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Biology Form 4Biologi Tingkatan 4Chapter 8 : Dynamic Ecosystem
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Dynamic Ecosystem
ECOSYSTEM:Collection of living
things and the environment which
they live
ENVIRONMENT:Consist of living
organisms (biotic factor) & non-living organisms
(abiotic factor) ECOLOGY: Scientific study on the
relationships of organisms with their physical
environment and with one another
Natural Ecosystem
Natural Ecosystem
Artificial ecosystem
Ecosystem
Biotic Components
Abiotic Components
ABIOTIC COMPONENTS
ABIOTIC FACTOR
pH value temperature
Light intensity
Topography Microclimate
Humidity
pH value
• Acidic , neutral or alkaline• Influences the growth & distribution of aquatic & land
organisms
SLIGHTLY ACIDIC SLIGHTLY ALKALINE
Maize Soya Bean
TomatoBarleyPotato
FernsCoconut
Casuarinas
Temperature
Temperature influences the :
the productivity of producers
distribution of soil organisms
a. Productivity of producers
• In polar regions & desert• productivity is low• Living things in these places have adaptations to survive• E.g. • Poikilothermic –found in warm climate• Homoeothermic - widespread• Thick fur in cold climate• Absence of leaves in the cactus that live in desert
b. Distribution of soil organisms
• Low soil temp : reduce the rate of water & mineral soil absorption• Organisms living in ground : population do not change
much because temp uniform• Above the soil: daily & seasonal temp change influence
distributions & populations & living organism• Temp of sea : more stable because aquatic animals do not
adapt well to big temperature change
Light intensity
• Influence the rate of photosynthesis• Distribution of green plants denser in areas
of high light intensity• Aquatic plants : found near the surface of
water
Humidity
• Influences the rate of water loss in plants & animals• Many plants & animals thrive in humid ecosystem of
sheltered caves or jungles
Topography
• The description of the surface features of a place• Altitude, gradients of a slope & other physical aspects :
determine of sunlight reach earth surface
Microclimate
• Refers to the climate of a small place / habitat• Involves differences in terms of quantity of rain, relative
humidity, light intensity, change in temperature• Influences the number and distribution of living
organisms
BIOTIC COMPONENTS OF AN ECOSYSTEM
Biotic components
Plants
ManAnimals
Biotic components of an ecosystem
• Biotic components interact with each other directly / indirectly
• Types of relationship between biotic components:a) Competition
b) Symbiosis
c) Saprophytism
d) Prey-predator interaction
Classifying biotic components into trophic levels
• Ecosystem has three main nutritional groups:
1) Producers
2) Consumer
3) Decomposer
Producer
• Green plants ; photosynthesis
• Produce enough food for their own consumption & consumer
Consumer
• Primary• Secondary • Tertiary
Decomposer
• Consist of bacteria & fungi
• Break down waste products & dead bodies of other organisms into simpler substances
• Can be use again
Food Chain & Food Web
Trophic levels
Revision
An ecosystem is a community of organisms / biotic components which interact with their non living environment / abiotic components
Squirrel eat fruits from the tree // Big bird eat mouse in the garden
10% X 1500 kJ= 150 kJ
. Lost to atmosphere as heat energy
. Used to decompose dead matter (by decomposer)
. Used to carry out metabolism reaction in cells
. Respiration
. Excretion
. Defecation
F : Deforestation / logging / open burningE1 : Extinction / destroy of flora / faunaE2 : loss of biodiversityE3 : disruption of food chain / webE4 : Land slides / soil erosion / water pollution / flash flood
Interaction between Biotic Components in Relation to Feeding
• Four types of biotic interactions:
a. Symbiosis
b. Saprophytism
c. Prey-predator
d. competition
Symbiosis
• Means ‘living together’
• Close & permanent relationship
• Between 2 or more different species
Symbiosis
Commensalism parasitism mutualism
commensalism
• Benefits one species (commensal) but neither benefits nor harms the other species (host)
Commensalism
Epiphytes Epizoics
Epiphytes
• Green plants that grow on branches or tree
• Do not derive their nutrition from the tree
Epiphytes ferns
• Adaptations:• Thick waxy cuticle to
prevents water loss• “nest” collects fallen
leaves, pieces of tree bark etc
• Ants nests – increase organic matter
Staghorn fern (Platycerium coronarium)
Bird’s nest fern(asplenium nidus)
Epizoics• An animal commensal
attched to other animals (its host)
• For free transport, feed on leftovers from their host meal
• Host neither suffer loss nor benefits
cyclops
vorticella
daphnia
Shark & remora fish
Parasitism
• Relationship between two organism • The parasite benefits; Host is harmed• Two types:• Endoparasites• Ectoparasites
Endoparasites
• Adaptations:• Reduction in nervous
system & sense organs• Reduced digestive tracts• Have protective cuticles
& produce mucus and anti-enzymes
• Have flattened shape• Anaerobic respiration• Produce a lot of gametes
tapeworm
fluke
Round worm
Ectoparasites
• Adaptations:• Have hooks to attach
themselves• Have sharp mouth
parts for hooking, sucking or biting
aphid
Tree bugs
lice
Plant parasite
Dendrophthoe sp (dedalu)
Mutualism
• Relationship between two species of living organisms • Both benefits• E.g.• Lichens• Sea anemone & hermit crab• Rhizobium in the nodules of leguminous plant• Microorganisms & herbivores
Lichens
• Green alga + fungus• Grow on tree bark• Green alga gets• shelter, water, minerals
& nitrogenous compounds
• Fungus gets• food & oxygen
Sea anemone & hermit crab
• Hermit crabs gets protection from tentacles of sea anemone
• Sea anemone gets transport & left over food
Rhizobium in the nodules of leguminous plants
• The bacteria convert atmospheric nitrogen into ammonium compound that are used by the plants
• Bacteria get shelter & energy rich compounds from the plants
Microorganism (protozoa & bacteria) and herbivores
• Bacteria lives in the alimentary canal• Produce cellulase• Large part of the sugar produced absorbed by host• Microbes gets shelter & food
Saprophytism
Saprophytes Saprozoites
Saprophytes
• Plant that gets its food from dead organism
• Cannot make own food• Produces enzymes to
digest & decompose dead complex organic matter
• E.g.:• Bread mould• Mushrooms• Bracket fungus
Saprozoites
• Animals that feed on dead organic matter that has been digested
• E.g.:• Protozoa found in the
intestine of the frog (Opalina sp. & Balantidium sp.)
• In rectum (Nyctotherus sp.)
Opalina sp
Balantidium sp
Nyctotherus sp
Prey predator relationship
Prey-predator relationship
• Exists when a weaker animal (prey) is hunted & eaten by another stronger animals (predator)
• Predator : moves fast, long canine teeth/ sharp claws• Prey : use speed & camouflage• Important to keep different animal populations of an
ecosystem in balance
PREDATOR
PREY
Prey-predator relationship
• Predator : moves fast, long canine teeth/ sharp claws• Prey : use speed & camouflage
Prey-predator relationship
• important to keep different animals population in an ecosystem in balance
• Self regulating and keep the populations of both the predator and prey in a DYNAMIC EQUILIBRIUM
Interactions between the Biotic Components in relation to Competition
Competition
• An interaction between organisms living together in a habitat and competing for limited resources
• Animals :• Food, shelter & breeding mates
• Plants:• Light, nutrients & water
• Two types of competition:a) Interspecific competition
b) Intraspecific competition
Interspecific Competition
• Competition between individuals of two or more different species
P. caudatum
P. aurelia
Interspecific Competition
Intraspecific competition
• Competition between individuals of the same species
EXERCISE