CHAPTER 8:DYNAMIC ECOSYSTEM

NAME: MUHAMMAD HAFIZUDDIN BIN HAJA NAZYMUDEEN

CLASS: 4 SCIENCE 4

SUBJECT: BIOLOGY

TEACHER NAME: PN.NORMA BT. SELIMIN

SCHOOL NAME: SEK. MEN. KEB. PUCHONG UTAMA (1)

2 .0 L IST OF CONTENTSNO. ARTICLE PAGE

LETTER

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1. 1.0 TITLE

2. 2.0 TABLE OF CONTENTS

3. 3.0 APPRECIATION

4. 8.0 DYNAMIC ECOSYSTEM(Chapter 8)

8.1.The Abiotic and Biotic Components of the Environment

8.2.The Colonisation and Sucession in an Ecosystem

8.3.Population Ecology

8.4.Biodiversity

8.5.Impact of Microorganisms on Life

5. 9.0. ENDANGERED ECOSYSTEM(Chapter 9)

9.1. Human Activities that Endanger an Ecosystem

9.2. The Greenhouse Effect and the Thining of the Ozone Layer

9.3. The Importance of Proper Management of Devolopment Activities and the Ecosystem

3.0 APPRECIATION

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First of all, thanks to my Biology teacher, Miss Norma Bt. Selimin 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 year’s 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 parents Haja Nazymudeen and Rabiyathul Basirya 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.

8.0 Biotic and Abiotic Components (CHAPTER 8)

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An ecosystem is a system formed by the interaction of living

organisms with one another and with their environment.

Examples of ecosystems are forest, grassland, pond, field, river, lake

and sea.

An ecosystem consists of two components:

a) Abiotic components (physical factors)

b) Biotic components (biological factors)

Abiotic components are the non-living components in the ecosystem

such as air, water, soil, temperature and light intensity.

Biotic components are the living components in the ecosystem such

as plants and animals.

8.1 The Abiotic Components

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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 pH value of the soil and water affects the distribution of

organisms.

a) Most organisms live in a neutral or nearly neutral environment

(pH6-7.5)

b) Some plants, like the maize, grows well in an acidic condition

while coconuts grow well in an alkaline condition.

Temperature affects the biochemical reactions in the organisms.

a) Organisms can live within a certain range of temperature.

b) Poikilotherms are animals that cannot control their body

temperature as their body temperature varies with the

environmental temperature.

c) Homoiotherms are animals that can maintain their body

temperature.

d) Plants and animals have specific characteristics to help them

adapt to areas of extreme temperature.

Light intensity affects the rate of photosynthesis.

a) The distribution of green plants will be more extensive in areas

with higher light intensity.

b) All organisms that live in soil prefer a dark environment.

Topography refers to the shape of the Earth’s surface.

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a) Topography of a place determines the temperature, light

intensity and humidity in an area.

b) Three tomography factors that affect the distribution of

organisms are altitude, slope(gradient) and aspects.

Microclimate refers to the climate in a small habitat such a the

climate in the soil and the climate below a tree trunk or a large rock.

a) Microclimate has specific temperature, humidity and light

intensity within its small habitat.

b) Each type of organisms finds a habitat that has a microclimate

that is suitable for it.

The biotic Component.

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The abiotic components are classified into three groups:

a) Producers

b) Consumers

c) Decomposers

The green plants are the producers because they can synthesise

food through photosynthesis.

Consumers are organisms that feed on plants or other organisms.

a) Primary consumers are herbivores that feed on plants

directly.

b) Secondary consumers are carnivores that feed on primary

consumers directly while tertiary consumers are carnivores

or omnivores that feed on secondary consumers.

Decomposers are the bacteria and fungi that break down dead

plants and dead animals into simple substances.

Food Chain, Food Web and Trophic Levels

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A food chain shows a sequence of organisms through which energy

is transferred.

Each stage in a food chain is known as a trophic level.

Through the food chain, organisms obtain energy.

In an ecosystem, several food chains interact to form a network

called a food web.

In a food chain, energy is transferred from one trophic level to

another trophic level.

When energy is transferred from one trophic level to another trophic

level as much as 90% of the chemical energy in the food consumed

is used for its metabolic activities and lost as heat, excretory products

and undigested matter.

Only 10% of the energy in an organism is passed on to the organism

at the next trophic level.

Pyramid Of Number

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A pyramid of numbers represents the number and size of organisms

in food chain

A food web consists of few food chains which were interconnected and depend on each other.It can represent a more precise food relationship in the ecosystem

Organisms need food to sustain the of living. Some organisms obtain food on their own while other organisms depend on other organisms to obtain food.

Interactions between biotic components

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Based on the feeding relationship, the interaction between biotic

components is divided into three main types which are symbiosis,

saprophytism and prey-predator interaction.

Interaction between Biotic Components

Symbiosis

symbiosis is an interaction between two organisms of different

species that live together.

in symbiosis, one organism will live in or with another organism called

the host.

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The organism that interacts with the host will benefit from the

interaction.

Symbiosis is further classified into three types:

a) Commensalisms

b) Paratism

c) Mutualism

i. Commensalism

Commensalisms is an interaction between two organisms where only

one organism benefits from the relationship. The other is neither

benefit nor harmed.

The organism that benefits is called the commensal while the other

organism is called the host.

Examples of commensal are epiphytes and epizoites.

Epiphytes are green plants which grow on other plants to obtain more

sunlight and for support.

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Examples of epiphytes are:

a) Pigeon orchid

b) Staghorn fern

c) Birds nest fern

Epizoites are animals that live in external surface of another animal.

The benefits that epizoites get from their hosts are transport,

protection and leftover foods from the mouth of the hosts.

Examples of epizoites are

a) remora fish which attaches itself to the shark

b) protozoa which attaches itself to Cyclops sp.(water flea)

c) barnacles which attach themselves to shells of crabs or snails.

ii. Parasitism

Parasitism is an interaction between two different organisms where

one organism called the parasite benefits and the other organism

called the host is harmed.

Two types of parasites:

a) Ectoparasites which live on the external body surface of the

host

b) Endoparasites which live in the body of their host.

Ectoparasites depend on their hosts for food, protection and

transportation.

Examples of ectoparasites that live on the bodies of animals are the

various types of flea and lice that feed on the blood of the host.

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Endoparasites that live in animals are the various types of worms

that live in the alimentary canals of their host and absorb nutrients

from the intestines of their hosts.

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Examples of mutualism:

a) Algae and fungi in lichen(both plants)

b) Hermit crabs and sea anemone(both animals)

c) Rhizobium bacteria and legume plants(one animal and one

plant)

In the interaction between sea anemones and hermit crabs, the sea

anemones attach themselves to the shells of hermit crabs.

a) Sea anemone obtains transport and leftover food from the

hermit crab

b) The hermit crab obtains protection from its predators because

of the poisonous tentacles of the sea anemone.

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Interaction between biotic components (DIET) – Saprophytism

Saprophytism is an interaction whereby an organism lives and feeds

on decaying organic matter.

Saprophytes refer to plants which obtain food from decayed organis

matter.

Examples of saprophtes are the various types of fungi such as

mushrooms, bread mould and bracket fungus.

Saprozoites are microscopic animals that feed on decayed organic

matter.

Some examples are paramecium sp. And amoeba sp. Which feed on

organic matter from dead organisms.

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Interaction between biotic components (DIET) – Prey – Predator

This is an interaction between two population of organisms in which

one organism, called the predator, hunts, captures and kills the other

organisms, called the prey, for food.

This interaction is a natural method to regulate the population size of

the prey.

The size of the prey is usually smaller than the predator but the

number of prey is always more than the predator.

However, the population sizes of both predator and prey fluctuate

together

a) When the population of a predator is high, the population of its

prey decreases because the prey are eaten by the predator.

b) When the population of the prey falls, there is insufficient food,

which results in a decline in the population of the predator.

c) When the population of the predator is low, the prey recovers

and its population increases. This will result in an increase in

the population of the predator.

The population sizes of both predator and prey are maintained in

dynamic equilibrium even as they fluctuate together. However, the

fluctuations in the predator population usually lag slightly behind

those of the prey.

The prey-predator relationship helps to control the population of

organisms in an ecosystem and maintain balance in nature.

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Interaction between biotic components (Competition)

Competition is the interaction between two organisms or

two populations to obtain common basic needs of life that

are limited.

The common basic need are space, water, minerals,

sunlight, food and mates for plants and animals.

In a competition, organisms which are strong will obtain

their common basic needs to survive and hence win in the

competition. The organisms which are weak will migrate to

other areas or die.

There are two types of competition:

a) Intraspecific competion

b) Interspecific competition

i. Intraspecific competition

Occurs between members of the same species of plants

and animals to obtain their common basic needs.

ii. Interspecific competition

Competition between individuals from different species.

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8.2.The Colonisation and Sucession in Ecosystem

Colonisation is a process of taking over of a new habitat by plants.

The first plant species to inhabit a new place is called a pioneer

species.

They have special adaptations that enable them to survive on dry

and nutrient-poor soil.

Pioneer plants are hardy plants which usually have dense root

systems to bind the sand particles and hold water and humus.

The pioneer species change the new habitat gradually to make the

habitat more suitable for another species to live.

As a result, the new habitat which is not suitable for the pioneer

species is then gradually replaced by another new species and

succession begins.

The process of succession is a process in which a certain

dominant plant species in a habitat is gradually replaced by another

plant species(successor species.)

These plants then become the new dominant species that can

grow faster and so they out-compete the pioneers which grow at a

slower rate.

Succession is a very slow and continuous process which occurs in

stages until a stable and matured community which is equilibrium

with the environment is formed.

The stable and matured community is called the climax

community. An example tropical rain forest in Malaysia.

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The Colonisation and Sucession in Mangrove Swamp

Mangrove swamps are found in tropical and subtropical regions

where freshwater meets salt water.

The environmental conditions in the mangrove swamp which make

it unsuitable for habitation are:

a) Soft muddy soil

b) Waterlogged soil which lacks oxygen

c) Seawater with high salinity(high salt content)

d) Strong sunlight and extreme heat.

There are three types of mangrove trees which are involved in the

process of colonisation and succession in a mangrove swamp:

a) Avicennia sp. and Sonneratia sp. (pioneer species)

b) Rhizophora sp. (successor)

c) Bruguiera sp. (successor)

Mangrove trees have adaptive characteristics to overcome the

problems it faces in the environment.

a) A root system that spreads out widely to provide support for

the mangrove trees in the soft muddy soil.

b) Breathing roots that protrude out of the soil and which are

called pneumatophores. In waterlogged soil, which lacks

oxygen the pneumatophores enable gaseous exchange occur

at the roots.

c) The leaves of mangrove trees have thick cuticle and sunken

stomata to reduce transpiration in a hot environment due to

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the strong sunlight. The leaves are also thick and succulent to

store water.

d) 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 for lack of air in

a waterlogged environment. It also prevents the seed from

dehydration in the highly saline sea water.

The profile of a beach in a mangrove swamp can be divided into

three zones according to the dominant flora.

a) Avicennia sp. and Sonneratia sp. (pioneer species)

b) Rhizophora sp. (successor)

c) Bruguiera sp. (successor)

i. Avicennia 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.

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ii. 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.

iii. 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 knee-

shaped 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.

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The Colonisation and Sucession in Pond

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8.3.Population Ecology

Quadrat Sampling Technique:-

A sampling technique is used to estimate the number and distribution of plants in a habitat.

A quadrat is a rectangular frame that is made from wood or metal and placed randomly to represent the plants in a habitat.

The estimated number and distribution will be more accurate if more quadrats are used.

Information from the quadrats can be used to determine the following.

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Capture, Mark , Release and Recapture Technique

This sampling technique is used to estimate the population of animals that move freely in a habitat.

The animals involved will be captured randomly and then marked and released into habitat.

The material used to mark the animals must not be poisonous, must be waterproof (so that it will last), must not restrict the movement and must not attract predators

The assumption made in this technique is that the animals will mingle in the habitat randomly until the second capture.They will not die or

move out of the habitat. The estimated size of the population of

animals can calculated by using this formula

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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 CharacteristicsMoneraExample: bacteria, cyanobacteria

Prokaryotes- cells without true nucleus, no nuclear membrane and membrane-bound organellesUnicellularMaybe autotrophs or heterotrophs

ProtistaExample: algae, protozoa

Eukaryotes- cells with nucleus and organelles surrounded by membraneAutotrophic (plant- like protists, algae) or heterotrophicMostly unicellular but some are multicellularNo specialization of tissues

FungiExample: yeast, mould, mushroom

EukaryotesMostly multicellullar and some unicellular (yeast)Plants without chlorophyllCell wall contains chitinEither saprophytes or parasitesMain body is made up of a network of hyphae called mycelium

PlantaeExample: ferns, mosses, flowering plants

MulticellularContains chlorophyllAutotrophsCell wall made up of celluloseHave specialized tissues- xylem and phloemImmobile

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AnimaliaExample: Fishes, reptiles, amphibians, birds, mammals

Multicellular organismsCell without cell wall and chloroplastsHeterotrophsMobileDigest their food internally

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The Hierarachy in the Classification of Organisms

The 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 Human being HibiscusKingdom Animalia PlantaePhylum Choradata TracheohytaClass Mammalia AngiospermaOrder Primates MalvalesFamily Hominidae MalvaceaeGenus Homo HibiscusSpecies sapiens Rosa-sinensis

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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 CharacteristicsBacteria The majority of bacteria range in

size from 0.5µm t0 5.0µm. Bacteria are unicellular 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 Algae are photosynthetic, plant-like organisms.

They are very simple organisms which contain chlorophyll.

Their cell walls are made up of cellulose.

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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 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.

Viruses 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

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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.

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Factors that Affect the Activities of Microorganisms

The 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.

pH

Each 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.

Temperature

Microorganisms 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 Intensity

Microorganisms 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.

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Role of Useful Microorganisms

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Harmful microorganisms

Pathogens are a microorganisms that can cause diseases. Vectors refers to organisms that transfer pathogen. A methods of transfer of diseases and how these diseases can be

prevented.

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Methods of Controlling Pathogens

There are many methods that can be used to control pathogens. Some of the methods used to control pathegons.

The Use of Microorganisms in Biotechnology

Biotechnology refers to the field that uses microorganisms. Some of the uses of microorganisms

a) To produce antibiotics and vaccinesb) To clean up oil spills in the sea by using certain types of

bacteria To decompose the oil to carbon dioxide and water

(biorecovery)c) To treat toxicated waste – convert waste into non – harmful

subtances which are released into the environmentd) To process food – yeast is used up in fermentation to produce

wine, beer and breade) To create energy from biomass – waste organic matter is

treated by anaerobic bacteria to produce biogas such as methane. Biogas is used as a domestic fuel.

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9.0. ENDANGERED ECOSYSTEM(Chapter 9)9.1.Human Activities that Endanger an Ecosystem

Human Activities Rapid development in the field of medicine, modern agricultural technology

and infrastructure increase the world population. Because of rapid development, human activities continue to increase.

Without careful planning, these activities will threaten the ecosystem. Human activities that can threaten other living things and the environment.

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Air Pollution

1. Air pollution occurs when pollutants (such as gas and particles) are released into the atmosphere.

2. The accumulation of these pollutants can have bad effect on living organisms and the environment

3. Some of the human activities which contribute to air pollution.

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Water Pollution

1. The release of solid or liquid waste into source of water such as rivers, lakes and seas can destroy aquatic organisms.

2. Some of the human activities that contribute to water pollution.

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Thermal Pollution

1. Thermal pollution occurs due to excessive loss of heat to environment.2. Pollution is harmful to living organisms and the environment.3. Examples of human activities that contribute to thermal pollution.

Noise Pollution

1. Noise pollution is caused by motor vehicles, agricultural machinery, industrial machinery and work at construction sites.

2. Continously exposure to loud sounds and more than 80 decibels (dB) in the long term can cause deafness.

3. Extreme noise can also cause stress – related problems such as high blood pressure, heart attacks, depression and headaches.

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9.2. The Greenhouse Effect and the Thining of the Ozone Layer

The Greenhouse Effect

1. Sunlight reaching the Earth will warm up the Earth.2. The heat produced will be reflected back to space as infrared radiation.3. The presece of greenhouse gases such as carbon dioxide,

chlorofluorocarbons (CFCs), methane, nitrogen oxides and ozone in the atmosphere will trap and reflect heat back to Earth`s surface.

4. Extensive human activities such as burning of fossil fuels and deforestation increase the amount of carbon dioxide and cause Earth`s temperature to increase.

5. The effect of the accumulation of greenhouse gases results in the melting ince and glaciers at the Poles thus increasing the sea levels. As a result, lowland areas will be flooded.

Thinning of the Ozone Layer

1. The ozone (O3) layer is a protective layer to humans and all living things from ultraviolet rays (UV) of the sun.

2. Thinnning of the ozone layer occurs as a result of the releaseof CFCs, chemical compounds containing chlorine (Cl), carbon (C) and fluorine (F).

3. CFCs are used widely in refrigeration system (such as refrigerators and air conditioners) and aerosol sprays (such as insecticide sprays and fire

extinguishers).

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9.3. The Importance of Proper Management of Devolopment Activities and the Ecosystem

Effect of Increasing Population

1. Rapid population growth requires additional of food, housing, education, medicine, energy, transport and other developments of infrastructure

2. Forests are cut down to provide areas for rapid development such as road construction, plantation, dams and residential areas to meet the demands of the population.

Managements of Development and the Balance of Nature

1. Planning for land or industrial development should be done carefully and long term effect on the environment should be considered,

2. The development of a country can be managed in the following ways:a) Implementation of laws to protect the natural resourcesb) The development of technology such as the use of lead – free fuels,

biomass fuels and sewage treatment to reduce and overcome the problem of environmental pollution

c) Education on the management of resource such as the 3R campaign (reduce,reuse and recycle) to manage the materials used

d) Preservation and conservation of the natural resources such as soil, water, flora and fauna of forest and mangrove

e) The efficient use of energy by using renewable energy such as solar energy

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f) Practising biological control to reduce the release of harmful chemicals in controlling pests

3. Protection of the ecosystem through beneficial activities to educate and enlighten the public to protect the environment by conducting campaigns.

The end of this chapter

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