ACKNOWLEDGEMENTFirst of all, thanks to my Biology teacher, Miss Siti Hanani for being such good guider for us while we were doing this task. She had given us appropriate example and knowledge in order to make us understand more about this ecological study. We take some idea from the past years students work. She spends her time to carry out each and every experiment related to this ecological study. She also makes sure that we understand everything she told and gives some explanation before we begin to work on these practical assessments. I also appreciate the school authority for giving us permission to carry out experiment in school laboratory and going our quadrates and transect sampling technique in school ground. School also provided all the apparatus and materials that we used in the ecological study task. I also want to thank to my classmates who are willing to share their information about this ecological study. They give me a lot of ideas about the tasks and I use all their information especially in transect sampling technique which required us to work together in order to complete the ecological study folio.Also, a great thanks to my family who tried their best to give their support either by giving me a lot of encouragement for keep us with this task or by supporting the financial for use to pay all the cost required to complete this ecological study.

IntroductionEcology is the scientific study of the way that living organisms interact with their environment. Ecology comes from the Greek words oikos, means housing and logos, means logic or knowledge. The term was coined by German zoologist (scientist who studies animals) Ernst Haeckel in 1870. While many people confused the work of an ecologist with an environmentalist. There are significant differences between the two occupations. Environmentalist seeks to preserve natural systems while ecologists may shared the ideals of environmentalists, are mainly involved with gathering the information about the communities of animals and plants, as well as the physical elements (such as rocks and soil) present in a given geographical area.

8.1 The Abiotic and Biotic Components of The EnvironmentAn environment consists of living organisms and non-living organisms. The living organisms in the environment are called biotic components and the non-living components are called abiotic components. In any ecosystem, abiotic components such as pH, temperature, light intensity, humidity, topography and microclimate determine the population size and distribution of the biotic components.

The Abiotic Components (a) pH value

The pH value of the soil and water has a significant effect on the

distribution of organisms that live in a habitat. Most organisms can survive well in a neutral or nearly neutral environment. Aquatic organisms are sensitive to the effects of the pH of water and may kill if the changes in pH are considerable. Certain plants such as pineapple plants prefer acidic soil, while other plants such as coconut grow well in alkaline soil.

(b) Light Intensity Light intensity affects the distribution and growth of plants and animals. The

sun is the source of energy for photosynthesis in plants. The varying intensities of sunlight in a forest result in the growth of different types of plants. For example, tall trees that are exposed to high intensity of sunlight from the canopy of a forest , while plants such as ferns and vines survive under the cover of shady trees. Birds, tree frogs and bats are some of the animals that live under the canopy. At the ground level, where light intensity is low, mosses and animals such as ants and earthworms thrive. Bacteria and fungi that live in the soil decompose organic material.

(c) Temperature Temperature affects the physiology activities of plants and animals. Most

living organisms can only tolerate a narrow range of temperature. Usually, they survive within the temperature range 0 C to 45C. A drop in temperature within a certain range usually results in a decrease in the metabolic activities of the organisms. Temperatures higher than 45C usually cause enzymes to be denatured. However, there are some species of organisms that can live under extreme temperature. For example, thermophilic bacteria can survive in hot springs. Aquatic environment undergo less extreme temperature changes and therefore provide more stable habitats than terrestrial environments.

(d) Humidity Humidity is the amount of water vapour present in the air. The humidity of

air affects the rate of water loss by plants and animals. When the humidity is low, water evaporates from the moist surfaces at a faster rate. Humidity

is usually higher at night but lower during the day. Organisms such as snakes, grogs, liverworts and mosses prefer humid areas. Some organisms regulate their activities to prevent dehydration. For instance, woodlice are usually found under stones and rotting tree stumps.

(e) Topography

Topography is the variety of shapes found on the landscape determined by slopes, elevation, and aspects. The topography of grassland ecosystems is a varied landscape of gently rolling hills and prairies, rock outcrops, cliffs and low lying areas. Diverse topography is what gives incredible variety to grassland ecosystems. Aspects refer to the direction in which a piece of land is facing. Areas that face towards the south or the sun are hotter and drier than areas that face north or away from the sun. The slope of an area is the angle at which the land lies. Slope is important in our grassland as water may run downhill rather than soak into the ground where it is available for plants. An area that slopes with a southern aspect will be much drier than other hotter area that slopes with a northen aspects. Elevation describes the height of land above sea level. Temperatures are generally cooler and rainfall is higher as elevation is gained.

Gradient or the steepness of a slope is another topographic factor. Steep

slops result in rapid drainage and run-off. Therefore, the soil layer is thinner and drier. Hence, this area is not suitable habitat for organisms.

(f) Microclimate

Microclimate refers to the climate in a microhabitat. For example, underneath a rock. Microclimate includes the humidity, temperature, light intensity and atmospheric conditions of a habitat where organisms live.

The Biotic Components

The biotic components refers to living organisms in an ecosystem which are grouped as producers, consumers and decomposers. These organisms interact and are interdependent. In an ecosystem, the primary source of energy for all organisms comes from sunlight. Green plants are called producers because they use light energy to synthesis organic substances (food). They also absorb nutrients from the soil, storing them for future use by themselves and by other organisms. Consumers are organisms that do not have the ability to capture the energy produced by the sun. They consume plant or animal material to gain their energy for growth and activities. There are three types of consumers divided based on their ability to digest plant and animal material: Herbivores eat only plants, such as goat and cow. [Primary consumers] Omnivores eat both plants and animals, such as black bear and rats. [Tertiary consumers] Carnivores eat only animals, such as tiger, snake and hawk. [Secondary consumers]

Decomposers such as bacteria and fungi are microorganisms that break down waste products and dead bodies of other organisms into simpler substances to be used again by plants. Tertiary consumer Secondary consumer

Primary consumerProducer

A pond ecosystem

Food Chain, Food Webs and Trophic LevelsFood chain shows a sequence of organisms through which energy is transferred. It usually starts with a producer and ends with a top consumer. Each organism is the food of the next organism in the chain is known as trophic level. The food chains in a community are usually interconnected to form a food web.

In a food web, the source of energy is sunlight. Green plants convert solar energy into chemical energy which is stored in food during photosynthesis. When a primary consumer feeds on the producers, some of the energy stored in the plants is passed on to the primary consumer, which later passes its energy to the secondary consumer. In this way, energy flows through a food web.

Interaction Between Biotic ComponentsIn an ecosystem, organisms interact with one another in order to survive.

SYMBIOSISSymbiosis is a close relationship between two or more different species whish live closely together and interact with each other. Symbiosis relationships can be classified into 3 categories: Commensalism

Mutualism Parasitism

Commensalism- interaction between one organism (commensal) benefits andthe other (host) neither benefits nor is harmed. The remora fish attaches itself to the shark to get free transport, protection and scraps of food left by the shark. The shark does not benefit from this relationship.

A shark and a remora fish Commensalism is also shown by epiphytes which grow on branches of trees but do not obtain nutrients from the trees.

Mutualism- interaction between two species of organisms in which bothorganisms benefit.

Lichens A lichen is a mutualistic relationship of an alga and a fungus. The green alga

produces food for itself and for the fungus. In return, the fungus supplies carbon dioxide and nitrogenous compounds for the alga to manufacture its own food.

Parasitism- interaction between two organisms in which one organism (parasite)benefits and the other (host) is harmed. Ectoparasites are parasites that feed on the external surface of a host. Endoparasites are parasites that live within the tissue of their host.

flea A flea obtained their food and shelter from the host.

SAPROPHYTISMSaprophytism is a type of interaction in which living organisms obtain food from dead and decaying organic matter. Examples of saprophyte are saprophytic bacteria, mucor species and mushrooms.

Mushrooms growing on decaying wood

PREY-PREDATORPrey-predator interaction occurs when an organism, the prey, is haunted and eaten by a stronger and bigger organism called the predator.

A tiger and a rat

COMPETITIONCompetition is an interaction between organisms which live together in a habitat and compete for the same resources that are limited supply. Plants always compete for light, nutrients, water and space while animals compete for food, shelter and breeding metes. The competition between individuals of different species is known as inter specific competition. The competition between individuals of different species is called inter specific competition.

Trees in the rain forest compete to gain sunlight

8.2 Colonisation and Succession in an EcosystemEcosystemAn ecosystem is a community of organisms which interact with their non-living environment and function as a unit. It is a dynamic system where the biotic components are well balanced with one another and with the abiotic components. Ecosystem is vary in size.

Example of ecosystem

Habitat Habitat is a natural environment where organisms live. A habitat providesorganisms with the basic resources of life such as food, shelter, living space, nesting sites and mates.

Habitat of Polar Bears

Species A species is a group of organisms that look alike and have similar characteristics, share the same roles in an ecosystem and are capable interbreeding to produce fertile offspring.

Population A population is a group of organisms of the same species living in the same habitat at the same time. Populations contain genetic variation within themselves and between other populations.

Community Several populations of different species living in the same habitat in an ecosystem is called community. The members of the community are interdependent and interact with one another in order to survive. A change in any of the populations will affect the distribution or other populations.

Colonisation and Succession

Ecosystem undergoes changes in their structure and function as time passes. These changes can be caused by changes in climate, external factors such as fires, pollution and development. Colonisation takes place in newly formed areas where no life previously existed. For example, very few species can survive in an environment of sand and stones since it stores little water and has few available nutrients. The first coloniser is called pioneer coloniser. They have special adaptations that enable them to survive on dry and nutrient-poor soil. Pioneer species are hardy plants which usually have dense root system to bind the sand particles and hold water and humus. They have a short life cycle. When they die, their remains add to the humus content of the soil. Hence, the pioneer species modify the environment, eventually creating conditions which are less favourable to themselves. Instead, they establish conditions that are more conducive to other species, which are called successor species. These plants grow bigger than the pioneer species, thus reducing the amount of sunlight that reaches them and gradually replacing them. Most of these plants have small winddispersable seeds which are able to spread and growth rapidly. The successor species also change the structure and quality of the soil, making it more conducive for larger plants to grow. These plants then become the new dominant species that can grow faster and so they out-compete the pioneer which grow at a slower rate As time passes, the dominant species in turn modify the environment which allows larger trees to grow. The larger trees out-compete the shrubs, which are replaced by forest-floor species which required lower light intensity. The gradual processes through which one community changes its environment is called succession. Succession is a very slow and continuous process which occurs in stages. Ecological succession leads to a relatively stable community which is equilibrium with its environment. This is called climax community. A climax community is a stable community that undergoes little or no change in its species composition. Hence, succession stops at the climax stage, assuming that the environment does not change.

The Process of Succession

Mangrove Swamps.

Mangrove swamps are found in tropical and subtropical regions where freshwater meets salt water. They are characterised by soft, muddy oil with a high concentration of salt and very low levels of oxygen. In addition, mangrove swamps are exposed to a high intensity of sunlight. There are 2 types of mangrove trees: (a) Avicennia sp. - have long underground cable roots that support them in the soft and muddy soil and protect them from strong coastal winds. - produce hundreds of thin, vertical breathing roots called pneumatophores which project above the water around the trees.

(b) Rhizophora sp. - have prop roots, aerial roots that not only anchor the plants to the mud, but also plant an important role in aeration. - aeration can take place through lenticels found on the tree bark Rhizophora sp.

The presence of this species gradually changes the physical environment of the habitat. The extensive root systems of these plants trap and collect sediments, including organic matter from the plant parts. As time passes, the soil becomes more compact and firm. This condition favours the growth of Rhizophora sp. Gradually the Rhizophora sp. replaces the pioneer species. The prop root system of the Rhiizophora sp. traps silt and mud, creating a firmer soil structure over time. The ground becomes higher. As a result, the soil is drier because it is less submerged by sea water. The condition now becomes more suitable for the Bruguiera sp., which replaces the Rhizophora sp.

The buttress root system of the Bruguiera sp. forms loops which extend from the soil to trap more silt and mud. As more sediment is deposited, the shore extends further to the sea. The old shore is now further away from the sea and is like terrasterial ground. Over time, terrestrial plants like nipah palm and Pandanus sp. begin to replace the Bruguiera sp.

8.3 Population Ecology Population ecology is a branch of ecology that studies the structure and dynamics of populations. In the study of an ecosystem, it is often important to study the size of the populations. A population is defined as a group of organisms of the same species occupying a particular habitat. For example, a population of frog in a paddy field refers to all the frogs in the paddy field. The population size of an organism is affected by: (a) abiotic factors of the environment (b) biotic factors (c) rates of birth and death (d) immigration and emigration of organisms Methods to study population ecology: (a) Quadrat sampling technique to determine the density, frequency and percentage coverage of plants. (b) Capture, mark, release and recapture method to estimate the population size of animals.

Quadrat Sampling Technique A quadrat is a square frame made from wood, metal or rope and can be subdivided into smaller squares within. The size of the quadrat used (1mx 1m, 10cmx10cm) depends on the plant population under study. In this technique, a number of quadrats are randomly placed in a particular area to study the population of one or more plant species. The distributions of the plants species under study can be determined by:

(a) Density- the number of individuals per unit area (not suitable for plants which reproduce vegetatively)

Quadrat Number of species X Area of quadrat = 1mx1m=1m2 Density = = = 11 individuals per m2

1 2 3 4 12 10 15 8

5 10

(b) Frequency- the number of times a particular species is found from all quadrats used

Quadrat Presence of species Y key: = present X = absent

1 2 3 4 5 X

Frequency = = x 100% = 80%(c) Percentage coverage- how much of an area is covered by a particular species in percentage

Percentage =

X 100%

Capture, Mark, Release and Recapture Method This method is used to estimate the population size of animals that move freely in an area. For example, the population of garden snails in a garden and the population of woodlice under a tree. Initially, a number of animals are captured at random and marked with a ring, a tag or with nontoxic and waterproof coloured such as Indian ink or cellulose paint so they will not be washes off by rain. The marking must not injure the animal, hinder their movement or make them more conspicious to predators. The marked animals are then released into the general populations and allow to mix with those that are unmarked. After a period of time (days or weeks), a second capture is carried out at random. The total number captured in the second sample and the number of marked animals recapture are recorded.

Population size = Example: First captured: 50 animals caught and then marked Second captured: 20 unmarked animals and 20 marked animals caught Population size = =100

Assumption made in this method to estimate the population size of an organism The population is stable and does not change during the time of investigation. The manner used to mark the animals does not harm or kill the animals or make them obvious to predators. Recapture is done randomly. The marked animals are allowed to mix freely with the other animals in the habitat. The marked animals have the same probability of being captured.

Abiotic factors that affect the distribution of an organisms

Light intensity Temperature Humidity Ph

(a) pH value The pH value of the soil and water has a significant effect on the

distribution of organisms that live in a habitat. Most organisms can survive well in a neutral or nearly neutral environment. Aquatic organisms are sensitive to the effects of the pH of water and may kill if the changes in pH are considerable. Certain plants such as pineapple plants prefer acidic soil, while other plants such as coconut grow well in alkaline soil.

(b) Light Intensity Light intensity affects the distribution and growth of plants and animals. The

sun is the source of energy for photosynthesis in plants. The varying intensities of sunlight in a forest result in the growth of different types of

plants. For example, tall trees that are exposed to high intensity of sunlight from the canopy of a forest , while plants such as ferns and vines survive under the cover of shady trees. Birds, tree frogs and bats are some of the animals that live under the canopy. At the ground level, where light intensity is low, mosses and animals such as ants and earthworms thrive. Bacteria and fungi that live in the soil decompose organic material.

(c) Temperature Temperature affects the physiology activities of plants and animals. Most

living organisms can only tolerate a narrow range of temperature. Usually, they survive within the temperature range 0 C to 45C. A drop in temperature within a certain range usually results in a decrease in the metabolic activities of the organisms. Temperatures higher than 45C usually cause enzymes to be denatured. However, there are some species of organisms that can live under extreme temperature. For example, thermophilic bacteria can survive in hot springs. Aquatic environment undergo less extreme temperature changes and therefore provide more stable habitats than terrestrial environments.

(d) HumidityHumidity is the amount of water vapour present in the air. The humidity of air affects the rate of water loss by plants and animals. When the humidity is low, water evaporates from the moist surfaces at a faster rate. Humidity is usually higher at night but lower during the day. Organisms such as snakes, grogs, liverworts and mosses prefer humid areas. Some organisms regulate their activities to prevent dehydration. For instance, woodlice are usually found under stones and rotting tree stumps.

8.4 Biodiversity Biodiversity refers to the wide variety of plant and animal species on Earth.

Organisms are classified based on their common characteristics into five Kingdoms as shown.

Kingdom and examples Characteristics Monera Prokaryotes- cells without Example: bacteria, cyanobacteria true nucleus, no nuclear membrane and membranebound organelles Unicellular Maybe autotrophs or heterotrophs Protista Example: algae, protozoa Eukaryotes- cells with nucleus and organelles surrounded by membrane Autotrophic (plant- like protists, algae) or heterotrophic Mostly unicellular but some are multicellular No specialization of tissues Eukaryotes Mostly multicellullar and some unicellular (yeast) Plants without chlorophyll Cell wall contains chitin Either saprophytes or parasites Main body is made up of a network of hyphae called mycelium Multicellular Contains chlorophyll Autotrophs Cell wall made up of cellulose Have specialized tissuesxylem and phloem Immobile Multicellular organisms Cell without cell wall and chloroplasts Heterotrophs

Fungi Example: yeast, mould, mushroom

Plantae Example: ferns, mosses, flowering plants

Animalia Example: Fishes, reptiles, amphibians, birds, mammals

Mobile Digest their food internally

The Hierarachy in the Classification of OrganismsThe classification of millions of organisms on Earth into only five kingdom means each kingdoms is made up of a large number of organisms. Therefore, it is necessary to divided each kingdom into smaller groups. The kingdom is the largest unit of classification and contains the largest number of organisms. A kingdom can be divided into a number of phyla (singular: phylum). Organisms in the same phylum have some characteristics in common which is different from organisms in other phyla. For example, all animals in the phylum Arthropoda have jointed legs and a chitinuos exoskeleton. These characteristics differentiate them from organisms in other phyla.

A phylum can be subdivided into a number of classes, each class can be subdivided into orders, each order into families, each family into genera (singular: genus), and each genus into species. Species is the smallest group in the system of classification. They are classified into 7 levels, namely kingdoms (alam), phylum, class, order, family, genus and species. (Aphycofags) The hierarachy of classification is the stages of groupings in the system of classification from kingdom to species. Hierarachy in the classification of humans and the hibiscus plant:

Classification Kingdom Phylum Class Order Family

Human being Animalia Choradata Mammalia Primates Hominidae

Hibiscus Plantae Tracheohyta Angiosperma Malvales Malvaceae

Genus Species

Homo sapiens

Hibiscus Rosa-sinensis

Importance of BiodiversitySource of biological products- forces such rainforests provide raw materials for medicine, for example, in the treatment of cancer, food for organisms and economic resources (timber, rubber, organic oils) Important of Biodiversity Provide shelter and food for the variety of interacting organisms in an ecosystem. Diversity in genetic pool gives rise to genetic variation and new species.

Provide environmental services- regulation of atmospheric temperature, and gases ( O2, CO2 and N2), pollination and recycling of nutrients.

8.5 Impact of Microorganisms on Life Microorganisms are tiny organisms that can only be seen clearly under a microscope. Most microbes are harmless and useful to humans while others can cause diseases in plants and animals, including humans. Microorganisms are divided into five types, namely viruses, bacteria, algae, protozoa and fungi.

Types of organisms Bacteria

Characteristics The majority of bacteria range in size from 0.5m t0 5.0m. Bacteria are unicellular

Algae

organisms which have a basic cell structure that includes a cell wall, plasma membrane and DNA that is not enclosed in a membrane. Bacteria cell walls are made of a unique polymer called peptidoglycan which is made up of protein and a complex polysaccharide. They form spores under unfavourable conditions. Bacteria can be spherical (coccus), rod-like (bacillus), spiral (spirillium) or comma-shaped (vibrio). Certain bacteria have a slimy capsule outside their cell wall for extra protection. Examples of bacteria are Lactobacillus sp. and Staphylococcus sp. Algae are photosynthetic, plant-like organisms. They are very simple organisms which contain chlorophyll. Their cell walls are made up of cellulose. They have no leaves, stems or roots. Examples of algae are phytoplankton and Spirogyra sp.

Fungi

Microscopic fungi are heterotrophic microorganisms whichdo not have chlorophyll, stems, roots or leaves. Fungal cell walls are made of chitin. Fungi feed by secreting enzymes that break down

the surrounding organic material into simple molecules before absorbing them. Examples of fungi are yeast and Mucor sp.

Protozoa

Viruses

Protozoa are unicellular organisms. Protozoa have a nucleus, cytoplasm and a plasma membrane. They can carry out life processes such as respiration, reproduction and excretion. They move by using flagella, cilia or microtubules. Examples of protozoa are Euglena sp., Paramecium sp ,Trypanosoma sp. A virus is the smallest microorganism and can only be seen under an electron microscope. A virus is non-living cell because it cannot survive or reproduce on its own outside the cells of its host. All viruses are infectious. They must infect living cells to reproduce. Since a virus does not have its own cellular machinery, it must utilise the cellular machinery of the host to make copies of itself. Each type of virus has two basic parts: an inner core which is composed of nucleic acid, either DNA or

RNA, and an outer capsid of protein sub-units. Viruses can be purified and crystallised. Examples of viruses are T4bacteriophage and tobacco mosaic virus. Bacteriophages are viruses that are parasitic on bacteria while the tobacco mosaic virus causes the tobacco mosaic diseases.

The Effect of Abiotic Components on The Activity of MicroorganismsThe activity of microorganisms is affected by abiotic components such as the: (a) Concentration of nutrients (b) pH (c) Temperature (d) Light intensity

Nutrients and water

Microorganisms need nutrients and water for reproduction and growth. Without nutrients or water, microorganisms will die or form spores.

pHEach species of microorganisms has an optimum pH. Most bacteria prefer slightly alkaline conditions (pH around 7.4) while moulds, yeast and protozoa prefer acidic conditions (pH around 4.5-5.0). Extreme pH can kill the microorganisms.

TemperatureMicroorganisms are inactive at low temperatures. The optimum temperature of most microorganisms is between 35 C-40 C. Beyond 60 C, the growth of microorganisms is inhabited. Microorganisms and their spores can only be destroyed when they are sterilised at a temperature of about 121 C.

Light IntensityMicroorganisms prefer dark or low light densities. High intensities of sunlight or ultraviolet rays can kill algae and bacteria are more active under high light intensities because they need light to carry out photosynthesis.

Role of Useful Microorganisms in the EcosystemNITROGEN CYCLE.

Atmospheric nitrogen cannot be absorbed directly by plants. Plants can only use nitrogen in the form of ammonium, nitrate or nitrite ions which they can absorb from the soil. Nitrogen-fixing bacteria such as Nostoc sp., which live freely in the soil and Rhizobium sp., which live in the root nodules of leguminous plants, can assimilate atmospheric nitrogen into ammonium compounds through a process called nitrogen fixation. Nitrates, in particular, are readily taken up by plant roots and converted into plant proteins. When animals eat plants, the organic nitrogen is transferred into the body of the animals and becomes animal protein. Waste matter, plants and animals die, decompose and then are converted into ammonium compounds. Ammonium compounds are converted into nitrites and nitrates by nitrifying bacteria through a process called nitrification. The cycle is balanced by a continuous return of nitrogen to the atmosphere by denitrifying bacteria through denitrification. These bacteria break down nitrates into gaseous nitrogen and oxygen. The oxygen is used by the bacteria while the nitrogen is returned to the atmosphere.

DECOMPOSITION Decomposers are organisms that secrete digestive enzymes to break down organic matter and animal wastes into simple molecules, such as carbon dioxide,

water and ammonium compounds. These molecules can be used by autotrophs such as green plants. Saprophytic bacteria and fungi are the main decomposers in and ecosystems which return the nutrients contained within the remains of organic matter to the atmosphere, soil and water. Without them, the nutrients stored in the dead bodies cannot be used to enrich the soil. As a result, the soil would become less fertile and can no longer sustain plant life and the community on the whole.

8.6 Appreciating BiodiversityThe biodiversity around us should be conserved and preserved because of their importance to all living organisms through the following method: Reinforcement of laws to protect wildlife species and ecosystems. Designate areas as forest reserves and national parks Educate people (schools and societies) on the importance of biodiversity Prevent hunting and discourage the buying of goods made from animal parts or plants.