FORM 4CHAPTER 8

DYNAMIC ECOSYSTEM

COMPONENTS OF ECOSYSTEM

Ecosystem Components

Abiotic component

Biotic component

Abiotic Components

Light Intensity

Topography

Microclimate

Humidity

Temperature

Gradient

pH

the pH value of soil and water has important effect on the types of organisms

a drastic change in pH may kill the organisms

affects the physiological activities of organisms most of organisms cannot tolerate extremes

temperatures

pH

temperature

affects the distribution and growth of organisms

some plants show adaptation to reach the light and most animal need sunlight but some show adaptation to live in the dark

is the amount of water vapour in the air plant and animal that live in wet have special

adaptation

Light intensity

Light intensity

Refers to local climate in a small area Humidity, temperature and light intensity

affect the microclimates

steepness of a slope cause a faster drainage and run off the water

Light intensity

Gradient

influence local climate and soil development the main factor is altitude and aspect higher altitude : lower atmospheric pressure

and temperature so different plants can growing at different altitude

sloppy areas receive more sunlight compared to valley

Topography

Biotic Components

producers consumers decomposers

Interaction Between Organisms

Long-lasting interactions Temporary interactions

Symbiosis

Saprophytism

Prey-predator

Competition

Commensalism Mutualism Parasitism

Means ‘living together’

Permanent and close relationship between 2 or more different species.

There are 3 categories:

• Commensalism

• Parasitism

• Mutualism

Symbiosis

COMMENSALISMRelationship between 2 species that benefits

one species but either benefits nor harms the other species.

Two exampless of commensals are epiphytes and epizoics.

EPIPHYTES Green plants

Does not drive nutrition from its host (photosynthesis)

Faces difficulties in getting water & minerals

Examples of epiphytes are bird’s nests fern, staghorn fern, pleurococcus and orchid

Adaptation:

has a swollen stem at its base to store water.

Has special roots (aerial roots) to absorb moisture.

Roots are coated with spongy layer which prevents roots tissue from drying out.

Has sunken stoma to reduce water loss.

EPIZOICS• An animal (commensal) attached to another

animal (host).

• Epizoics attach themselves to the bodies of their hosts for free transport, protection and feed leftover from their hosts meals.

• The host neither suffer loss nor benefit from the epizoics

CrabBarnacle (teritip)

Cyclops (kutu air)

protozoa

shark

PARASITISM

Relationship between two organisms where the parasite benefits but the host is harmed.

2 types:

Endoparasites

Ectoparasites

ENDOPARASITES• Examples: Tapeworms, flukes, plasmodium

(caused malaria)

• Adaptation: no nervous systems and sense organ.

no digestive tracts, they absorb food through the whole body surface.

have protective cuticle & anti-enzymes to prevent being digested by hosts’ enzymes, acids or alkalis.

have flattened shape to cling on to the host.

carrying out anaerobic respiration.

great reproductive system.

ECTOPARASITES• Animal ectoparasites on

plant hosts

Have hook to attach themselves on their hosts

Have sharp mouth parts for hooking, sucking or biting

MUTUALISMRelationship between two

organism which both benefit Examples: Lichen

• Combination of a green alga and a fungus.

• The green alga cells get shelter, water, mineral salts from fungus.

• The fungus gets food and oxygen from alga cells which carry on photosynthesis.

Saprophytism Animals that feed on dead organic matter that

has been digested.

Saprophytes produce enzymes to digest and decompose the dead complex organic matter.

• Prey-predator InteractionType of interaction in which an animal (predator) hunts

and eats another animal (prey)• Competition

Interaction between 2 organisms living together in a habitat and competing for limited recourses.

Animal usually compete for food, shelter and breeding mates, while plants compete for space, light, nutrients and water.

2 types:

Interspecific competition.

Intraspecific competition

COLONISATION AND SUCCESSION

•Colonisation

The process whereby living organisms move into this newly formed area which is completely devoid of life.

SuccessionThe gradual process where one community changes its environment so that it is replaced by another community.

Bare ground

Pioneer species

Succesor species

Climax community

Colonisation & Succession in Mangrove Swamps

Mangrove swamps found in tropical regions where fresh water meets salt water.

They have a bad environment for normal plants.

soft muddy soil and strong coastal wind

high concentration of salt

very low levels of oxygen

Exposed to high intensity of sunlight

PROBLEM FACED BY MANGROVE TREE

ADAPTIVE STRUCTURE OF MANGROVE TREE

Ground too soft to provide support

Have long, branched cable roots or prop roots

Very little oxygen in waterlogged mud

Have breathing roots called pneumatophoresGaseous exchanges occurs through lenticle

High salt content of sea water sea water enter roots by osmosis the excess salt is eliminated through hydathode

Exposure to strong sunlight and intense heat leads to higher rate of transpiration

Leaves with thick cuticle and sunken stomata to reduce transpirationStore water in succulent leaves

Distribution of different mangrove species at the mouth of a river.

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PROCESS OF COLONISATION AND SUCCESSION IN A POND

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.

Sucession 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

Succession by amphibious plants

• Dead aquatic floating plants and eroded soil 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.

Succession by herbaceous plants

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

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 woody plants will replace the amphibious plants and form a jungle.

Climax community

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

POPULATION ECOLOGY

• A branch of ecology that studies the structure and dynamics of population.

• Population density – number of organism per unit area of habitat

• Affected by abiotic and biotic factors, birth rate, death rate, immigration and emigration.

QUADRAT SAMPLING TECHNIQUE

• Used to determine the distribution of plants whereby the density, frequency and percentage coverage of the plants

• A quadrat – metal, wooden frame or PVC pipe frame which form a square of a known area (1 m2 ).

• Placed randomly in an ecosystem where sampling is carried out.

8.4 BIODIVERSITY

Refers to the wide variety of species of organism on the Earth

Classification of organisms

Organisms are classified into 5 major

kingdoms

Monera

Protista

FungiPlantae

Animalia

Monera

• Examples : bacteria , cyanobacteria

Unicellular microorganisms

Consists of

bacteriaCan

move

PROTISTA

• Consist of protozoa and algae• Mostly unicellular• Has nuclear membrane• Examples : Amoeba , Euglena , Paramecium ,

Spirogyra

FUNGI

• Consist of a filaments called hyphae that absorbs nutrients

• Plants without chlorophyll• Examples : Mucor (bread mould) ,

saccharomyces(yeast) , agaricus(mushroom)

Plantae

• Multicellular plants• Contain chlorophyll• Examples : moss, ferns , conifers ,

monocotyledon plants , dicotyledon plants

ANIMALIA

• Multicellular animals• Examples : fish , snake , birds , insects

Hierarchy in the Classification of Organisms

• Living organisms are classified into 7 main groups

• The number of organism in each unit decrease from kingdom to species

The Importance

of Biodiversity

Maintaining a balanced

nature

Source of food

Source of medicine

Clean airShelter

Clean drinking water

Preserved all living

organisms from become

extinct

8.5 The Impact of microorganisms 0n Life

• Microorganisms are microscopic organisms that cannot be seen with the naked eyes.

• Microorganisms are classified into 5 major types :

Protozoa virus

bacteria

algae

fungi

Protozoa

• aquatic unicellular animal• can be seen under a microscope at low power• has nucleus, cytoplasm and is surrounded by a plasma membrane• takes in food (feeding), removes excretory products and reproduces• reproduces sexually and asexaully• lives freely in the river, pond, fresh water, soil or on another organism.

Some live as parasites• heterotrophs• examples: Amoeba sp., Paramecium sp• kingdom; Protista

Fungi

• unicellular plant (yeast) or multicellular plant (mushroom and Mucor sp• can be seen under a microscope at low power or with a magnifying glass• a plants Without chlorophyI• Reproduces by budding (yeast) and formation of spores (mushroom and

Mucor sp.)• lives as saprophytes and parasites• heterotrophs• examples: Yeast, Mucor sp. (bread mould), mushroom• Kingdom: Fungi

Algae

• exists as unicellular, in a colony and in filaments (multicellular)• lives in the sea, pond, river, paddy field, tree stem, damp soil• the most simple green plants• contains chlorophyll• autotrophs• carries out aerobic respiration• reproduces asexualIy and sexually• examples: Phytoplankton (Chlamydomonas sp.)pleurococcus sp.

Spirogyra sp.• Kingdom: Protista

Bacteria

• unicellular microorganism• can be seen under a microscope at high power• has a cell wall• genetic material scattered in the cytoplasm because there is no

nuclear membran• reproduces asexualy by binary fision• forms spores when conditions are not suitable• able• examples: Lactobacillus sp., StaphyIococcus sp.• Kingdom: Monera

Virus

• microscopic microorganism• can only be seen under an electron microscope• consists of nucleic acid that is ribonucleic acid (RNA) or deoxyribonucleic

acid (DNA)• has a layer of protein for protection• has no cytoplasm, nucleus or plasma membrane• Exits as crystals outside host cells, no signs of life• can only reproduce when in living cells of hosts• exists in various forms• all are parasites• examples: Bacteriophage• Kingdom: Viruses cannot be placed in any kingdom because they have their

own characteristics, without showing any characteristics of living things

Abiotic Components Affecting The Activity of Microorganisms

Nitrogen Cycle

• It is the most important cycle• The atmosphere is 78% nitrogen• Nitrogen is an essential element for all organisms BUT plants and

animals cannot get it directly from the atmosphere SO the nitrogen cycle begins.

• The main process in nitrogen cycle are a) Nitrogen fixationb) Decompositionc) Nitrificationd) Denitrification

a) Nitrogen fixation • A conversion of atmospheric nitrogen into

ammonia for living organisms

b) Decomposition• The process of converting organic nutrients

into ammonia when animal die• This process is carried out by Saprophytes like

Fungi and Bacteria

Nitrogen Ammonia

c) Nitrification• The bacteria which is involved in nitrification is

known as nitrifying bacteria• It is the process in which Ammonium

compound are oxidised to form nitrites by Nitrosomonas

• Then Nitrites are oxidised to nitrates by Nitrobacter

Ammonium compound

Nitrites Nitrates

d) Denitrification• The process which converts nitrates to

gaseous nitrogen• The microorganisms involved is known as

denitrifying bacteria• Through this process, nitrogen is returned to

the atmosphere

Nitrate Nitrogen

Nitrogen

Nitrate

Ammonia

Nitrite

Nitrate

Nitrogen

Nitrogen fixation

decomposition

nitrification

nitrification

denitrification

Effect of Harmful Microorganism

• Microorganism that can cause disease and spoilage of food and substances

• Pathogens – Microorganism that cause disease by

a) Attack and destroy cells or body tissueb) Release toxins into the body of organisms• Vectors – organisms which transmit pathogens

Method in Transmission of Diseases• Airi. Breathing in contaminated droplets of moisture produced by coughing or

sneezingii. Breathing in spores of bacteria produced when the salive spit out by a

patient dries up• Physical contacti. Direct contact with an infected personii. Indirect contact through sharing of personal thingsiii. Through sexual relationship• Wateri. Poor sanitationii. Drinking unboiled water or water contaminated with the infecting

microorganismiii. Flood (when water is contaminated)

Method to control pathogens• Destroy and prevent growth and reproduction of bacteria• Examples : Penicillin and StreptomycinAntibiotics• Inject dead or weakened pathogens into the body to stimulate

production of antibodies by lymphocytes• Examples : Vaccine B.C.G and Vaccine SalkVaccines• Use only on the external parts of the body• Apply on wound to kill and prevent reproduction of microorganisms

• Examples : Hydrogen peroxide and iodineAntiseptics

• Stronger than antiseptic• kill microorganisms• Only use on non-living things• Examples : Formalin and phenol

Disinfectants

8.6 Appreciating Biodiversity

Biodiversity can be appreciated through conservation and preservation

THANK YOU, BYEBYE