Folio Biology Chapter 9

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Short note on biology chapter 9. One of the chapter in form 4 syllabus.

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SEKOLAH MENENGAH KEBANGSAAN SIMPANG PULAI

BiOLOgy F4

Dynamics Ecosystem
Name : Syahida Binti Ahmad Nizam Class : 4 Amanah (2013) Teacher’s name : Pn. Syakirah bt. Abdullah

8.1 The Abiotic and Biotic Components of the Environment
 An Ecosystem is a system formed by the interaction of living organisms with one another and with their environment  Abiotic Components : The non-living components in the ecosystem such as air, water, soil, temperature and light intensity  Biotic Components : The living components in the ecosystem such as plants and animals

Abiotic Components of an Ecosystem
 pH Value of the soil and water 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  Temperature a. Poikilotherms are animals that cannot control their body temperature varies with the surrounding temperature. b. Homoiotherms are animals that can maintain their body temperature.  Light intensity a. All organisms in the soil prefer dark environment.  Humidity of air a. Affects the rate of transpiration in plants and the rate of water evaporation from animals.  Topograpy Three topography that affects distribution of organisms are:

a. Altitude Less organisms at a high altitude because temperature, atmospheric pressure and air humidity are low. b. Gradient/Slope The gradient of a place affects the rate of water flow. c. Aspect Refers to the direction facing or opposing the wind and sunlight.  Microclimate a. Refers to the climate in a small habitat. b. Has specific temperature, humidity and light intensity

Biotic Component of an Ecosystem
Producer (1st trophic level)
 Can synthesis food through photosynthesis  Ex : Grass, paddy

Primary Consumer (2nd trophic level)
 Herbivores  Ex : Grasshopper

Secondary Consumer (3rd trophic level)
 Small animals  Carnivore  Ex : Frog

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

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 is called as host  Example : Epiphyte o Green plants o Doesn’t drive nutrition from its host o Faces diffulties in getting water and minerals

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 host’s meal o Their host neither suffer loss nor benefits from the epizoicx o Ex : Shark and remora fish, protozoa and Cyclops, Crab and barnacles

 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 organ 2. No digestive tracts 3. Have protective cuticle and anti enzymes 4. Carrying out anaerobic respiration 5. Great reproductive system

Ectoparasites o Have hook to attach themselves on their host o Have sharp mouth part for hooking, sucking, bitting o 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 on photosynthesis.

 Rhizobium in the nodules of leguminous plants o 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 & bacteria living in the alimentary canal of herbivore, 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

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 decayed organism matter » Saprozoites are microscopic animals that feed on decayed organic matter

Prey-Predator Relationship
» The relationship exists when a weaker animal is hunted and eaten by another stronger animal » This relationship is important to keep different animals population of an ecosystem in balance

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. • There are two types:  Intraspecific competition. Occurs between members of the same species of plants and animals to obtain their common basic needs.  Interspecific competition. Competition between individuals from different species.

8.2 Colonisation and Succession in an Ecosystem
 An Ecosystem is a dynamic system formed by the interaction of organisms with one another and with the non-living organisms.  It is a dynamics system where the living organisms are in balance with each other and with the abiotic components.

Habitat Species Population Community Niche

Which an organisms live and obtains its basic resources A group a organisms which can interbreed to produce fertile offsprings Organisms of the same species living in the same habitat in the same time Diffrerent population of plants and animals living and interacting in the habitat of an ecosystem The roles and activities of organisms in its habitat. Two organisms sharing the same habitat may have different niche

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 is called the pioneer species 3. The pioneer species have special adaptions to survive in unfavourable land conditions  The pioneer species gradually changes the condition of the habitat, 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 is formed. This type of community is known as the climax community

Process of Colonisation and Succession in a Mangrove Swamp
 The environmental condition in the mangrove swamp which make it unsuitable for habitation are: i. ii. iii. iv. Soft muddy soil Waterlogged soils which lacked oxygen Seawater with high salt content Strong sunlight and extreme heat

 Three types of mangrove tree which are involved in process colonization and succession in mangrove swamp i. ii. iii. i. ii. Avicenna sp. and Sonneratia sp. (pioneer species) Rhizophora sp. (successor) Bruguiera sp. (successor) A root system that spreads out widely to provide support for mangrove tree Breathing roots that protrude out of the soil are called pneumatophores. Enable gaseous exchange when waterlogged soil iii. The leaves of mangrove trees have thick cuticle and sunken stomata to reduce transpiration in a hot environment due strong sunlight. The leaves are also thick and succulent to store water Many mangrove trees have viviparity seed that begin to germinate while still attached to the parent tree. This ensures that the seeds will get sufficient oxygen from the atmosphere during germination and will not be suffocated

 Adaptive characteristic :

iv.

for lack of air in a waterlogged environment. It also prevents the seed from dehydration in the highly saline sea water.

Avicenna sp. and Sonneratia sp. zone

· The pioneer species in a mangrove swamp are the Avicennia sp. and Sonneratia 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 is sheltered. · The adaptations of the pioneer species to the soft muddy soil and waterlogged area are as follows: a) A root system that spreads out widely to give support to the trees in the soft muddy soil. b) The Avicennia sp. and Sonneratia sp. have asparagus-shaped pneumatophores that grows vertically upwards from the main roots through the mud into the air. The pneumatophores are very spongy 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 tree in 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.

Bruguiera sp. Zone  Trees of Bruguiera sp. grow well in hard clay soil that subjects to flooding during the high tide.  Trees of Bruguiera sp. have buttress roots for support and kneeshaped pneumatophores for gaseous exchange.  As more sedimentation of decayed substances occur, new mud banks are being built up seawards while the old banks move further 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, is formed.

Avicennia sp.

Bruguiera sp.

8.3 Population Ecology
Sampling 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 the size 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 a certain number of times. b. Density = Density is the mean number of individuals of a species per unit area.

c. Percentage coverage = percentage coverage is an indication of how much area of the quadrant is occupied by a 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 such as garden snails and wood lice in a community.  In this technique, the first sample is the number of a certain animal is caught, marked and then released.  After a few days, a second sample is taken and recorded. The number of individuals marked in the recaptured sample is counted and 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 using the formula below:

8.4 The Concept of Biodiversity
The Hierarchy in the classification of organisms  Organisms are classified from kingdom (the largest) to the species(thsmallest) in the hierarchy system of classification.  Each kingdom is divided into phylum. Organisms in the same phylum have the same specific characteristics. These characteristics differ from organisms in other phyla.  Each phyla is then divided into class. Organisms in the same class 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 is most specific classification based on the hierarchy. Nitrogen Cycle  The nitrogen cycle is important in maintaining the balance of nitrogen content in the water, soil and atmosphere.  Microorganisms such as bacteria, fungi and algae play important roles in nitrogen cycle.  The main processes in the nitrogen cycle are: i. Nitrogen fixation ii. Decomposition iii. Nitrification iv. 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.

 The nitrogen fixation process is carried out by nitrogenfixing  bacteria and blue-green algae.  During thunderstorms, the energy of the lightning causes the oxygen and nitrogen to combine to form oxide of nitrogen. This gas involves in raindrops to form nitric acid which combines with the minerals in the soil to form nitrates and nitrites. Decomposition  Bacteria and fungi that are saprophytes carry out decomposition.  These decomposers (putrefying bacteria and fungi) break down the protein in dead plants and animals into ammonium compounds. Nitrification  Microorganisms that are involved in the nitrification process are 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 to gaseous nitrogen.  The microorganisms involved in denitrification is the denitrifying bacteria.  Through this bacterial process, nitrogen is returned to the atmosphere. Microorganisms and its benefits in life  Microorganisms are microscopic organisms that cannot be seen with the naked eye.

 Microorganisms are all around us and affect our life.  Microorganisms can be classified into five types based on their basic characteristics. i. Protozoa ii. Fungi iii. Algae iv. Bacteria v. Virus Abiotic components affecting the activity of microorganisms The activities of microorganisms such as respiration, growth and reproduction is affected by the following abiotic components: a. Temperature b. pH level c. Light d. Nutrients Temperature  The optimum temperature for the growth of most microorganisms is 35°C - 40°C.  At temperature above 60°C, most microorganisms die as the high  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.

Light

 A pH value that is too low or too high can inhibit growth and destroy most microorganisms.  Microorganisms that are autotrophs need light for photosynthesis.  The activities of other microorganisms is inhibited under a high light intensity because the ultraviolet rays can destroy these microorganisms.  In the dark (low light intensity), growth and reproduction of microorganisms such as fungi, bacteria and protozoa occur actively.

Nutrients  Proper nutrients are required for the activities of microorganisms.  Autotrophs such as the algae obtain its inorganic nutrients from the surroundings.  Microorganisms that are heterotrophs obtain their nutrients 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 a group 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 nutrients in the soil. The nitrogen cycle  Nitrogen is an important element in the synthesis of plant and animal proteins.

 Plants can only absorb nitrogen in the form ammonium ions and nitrate ions.  Nitrogen fixing bacteria can convert atmospheric nitrogen to a form that can be used by plants.  For example, Nostoc sp. can be found freely in the soil and Rhizobium sp. lives in the nodules of leguminous plants.  They fix atmospheric nitrogen and convert it into ammonium compounds.  When animals eat the plants, the organic nitrogenis transferred into the body of the animals.  When the animals and plants die, decomposit produces ammonia that can be converted into nitrites(by Nitrosomonas sp.) and nitrates(by Nitrobacter sp.) by nitrifying bacteria.  The denitrifying bacteria convert nitrates back into atmospheric nitrogen to complete the nitrogen cycle. Alimentary canal of termites  The flagellated protozoa called Trichonympha sp. lives freely in mutualism in the alimentary canals of termites.  The protozoa secretes the enzyme cellulose to digest the cellulose into simpler sugars which is then absorbed by the termite.  The protozoa enables the termite to digest cellulose which is found in the wood it feeds on. Digestive system in humans  The cellulose in humas is the undigested food which is channeled into the 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 blood clotting. The harmful microorganisms

 Harmful microorganisms are microorganisms that can cause diseases, spoilage of food and other materials through their activities.  Microorganisms that cause diseases are called pathogens.  Organisms which transmit pathogens are called vectors. Examples are mosquitoes, houseflies, lice and rats.  Other diseases that are transmitted by vectors are as follows: i. Elephantsiasis (caused by filarial worms) – Culex mosquitoes ii. Typhus fever (caused by virus) – lice iii. Plague – rats Uses of microorganisms in Biotechnology  Biotechnology is the development of techniques for the application of  biological process to produce materials used in medicine and industry.  Microorganism plays an important role in biotechnology.

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