Nsw Prelim Biology 8.2 a Local Ecosystem Notes

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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| * Water provides much more buoyancy than air – jellyfish | Very small amount of buoyancy in air – skeletal structures| * Organisms and plants must adapt| Viscosity| * Much higher viscosity than air = streamlined shapes| * Less resistance = easier for movement of organisms| * Organisms and plants must adapt| Exposure to natural forces| * Water bodies need to cope with strong tides, current and waves| * Different strengths of winds and rain | * Varies according to seasonal changes|

* identify the factors determining the distribution and abundance of a species in each environment Distribution refers to the region where an organism is found Abundance refers to the number of individuals within the area Biotic factors

* Food source
* Predators
* Competitors
* Parasites
* Disease-causing pathogens
* Compatible species
* Impact of human activities
Biotic factors
* Food source
* Predators
* Competitors
* Parasites
* Disease-causing pathogens
* Compatible species
* Impact of human activities
Physical factors
* temperature,
* soil composition
* rainfall patterns
* altitude
* pressure
* light penetration
Chemical Factors
* Salinity
* pH levels
Dynamic factors
* weathering (wind, wave motion)

* describe the roles of photosynthesis and respiration in ecosystems Photosynthesis occurs in green (chlorophyll) plants and involves the processing of carbon dioxide to oxygen with the presence of sunlight, water and chlorophyll. The oxygen is produced as a by-product in the creation of carbohydrates (food) in plants. This allows for plants to directly source energy from sunlight which is carried through to organisms which consume the plants for food. * identify uses of energy by organisms

Organisms use energy for pretty much everything they do.
* identify the general equation for aerobic cellular respiration and outline this as a summary of a...
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