Dynamic Ecosystem

CHAPTER 8

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8.1 The Abiotic and Biotic Component of the Environment

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The abiotic component

The non-living components such as1.pH value – soil and water2.Light intensity – as source of energy 3.Temperature 4.Humidity – amount of water vapour present in

the air5.Topography – physical features of land (altitude,

gradient and aspect of region)6.Microclimate – climate in a microhabitat

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The biotic component

The living organisms in the environment such as

Producers – synthesise organic substances (plants)

Consumers – eat other organisms (primary consumer, secondary consumer, tertiary consumer)

Decomposers – microorganisms that break down waste products and dead bodies (bacteria and fungi)

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Food chain, food web and trophic levels

Food chain - sequence of organisms through which energy is transferred. Each stage - trophic level

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Food chain, food web and trophic levels

Food web – food chain interconnected. Energy flows through food web and lost when it transferred from one level to another level

of the trophic levels in the form of heat

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The interaction between biotic component in relation to feeding

Organisms interact with one another in various ways such as

Symbiosis Saprophytism Prey-predator

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Symbiosis

close relationship between two or more different species which live closely together and interact with each other

three categories: Commensalism

Mutualism Parasitism

Commensalism One species (the commensal) benefits, the other

(the host) don’t get benefits nor is harmed E.g. epiphytes grows on branches of trees

Mutualism Relationship between two species of organisms in

which both benefit E.g. bacteria in the digestive system of human

Commensalism

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One species (the commensal) benefits, the other (the host) don’t get benefits nor is harmed

E.g. epiphytes grows on branches of trees

Mutualism Relationship between two species of organisms in

which both benefit E.g. bacteria in the digestive system of human

Parasitism

Relationship between two organisms in which one organism (the parasites) benefits from the other organism (the host)

Two types: Ectoparasites – live on the surface of the host (e.g. ticks

and fleas) Endoparasites – live inside the body of the host (e.g.

tapeworms)

Prey-predator10

Relationship where an organism which is smaller, called the prey, is haunted and eaten by a stronger animal, the predator

E.g. an owl (predator) and a rat (prey) The interaction takes place in a cycle that

keeps the populations of both organisms in a dynamic equilibrium

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The interaction between biotic component in relation to competition

Competition – interaction between organisms living together in a habitat and competing for the same resources that are limited supply Two types: Intraspecific – competition between the same species

Interspecific – competition between different species

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8.2 Colonisation and Succession in an Ecosystem

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Ecosystem

A community of organisms which interact with their non-living environment & function as unit.

Vary in size. Have level of organisation:

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Organism

Species

Populations

Communities

Ecosystem

Species – a group of organisms that have similar characterisitics, share the same roles in an ecosystem and are capable of

interbreeding. Population – a group of organisms of same

species living in the same habitat at the same time.

Community – several different species living in the same habitat in an ecosystem

Niche – role of an organism in ecosystem

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Colonisation and succession

Colonisation takes place in a newly formed areas where no life previously existed.

The first organism occupy a newly formed area are called pioneer species.

Characteristics:1.Hardy plant that have dense root system (grass)2.Short life-cycle They modify and creating more conducive

condition to other organisms

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Second species came after the pioneer species are the successor species.

Characteristics:1.Bigger than pioneer species (herbs)2.Have small wind-dispersal seeds (to spread and

grow rapidly) They change the structure and quality of the

soil and creating more conducive condition for larger plants to grow.

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Third and permanent species are the dominant species (shrub).

Modify the environment for larger trees to grow.

Succession – the gradual process through which one community changes its environment to be replaced by another community.

Climax community – ecological succession leads to relatively stable community (equilibrium with its environment)

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8.3 Population Ecology

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population ecology

A branch of ecology that studies the structure and dynamics of population.

Population density – number of organism per unit area of habitat

Affected by abiotic and biotic factors, birth rate, death rate, immigration and emigration.

Direct counting – method to estimate the size and density of population (impractical due to the size of ecosystem, the number of plants involved and the movement of the animal).

Sampling technique – more practical way, enable us to estimate the total population size of the organism.

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The quadrat sampling technique

Used in estimating the size of plant population and immobile animal.

A quadrat – metal, wooden frame or PVC pipe frame which form a square of a known area (1 m2).

Placed randomly in an ecosystem where sampling is carried out.

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Frequency – number of times a particular species is found present when a quadrat is thrown a certain number of time

Density – the mean number of individuals of species per unit area

Percentage coverage – an indication of how much the area of quadrat is occupied by a species

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The capture, mark, release and recapture technique

Used to estimate mobile animals (small mammals, butterflies, birds and insects)

Procedure:1.Animal sample is captured 2.Marked 3.Released4.Second sample captured & number of marked animal recorded.

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8.4 Biodiversity

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What is meant by biodiversity…

The diverse species of plants and animal interacting with one another on Earth.

Need to be classified because there are many organisms in this world.

Classification of Organisms

Taxonomy – branch of Biology concerned with identifying, describing and naming organisms.

Systematic method of classifying plants and animal based on the similarities in their characteristics.

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Classification of Organisms

Organisms can be classified into 5 major kingdom:1.Monera / Prokaryotae 2.Protista 3.Fungi 4.Plantae 5.Animalia

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The hierarchy in the classification of organisms

7 hierarchy levels1.Kingdom2.Phylum3.Class4.Order5.Family6.Genus 7.Species

The number of organisms at each levels decreases

Naming of organisms is based on Linnaeus binomial system.

Each organism has two names in Latin – first name is the name of genus (begins with capital letter) & second name is the name of species (begins with small letter)

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E.g. Mimosa pudica – Mimosa refers to the genus and pudica refers to the species.

Specific names are written in italic or underline.

E.g. Mimosa pudica or Mimosa pudica

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The importance of biodiversity

Provide various biological products – food, medicine, timber, etc.

Provide many environmental services – nutrient cycle, pollination, etc.

Give diversity in the genetic pool.

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8.5 The impact of Microorganisms on Life

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Microorganism Tiny living things that only can be seen

using microscope Classified based on their characteristics

(appearance, shape, size, method of reproduction, nutrition and habitat)

Classified into 5 groups:1.Viruses – smallest microorganisms, not a living

cell and must use living cells to reproduce. (E.g. HIV, Influenza virus etc.)

2.Bacteria – unicellular organisms, have cell wall, form spores under unfavourable condition and have 3 common shape à spherical, rod-shaped and spiral. (E.g. Lactobacillus sp., Straphyloccous sp. etc.)

3.Protozoa – unicellular organism, have plasma membrane and can carry out living processes. (E.g. Amoeba sp., Paramecium sp. etc.)

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4.Algae – have chlorophyl and chloroplast, can undergoes photosynthesis process. (E.g. Spirogyra sp.)

5.Fungi – heterotrophic microorganisms, feeds by secreting enzymes that break down the surrounding organic material into simple molecule before absorb them. (E.g. Mucor sp., yeast etc.)

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The role of useful microorganisms in the ecosystem

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The harmful microorganisms

Microorganisms that cause diseases are called pathogens

Pathogens are classified as parasites or saprophytes

They cause diseases in two ways:1.Produce poisonous chemical2.Attack and destroy host cells and body tissues

Transmission of diseases1.Air2.Water3.Food4.Vectors5.Direct Contact6.Indirect Contact

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Controlling pathogens

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The uses of microorganisms in biotechnology

Biotechnology – application of biological processes in the manufacturing and servicing industries

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Appreciating Biodiversity

• Through conservation and preservation.

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Endangered Ecosystem

CHAPTER 9

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9.1 Human Activities that Endangered an Ecosystem

Pollution Pollution - Any undesirable change in the natural

environment caused by pollutant. Pollutant – substance that cause pollution Pollution – being make dirty Types of environmental pollution:1. Air pollution2. Water pollution3. Soil pollution4. Pollution caused by solid waste and hazardous

(dangerous) waste5. Noise pollution

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Air pollution

Air pollution is responsible for major health effects.  Every year, the health of countless people is ruined or endangered by air pollution.

Many different chemicals in the air affect the human body in negative ways.  Just how sick people will get depends on what chemicals they are exposed to, in what concentrations, and for how long.

Studies have estimated that the number of people killed annually in the US alone could be over 50,000.

Older people are highly vulnerable to diseases induced by air pollution.  Those with heart or lung disorders are under additional risk.  Children and infants are also at serious risk.

Because people are exposed to so many potentially dangerous pollutants, it is often hard to know exactly which pollutants are responsible for causing sickness.  Also, because a mixture of different pollutants can intensify sickness, it is often difficult to isolate those pollutants that are at fault.

Many diseases could be caused by air pollution without their becoming apparent for a long time.  Diseases such as bronchitis, lung cancer, and heart disease may all eventually appear in people exposed to air pollution.

Air pollutants such as ozone, nitrogen oxides, and sulfur dioxide also have harmful effects on natural ecosystems.  They can kill plants and trees by destroying their leaves, and can kill animals, especially fish in highly polluted rivers.

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Water pollution

Boston Harbor is a strong example of how badly pollution can damage bodies of water.  The water is filled with toxic waste and sewage, and routinely receives more waste when rainfall pushes it into the harbor.

Many bodies of water near urban areas are highly polluted.  This is the result of both garbage dumped by individuals and dangerous chemicals legally or illegally dumped by industries.

The main problem caused by water pollution is that it kills life that inhabits water-based ecosystems.  Dead fish, birds, dolphins, and many other animals often wind up on beaches, killed by pollutants in their habitat.

Pollution disrupts the natural food chain as well.  Pollutants such as lead and cadmium are eaten by tiny animals.  Later, these animals are consumed by fish and shellfish, and the food chain continues to be disrupted at all higher levels.

Eventually, humans are affected by this process as well.  People can get diseases such as hepatitis by eating seafood that has been poisoned.

Ecosystems can be severely changed or destroyed by water pollution.  Many areas are now being affected by careless human pollution, and this pollution is coming back to hurt humans.

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Soil pollution

Not enough oxygen in the soil, acidy soils that may burn the plant, bugs will go and start an infestation in the soil, it effects plants growth, the soil pollution eats away at the nutrients and

becomes a bigger soil polluter, not enough drainage, new soil diseases develop every year, not enough moisture in the soil.

Noise Pollution

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Noise pollution disturbs our health and behavior in a number of ways including deafness causing lack of sleep, irritability, indigestion, heartburn, high blood pressure, ulcers, and heart disease. Just one noise explosion from a passing truck drastically alters our endocrinal, neurological, and cardiovascular functions in many individuals. If this is prolonged or frequent, the physiological disturbances become chronic and contribute to mental illness.

Sometimes, even low levels of noise are irritating and can be frustrating, and high volumes can be annoying. Natural sounds are less irritating than those we find uncontrollable but intermittent sounds such as a tap dripping water can be more irritating than the sound of falling rain.

Noise more than 50dB can be very difficult to hear and interpret and cause problems such as partial deafness.

Increased noise levels gives rise to a lack of concentration and accuracy at work, and reduce one’s productivity and performance. Difficult tasks can be impaired, and instructions or warnings difficult to be heard and interpreted, causing accidents.

The Greenhouse Effects and the Thinning of the Ozone Layer

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Greenhouse effect.

Occur when greenhouse gases accumulates in the atmosphere to form a layer of gases

Greenhouse gases – carbon dioxide, chlorofluorocarbon, nitrogen oxides, methane and water vapour

The layer of gases trap the Sun’s heat around the world

Greenhouse effect cause the global warming

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Ozone layer

located in the atmosphere. consist of ozone molecules which made up of three

oxygen atom (O3). act as protective shield that absorb the Sun’s

harmful UV radiation

Thinning of ozone layer

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Main cause - chlorofluorocarbon (CFC)

CFC – man made gases used as refrigerant (substance that make things cold or freeze) and propellants (compressed gas that forces out the content of an aerosol container)

CFC when exposed to UV radiation will release chlorine atom which can break down ozone molecules in chain reaction causing the ozone layer become thinner

The Importance of Proper Management of Development Activities and the Ecosystem

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The need for development and the effects of an increasing population on the ecosystem

The increasing in population cause the increase in development.

Development interfere the balance in nature. Unplanned and unmanaged development cause

environmental problems. Proper management of development activities are

important

The importance of proper management of development activities

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Natural resource are non-renewable means once they have been used they cannot be replaced.

They need to be manage in proper ways to maintain balance in nature.

Uncontrolled use of the natural resources will cause them to be used up.

The importance of proper management of development activities

Carry out sustainable development to balance the demands and the needs for resources with the need to conserve the resources.

Measures taken in the management of development activities

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1. Implementation of laws2. Use of technology3. Education on the management of resources4. Preservation and conservation activities5. The practice of biological control

BY IDZY_93

MRSM MELAKA49

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