Form 4 Biology Chapter 8 Dynamic Ecosystem

Form 4 Biology Chapter 8 Dynamic Ecosystem 8.1 Food Chain, Food Web and Trophic Level

6

(b)

(ii) Explain the energy transfer in the food chain.

[4 marks]

The interaction between Biotic Components in Relation to Feeding 1 Competition Graph A - Intraspecific competition Competition between the same species of Paramecium . Competing for the same niche, food, nutrient and space. At the end of experiment, the population of Paramecium aurelia is higher compared to the population of P. caudatum. Graph B - Interspecific competition Competition between different species of Paramecium. Competing for the same niche, nutrient and space. At the end of the experiment, the population of P. aurelia increases whereas P. caudatum decreases. Showing that P. aurelia are more adaptable / stronger compared to P. cautadum. 2

Prey-predator relationship

Form 4 Biology Chapter 8 Dynamic Ecosystem

Colonisation and Succession in Mangrove Swamp Adaptation of mangrove swamp

Zonation of Mangrove Swamp

Figure 8.13 Different zones at a mangrove swamp (i) The seaward zone is fully exposed to high tides twice daily. The mangrove species that inhibit this zone are the Anicennia sp. and Sonneratia sp. (ii) The middle zone is inhibited by the Rhizophora sp. (iii) The inland zone, which is less frequently covered by sea water and often receives freshwater from the ground, is inhibited by the Bruguiera sp.

7. Diagram 7 shows a mangrove swamp.

Diagram 7

(i) (ii)

Explain why most plants cannot colonise and grow in the swamps. [5 marks] Explain how the mangrove trees adapt themselves to the harsh living conditions. [5 marks] Answer scheme: (i) P1: The ground is too soft and unable to support plants, P2: The water-logged / muddy swamps provide very little oxygen for root respiration. P3: The swamp water has a high concentration of salt and is hypertonic. P4: The plants growing in swamp will have the problem of dehydration.

P5: ________________________________________________________________ P6: ________________________________________________________________ P7: ________________________________________________________________

(ii)

P1: Root system which is highly branched and spreads over a big area to give good support to the plants. P2: Pneumatophores (breathing roots) which grow protruding upwards above the ground. P3: The plant cells have high concentration of cell sap. P4: Hence, the cells are able to withstand the high salt content of the swamp. P5: _________________________________________________________________________

P6: __________________________________________________________________ P7: __________________________________________________________________ P8: _________________________________________________________________________

Trial SPM Biolgoy 2012

Bhgvwc3 Year 1870 P1: Colonization process occur P2: pioneer species colonises the newly formed pond P3: pioneer species/floating plant causes change in the pond P4: so that the environment in the pond is more favourable for other species P6 : Pioneer die, the remains accumulated at the base of the pond P7 : Decomposes by bacteria/fungi P8 : Soil more nutrients / more fertile P9 : The pond bank more shallower Year 1950 P10: Succession occur P11: successor plant/emergent plant gradually replace floating plant P12: result in greater plants death that sink to the bottom of the pond P13: raising the pond bed/making the pond more shallow//water level in the pond decreases P14 : No longer favourable for the successor P15 : more favourable to the terrestrial plants