Nsw Prelim Biology 8.2 a Local Ecosystem Notes
8.2 A Local Ecosystem
1. The distribution, diversity and numbers of plants and animals found in ecosystems are determined by biotic and abiotic factors
Students Learn to: * Compare the abiotic characteristics of aquatic and terrestrial environments
The impact of abiotic characteristics on environments Abiotic Characteristic | Differences | Similarities | | Aquatic | Terrestrial | | Temperature | * Small, gradual changes occur | * Large variations may occur | * Temperature is not stable | Pressure | * Large variations occur - Deeper water, higher pressure | * Small changes occur – closer to sea level, higher pressure | * Pressure varies according to sea level/water surface | Light availability + penetration | * Depends on physical properties. * Light may penetrate up to 100m deep | * Abundant on land * Tropical rainforests may have diff. vertical levels | * Organisms and plants must adapt | Landscape position (slope/aspect) | * Affect exposure to currents, tides and waves | * Affect exposure to runoff, erosion | * Affects light availability, and exposure to other abiotic factors | Gases (O2/CO2) | * Gases readily dissolve in water. * Increased surface area = more movement = more gas dissolved | * Found in abundance in atmosphere –air | * Organisms and plants must adapt | Water availability | * Highly abundant in aquatic enviros (duh) but may not be readily available. | * Not freely available * Rainfall, soil or consumed | * Organisms and plants must adapt | Salinity and ion availability | * Marine environments, ions (Na+) are abundant * Currents distribute decomposition ions | * Dissolved ions found in soil water * Different soils have different salinities | * Organisms and plants must adapt | pH | * Depends on organic material and dissolved gases. | * Dissolved salts in soils affect pH | * Organisms and plants must adapt | Buoyancy |
1. The distribution, diversity and numbers of plants and animals found in ecosystems are determined by biotic and abiotic factors
Students Learn to: * Compare the abiotic characteristics of aquatic and terrestrial environments
The impact of abiotic characteristics on environments Abiotic Characteristic | Differences | Similarities | | Aquatic | Terrestrial | | Temperature | * Small, gradual changes occur | * Large variations may occur | * Temperature is not stable | Pressure | * Large variations occur - Deeper water, higher pressure | * Small changes occur – closer to sea level, higher pressure | * Pressure varies according to sea level/water surface | Light availability + penetration | * Depends on physical properties. * Light may penetrate up to 100m deep | * Abundant on land * Tropical rainforests may have diff. vertical levels | * Organisms and plants must adapt | Landscape position (slope/aspect) | * Affect exposure to currents, tides and waves | * Affect exposure to runoff, erosion | * Affects light availability, and exposure to other abiotic factors | Gases (O2/CO2) | * Gases readily dissolve in water. * Increased surface area = more movement = more gas dissolved | * Found in abundance in atmosphere –air | * Organisms and plants must adapt | Water availability | * Highly abundant in aquatic enviros (duh) but may not be readily available. | * Not freely available * Rainfall, soil or consumed | * Organisms and plants must adapt | Salinity and ion availability | * Marine environments, ions (Na+) are abundant * Currents distribute decomposition ions | * Dissolved ions found in soil water * Different soils have different salinities | * Organisms and plants must adapt | pH | * Depends on organic material and dissolved gases. | * Dissolved salts in soils affect pH | * Organisms and plants must adapt | Buoyancy |