Posts Tagged ‘temperature’

  • Define the term biome.
Biome:
A collection of ecosystems sharing similar climatic conditions, like tundra, tropical rainforest and desert. A biome has distinctive abiotic factors and species which distinguish it from other biomes. Water, insolation and temperature are the climate controls important when understanding how biomes are structured, how they function and where they are found round the world. Biomes usually cross national boundaries and do not stop at a border.
  • Explain the distribution, structure and relative productivity of tropical rainforests, deserts, tundra and any other biome.
It is possible to group the biomes into 6 categories with sub-categories in each one:
  • freshwater
  • marine
  • desert
  • forest
  • grassland
  • tundra
In IB however it is required that you need to be able to explain the distribution, structure and relative productivity of tropical rainforests, deserts, tundra and one other biome.Climate should only be explained in terms of temperature, precipitation and insolation only.
In this picture you can see where each biome is located.
Tropical rainforest:
  • high temperatures (average 26 C )
  • high rainfall (over 2500 mm yr -1)
  • near the equator
  • high light levels throughout the year
  • all-year round growing season
  • high levels of photosynthesis
  • high rates of NPP throughout the year
  • high diversity of animals and plants
  • low levels of nutrients in the soil
Deserts:
  • cover 20-30 percent of the land surface
  • dry air
  • high temperatures (45-49 C in day)
  • low precipitation (250 mm yr-1)
  • low rates of photosynthesis
  • low NPP rates
  • vegetation scarce
  • soil rich in nutrients and can support plant that can survive there
Tundra:
  • found in high latitudes
  • days are short
  • limit levels of sunlight
  • water may be locked up in ice, limiting water resources
  • photosynthesis and productivity rates are low
  • low temperatures
  • soil may be permanently frozen
  • nutrients in soil are limited
Temperate forest:
  • seasonal weather (hot summers/cold winters)
  • 2 types of tree types in forests; Evergreen + deciduous could be in one forest or contain both trees
  • rainfall average between 500-1500 mm yr-1
  • productivity lower than rainforest
  • mild climate, lower average temperature / lower rainfall

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  • List the significant abiotic (physical) factors of an ecosystem.

Ecosystems can be divided into 3 types:

  • Marine: the sea, salt marshes mangroves are all characterized by the salt content.
  • Freshwater: rivers, lakes and wetlands.
  • Terrestrial: land-based.

Each ecosystem has its on abiotic factors:

Marine:

  • salinity
  • pH
  • temperature
  • dissolved oxygen
  • wave action

Freshwater:

  • turbidity
  • flow velocity
  • pH
  • temperature
  • dissolved oxygen

Terrestrial:

  • temperature
  • light intensity
  • particle size
  • slope/aspect
  • soil moisture
  • drainage
  • mineral content
  • Describe  and evaluate methods  for measuring at least three abiotic (physical) factors within an ecosystem.

Abiotic factors that can be measured within an ecosystem include the following:

Marine:

  • salinity: this can be measured  using electrical conductivity ( with a datalogger) or by the density of the water (water with high salt content is more denser than low-salt water).
  • pH: this can be measured using a pH meter, or datalogging pH probe. Indicator solution may also be used.
  • temperature: ordinary thermometers are too fragile to use for fieldwork, and are hard to read. An electric thermometer allows temperature to be measured  in depth.
  • dissolved oxygen: a meter with oxygen-sensitive electrodes connected that measures dissolved oxygen. One should be careful as doing things wrong may contaminate the air.
  • wave action: this is measured by using a dynomometer which measures the force in waves.

Freshwater:

  • turbidity: can be measured using a Secchi disc, nephlometer or turbidimeter.
  • flow velocity: can be measured by timing how long it takes a floating object to travel a certain distance or by using a flow-meter.
  • temperature: ordinary thermometers are too fragile to use for fieldwork, and are hard to read. An electric thermometer allows temperature to be measured  in depth.
  • dissolved oxygen: a meter with oxygen-sensitive electrodes connected that measures dissolved oxygen. One should be careful as doing things wrong may contaminate the air.

Terrestrial:

  • temperature: ordinary thermometers are too fragile to use for fieldwork, and are hard to read. An electric thermometer allows temperature to be measured  in depth.
  • light intensity: is measured using a light-meter.
  • wind speed: a Beufort-scale is used to measure wind speed and precise measurements can be made with a digital anemometer.
  • particle size: this determines the drainage and water-holding capacity and is measured by using a series of sieves.
  • slope: this is measured using a clinometer and using a compass.
  • soil moisture: by weighing the samples then heating them it shows the amount of water that has evaporated and the moisture levels.
  • mineral content: the loss on the ignition test can determine mineral content. The samples are heated for several hours to let volatile substances to escape.
Abiotic data can be collected using instruments that avoid issues of objectivity as they directly measure quantitative data. Instruments allow us to record data that would otherwise be beyond the limit of our perception.