What is the productivity of an ecosystem

1
What is the productivity of an ecosystem?
Tuesday 7th March 2006

• Learning Objective
• To understand that productivity varies between
  ecosystems.
• To begin to explore the case study for this unit.

2

• Listen to the sounds which ecosystem do you
  think this is taken from.
• You have 5 minutes to draw a Mineral Nutrient
  Model to represent that ecosystem.
• Look back at your notes from last lesson to help
  you.

3
Tropical Rainforest

• Many species to plants and animals
• High temperatures
• Heavy rainfall throughout the year
• Deep oxidised soils

4
Tropical Rainforest
5
Productivity varies between ecosystems

• Gross primary production (GPP) is the total
  amount of energy that is absorbed and used for
  life processes and for growth.
• Net primary production (NPP) is the element
  used for growth only. Energy fixed in
  photosynthesis (GPP) minus energy lost by
  respiration.

6
A high productivity ecosystem The Tropical
Rainforest
7
True or False?

• 1. Tropical rainforest is the natural vegetation
  of places with an equatorial climate.
• True.
• 2. The climate is hot and dry throughout the
  year.
• False The climate is hot, wet and humid
  throughout the year.
• 3. One-third of the worlds trees grow in
  Tropical rainforests.
• True.
• 4. Recently, large areas of forest have been
  cleared for development. This is known as
  desertification.
• False Recently, large areas of forest have
  been cleared for development. This is known and
  deforestation.
• 5. A Tropical rainforest is a tangled mass of
  vegetation.
• False Vegetation grows in distinct layers.
  The lowest layer consists of shrubs. Above this
  is the under canopy, the main canopy and, rising
  above, the emergent, which grow to 50 metres in
  height.
• 6. Tropical rainforests can be described as low
  productivity ecosystems.
• False A Tropical rainforest is a high
  productivity ecosystem. Rainforests receive high
  amounts of solar energy and rainfall and the
  amount of biomass produced is much greater than
  any other ecosystem. Trees grow very close
  together and compete for light and energy by
  growing very tall.
• 7. Brazil has over 1,500 different birds and over
  450 species of reptile.
• True.
• Tropical rainforest soils are very shallow and
  acidic.
• False Rapid chemical weathering of the rocks
  creates very deep soils (10-100m). They are very
  acid with a pH of less than 6.5.
• Trees have dark green and waxy leaves. This
  limits moisture loss in high temperatures, but
  allows water to run off easily in heavy storms.
• True.
• Brazil has over 55,000 different species of
  plants.

8
Homework!

• Take notes on the location and characteristics of
  Tropical Rainforest.
• Waugh 292-294.
• Due next Tuesday.