Examples of vaccine are Sabine vaccine and BCG

Antiseptics消毒剂

Are used on cuts and wounds to kill and inhibit the growth of microorganisms. Examples of antiseptics are acriflavinand iodine solution

Disinfectants消毒剂

Use to kill microorganisms on the floor, buildings or furniture and sterilise surgical equipment. Example : phenol, formaldehyde and carbolic acid