DEMOGRAPHIC TRANSITIONDEMOGRAPHIC TRANSITION
Way to explain changes in population Way to explain changes in population composition e.g. high to low birth rate. composition e.g. high to low birth rate. FOUR STAGES:FOUR STAGES:
STAGE ONE:STAGE ONE:Both death and birth rate high (Both death and birth rate high (pre-pre-industrialindustrial).).Balance in population.Balance in population.
DEMOGRAPHIC TRANSITION DEMOGRAPHIC TRANSITION STAGE TWO:STAGE TWO:
DEVELOPING COUNTRIESDEVELOPING COUNTRIES
Death rates drop dramatically – better food Death rates drop dramatically – better food and sanitation, less disease. Better and sanitation, less disease. Better education, healthcare, access to technology, education, healthcare, access to technology, better farming techniques.better farming techniques.
Birth rates continue to be high.Birth rates continue to be high.
Increase in population occurs, pressure on Increase in population occurs, pressure on economy, health care, education etc.economy, health care, education etc.
DEMOGRAPHIC TRANSITIONDEMOGRAPHIC TRANSITIONSTAGE THREE:STAGE THREE:
DEVELOPING TO DEVELOPED COUNTRIESDEVELOPING TO DEVELOPED COUNTRIES
Birth rates fall – contraception, higher wages, Birth rates fall – contraception, higher wages, urbanisation, decrease in subsistence agriculture, urbanisation, decrease in subsistence agriculture, increase in education and status of women, children increase in education and status of women, children don’t work, parents invest in children’s education.don’t work, parents invest in children’s education.
Population growth begins to level off.Population growth begins to level off.
DEMOGRAPHIC TRANSITIONDEMOGRAPHIC TRANSITIONSTAGE FOUR:STAGE FOUR:
DEVELOPED COUNTRIESDEVELOPED COUNTRIES
Low birth rates, low death rates.Low birth rates, low death rates.
Birth rate may drop to below replacement level Birth rate may drop to below replacement level (Germany, Italy, Japan). Death rate may increase (Germany, Italy, Japan). Death rate may increase due to lifestyle diseases and ageing population.due to lifestyle diseases and ageing population.
Threat to industries relying on population growth. Threat to industries relying on population growth. Economic burden on shrinking working population.Economic burden on shrinking working population.
Factors that can cause a decrease Factors that can cause a decrease in population growthin population growth
Diseases such as Diseases such as HIV/AIDS, bird flu, HIV/AIDS, bird flu, H1N1 etc.H1N1 etc.Better living Better living conditions and better conditions and better education leading to education leading to better family planning.better family planning.Better contraceptives.Better contraceptives.Wars.Wars.Natural disasters.Natural disasters.Kaposi sarcoma, a skin cancer
typical of HIV/AIDS
Factors that influence Factors that influence community structurecommunity structure
PredasiePredasieKompetisieKompetisieKompeterende Kompeterende uitsluitinguitsluitingHulpbronafbakeningHulpbronafbakeningSimbioseSimbioseSuksessieSuksessie
PredationPredationCompetitionCompetitionCompetitive Competitive exclusionexclusionResource Resource partitioningpartitioningSymbiosisSymbiosisSuccessionSuccession
PREDATOR-PREY-RELATIONSHIP
PREDASIEPREDASIE
PREDATOR-PREY RELATIONSHIPPREDATOR-PREY RELATIONSHIP
Direct link between predator and prey Direct link between predator and prey numbers.numbers.As prey increase, there will be more food As prey increase, there will be more food for predators, so will predators increase.for predators, so will predators increase.Increase in predator numbers put pressure Increase in predator numbers put pressure on prey numbers. Prey will decrease.on prey numbers. Prey will decrease.Decrease in prey will mean less food for Decrease in prey will mean less food for predators, numbers will decrease etc.predators, numbers will decrease etc.
ROL VAN KOMPETISIEROL VAN KOMPETISIE
Kompeteer om Kompeteer om dieselfde, maar dieselfde, maar beperkte bronne bv. beperkte bronne bv. Water, lig, voedsel, Water, lig, voedsel, gebied, paarmaat.gebied, paarmaat.Intraspesifiek – Intraspesifiek – dieselfde spesie.dieselfde spesie.Interspesifiek- Interspesifiek- verskillende spesies.verskillende spesies.
Intraspecific or interspecific? Explain your choice
Hyena and lion
CompetitionCompetition1. Intraspecific competition: the competition between organisms of the same species depending on the same resources like food, space, shelter, water and access to mates.
CompetitionCompetition2. Interspecific competition: the competition between organisms of different species depending on the same resources e.g. light, space, water, shelter, food
COMPETITIVE EXCLUSION: COMPETITIVE EXCLUSION:
The competition in which one of the two The competition in which one of the two competing species is much more successful that competing species is much more successful that the other, to such an extent that the successful the other, to such an extent that the successful species survives and the other species species survives and the other species disappears.disappears.
Kompeterende uitsluiting: Kompeterende uitsluiting: Een van die spesies Een van die spesies is ‘n baie beter kompeteerder; wanneer hy saam is ‘n baie beter kompeteerder; wanneer hy saam met ‘n ander spesie in diese3lfde habitat is, sal met ‘n ander spesie in diese3lfde habitat is, sal hy oorleef en die ander uitsterf.hy oorleef en die ander uitsterf.
Competitive Competitive exclusionexclusion
Wie isdie beter kompeteerder?
RESOURCE PARTITIONINGRESOURCE PARTITIONING: :
The kind of competition situation in which The kind of competition situation in which competing species coexist in the same habitat competing species coexist in the same habitat since they use the resources slightly differently.since they use the resources slightly differently.
HULPBRONAFBAKENING:HULPBRONAFBAKENING:
Kompeterende spesies kan saam bestaan en Kompeterende spesies kan saam bestaan en oorleef omdat hulle bronne op verskillende oorleef omdat hulle bronne op verskillende maniere benut.maniere benut.
Resource partitioning amongst Resource partitioning amongst plantsplants
Resource partitioning: co-existing Resource partitioning: co-existing shore birdsshore birds
Wat is simbiose?Wat is simbiose?
Simbiose beteken letterlik “saamleef” – Simbiose beteken letterlik “saamleef” – symsym = saam, en = saam, en biobio = lewe. = lewe.Die saamleefverhouding is gewoonlik Die saamleefverhouding is gewoonlik lewensbelangrik vir ten minste een van die lewensbelangrik vir ten minste een van die partye.partye.Dit is ‘n langtermyn saamleef en nie Dit is ‘n langtermyn saamleef en nie toevallig of tydelik nie.toevallig of tydelik nie.
MUTUALISMEMUTUALISME
Tot voordeel van Tot voordeel van beide partye.beide partye.Geen party word Geen party word benadeel nie.benadeel nie.Voorbeeld: vlinder en Voorbeeld: vlinder en blom – blom word blom – blom word bestuif, vlinder kry bestuif, vlinder kry nektar.nektar.
Verpligte Verpligte mutualismemutualisme
Die saamleef-Die saamleef-verhouding is verhouding is lewensbelangrik vir lewensbelangrik vir albei partye.albei partye.Ligene (korsmosse) – Ligene (korsmosse) – swamme verskaf swamme verskaf blyplek en absorbeer blyplek en absorbeer water; alge fotosinteer water; alge fotosinteer en verskaf voedsel.en verskaf voedsel.
Nie-verpligte mutualismeNie-verpligte mutualisme
Die saamleef-verhouding Die saamleef-verhouding is steeds belangrik,maar is steeds belangrik,maar nie noodwendig tussen nie noodwendig tussen twee spesifieke individue twee spesifieke individue nie bv. Die vlinder en nie bv. Die vlinder en blom (reeds genoem).blom (reeds genoem).Die bosluisvoël kry Die bosluisvoël kry voedsel en die wildsbok voedsel en die wildsbok is vry van parasiete.is vry van parasiete.
KOMMENSALISMEKOMMENSALISME
Die een party word Die een party word bevoordeel – die bevoordeel – die ander party word nie ander party word nie bevoordeel of bevoordeel of benadeel nie bv. benadeel nie bv. Beesryer wat hier ‘n Beesryer wat hier ‘n saamry-geleentheid saamry-geleentheid kry, maar goggas op kry, maar goggas op grond vreet waar grond vreet waar bees vroetel.bees vroetel.
Nog kommensalisme …Nog kommensalisme …
Die remora-suigvis Die remora-suigvis gebruik die haai as ‘n gebruik die haai as ‘n taxi en vreet van die taxi en vreet van die afvalstukkies voedsel afvalstukkies voedsel wanneer die haai wanneer die haai vreet.vreet.
SUIER AAN BO-KANT VAN REMORA
PARASITISMEPARASITISME
Een party word Een party word bevoordeel, die ander bevoordeel, die ander word beslis benadeel.word beslis benadeel.Parasiete wat op Parasiete wat op diere teer (en self diere teer (en self diere is), kan diere is), kan ektoektoparasiete of parasiete of endoendoparasiete wees.parasiete wees.
PlantparasietePlantparasiete
Semi-parasiete is slegs Semi-parasiete is slegs vir water en minerale van vir water en minerale van die gasheer afhanklik en die gasheer afhanklik en kan self fotosinteer bv. kan self fotosinteer bv. voëlent (voëlent (ViscumViscum).).Holoparasiete is geheel Holoparasiete is geheel en al afhanklik van die en al afhanklik van die gasheer en bevat geen gasheer en bevat geen chlorofil nie bv. Dodder.chlorofil nie bv. Dodder.
Community change over time: Community change over time: Ecological successionEcological succession
TERMINOLOGY IMPORTANTTERMINOLOGY IMPORTANT1.1. Primary successionPrimary succession: :
the sequence of the sequence of organisms that occupy a organisms that occupy a new habitat.new habitat.
2.2. Pioneer plantPioneer plant: a plant : a plant that can colonise bare that can colonise bare soil and that is part of soil and that is part of the community that the community that forms the first stage in forms the first stage in the process of the process of successionsuccession
3. 3. Secondary successionSecondary succession: : the sequence of organisms the sequence of organisms that occupy a disturbed that occupy a disturbed habitat or when an habitat or when an established community has established community has been disturbed in a been disturbed in a catastrophic manner.catastrophic manner.
4.4. Climax communityClimax community: the : the final stage in the process final stage in the process of succession that refers to of succession that refers to a mature community of a mature community of plants that will remain plants that will remain stable with few, if any, stable with few, if any, changes over timechanges over time
The gradual replacement The gradual replacement of one plant community of one plant community by another through by another through natural processes over natural processes over timetime
SuccessionSuccession
colonization of new sites by colonization of new sites by communities of organisms communities of organisms – takes – takes place on bare rockplace on bare rock
Simple plants like mosses Simple plants like mosses and ferns can grow in the and ferns can grow in the new soilnew soil
plantecology.wordpress.com
Primary SuccessionPrimary Succession--
Rock
Begins in a place that ALREADY has Begins in a place that ALREADY has soil and was once the home of living soil and was once the home of living organismsorganisms
Occurs faster and has DIFFERENT Occurs faster and has DIFFERENT pioneer species than primary pioneer species than primary succession.succession.
