folio biology chapter 9
TRANSCRIPT
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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.