Folio Biology Chapter 9

8/13/2019 Folio Biology Chapter 9

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SEKOLAH MENENGAH KEBANGSAAN SIMPANG

PULAI

BiOLOgy F4

Dynamics

EcosystemName : Syahida Binti Ahmad Nizam

Class : 4 Amanah (2013)

Teachers name : Pn. Syakirah bt. Abdullah


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8.1 The Abiotic and Biotic Componentsof the Environment

An Ecosystem is a system formed by the interaction of livingorganisms with one another and with their environment

Abiotic Components : The non-living components in the ecosystemsuch as air, water, soil, temperature and light intensity

Biotic Components : The living components in the ecosystem suchas plants and animals


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Abiotic Components of an Ecosystem

pH Value of the soil and watera.Most organisms live in a neutral or nearly neutral

environment (pH 6-7.5)

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

conditionTemperature

a.Poikilotherms are animals that cannot control theirbody temperature varies with the surrounding

temperature.

b.Homoiotherms are animals that can maintain their bodytemperature.

Light intensitya.All organisms in the soil prefer dark environment.

Humidity of aira.Affects the rate of transpiration in plants and the rate

of water evaporation from animals.

TopograpyThree topography that affects distribution of organisms

are:


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a.AltitudeLess organisms at a high altitude because

temperature, atmospheric pressure and air humidity

are low.

b.Gradient/SlopeThe gradient of a place affects the rate of water

flow.

c.AspectRefers to the direction facing or opposing the windand sunlight.

Microclimatea.Refers to the climate in a small habitat.b.Has specific temperature, humidity and light intensity


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Biotic Component of an Ecosystem

Producer (1sttrophic level)

Can synthesis food through photosynthesis Ex : Grass, paddy

Primary Consumer (2nd

trophic level)

Herbivores Ex : Grasshopper

Secondary Consumer (3rdtrophic level)

Small animals Carnivore Ex : Frog

Tertiary Consumer

Carnivore or omnivore that feed on second consumer Ex : Snake, eagle


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Interaction between Biotic Components in

Relation to Feeding

Symbiosis

Means Living Together Permanent and close relationship between 2 or more different

species

There are three categories :

Commensalism Relationship between 2 species that benefits one species but

either benefits nor harms the other species

The organisms that benefits is call commensal while the others iscalled as host

Example :Epiphyte

o Green plantso Doesnt drive nutrition from its hosto Faces diffulties in getting water and minerals


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Epizoics

o An animal (commensal) attached to another animal (host)o Epizoics attached themselves to the bodies of their host

for free transport, protection and food leftovers from their

hosts meal

o Their host neither suffer loss nor benefits from theepizoicx

o Ex : Shark and remora fish, protozoa and Cyclops, Crab andbarnacles

Parasitism Relationship between two organisms where the parasite benefits

but the host is harmed

Two types :Endoparasites

o Tapeworms, flukes, plasmodium (causes malaria)o Adaptation :

1. No nervous system and sense organ2. No digestive tracts3. Have protective cuticle and anti enzymes4. Carrying out anaerobic respiration5. Great reproductive system


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Ectoparasites

o Have hook to attach themselves on their hosto Have sharp mouth part for hooking, sucking, bittingo Animal ectoparasites :

Pig lice, human hair lice, dog lice

o Plant ectoparasites :Have no leaves, stem or roots

Mutualism Relationship between two organisms which both benefits Lichen (kulampair) 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 onphotosynthesis.


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Rhizobium in the nodules of leguminous plantso Its convert atmospheric nitrogen into ammonium compounds that are

used by plants.

o In return, the bacteria get shelter and food from the plants. Microorganisms (protozoa & bacteria) and herbivores

o There are protozoa & bacterialiving in the alimentary canal ofherbivore, produce the enzyme cellulase to digest the cellulose of

plant material taken by host.o A large part of the sugar produced is absorbed by the host

herbivore. The balance is used by the microorganisms


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Saprophytism

Animals that feed on dead organic matter that has been digested Saprophytes produce enzymes to digest and decompose the dead

complex organic matter.

Saprophytes refer to plants which obtain food from decayedorganism matter

Saprozoites are microscopic animals that feed on decayedorganic matter

Prey-Predator Relationship

The relationship exists when a weaker animal is hunted and eatenby another stronger animal

This relationship is important to keep different animalspopulation of an ecosystem in balance


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Competition

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

Animalusually compete for food, shelterand breeding mates, whileplantscompete for space, light, nutrientsand water.

There are two types:Intraspecific competition.Occurs between members of the same species of plantsand animals to obtain their common basic needs.

Interspecific competition.Competition between individuals from different species.


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8.2 Colonisation and Succession in an

Ecosystem

An Ecosystem is a dynamic system formed by the interaction oforganisms with one another and with the non-living organisms.

It is a dynamics system where the living organisms are in balance witheach other and with the abiotic components.

Habitat Which an organisms live and obtains its basicresources

Species A group a organisms which can interbreed to

produce fertile offspringsPopulation Organisms of the same species living in the same

habitat in the same time

Community Diffrerent population of plants and animals livingand interacting in the habitat of an ecosystem

Niche The roles and activities of organisms in its habitat.Two organisms sharing the same habitat may have

different niche


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Colonisation and Succession

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

2. Later, some organisms will come to occupy the bare land The process in which living organisms arrive at a new habitat,

live, reproduce and take control of the habitat is known as

colonisation

The first species of organisms to colonise a new habitat iscalled the pioneer species

3. The pioneer species have special adaptions to survive in unfavourableland conditions

The pioneer species gradually changes the condition of thehabitat, making it no longer suitable for itself but more

suitable for other species called, the successor species.

Gradually, the successor species take place of the pioneer

space The process whereby a pioneer species is gradually replaced by

other successor species is called is succession

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

community


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Process of Colonisation and Succession in a

Mangrove Swamp

The environmental condition in the mangrove swamp which makeit unsuitable for habitation are:

i. Soft muddy soilii. Waterlogged soils which lacked oxygeniii. Seawater with high salt contentiv. Strong sunlight and extreme heat

Three types of mangrove tree which are involved in processcolonization and succession in mangrove swamp

i. Avicenna sp. and Sonneratia sp. (pioneer species)ii. Rhizophora sp. (successor)iii. Bruguiera sp. (successor)

Adaptive characteristic :i. A root system that spreads out widely to provide support

for mangrove tree

ii. Breathing roots that protrude out of the soil are calledpneumatophores.Enable gaseous exchange when

waterlogged soil

iii.

The leaves of mangrove trees have thick cuticle and sunkenstomata to reduce transpiration in a hot environment duestrong sunlight. The leaves are also thick and succulent tostore water

iv. Many mangrove trees have viviparity seed that begin togerminate while still attached to the parent tree. Thisensures that the seeds will get sufficient oxygen from the

atmosphere during germination and will not be suffocated


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for lack of air in a waterlogged environment. It alsoprevents the seed from dehydration in the highly saline seawater.

Avicenna sp. and Sonneratia sp. zone

The pioneer species in a mangrove swamp are the Avicennia sp. andSonneratia sp.

The Avicennia sp. grows in the part of the mangrove swamp that faces

the sea while Sonneratia sp. grows at the mouth of the river which issheltered.

The adaptations of the pioneer species to the soft muddy soil andwaterlogged area are as follows:

a)A root system that spreads out widely to give support to the treesin the soft muddy soil.

b)The Avicennia sp. and Sonneratia sp. have asparagus-shaped

pneumatophores that grows vertically upwards from the mainroots through the mud into the air. The pneumatophores are veryspongy and take in air for respiration of the root system.

Rhizophora sp. zone

This zone is higher and less waterlogged. The adaptations of Rhizophora sp. for this zone are as follows:

a) The Rhizophora sp. has prop roots to support and anchor the treein the soft muddy soil.

b) The Rhizophora sp. has viviparity seed to ensure that the

seedlings can grow and are not carried away by the seawater.


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Bruguiera sp. Zone

Trees of Bruguiera sp. grow well in hard clay soil that subjects toflooding during the high tide.

Trees of Bruguiera sp. have buttress roots for support and knee-shaped pneumatophores for gaseous exchange.

As more sedimentation of decayed substances occur, new mudbanks are being built up seawards while the old banks movefurther inland, away from the sea. The soil become harder and

dry land is formed.Finally, after a few hundred years, the process of succession

stops and a tropical rain forest, which is the climax community, isformed.

Avicennia sp. Bruguiera sp.


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8.3 Population EcologySampling Techniques The distribution of organisms in a community is affected by the

biotic factors and abiotic factors. A sampling technique is used to study the population size of an

organism. A sampling technique involves collecting, counting, and making

observations on the organism studied. Sampling is done at random and systematically. The sampling technique to estimate the population size of an

organism in a habitat is the capture-mark-release and recapture technique. The sampling technique to determine the distribution of plants in a

habitat is the quadrat sampling technique.

The Quadrant Sampling Techniques

The quadrant sampling technique is primarily used in estimating thesize of the plant populations.

The technique uses quadrant of specific size. A quadrant is a square frame made of wood, string or metal. The size of a quadrant used depends on the organisms being studied. Quadrant sampling is carried out at random in the habitat studied. The distribution of plants in a habitat being investigated is based on

the following aspects:a. Frequency = Frequency is the number of times a particular

species is found present when a quadrant is thrown acertain number of times.

b.Density = Density is the mean number of individuals of aspecies per unit area.


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c. Percentage coverage = percentage coverage is anindication of how much area of the quadrant is occupied bya species. The percentage is useful when it is not possible

to identify separate individuals.

The Capture, Mark, Release and Recapture Method

This method is used to estimate the population size of animals suchas garden snails and wood lice in a community.

In this technique, the first sample is the number of a certain animalis caught, marked and then released.

After a few days, a second sample is taken and recorded. Thenumber of individuals marked in the recaptured sample is countedand recorded.

Initially, a specific animal sample is captured and marked with a ring,a tag or with waterproof coloured ink, paint or nail varnish.

The population size of the animals in the area can be estimated usingthe formula below:


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8.4 The Concept of BiodiversityThe Hierarchy in the classification of organisms

Organisms are classified from kingdom (the largest) to thespecies(thsmallest) in the hierarchy system ofclassification.

Each kingdom is divided into phylum. Organisms in the samephylum have the same specific characteristics. These

characteristics differ from organisms in other phyla. Each phyla is then divided into class. Organisms in the sameclass have the characteristics but differ from organisms

in other classes. Subsequently, class is divided into order, order into

family,family into genus, and genus into species. Species ismost specific classification based on the hierarchy.

Nitrogen Cycle

The nitrogen cycle is important in maintaining the balance ofnitrogen content in the water, soil and atmosphere.

Microorganisms such as bacteria, fungi and algae playimportant roles in nitrogen cycle.

The main processes in the nitrogen cycle are:i. Nitrogen fixationii. Decompositioniii. Nitrificationiv. Denitrification

Nitrogen fixation Nitrogen fixation is a process by which nitrogen in the air is

converted to nitrogen compounds required for growth. The nitrogen in the air that is trapped in the soil is

absorbed by nitrogen fixing bacteria which convert it to

nitrogen compounds as nitrates.


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The nitrogen fixation process is carried out by nitrogen-fixing

bacteria and blue-green algae.

During thunderstorms, the energy of the lightning causesthe oxygen and nitrogen to combine to form oxide ofnitrogen. This gas involves in raindrops to form nitric acidwhich combines with the minerals in the soil to formnitrates and nitrites.

Decomposition

Bacteria and fungi that are saprophytes carry outdecomposition.

These decomposers (putrefying bacteria and fungi) breakdown the protein in dead plants and animals into ammoniumcompounds.

Nitrification

Microorganisms that are involved in the nitrification processare nitrifying bacteria such as Nitrosomonas sp. and

Nitrobacter sp. Nitrification is the process in which ammonium compounds

are oxidized to nitrites and then nitrates in two stages. The nitrates formed are absorbed by plants for growth.

Denitrification

Denitrification is the process which converts nitrates togaseous nitrogen.

The microorganisms involved in denitrification is thedenitrifying bacteria.

Through this bacterial process, nitrogen is returned to theatmosphere.

Microorganisms and its benefits in life

Microorganisms are microscopic organisms that cannot beseen with the naked eye.


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Microorganisms are all around us and affect our life. Microorganisms can be classified into five types based on

their basic characteristics.

i.

Protozoaii. Fungiiii. Algaeiv. Bacteriav. Virus

Abiotic components affecting the activity of microorganisms

The activities of microorganisms such as respiration, growth andreproduction is affected by the following abiotic components:

a. Temperatureb. pH levelc. Lightd. Nutrients

Temperature

The optimum temperature for the growth of mostmicroorganisms is 35C - 40C.

At temperature above 60C, most microorganisms die as thehigh

temperature is not suitable for growth and reproduction of microorganisms. This is because at very high temperatures, enzymes

(protein) in the microorganisms are denatured.

pH value

Every microorganism has it own optimum pH value. A slightly alkaline medium is more suitable for the growth

and reproduction of bacteria. A slightly acidic medium is more

suitable for the growth of fungi.


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A pH value that is too low or too high can inhibit growth anddestroy most microorganisms.

Light

Microorganisms that are autotrophs need light forphotosynthesis.

The activities of other microorganisms is inhibited under ahigh light intensity because the ultraviolet rays can destroythese microorganisms.

In the dark (low light intensity), growth and reproduction ofmicroorganisms such as fungi, bacteria and protozoa occur

actively.

Nutrients

Proper nutrients are required for the activities ofmicroorganisms.

Autotrophs such as the algae obtain its inorganic nutrientsfrom the surroundings.

Microorganisms that are heterotrophs obtain theirnutrients in the form of starch, fat, glucose and amino acis

by means of saprophytism or parasitism.

The role of useful microorganisms in the ecosystem

Decomposition

Decomposition of dead organic remains is carried out by agroup of saprophytic bacteria and fungi, which are called the

decomposers. Decomposers breakdown the dead remains of plants and

animals and waste products of animals and release nutrientsin the soil.

The nitrogen cycle

Nitrogen is an important element in the synthesis of plant and animalproteins.


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Plants can only absorb nitrogen in the form ammonium ions andnitrate ions.

Nitrogen fixing bacteria can convert atmospheric nitrogen to aform that can be used by plants.

For example, Nostoc sp. can be found freely in the soil andRhizobium sp. lives in the nodules of leguminous plants.

They fix atmospheric nitrogen and convert it into ammoniumcompounds.

When animals eat the plants, the organic nitrogenis transferred intothe body of the animals.

When the animals and plants die, decomposit produces ammonia thatcan be converted into nitrites(by Nitrosomonas sp.) and nitrates(byNitrobacter sp.) by nitrifying bacteria.

The denitrifying bacteria convert nitrates back into atmosphericnitrogen to complete the nitrogen cycle.

Alimentary canal of termites

The flagellated protozoa called Trichonympha sp. lives freely inmutualism in the alimentary canals of termites.

The protozoa secretes the enzyme cellulose to digest the celluloseinto simpler sugars which is then absorbed by the termite.

The protozoa enables the termite to digest cellulose which is foundin the wood it feeds on.

Digestive system in humans

The cellulose in humas is the undigested food which is channeled intothe caceum of the large intestine.

Useful symbiotic bacteria are found in the human colon. They synthesise vitamin B12 and vitamin K. A deficiency in vitamin

B12 can lead to anaemia while vitamin K is essential for bloodclotting.

The harmful microorganisms


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Harmful microorganisms are microorganisms that can causediseases, spoilage of food and other materials through theiractivities.

Microorganisms that cause diseases are called pathogens.

Organisms which transmit pathogens are called vectors. Examplesare mosquitoes, houseflies, lice and rats.

Other diseases that are transmitted by vectors are as follows:i. Elephantsiasis (caused by filarial worms) Culex

mosquitoesii. Typhus fever (caused by virus) liceiii. Plague rats

Uses of microorganisms in Biotechnology

Biotechnology is the development of techniques for the applicationof

biological process to produce materials used in medicine andindustry.

Microorganism plays an important role in biotechnology.

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Folio Biology Chapter 9