biology - colonisation and succession

Download Biology - Colonisation and Succession

Post on 26-May-2015




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hopefully, this could help you to understand much better in this chapter..... biology is fun!!


  • 1. 8.2 COLONISATION ANDSUCCESSION IN AN ECOSYSTEMA community of organisms which interact Ecosystemwith their non-living environment andfunction as a unitBiotic components are well balanced with Dynamic Ecosystemone another and with the abioticcomponents- Natural environment where organisms liveHabitat-Provides basic resources og life such as food,shelter, living space, nesting sites and mates

2. SpeciesA group of organisms that:look alike and have similar characteristicsshare the same roles in an ecosystemcapable of interbreeding to produce fertile offspring 3. populationA group of organisms of the same speciesliving in the same habitat at the same time 4. Community- A several populations of different species living in the same habitat of an ecosystem-Interpendent and interact with oneanother in order to survive 5. NICHE -A niche of an organism is its role in theecosystem -Niche of a population: ranges of temperatures at which it lives the type of food it eats the space it occupies -animals that undergo metamorphosis intheir cycle occupy different niches. A tadpole lives A frog lives mainlyentirely in wateron the land 6. BARE GROUND An environment of bare rocks and sand leftbehind by a forest fire is not suitable for mostorganisms. After the ground cools down, water re-entersthe environment. When water, air, nutrientsand sunlight are available, spores and seeds ofcertain plants start to germinate and grow. 7. PIONEER SPECIES The first colonizers Special adaptations is enable to survive on dryand nutrient-poor soil Hardy plants which usually have dense rootsystem to bind the sand particles and holdwater and humus Short life cycle When die, they remains add to the humuscontent of soil 8. Successor species Modify the environment, eventually creatingconditions which are less favorable to themselves Grow bigger than pioneer species, thus reducingthe amount of sunlight that reaches them andgradually replacing them Have small wind-dispensable seeds which areable to spread and grow rapidly Change the structure and quality of the soil,making it more conductive for larger plants togrow 9. Dominant species Can grow faster and so they out-compete thepioneers which grow at a slower rate Turn modify the environment which allowslarger trees to grow The larger trees out-compete the shrubs,which are replaced by forest-floor specieswhich require low light intensit(succession) 10. Ecological success leads to a relatively stablecommunity which is in equilibrium with itsenvironment Example: tropical rainforest in Malaysia A stable community that undergoes little orno change in its species composition 11. Colonisation A process whereby a species invades andoccupies a newly formed area where nolife has existed previously 12. Succession The gradual process through which onecommunity changes its environment so that itis replaced by another community