DYNAMIC ECOSYSTEMDYNAMIC ECOSYSTEM

ATLASIANS

1. SHARIFAH AMIRAH

2. FARIHAH

3. IZZAH ATHIRAH

4. AISYAH HANISAH

ABIOTIC & BIOTIC COMPONENTS

An ecosystem is a system formed by the interaction of living organisms with one

another and with their environment. Examples : forest,grassland,pond,field,lake and sea

An ecosystem consists of two components :

a)Abiotic components (physical factors) b)Biotic components (biological factors)

THE ABIOTIC COMPONENTS

In any ecosystem, abiotic components such as pH, temperature, light intensity, humidity, topography & microclimate determine the

population size and distribution of the biotic components.

The pH value of the soil and water affects the distribution of organisms

a) Most organisms live in a neutral or nearly neutral environment (pH 6-7.5).

b) Some plants, like the maize, grows well in an acidic condition while coconuts grow well in an alkaline condition.

LIGHT INTENSITY AFFECTS THE RATE OF PHOTOSYNTESIS AND GROWTH

a) The distribution of green plants will be more extensive in areas with higher light intensity

b) All organisms that live in soil prefer a dark environment where the light intensity is low

TEMPERATURE AFFECTS THE PHYSIOLOGICAL REACTIONS IN THE ORGANISMS.

a) Organisms can live within a certain range of temperature

b) Plants and animals have specific characteristics to help them adapt to areas of extreme temperature

HUMIDITY AFFECTS THE RATE OF WATER LOSS BY PLANTS AND ANIMALS.

a) Usually higher at night but lower during the day b) Some organisms prefer humid areas e.g : snakes,

frogs c) Woodlice regulate their activities to prevent

dehydration

TOPOGRAPHY REFERS TO THE SHAPE OF THE EARTH’S SURFACE.

a) Topography of a place determines the temperature, light intensity & humidity in an area

b) Three topography factors that affect the distribution of organisms are altitude, slope (gradient) & aspect

MICROCLIMATE REFERS TO THE CLIMATE IN A

MICROHABITAT. a) Microclimate has specific temperature, humidity

and light intensity within its small habitat b) Each type of organisms finds a habitat that has

a microclimate that is suitable for it

THE BIOTIC COMPONENTS Classified into 3 groups :

1) Producers The green plants are the producersproducers because they can

synthesise food through photosyntesis

2) CONSUMERS

Consumers are organisms that feed on plants or other organisms

. PRIMARY = herbivores as they obtain food & energy from producers

. SECONDARY = carnivores as they obtain food & energy by feeding on primary consumers

. TERTIARY = carnivores as they feed on secondary consumers

3) Decomposers Decomposers are bacteria & fungi that break

down waste products and dead bodies of other organisms into simpler substances

FOOD CHAIN,FOOD WEB AND TROPHIC LEVELS

• A food chain shows a sequence of organisms through which energy is transferred

• Each stage in a food chain is known as a trophic level

• Through the food chain, organisms obtain energy• In an ecosystem, several food chains interact to

form a network called a food web• In a food chain, energy is transferred from one

trophic level to another trophic level• 90% of the chemical energy in the food consumed

is used for its metabolic activities and lost as heat, excretory products and undigested matter

• Only 10% of the energy in an organism is passed on to the organism at the next trophic level

INTERACTION BETWEEN BIOTIC COMPONENTS IN RELATION TO FEEDING

Symbiosis

Symbiosis is an interaction between two organisms of different species that live together.

In symbiosis, one organism will live in or with another organism called the host.

The organism that interacts with the host will benefit from the interaction.

Symbiosis is further classified into three types:

a)Commensalisms

b)Paratism

c)Mutualism

i. COMMENSALISM

Commensalisms is an interaction between two organisms where only one organism (commensal) benefits from the relationship. The other (host) is neither benefit nor harmed.

Examples of commensal are epiphytes and epizoices

Epiphytes are green plants which grow on other plants to obtain more sunlight and air.

Examples : Birds nest fern & pigeon orchid

Epizoics are animals which live as commensals on the outside of other animals

Examples : barnacles & remora fish

ii. PARASITISM Parasitism is an interaction between two organisms

in which one organism (parasite) benefits and the other (host) is harmed.

Two types of parasites:

Ectoparasites which live on the outside of their host e.g : fleas, ticks, lice

Endoparasites which live inside their host. e.g : tapeworms, flukes

iii. MUTUALISMMutualism is the interaction between two organism in which both

organisms benefit.

Examples of mutualism :

a) Algae & fungi in lichen (both plants)

b) Hermit crab & sea anemone (both animals)

c) Rhizobium bacteria & legume plants (one animal and one plant)

“Sea anemone obtains transport and leftover food from the hermit crab.

The hermit crab obtains protection from its predators because of the poisonous

tentacles of the sea anemone.”

SaprophytismSaprophytism is an interaction in

which a living organism obtains food from dead and decaying matter

Saprophytes (plants which feed on decaying organic matter)

Examples : saprophytic bacteria, fungi (Mucor sp.)

Saprozoites (animals which feed on decaying organic matter)

Examples : amoeba, opalina

Prey-predator interaction A type of interaction in which an animal

(predator) hunts and eats another animal (prey). Predators are usually bigger, stronger animals

with sharp vision, sharp claws & canine teeth and usually move fast

The size of the prey is usually smaller than the predator but the number of prey is always more than the predator

THE INTERACTION BETWEEN BIOTIC COMPONENTS IN RELATION TO

COMPETITION

Competition is an interaction between organisms living together in a habitat & competing for the same resources that are in limited supply.

Plants compete for water, light, nutrients and space.

Animals compete for food, space & breeding mates

There are 2 types of competition:a. Intraspecific (refers to the competition among

organisms of the same species)e.g : competition among Bryophyllum sp. plant

b. Interspecific (refers to competition among organisms of different species)

e.g : competition between two species of Paramecium, P.aurelia & P.caudatum

8.2 Colonisation and Succession in an

Ecosystem

What is an ecosystem ?1. An ecosystem is a dynamic system

formed by the interactions of organisms with one another and with the non-living environment.

2. It is a dynamic system where the living organisms are in balance with each other and with the abiotic components.

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

Species A species is a group of organisms which can interbreed to produce fertile offspring.

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

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

Niche The niche of an organism is the roles and activities of the organism in its habitat. Two organisms sharing the same habitat may have different niches.

COLONISATION AND SUCCESSION

1. Natural phenomena or human activities such as volcanic eruptions, fires, earthquakes and uncontrolled mining activities leave the land with no living organisms.

2. Later, some organisms will come to occupy the bare land.

3. The process in which living organisms arrive at a new habitat, live, reproduce and take control of the habitat is known as colonisation.

4. The first species of organisms to colonise a new habitat is called the pioneer species.

5. The pioneer species have special adaptations to survive in unfavourable land conditions.

6. The pioneer species gradually changes the conditions of the habitat, making it no longer suitable for itself but more suitable for other species, called the successor species. Gradually, the successor species takes over the place of the pioneer species.

7. The process whereby a pioneer species is gradually replaced by other successor species is called succession.

8. Succession will carry on until a relatively stable community is formed. This type of community is known as the climax community.

9. In Malaysia, the tropical rainforest is the climax community.

10. It usually takes hundreds of years to form a climax community. After that it has little or no changes in its species structure. Therefore, we should treasure our forests.

COLONISATION AND SUCCESSION IN A MANGROVE SWAMP

1. Swamps are formed by deposition of mud and silt carried down by the river. It is found at the estuary, that is where the river meets the sea.

2. Only mangrove trees are able to colonise the soft, waterlogged, muddy soil which has a low oxygen level but high salt concentration.

3. Mangrove trees have adaptive structures to overcome the harsh conditions in a swampy area.

A mangrove swamp

ADAPTATIONS OF MANGROVE TREES

Problems faced by mangrove trees

Adaptive structures of mangrove trees

Ground too soft to provide support

Have long, branched cable roots or prop roots to support the plants in soft ground.

Very little oxygen in waterlogged mud

Have breathing roots called pneumatophores which grow upwards and protrude out of the ground.

Gaseous exchanges also occurs through lenticels on the bark of mangrove tress.

The root systems of mangroves

Pneumatophores of Avicennia sp.

Prop roots of Rhizophora

sp.

Buttress roots of Bruguiera sp.

Problems faced by mangrove trees Adaptive structures of mangrove trees

High salt content of sea water The cell sap in root cells has a higher salt content. Sea water enters the roots by osmosis. Excess salt from the sea water is eliminated through hydathodes found at the lower epidermis of leaves.

Seeds sink into the mud and die due to insufficient oxygen

Have viviparous seeds. A radicle grows from the germinated seed when it is still attached to the parent tree. When the seedling is released, the radicle holds the shoot above the mud.

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

Leaves with thick cuticle and sunken stomata to reduce transpiration

Store water in succulent leaves

Viviparity

4. Avicennia sp. and Sonneratia sp. are the pioneer species of a mangrove swamp. Avicennia sp. grows in areas facing the sea while Sonneratia sp. is found in more sheltered areas.

5. The extensive cable root system of these plants traps more mud and slit as well as organic matter from decaying plant parts.

6. As time passes, the soil becomes more compact and the shore level is slightly raised. The soil becomes firmer and less waterlogged. Such conditions favour the growth of another kind of mangrove tree, namely Rhizophora sp.

7. Gradually, Rhizophora sp. replaces the pioneer species.

8. The prop root system of Rhizophora sp. continues to trap more slit and mud. Humus is formed from the old pioneer species as well as decaying leaves of Rhizophora sp. The soil becomes firmer, more compact and fertile. The shore level is raised and is less saline. The condition now is more suitable for Bruguiera sp.

9. The buttress root system of Bruguiera sp. Traps more silt and mud causing the shore to extend further to the sea.

10. As time passes, coconut trees, Nipah and Pandanus sp. gradually replace the Bruguiera sp. when the soil becomes more like terrestrial ground.

11. Eventually a tropical rainforest, which is the climax community, is formed.

Distribution of different mangrove species at the mouth of a river

COLONISATION AND SUCCESSION IN A POND 1. Colonisation by pioneer species (a) Submerged plants such as Hydrilla sp.,

Elodea sp. and Cabomba sp. as well as phytoplankton are the pioneer species in a pond.

(b) These submerged plants have adaptive features such as long fibrous roots which penetrate deep into the soil to absorb nutrients and hold the sand together. Fine leaves enable the plants to flow with the water.

Submerged plants

Hydrilla sp. Elodea sp.

Cabomba sp.

2. Succession by floating plants (a) When the pioneer species die, they settle to

the bottom of the pond and become humus. At the same time, the soil eroded from the sides of the pond makes the pond shallower.

(b) Such a condition becomes unfavourable for the submerged plants but more suitable for floating plants such as Nymphaea sp. (lily), Lemna sp. (duckweed) and Eichornia sp. (water hyacinth) which gradually replace the pioneer species.

Floating plants Water lily

Water hyacinth

Pistia sp.

3. Succession by emergent (amphibious) plants (a) The floating plants reproduce rapidly as they

receive enough sunlight for photosynthesis. They cover a large area of the surface of the pond. This prevents sunlight from reaching the bottom of the pond.

(b) Without sunlight, the submerged plants cannot perform photosynthesis. As a result, these plants die and become humus.

(c) The amount of humus deposited at the bottom of the pond increases. More soil erosion occurs which results in the pond becoming shallower. This makes the pond too shallow for the floating plants.

(d) Floating plants are gradually being replaced by emergent plants such as Fimbristylis sp. and Lepironia sp.

(e) Emergent plants can live in water as well as on land. Their extensive rhizomes grow rapidlly to bind the soil together and to absorb nutrients, changing the habitat. They grow from the edge of the pond to the middle of the pond.

AMPHIBIOUS PLANTS

Cyperus sp.

Scirpus grossus

Scirpus mucronatus

4. Succession by terrestrial plants (a) The death of emergent plants as well as

deposition of more organic matter make the pond even shallower. Evaporation of pond water finally dries the pond.

(b) Terrestrial plants such as creepers, grasses, ferns and herbaceous plants begin to grow.

(c) Later, shrubs and woody plants begin to grow.5. Climax community Over hundreds of years, a tropical rainforest which

is a climax community is formed.

8.3 POPULATION ECOLOGY

WHAT IS POPULATION?

A group of organisms that’s:

Same species

Occupy a particular area

FACTORS AFFECTING SIZE OF POPULATIONAbiotic factor

Biotic factor

Birth and death rate

Immigration

Emigration

TECHNIQUE TO ESTIMATE POPULATION AREA

1. Quadrat sampling

2. Capture, mark, release, and recapture technique

QUADRAT SAMPLING

Plants

Immobile animals

HOW? Quadrat consist of square/rectangular frame

(wood/metal)

Strings subdivided the quadrat into smaller squares

Frame is pegged to the ground

A number of quadrats are set up randomly thoughout the are being studied

Species present within the frame is counted and recorded

THE DATA CAN DETERMINE : Frequency of species

[no. of times a particular species is found]

PercentageFrequency =

No. of quadrats containing the species

No. of quadrats sampled

x 100

Density of species[mean no. of individuals per unit area]

Density =

Total no. of individuals of a species in all quadrats

No. of quadrats samples x

Area of each quadrat sampled

Percentage Coverage[indication of the area of the quadrat occupied by a species]

Percentage Coverage

=

Aerial coverage of all quadrats (m²)

No. of quadrats sampledX

Quadrat area

CAPTURE, MARK, RELEASE & RECAPTURE

For mobile animals only

HOW? A specific animal sample is captured and marked

Marked animals released into the general population

After a period of time, a second sample is captured and no. of marked animal in the 2nd sample is counted and recorded

Based on the data, population size can be determine by using the formula :-

Population Size =

No. of organisms in 1st sampleX

No. of marked organisms captured

No. of marked organisms captured

ABIOTIC FACTORS AFFECTING POPULATION DISTRIBUTION

Temperature

Light intensity

Humidity

pH

8.4 - BIODIVERSITY

WHAT IS BIODIVERSITY?

Diverse species of plants & animals in different ecosystem on earth

CLASSIFICATION OF ORGANISMS

Taxonomy : Branch of biology concerned with the identification, naming, & classification of organisms.

5 Kingdoms :

MoneraProtistaFungiPlantaeAnimalia

> MONERA

Unicellular

Have a cell wall, but no organelles & nucleus

Don’t have nuclear membrane – genetic material is scattered

3 shapes: rod-shaped, round, or spiral

> PROTISTA

Includes algae and protozoa

Contain nuclei & numerous organelles that surrounded by membrane

Plant-like protists have chloroplast

Can be heterotrophic or autotrophic, or both

The cells of multicellular protists are not specialised to perform specific functions

> FUNGI Mostly multicellular, but some fungi are

unicellular

The cell walls of fungi contain ‘chitin’

Main bodies consist of a network of thread-like hyphae – mycelium

All fungi are saprophytic

No chlorophyll, obtain energy by decomposing decaying organisms and absorb nutrients

> PLANTAE

Immobile, multicellular, with chlorophyll

Plant cells are enclosed in cellulose cell walls

Organised into specialised tissue

> ANIMALIA

Multicellular, heterotrophic with well-developed tissues

Do not have rigid cell walls & chloroplast

Most are mobile

Mammals, reptiles, fishes, amphibians, birds

Digest food internally

HIERARCHY IN THE CLASSIFICATION OF

ORGANISMS

KingdomPhylum

Class

Order

Family

Genus

Species

• No. of organisms = decreases

• Similar features of an organisms = increases

King Philip Came Over From Great Spain

NAMING

Genus + Species(eg: Homo sapiens)

IMPORTANCE OF BIODIVERSITY

• Provide various biological products which play important role in economics

• Provides many environmental services

• Food, shelter, basic needs

• Diversity in genetic pool- Genetics variation in the different

population

8.5 THE IMPACT OF MICROORGANISMS ON LIFE

WHAT IS MICROORGANISMS?

Very tiny organismsHarmless & usefull or can cause

disease5 types :

BacteriaAlgaeFungiProtozoaViruses

BACTERIA

CHARACTERISTIC :

Unicellular, basic cell structureCell walls made of peptidoglycan

Spherical, rod-shape, spiral

Coccus

Bacillus Spirillum

ALGAE

CHARACTERISTIC :

Photosynthetic eukaryotic plant-like

From ProtistaHave chlorophyll, chloroplastCell wall made of celluloseNo leaves, stems or roots

FUNGI

CHARACTERISTIC :

Multicellular/unicellular No chlorophyll Cell walls made of chitin Lives as saprophytes and parasites Heterotrophs

PROTOZOA

CHARACTERISTIC :

UnicellularHave nucleus, cytoplasm, plasma

membraneCarry out living processesTo move; Flagella, cilia,

pseudopodia

VIRUSES

CHARACTERISTIC :

Smallest microorganismNot a living cellCan be crystalisedComposed of DNA/RNA, surrounded

by protein coat

EFFECTS OF ABIOTIC COMPONENTS ON MICROORGANISMS

ABIOTIC COMPONENTS :

Temperature

pH value

Light intensity

Nutrients

TEMPERATURE

Optimum temperature : 35ºC - 40ºC

At low temp : they are not active, low grow rate

Temp above 60ºC : inhibited

121ºC : die

PH VALUE

Each has its own optimum pH value

Most live best in neutral environment

Bacteria : slightly alkaline

Fungi : slightly acidic

LIGHT INTENSITY

Autotrophs need light

High light intensity : inhibited and destroy

Low light intensity : Growth rate is high

NUTRIENTS

Autotrophs : from surroundings

Heterotrophs : in the form of starch, fat, glucose, amino acid

• Decomposition• Nitrogen cycle• Alimentary canals of termites• Digestive system in humans

ROLE OF USEFUL MICROORGANISMS

DECOMPOSITION

Complex simple organic substance

Fungi & bacteria obtain food and energy

NITROGEN CYCLE

ALIMENTARY CANALS OF TERMITES

Live freely in mutualism in alimentary canals of termites

Secrets enzyme cellulose into simple sugars – then absorb by termites

DIGESTIVE SYSTEM IN HUMANS

In the caecum & colon, they break down remainder carbon hydrogen, carbon dioxide, methane

Break down remainder protein amino acid & hydrogen sulphide

Synthesis vitamin B12 & K

Help digest cellulose to form simple sugar

EFFECT OF HARMFUL MICROORGANISMS

PATHOGENS

Microorganisms that causes diseases

Can cause spoilage of food cause food poisoning

HOW?

Attack & destroy cells or body tissues

Release toxins into body of organisms

• Vectors : organisms which transmit pathogens

METHOD IN TRANSMISSION OF DISEASE

3 METHODS :

Water

Air (Air-borne transmission)

Physical contact

WATER

Drink unboiled water, flood, poor sanitation

Disease : cholera, typhoid, dysentery

Prevention :Drink boiled waterImprove sanitationAdd chlorine to tap water

AIR (AIR-BORNE)Breath in contaminated droplets of

moistureBreath in spores by bacteria

Disease : Common cold, tuberculosis, influenza, chicken pox, measles, leprosy

Prevention :Do not spitCover mouth & nose when

sneezing/coughing

PHYSICAL CONTACT

Direct contact/indirect contactSexual relationship

Disease : White spot, ringworm, AIDS, syphilis, gonorrhoea

Prevention : Avoid sharing personal thingsAvoid sharing needles with AIDS

patients

• Antibiotics• Vaccines• Antiseptics• Disinfectants

METHODS OF CONTROLLING PATHOGENS

ANTIBIOTICS

Chemical substance produce by fungi & bacteria

To treat disease caused by bacteria

VACCINES

Contain dead/weak virus and bacteria

Stimulate white blood cells

The antibodies produce will react with pathogens (1 antibody for 1 pathogens)

ANTISEPTIC

Chemical substance used on wounds/cuts

Only on external parts – prevent wound from become septic

DISINFECTANTS

To kill the pathogens of dangerous disease

Kill microorganisms, but not the spores

Only on non-living things to sterilise things

Stronger than antiseptic

Cannot be used on wounds

USES OF MICROORGANISMS IN BIOTECHNOLOGY

Production of antibiotics and vaccinesCleaning of oil spillsWaste treatmentFood processingProduction of energy from biomassProduction of bioplastic

8.6 APPRECIATING BIODIVERSITY

WHY?

Plants and animals provide large variety of food source and uses to humans

Certain species have medicinal values

Insects and animals are pollinating agents

SO WE MUST…

ConserveWise use of natural resourcesProtection, management, renewal

of natural resources

PreserveManagement of ecosystems to

ensure a healthy natural environment

THE END

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