DYNAMIC ECOSYSTEM

ECOLOGY

• Ecology: the scientific study of the interactions of living organisms with other living organisms and with the physical environment.

• Environment = Biotic components + Abiotic components.

• Biotic components: Living organisms• Abiotic components: Nonliving

components.

ABIOTIC COMPONENTS

1. pH value: pH of the soil and water. Most organisms survive well in neutral or nearly neutral environment

2. Light intensity: affects the distribution and growth of plants and animals

3. Temperature: most living organisms can only tolerate a narrow range of tempearture (0oC to 45oC): exceptional to certain species, example: termophilic bacteria that can survive in hot springs.

ABIOTIC COMPONENTS

4. Humidity: amount of water vapour present in the air. Humidity affects the rate of water loss by plants and animals

5. Topography: physical features of land. Topographic factors are altitude, gradient and aspect

TOPOGRAPHIC FACTORS1. Altitude: Higher altitude associates with lower

athmopheric pressure and temperature. Different plants grow at different altitudes.

2. Gradient : The steepness of a slope. Steep slopes result in rapid drainage and run off.

3. Aspect: associated with the direction of the wind. The slopes of a mountain facing the direction of the wind received more rain.

4. Microclimate: climate of a microhabitat. Microclimated includes the humidity, temperature, light intensity and atmopheric conditions

BIOTIC COMPONENTS

• Consists of producer (green plants), primary consumer, secondary consumer, tertiary consumer and decomposer (bacteria and fungi).

FOOD CHAIN, FOOD WEB & TROPHIC LEVELS

• Food chain: a sequence of organisms through which energy is transferred

• Each stage of food chain is known as a trophic level

• Food web: Interconnected food chains• In a food web, the source of energy is sunlight• Only 10% of energy is transferred to each

trophic level: see pyramid of numbers• Energy loss is in the form of heat energy,

decaying and etc.

INTERACTION BETWEEN BIOTIC COMPONENTS IN RELATION TO

FEEDING• Symbiosis: a close relationship between

two or more different species which live closely together and interact with each other.

• Symbiotic relationships: commensalism, mutualism and parasitism

COMMENSALISM

• Clown fish and sea anemones

• One species is benefit, the other species neither harmed nor get benefit.

MUTUALISM

• Mutualism refers to the relationship of two organisms where both benefit from the association. The example below is a lichen growing on the trunk of a mangrove tree. The lichen consists of a fungus and an algae growing together. The fungus gets food from the photosynthesising algae and the algae gets a place to live.

PARASITISM

• The association in the parasite host relationship is one in which one organism benefits from the relationship and the other is disadvantaged..

ECTOPARASITE ENDOPARASITE

DISCUSSION

• In groups, discuss about saprophytism, prey-predator relationships and competition.

• What do you understand about dynamic equilibrium? Discuss…