Chapter 18 G.2 Objectives Ecosystems and Biomass

1
Chapter 18 G.2 ObjectivesEcosystems and Biomass
2
Define Gross Production, Net Production, and
Biomass

• Gross Production total amount of energy trapped
  in the organic matter produced by plants per area
  per time in kilojoules.
• Net Production the gross production minus the
  energy lost through respiration.
• Biomass dry weight of an organism measured in
  g/m²yr

3
Calculate values for gross production and net
production using the equation gross production
respiration net production

• Example
• Gross production 809 kJ / m² yr
• Respiration 729 kJ / m² yr
• 809 729 80
• Net production 80 kJ / m² yr

4
Discuss the difficulties of classifying organisms
into trophic levels.

• Many animals such as eagles, coyotes, and lizards
  are not in just one trophic level because they
  can be considered as primary consumers, secondary
  consumers, or tertiary consumers depending on
  what they eat.
• Omnivores are also difficult to determine which
  trophic level because they eat both plants and
  animals.

5
Explain the small biomass and low numbers of
organisms in higher trophic levels

• Biomass is lost during respiration at each
  trophic level. When glucose is broken down for
  energy, it is converted into carbon dioxide gas
  and water. Carbon dioxide and water are excreted
  and the biomass of glucose is lost. Each
  successive level of the ecosystem loses more and
  more biomass. Energy per gram of food does not
  decrease, but total biomass of food is less at
  each trophic level.

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Pyramid of Energy
7
Distinguish between primary and secondary
succession, using an example of each.

• Primary succession is where plants start growing
  in a previously lifeless area such as a land that
  has experiences a volcanic eruption.
• Secondary succession is when a new organism takes
  over a upheaval. It is quicker then primary
  succession. This is because the soil is already
  in place, a prime example of this is after a
  forest fire.

8
Outline the changes in species diversity and
production during primary succession

• Fordune stage is the beginning stage where there
  is nothing present yet.
• Yellow dune stage is second and can take years,
  dead organisms piles up to make a new thin layer
  of soil.
• Grey dune stage is developed after years of
  plants dying and decomposing and humus is
  developed and can hold water.
• The final stage of the dune sucession is Mature
  dune, at this point the dune can support a
  forest.

9
Explain the effects of living organisms on the
abiotic environment, with reference to the
changes occurring during primary succession.

• Organic Matter Increases
• Resulting from the death and decay of animals and
  causes the earth to better absorb water, making
  it able to better support plants.
• Soil Gets Deeper
• Results from the mixer of decayed organic matter
  and abiotic materials (such as sand, rock, etc).
• Soil Erosion Reduces
• Plant roots stabilize the abiotic materials
  (sand, rock, etc) and soil.

10
Explain the effects of living organisms on the
abiotic environment, with reference to the
changes occurring during primary succession.

• Soil Structure Improves
• Sand and rock dont hold water, so when soil is
  produced, it holds water and minerals and allows
  the anchoring of plant roots.
• Mineral Recycling Increases
• Bacteria and fungus which thrives in such
  environments recycle the nutrients of dead
  organisms.

11
Distinguish between biome and biosphere.

• Biosphere
• All the living things that make up our world.
• Biome
• The division of the biosphere defined by type of
  vegetation and community structure.

12
Explain how rainfall and temperature affect the
distribution of biomes.

• Distribution of biomes
• The effective temperature and rainfall of each
  biome has a particular range for each biome
  representing the conditions in each.
• Two different biomes can have the same
  temperature or rainfall but usually differ in one
  or the other.
• EX. A desert can have the same temperature as a
  temperate forest but the temperate forest differs
  by having more rain fall each year causing it to
  have different flora and fauna than the desert
  due to having more life sustaining water.

13
Outline the characteristics of six (seven) major
biomes.
Biome Temperature Moisture Characteristics of Vegetation
Desert 60 degrees Celsius Less than 30cm/Yr Cacti and shrubs (adaptable to dry)
Grassland Cold in winter hot in summer Seasonal drought, medium moisture Prairie grasses (fires prevent invasion)
Shrubland Mild temperatures in winter, long hot summers Rainy winters, dry summers Dry woody shrubs that reproduce with fire
Temperate deciduous forest Very hot winter very cold winter High rainfall, frozen in winter Oak, hickory, maple, warmHerbaceous
Tropical rainforest Very warm More than 250cm/Yr High plant diversity with tree canopy
Tundra Very cold, layer of permafrost in soil year round Little precipitation Lichen, mosses, grasses, shrubs, no deep roots
Coniferous forest Slightly warmer than tundra Small amount, but lack of evaporation Cone bearing trees