Biology - Ecosystems

Ecological systems Biosphere Atmosphere Lithosphere Hydrosphere Ecosphere

Biomes Ecosystems with similar abiotic factors

Biomes 2 Canada Australia Dry aridTemperate forestTemperate reef

Ecosystems Habitat Particular area in which a population lives Abiotic factor Non living factors eg temperature, rainfall Population All the organisms from one species in an ecosystem Community All the organisms in an ecosystem Environment All the abiotic factors Biotic factor Living factors eg predation, competition Ecosystem is a term that describes ecological systems consisting of interacting organisms and their physical environment Microhabitats Smaller areas within a habitat with slightly different conditions

Ecological terms Autotroph makes own food (either by photosynthesis or chemosynthesis) = producer Heterotroph eats other organisms Producer makes own food (either by photosynthesis or chemosynthesis) = autotroph Consumer eats other organisms Decomposer feeds of wastes or dead animals = detrivore Detrivore feeds of wastes or dead animals = decomposer Detritus wastes or dead matter First order consumer eats producers Second order consumer eats 1 st order consumers Respiration manufacture of energy by burning organic compounds eg glucose Photosynthesis manufacture of organic compounds eg glucose using the energy of the sun Chemical energy Energy gained from chemical reactions eg respiration Thermal energy Heat energy Solar energy Energy from the sun Trophic level location on food chain eg producer

Niche Description of an organism’s role and or location within an ecosystem Eg the fox can be described as 2 nd order consumer or forest floor dweller

Food chains Arrows show movement of energy The direction of the arrow is from organism being eaten to the organism doing the eating

Food webs Arrows show movement of energy The direction of the arrow is from organism being eaten to the organism doing the eating

Abiotic factors – both aquatic and terrestrial FactorEffect on survivalMeasurement TemperatureTemperature affects cell activity – especially enzymes and reactions in the cell. At low temperatures, cellular reactions slow. As the temperature increases the rate of reactions increases. At extremely high temperatures, enzymes and structures can be damaged and the cell can die. If the cell freezes, ice crystals can burst the cell Thermometer LightLight is necessary for photosynthesis. It is affected by water depth and shade (eg trees). Light meter pH (soil or water)pH affects cell survival by altering proteins. This can damage cell membranes and enzymes in the cell. pH meter indicators Salinity (soil or water)Salinity affects water and ion movement into and out of cells. High salt conditions dehydrate cells, low salt conditions can cause cells to swell and burst Salinity meter Conductivity meters WindWind affects wave action in aquatic environments and humidity and water loss in terrestrial environment. Wind meter Anemometer

Abiotic factors – mainly aquatic FactorEffect on survivalMeasurement Wave actionWave action affects the amount of gases (oxygen and carbon dioxide) that can dissolve in the water. The greater the action, the more gases dissolve. Height in metre (swell) Water currentsThese affect the temperature of water at different levels. They can carry nutrients from estuaries and coasts to deeper water. Radar and infrared satellites BuoyancyThis is a measure of how easy it is to float. It is affected by salinity – the greater the salt content, the more buoyancy there is. ViscosityThis affects movement. The more viscous a material, the more effort is needed to move through it. TurbidityThis is a measure of small particles in the water (eg silt). High turbidity can reduce light penetration and interfere with gill function making it harder to survive. Secchi disc DepthThe deeper the water, the less light penetrates. The wavelength of light also varies – red penetrates the least far & violet the most. Sonar Plumb line GasesOxygen is needed for respiration, carbon dioxide is needed for photosynthesis Dissolved oxygen meter Chemical tests

Abiotic factors – mainly terrestrial FactorEffect on survivalMeasurement Amount of waterAll organisms need water to surviveRain gauge HumidityThis affects water loss from leaves and the effectiveness of sweating and panting (evaporative cooling) in animals Humidity meter Hygrometer Mineral salts (in soil)Plants need minerals to grow. Mineral salts affect salinitySalinity meter Chemical tests Soil typeThis is mainly determined by particle size, mineral salts and organic matter present. These affect water retention, fertility and the type of plants that will grow. Soil tests TopographyFeatures such as slope, hills, valleys affect water movement, soil formation or erosion, shade and altitude. All of these affect the growth of plants and the animals they can support. Inclinometers Mapping instruments AltitudeHeight above sea levels affects oxygen and carbon dioxide levels. Soil quality is also generally less at higher altitudes. Mapping instruments

Biotic factors – role in ecosystem Autotroph – makes its own food Producer – provides energy to a food chain by photosynthesis (using light to convert carbon dioxide and water into sugars) or chemosynthesis (using chemical reactions to make energy or organic compounds) Heterotroph can not make its own food, so must eat other organisms Consumer – gains its energy by eating other organisms Decomposer – gains its energy by feeding on dead or decaying living matter

Biotic factors – feeding relationships Herbivore – eats plants Carnivore – eats animals Detrivore – eats dead or decaying matter Saprophyte – eats dead or decaying matter Predator – animal that eats another Prey – animal species eaten by predator Parasite – lives or feeds in or on a host without killing it Host – organism that a parasite feeds on

Biotic factors – associations Competition – rivalry between two organisms/species for the same resources Collaboration - working together so both benefit but they can work without each other Mutualism – an association where both species benefit and both need each other eg lichen Commensalism – an association where one species benefits and the other is unaffected eg epiphytic ferns Pollination - animal species spread pollen for flowering plantsand are rewarded by food eg bees and nectar Dispersal – animal species spread seeds for a plant eg prickles or after eating the fruit Communication – signals are shared that allow individuals to recognise members of their group, possible mates or rivals or information about food or danger