Topic 8
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Transcript of Topic 8
CHAPTER 8DYNAMIC ECOSYSTEM
ECOSYSTEM COMPONENT
BIOTIC COMPONENT
ABIOTICCOMPONENT
ABIOTIC COMPONENTThe non living components
of an ecosystem
pH value
Temperature
Light intensity
Humidity
Water Topography
Microclimate
pH value
Temperature
• affects the physiological activities of organisms
• most of organisms cannot tolerate extremes temperatures
• the pH value of soil and water has important effect on the types of organisms
• a drastic change in pH may kill the organisms
Light intensity
• affects the distribution and growth of organisms
• the sun is the source of energy
• some plants show adaptation to reach the light
• most animal need sunlight but some show adaptation to live in the dark
Humidity
• is the amount of water vapour in the air
• plant and animal that live in wet have special adaptation
Water
• important for living process in all organisms
• but some organisms are able to survive under condition where there is a limited supply of water such as camel and cactus
Microclimate
• Refers to local climate in a small area
• Humidity, temperature and light intensity affect the microclimates
Topography
• influence local climate and soil development
• the main factor is altitude and aspect
• higher altitude : lower atmospheric pressure and temperature so different plants growing at different altitude
• sloppy areas receive more sunlight compared to valley
•Gradient : steepness of a slope cause a faster drainage and run off the water
BIOTIC COMPONENTSThe living components
in an ecosystem
Producers Consumers
Decomposers
Producers
• mainly green plants
• manufacture complex organic food substances from raw materials
•Convert light energy → chemical energy
• affect the lives of other organisms because they start the food chain and food web
Consumers
• Obtain their energy from the other organisms they feed on
• Cannot make their own food : heterotrophs (herbivores, carnivores, omnivores, saprophytes or decomposers )
Decomposers
• break down dead organisms through the decomposition process
• the product in this process is returned to environment and will used again by green plants
• saprophytic fungi and saprophytic bacteria
CLASSIFICATION OF BIOTIC COMPONENTS INTO TROPHIC LEVEL
Food chain
• A series of organisms through which energy is transferred in the form of food
• trophic level - each stages in the food change and can be shown in the form of pyramid number
• pyramid number show the interaction between a producers and consumers and the number of organisms
• during food transfer from one trophic level to next level a lot of energy is lost ( through undigested matter, excretory products, lost as heat during respiration)
• 90% : energy is lost
• 10% : transfer from one trophic level to the next
Food web
• in a community, food chains are linked together to form a food web
• gives a more complete picture of the feeding relationship in a community
Pyramids of numbers
INTERACTION BETWEEN ORGANISMS
Symbiosis Saprophytism Prey-predator Competition
Commensalism Mutualism Parasitism
Symbiosis
• Interaction in which there is a close and permanent relationship between two specific organisms.
• One species : benefits
• One species : unaffected, harmed or helped
Symbiosis
Commensalism • ( + , 0 )• example - clown fish & sea anemones - pigeon orchid
Mutualism
• ( + , + )
• example
- lichens
- root nodules
Parasitism
• ( + , - )
• example
- flea
- tapeworm
+ : benefits0 : neither benefit nor harm- : harm
Epiphytes(plant)
Epizoics(animal)
Ectoparasite Endoparasite
Lichens (alga + fungus)
Alga : produces foods for itself & fungus
Fungus : supplies CO2 &
nitrogenous products
Mutualism
Root nodules (bacteria & plant)
Nitrogen fixing bacteria :
convert Nitrogen into ammonium
Plant : provide energy-rich organic
compounds
Saprophytism
A type of interaction in which living organisms obtain food from dead and decaying organic matter
Enzymes are secreted onto the food and digestion occurs outside the cell
Example : saprophyte (plant) : fungus saprozoite (animal) : earthworm
Prey-predator(+ ,- )
• predator
- kills other animal for food
- larger and fewer in number than its prey
- the number of predator affects the
size of prey population
• prey
- the animal that kill by the predator
- must be able to protect itself from being killed
• example : owls & snakes, frogs & snakes
prey
predator
Time
Number
• In favourable condition, population of prey increases and followed by an increase of predator’s population
• When the population of prey decreases owing to increasing of predation and spread of diseases, the population of predator decreases.
• This interaction takes place in a cycle that keeps the populations of both organisms in a dynamic equilibirium
Competition
An interaction between organisms which live together in a habitat and compete for the same resources that are
in limited supply
Intraspecific
Competition between individuals of the same species
Compete for light, water, space and nutrients
Example : Bryophyllum sp
Interspecific
Competition between individualsof different species
Example : paramecium aurelia& paramecium caudatum
Bryophyllum sp
Paramecium aurelia and Paramecium caudatum.
Intraspecific competition
Interspecific competition
Number
the winner
the loser
Time
ECOSYSTEM
• An ecological system formed by the interaction of living organisms and their non-living environment
• Example : Mangrove swamp, desert, marine, forest
THE PROCESS OF COLONISATION AND SUCCESSION IN AN ECOSYSTEM
COMMUNITY
• Several populations of different organisms living together within the same habitat
• represent biotic components of an ecosystem
•Example : various group of organisms living in forest
POPULATION
• A group of individuals of the same species occupying the same habitat
• expressed by density
•The rate of change of a population density depends on birth rate, death rate and migration
SPECIES
•A group of closely related organisms which are capable of interbreeding to produce fertile offspring
ECOSYSTEM
COMMUNITY
POPULATION
SPECIES
HABITAT
• The place where the organism lives
• organism obtain its food, shelter and reproduces in its habitat
• example : ponds, rivers, forests
• within an ecosystem there will be several habitats
• microhabitat : smaller division of an a habitat
NICHE
• Is the function of an organism or the role it plays in the habitat
• organisms can live in the same habitat but they occupy different niches
• includes its habitat, its interaction, the types of food it consumes, the range of temperature it tolerate and the spaces it occupies
•Example : a caterpillar and aphid live in the same habitat (caterpillar eats the leaf but aphid sucks sap from the leaf)
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COLONISATION & SUCCESSION IN DISUSED PONDS
How does a disused pond become tropical rainforest ?
Mangrove swampPond
LEARNING OUTCOMES
• Explain the process of colonization,• Explain the process of succession,• Identify the successors in an ecosystem,• Identify the dominant species in an ecosystem• Identify the adaptive characteristic of pioneer species,• Identify the adaptive characteristics of successors,• Explain the changes in habitat caused by pioneer
species,• Explain the changes in habitat caused by successors at
every level of succession until a climax community is reached,
• Relate the abiotic components with the biotic components in an ecosystem during the processes of colonization and succession.
COLONISASION• Occurs in newly formed areas where no life
previously existed • The first colonisers : pioneer species• Special adaptation of pioneer species
1) hardy plant 3) have good dense root system (bind sand particles and hold water + humus)4) have short life cycle5) when die, their remains add to humus
content• Examples : grasses, ferns & sedges
SUCCESSION• The process in which one community changes its
environment so that it is replaced by another community
• The gradual & continuous process• Leads to a final and stable community which is in
equilibrium with its environment and is known as climax community
• Successor species : a series of plant that replaced the pioneer species (herbaceous plant)
• Successor : 1) grow bigger than pioneer thus reduced the
amount of sunlight 2) have small wind- dispersable seeds (able to spread and grow rapidly)3) can change the structure and quality of soil for
larger plant to grow example shrubs
• Dominant species : grow faster and dominate the slower growing pioneer and successor species
• Dominant species turn modify the environment which allows larger tree to grow
• The larger trees provide shade and the shrubs cannot compete and are replaced by forest floor species
• Ecological succession leads to a relatively stable community which is a climax community
EXAMPLE :
From bare ground → forest
COLONISATION & SUCCESSION IN DISUSED PONDS
1 Submerged/ sunken plant
Plankton
• Begin pioneer species which is submerged plant like Hydrilla sp., Cabomba sp., Elodea sp.
• Submerged species are autotrophs (carry out photosynthesis)• When they die, they contributes debris/humus (which supplies
nutrients for next group, successor) • The decomposition of dead pioneers species & soil erosion will add
silt & reduce water level• The new environment is now suitable for 1st successor (floating
plant)
2
• The floating plant like Lemna sp., Eichornia sp., Nymphea sp. will replace the pioneer group
• They have broad leaves which cover the water surface• The pioneer group receive less light for photosynthesis • Thus, the population of pioneer group decreases • The accumulation of humus increases gradually• The pond become shallower • This leads to the growth of 2nd successor (emergent/amphibian
palnt)
Floating plant
3
• The emergent plant such as cattails & sedges (Thypa sp., Cyperus sp.) will replace the floating plants
• They can live both water and on land • In earlier stages, these plant grow near the pond side – rhizomes
grows rapidly from edge to the middle pond – bind soil together.• As the accumulation of humus and silt increases, they will dominate
further in until the whole pond becomes land
Emergent/ amphibian plant
4
• The accumulation of humus makes land more fertile• The creepers, herb plants and shrub will replace the emergent
plants• The land now covered by bushes
Grasses
5
• Over a period of time, the bushes will replaced by a primary forest
• Finally, it reaches the climax community • Example :
tropical rain forest in Malaysia
Hydrilla sp. (water weed)
Elodea sp. (water weed)
Cabomba sp. (fan wort)
Submerged/ sunken plant
Lemna sp. (duck weed)
Eichornia sp. (water hyacinth)
Nymphaea sp. (water lily)
Floating plant
Thypa sp. (cattails) Cyperus sp. (sedges) Fimbristylis sp. (sedges)
Emergent / amphibian plant
MANGROVE SWAMP
MANGROVE SWAMP
• Found in tropical & subtropical regions where freshwater meets salt water
• Characteristics :
1) Soft & muddy soil
2) High concentration of salt
3) Low level of oxygen
4) Exposed to high intensities of sunlight & strong wind
• 4 species of mangrove :
1) Avicennia sp.
2) Sonneratia sp.
3) Rhizophora sp.
4) Bruguiera sp.
• The mangrove plants are well adapted to the harsh conditions of these regions.
ADAPTATIONS OF MANGROVE PLANTS
PROBLEMS ADAPTATIONS
Soft, muddy soilStrong coastal wind
Waterlogged conditions of soil
(↓ amount of O2)
Avicennia sp. : underground cable roots (long & branch)Rhizophora sp. : prop roots (aerial roots)- for anchor & aeration
Avicennia sp. : breathing roots (pneumatophores), grow vertically upwardsGaseous exchange through lenticels (on the bark)
PROBLEMS ADAPTATIONS
Direct exposure to the sun (↑ rate of transpiration)
High salinity of the sea water (soil hypertonic compared to the cell sap of the root cells)
Seeds which fall onto the ground die (submerged in the soft & waterlogged)
Leaves are covered by a thick layer of cuticle Leaves are thick & succulent (able to store water)
The cell sap in the roots cells has a higher osmotic pressure (hypertonic) than the soil.The excess salt is excreted as crystalline salt from hydatodes (pores on the lower epidermis)
Viviparity : seeds are able to germinate while still attached to the mother plant
Props roots
Excretion of crystalline salt from hydatodes Viviparity
Pneumatophores
Cable roots
Avicennia sp.
(pokok api-api)
Sonneratia sp. (pokok perepat)
Rhizophora sp.(bakau minyak)
Bruguiera parviflora(tumu merah)
Pioneer speciesAdaptations :
• pnematophores• aerenchyma tissue
• viviparous seedlings
Successor speciesAdaptations:• props roots
Successor speciesAdaptations :
• buttress roots• viviparous seedlings
• hydatodes• thick & succulent leaves
• waxy cuticles
Avicennia sp. & Sonneratia sp.
(pioneer species)
Rhizophora sp.1st successor)
Bruguiera sp.(2nd successor)
terrestrial plants(3rd successor)
COLONISATION & SUCCESSION IN MANGROVE SWAMPS
Colonisation
Succession
Climax community
COLONISATION
• The pioneer species : Avicennia sp. & Sonneratia sp.
• The extensive roots system of Avicennia sp. & Sonneratia sp. collect sediments & organic matter
• As times passes, the soil become more compact & firm
COLONISATION & SUCCESSION IN MANGROVE SWAMPS
SUCCESSION
• Rhizophora sp. replaces the pioneer species
• The arcing roots of Rhizophora sp. trap silt & mud, creating a firmer soil structure.
• As times passes, the ground becomes higher & the soil becomes drier
• Bruguiera sp. replaces Rhizophora sp.
COLONISATION & SUCCESSION IN MANGROVE SWAMPS
• The buttress roots of Bruguiera sp. form loops which protrude from the soil to trap more silt and mud. The soil structure changes
• Over time, terrestrial plants ( Nypa fruticans & Pandanus sp. replace Bruguiera sp.
• As times passes, the tropical plants replace the terrestrial plants to form climax community
COLONISATION & SUCCESSION IN MANGROVE SWAMPS
giant mudskipper (Periophthalmodon schlosseri)
POPULATION ECOLOGY
POPULATION ECOLOGY• Population ecology : a branch of ecology that
studies the structure and dynamics of populations• Population density : the number of organisms per
unit area of the habitat• Population density is affected by abiotic, biotic, birth
rate, death rate immigration & emigration.• Sampling technique : estimate the total population
size of the organisms• Type of sampling technique :
1) quadrat sampling technique (plant)2) the capture, mark, release &
recapture technique (animal)
Quadrat sampling technique (plant)
• Used to estimating the size of plant populations
• Made from a metal or a wooden frame
• The quadrat is placed randomly in the ecosystem
FORMULA
Frequency : the number of times a particular species is found present when a quadrat is thrown a certain number of times
Frequency : Number of quadrats containing the species Number of quadrats
X 100%
Density : the mean number of individuals of a species per unit area
Density : Total number of individuals of a species in all quadrats Number of quadrats X quadrat area
Percentage coverage : an indication of how much area of the quadrat is occupied by a species.
Percentage coverage : Aerial coverage of all quadrats (m2) Number of quadrats X quadrat area
X 100%
Frequency
Density
Example of percentage coverage
Capture, mark, release & recapture technique (animal)
• Used to estimate the populations of mobile animals• The method :
1) A specific animal sample is captured 2) The animal is marked (a ring, a tag or waterproof coloured ink/paint). 3) The marked animals are released into the general population 4) After suitable period of time, a second sample are recaptured 5 ) The number of marked animal is recorded
FORMULA
Population size : (no of individuals in the 1st sample) X (no of individuals in the 2nd sample) no of marked individuals recaptured
BIODIVERSITY
• Refers to the diverse species of plants and animals interacting with one another on Earth
• Taxonomy : a branch of biology concerned with identifying, describing and naming organisms
• Organism are classified into 5 major kingdoms :1) Monera2) Protista3) Fungi4) Plantae5) Animalia
MONERA
• composed of prokaryoteorganisms
• Unicellular, have cell walls, no membrane bound nuclei and organelles.
• photosynthetic and non-photosynthetic
• typical shapes: rod,round,spiral
• examples : cyanobacteria (blue-green algae) & bacteria
bacteria
cyanobacteria
PROTISTA
• Unicellular, algae, protozoa
• membrane-bound nuclei and organelles.
• Autotrophic , heterotrophic or both
• examples :Amoeba sp. , Paramecium sp.algae
FUNGI
• multicellular eukaryotes• Saprophytic , have
hyphae called mycelium• they have no
chlorophyll • examples :
moulds (Mucor sp.) mushrooms & yeast
Mucor sp.
yeast
PLANTAE
• all green plants• Multicellular, autotrophic
eukaryotes, immobile, photosynthetic
• have cellulose cell walls• examples :
flowering plants, ferns, conifers, moss
ANIMALIA
• multicellular heterotrophic
• eukaryotes• Well- developed
tissues• examples :• Mammals, reptiles,
fishes, amphibians, birds
HIERARCHY OF CLASSIFICATION OF ORGANISM