FORM 4 – CHAPTER 8: DYNAMIC ECOSYSTEM

Ecosystem- A biological community and the physical environment associated (related) with it. Examples of ecosystem: forest, sea, mangrove swamp.

Ecosystem consist of 2 components:A. Abiotic components (non-living)

(1) pH – pH value of soil and water affects the distribution of organisms. Mostly organisms only survive within certain range of pH, normally neutral (6.5 – 7.5)

(2) Temperature – temperature of an ecosystem can affect the biochemical reactions in the organisms. The normal range of temperature the most organisms can survive is from 0oC to 45oC. When the temperature > 45oC, enzymes denatured. When temperature is low, metabolic activities decrease.

(3) Light intensity – affects rate of photosynthesis. Plants distribution is more extensive in areas with higher light intensity. Organisms live in the soil normally prefer darker environment.

(4) Humidity of air – affects the rate of transpiration (plants) & rate of water evaporation (animals). The humidity increases, the rate of transpiration decreases (more water vapour in air, thus less water evaporated).

(5) Topography – shape of the Earth’s surface. 3 topography factors: altitude (ketinggian), slope / gradient (kecerunan) and aspects can affect the temperature, light intensity and humidity in an area.

(6) Microclimate – climate in a small habitat, e.g. climate below a large rock / climate in the soil, etc. Each type of organisms will find a habitat with microclimate that suitable for them.

B. Biotic components (the living organisms in the ecosystem)(1) Food chain (consists of producers, consumers, decomposers)

Groups of organisms Level of food chain (trophic level)

Producers (green plants) 1st trophic levelPrimary consumers (herbivores) 2nd trophic levelSecondary consumers (carnivores) 3rd trophic levelTertiary consumers (carnivores / omnivores) 4th trophic level

Decomposers (bacteria / fungi) break down plants and dead animals into simple substances that can be used by producers.

In an ecosystem, several food chain interact to form a food web. In a food chain, energy is transferred from one trophic level to another. Each time, 90% of energy are lost through excretion and defaecation during the transfer. Only 10% of available energy is passed to next trophic level. Energy released during cellular respiration is used for growth and movement, and as heat to maintain body temperature. The higher the trophic level, the smaller the population of organisms (the lesser the number of organisms).

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Vocabulary / notes

Poikilotherms – “cold-blood” animals such as fish, reptiles that cannot maintain their body temperature

Homoiotherms – “warm-blood” animals such as birds and mammals that can maintain their body temperature

paddy plants caterpillar birds hawks

(i) Arrange the above organisms into a pyramid of numbers. Label the trophic level in same diagram.

(ii) If the energy received by caterpillar is 300 000 kJ, what is the energy contained in paddy plants and energy transferred to hawks?

(2) Interaction in relation to feeding(i) Symbiosis : interaction between two organisms of different

species that live together. One organism live in/with another organism called the host.

3 types of symbiosis:a) Commensalism

One organism benefits (called commensal), another organism (host) does not benefits nor harmed. Plant commensals are called epiphytes. (e.g. money plant with tree, “Langsuya” plant with tree)Animal commensals are called epizoits. (e.g. remora fish with shark, barnacles with crabs)Example: Bird’s nest fern (epiphyte) grow on a big tree (host) to obtain more sunlight and for support (benefits) but the big tree is not harmed.

b) Parasitism One organism (parasite) benefits and one organism (host) is harmed.Parasites live on the external body surface of host is ectoparasites. (e.g. flea, aphid)Parasites live in the body of host is endoparasites. (e.g. worms)Example: cat flea (ectoparasite) lives on the body surface of cat and feed on the blood of the cat (host). Worms

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Vocabulary / notes

(endoparasite) lives in the alimentary canals of a kid (host) and absorbs nutrients from their intestines.

c) Mutualism Both organisms benefit.Example: algae and fungi in lichen (both plants); Rhizobium sp. Bacteria and legume plants; hermit crabs and anemones. Anemone obtains transport and leftover food from hermit crab. Hermit crab obtains protection from its predators because of the poisonous tentacles of the sea anemone.

(ii) Saprophytism : interaction where one organism lives and obtain its food from dead and decaying organic matter.

Saprophytes (plants) such as mushrooms, bread mould and fungus will grow on a decaying wood / tree trunk to obtain food, by releasing enzymes through their hyphae to the decaying organic matter to digest the food substances into simpler sugar, so that they can absorb the nutrients through hyphae.

(iii) Predator-prey interaction: interaction between 2 population – predator (pemangsa) and prey (mangsa). Predators gain benefits because it obtains food. Numbers of prey is usually more than predators, but their size is always smaller than predators.

Population of prey and predators fluctuate together. When the population of predator is high, population of prey decreases because preys are eaten by predator.

When population of prey is low, there is not enough food for predators so the population of predator declines (decreases).

When population of predator is low, the prey recovers and its population increases. As a result, population of predator also increases.

However, population sizes of both predator and prey are always maintained in a dynamic equilibrium. (refer page 179, Figure 8.4)

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Vocabulary / notes

(3) Interaction in relation to competition(i) Intraspecific competition: between members of same species of

plants / animals to obtain common basic needs

Example: maize (jagung) competes among themselves. Stronger individuals will grow taller, bigger in size/mass.(you can refer experiment 8.1)

(ii) Interspecific competition: between individuals from different species to obtain common basic needs.

Examples: maize competes with paddy plants. Stronger species will survive and grow better, with bigger mass/numbers of population.

Read about interspecific / intraspecific competition in Paramecium sp.(Do exercise in page 180, Activity 8.2)

Colonisation and succession in an ecosystem

The process of colonisation is a process which plants start to inhabit an uninhabited place.

Pioneer species is the first plant species that inhibit a new place. They have special adaptive characteristics to adapt to new environment. The pioneer species change the habitat gradually, making it more suitable for another new species. As a result, the habitat no longer suitable for pioneer species, eventually they are replaced by another new species, and succession begins.

The process of succession is a process which a dominant plant species in a habitat is gradually replaced by another plant species (successor species). Succession proceeds gradually stage by stage until a stable and matured community which is in equilibrium with the environment is formed.

This stable and matured community is called climax community, such as the tropical rainforest in Malaysia.

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Vocabulary / notes

Competition = interaction between 2 organisms / populations to obtain limited common basic needs of life.

Common basic needs = space, water, minerals, sunlight, food, mates

Vocabulary / notes

Niche = the status / role of an organism in its environment. It is defined by the types of food it consumes, and the activities it carries out.

Habitat = natural place where an organism lives.

Population = a group of organisms from same species living in same habitat

Community = populations of plants / animals that live in a certain habitat

(refer page 182-183, and Figure 8.7)

Colonization and succession in a pond

Colonisation: A process whereby a _____________ species invades and occupies a newly formed area where no life has existed previously.

Succession: The gradual process in which one community (________________ species) changes the environment so that it is replaced by another community.

Pioneer species ____________________ plants*Humus and soil eroded from the sides of the pond make the pond _________.*The condition becomes more favourable for __________________ plants.

Successor species _____________________ plants*The ______________ plants reproduce rapidly and cover the water surface. *The submerged plant dies, adding more ______________ matter to the base of the pond. *The pond becomes more shallower and unsuitable for _____________ plants.

Dominant species ____________________ plants*The _______________ plants replace floating plants. They are sometimes called amphibious plants. They grow at the banks of the pond. *Their extensive roots bind soil particles and spread rapidly. *When they die, their decomposed remains add to the ________________ of the pond. *This condition favours _________________ plants. *As time passes, land becomes _______________ and __________________ plants such as woody plants start to grow. *A primary forest, also known as a ___________ ________________ is eventually formed.

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Vocabulary / notes

Choices of words (some may use >1):

submergedpioneer shallower drieremergent herbaceous floating sediments terrestrial organic climax communitysuccessor

Colonisation and succession in a mangrove swamp

(also refer page 184, 185 and Figure 8.8)

Characteristics of mangrove swamps*found in tropical and subtopical regions, where freshwater meets salt water.*have soft, muddy soil with high salt concentration, low oxygen level, exposed to high light intensity.

Pioneer species _____________________, _______________________*Mangrove trees such as _____________________ and _________________ have extensive __________ systems that enable them to trap sediments, making the soil more _______________ and _______________.*Their roots also have thin, vertical breathing roots called ________________ which project above the water around the trees, to allow _______________ ______________ to take place. *This condition favours the successor species, which replace the pioneer species.

Successor species ________________________*The _____________________________ have ________ roots that trap silt and _________. *The soil becomes firmer, ___________ and higher.

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Vocabulary / notes

Choices of words (some may use >1):

compact rootmud Sonneratia sp. firm buttresspneumatophores tropical rainforest Rhizophora sp.propdrier less Avicennia sp. Bruguiera sp. gaseous exchange

*The soil is now more suitable for the dominant species.

Dominant species _______________________________*The __________________________ have _________________ roots that trap more silt and mud. *More sediments and deposited, the soil structure is modified. *The soil is more suitable for terrestrial plants to grow. Examples of terrestrial plants: Pandanus sp., nipah palm. *Eventually the terrestrial plants form terrestrial forest, then a ___________ __________________ (climax community) is formed after hundreds years.

Population Ecology= a branch of ecology that study the structure and dynamics of populations.

1.Population is a group of organisms of the same ______________ occupying a particular habitat. 2.Methods to estimate the total population size of organisms: a) for plants: ____________________________________________________b) for animals: ___________________________________________________

Quadrat sampling technique1.Quadrat is typically a square frame made of __________ and ___________.

The Capture, Mark, Release and Recapture technique1.This technique is for small and _________________ animals. 2.The specific animal sample is captured, and marked with a _____________, a _________ or with _____________________________________________.Then, the marked animals are _______________ into the general population. After a suitable period of time, a second sample is recaptured, and the number of marked animals is recorded.

Try this

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Frequency = number of quadrats containing the species x 100% Number of quadrats

Density = total umber of individuals of a species in all quadrats Number of quadrats x quadrat area

Percentage coverage = __aerial coverage of all quadrats (m 2 ) x 100% Number of quadrats x quadrat area

(number of individuals captured in first sample) x Population size = __(number of individuals captured in second sample) Number of marked individuals recaptured

Vocabulary / notes

In an experiment to estimate the population of woodlice in a habitat, the number of woodlice caught and marked is 120. The woodlice were then released. After 3 days, another 100 woodlice were caught and found that 40 of them were marked. What is the estimated population of the woodlice in the habitat? (show your workings)

BiodiversityRefers to the _____________ species of plants and animals interacting with one another on Earth. Taxonomy is about identifying, describing and naming organisms.

Classification of organisms are based on their basic features. There are 7 hierarchy in the classification of organisms.

Kingdom Phylum Class Order Family Genus Species

There are 5 kingdoms based on the classification:

Monera-prokaryotic organisms (unicellular, have cell walls, no membrane-bounded nuclei or organelles, some photosynthetic, some non-photosynthetic) -examples: bacteria, cyanobacteria (the blue-green algae)

Protista-eukaryotic organisms-unicellular, a few multicellular -have membrane-bounded nuclei or organelles-some heterotrophic, some autotrophic, some both-examples: algae (Spirogyra sp., Chlamydomonas sp.) Protozoa (Amoeba sp., Paramecium sp.)

Fungi-multicellular eukaryotes, some unicellular -heterotrophic (saprophytic)-have cell wall that contains chitin-do not contain chlorophyll-have root-like structure called _____________. The layer of hyphae is called _____________________. -examples: moulds (Mucor sp.), mushrooms, yeasts.

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Vocabulary / notes

Vocabulary / notes

Kingdom KayPhylum PohClass CiOrder OppaFamily FamousGenus GangnamSpecies Style!

Each organism is given a scientific name (Latin words) according to the Linneaus binomial system, which the first name is the Genus name in Capital letter, while the second name is the species name in small letter. The Genus sp. Name is written in italic.

Eukaryotic organisms = eukaryotes Prokaryotic organisms = prokaryotes

Plantae-multicellular photosynthetic eukaryotes-all land plants-immobile-examples: mosses, ferns, conifers, flowering plants.

Animalia-multicellular heterotrophic eukaryotes-mobile (can move from one place to another place)-examples : sponges, barnacles, fishes, reptiles, birds, mammals.

Importance of biodiversity-to maintain a ____________________ nature-to prevent ______________________ of flora and fauna

Impact of microorganisms on Life5 groups of microorganisms :

Bacteria-unicellular organisms , mostly prefer slightly alkaline conditions (7.4) -have cell wall, plasma membrane, DNA-forms __________________ under unfavourable condition-shapes: spherical (coccus), rod-shaped (___________________), spiral (spirillum)-Guess the shape of Lactobacillus sp. - _________________ Shape of Staphylococcus sp. - __________________________

Algae-photosynthetic multicellular plant-like organisms- have chlorophyll and chloroplasts- have cell wall made of ___________________- no leaves, no stems, no roots.-Examples: ______________________, ________________________

Fungi-heterotrophic multicellular / unicellular eukaryotes-do not have chlorophyll, prefer acidic condition (pH 4.5 – 5.0)- have cell wall that made of _______________- saprophytic : secreting enzymes to convert complex organic molecules into simpler molecules then absorb it. -Examples: ______________________, _______________________

Protozoa-unicellular, mostly prefer acidic condition (pH 4.5 – 5.0) -have nucleus, cytoplasm, plasma membrane.-carry out living process (___________________, ____________________, _______________________) -use _____________________, ________________ or _________________ to move.

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Vocabulary / notes

Kingdom KayPhylum PohClass CiOrder OppaFamily FamousGenus GangnamSpecies Style!

Each organism is given a scientific name (Latin words) according to the Linneaus binomial system, which the first name is the Genus name in Capital letter, while the second name is the species name in small letter. The Genus sp. Name is written in italic.

Eukaryotic organisms = eukaryotes Prokaryotic organisms = prokaryotes

Vocabulary / notes

Microbes = microorganisms

Abiotic factors that affects activities of microbes: -nutrients -pH-temperature(optimum 35-40oC, >60oC, growth of microbes inhibited,>121oC, microbes & their spores are destroyed/sterilized) -light intensity(preferable dark / low light intensity, except algae & photosynthetic bacteria)

All microbes need water and nutrients except viruses.

Choices of words:Spirogyra sp.bacillussporescellulosereproductionflagellaphytoplanktonMucor sp.chitin excretionpseudopodiayeastrespirationciliaAmoeba sp.

-Examples: ________________________, _____________________________

Viruses-smallest microbes (cannot be seen by naked eyes, only be seen under electron microscopes)-does not carry out living process-‘parasitic’ must infect and use living cells to reproduce-virus is protected by a _________________ coat. -virus can form ___________________ under unfavourable condition.-Examples: ________________________, __________________________

Useful microorganisms in ecosystem

1. Decomposition -break down the dead remains of animals & plants-break down waste products from animals-release nutrients into the soil-saprophytic bacteria & fungi

2. Nitrogen cycle

(a) Nitrogen fixation:- Nitrogen gas in atmosphere is converted into ammonium compound

in soils by ___________________________________ bacteria.- Nostoc sp. (exist freely in soil); Rhizobium sp. (lives in nodules of

leguminous plants)(b) Nitrogen nitrification:- Conversion of ammonium compounds into nitrites and nitrates by

_______________________ bacteria.- Ammonia/ ammonium compound (products from decomposition) is

converted into nitrites by _________________________.

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Vocabulary / notes

Microbes = microorganisms

Abiotic factors that affects activities of microbes: -nutrients -pH-temperature(optimum 35-40oC, >60oC, growth of microbes inhibited,>121oC, microbes & their spores are destroyed/sterilized) -light intensity(preferable dark / low light intensity, except algae & photosynthetic bacteria)

All microbes need water and nutrients except viruses.

Choices of words:Spirogyra sp.bacillussporescellulosereproductionflagellaphytoplanktonMucor sp.chitin excretionpseudopodiayeastrespirationciliaAmoeba sp.

Vocabulary / notes

Choices of words:atmospheric nitrogennitrogen fixing Nitrosomonas sp.organic nitrogenNitrobacter sp.nitrifying

- Nitrites are converted into nitrates by __________________________.

(c) Assimilation:- Nutrients such as nitrates are absorbed by the plants via roots and

converted into proteins. - The ____________________________ is transferred from plants to

animals via food chain. - Eventually it is returned to soil as ammonium compound through

decomposition.(d) Nitrogen denitrification :- Nitrates are converted back into ______________________________

to complete the nitrogen cycle.

3. Alimentary canal of termites- Termites feed mainly on wood which contains cellulose.- Trichonympha sp. are protozoa that lives in the alimentary canal of

termites which produce cellulose to help termites digest the cellulose.

4. Digestive system in humans:- Symbiotic bacteria in human colon helps to synthesize vitamin B12

(deficiency can cause anemia), vitamin K (for blood clotting).

Harmful microorganismsHarmful microorganisms that can cause diseases are called _______________.Organisms that transmit the pathogens are called _____________.

Ways of spreading diseases: 1. Direct contact:

-contagious diseases are can be spread by having contact with an infected person. E.g. sharing towels (ringworm), sexual intercourse (STD, AIDS)

2. Vectors :-diseases spread by organisms, such as malaria caused by protozoa named Plasmodium sp. is transmitted by the mosquito (Anopheles sp.)-cholera is spread by houseflies.

3. Airborne and droplet transmission:-pathogens in spores form transmitted by air. -liquid droplets of infected person enter other people’s respiratory system.

4. Food and water:-entry of pathogens into alimentary canal through contaminated food and water. (example: cholera)

Methods of controlling pathogens:

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Vocabulary / notes

Choices of words:atmospheric nitrogennitrogen fixing Nitrosomonas sp.organic nitrogenNitrobacter sp.nitrifying

Vocabulary / notes

Choices of words:

vectorpathogens

1. Vaccines: -injection / inoculation of a suspension (contains dead / weaken pathogens) into the body to induce production of antibodies. (e.g.BCG)

2. Antibiotics :- Chemicals that extracted from the microbes such as Penicillin and

streptomycin, which inhibit the growth or kill other microbes such as bacteria.

3. Disinfectants :- Solutions used to kill microbes on the non-living things (floor,

equipments, buildings), or used to sterilize surgical instruments. Example of disinfectants: phenol, formaldehyge, carbolic acid.

4. Antiseptics: - Used on surface of skin / living things, to kill and inhibit growth of

microbes. E.g. acriflavin, iodine solution.

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Vocabulary / notes

Choices of words:

vectorpathogens