The biosphere, lecture 31 Flashcards
The biosphere
The living component of the earth
Terrestrial ecosystems
make up what portion of land surface?
1/4 of Earth surface dry land
Which is more variable and complex - aquatic or terrestrial ecosystems?
terrestrial
Why are terrestrial ecosystems more variable and complex than aquatic ecosystems?
aquatic systems are only composed of one phase: water
terrestrial systems have three phases
Three phases of terrestrial ecosystems
- atmosphere/ climate
- soil
- organisms
Agriculture
controls flora and fauna to increase availability and ensure constant supply
Agriculture works within a
complex system
Atmosphere and (climate) phase of terrestrial ecosystems 3 points
- Source of oxygen for plant and animal respiration
- Source of carbon dioxide for photosynthesis
- Gases common and well mixed
(Atmosphere) and climate phase of terrestrial ecosystems
Are climate and temperature more variable in aquatic or terrestrial systems and why?
climate and temperature are more variable in terrestrial systems,
temp. because soils, rocks and vegetation have a low specific heat capacity
rapid heat gain and loss - high diurnal and seasonal fluctuation
Rainfall in terrestrial systems
irregular rainfall is an extreme stress for organisms
Soil phase of terrestrial ecosystems
provide 2 functions
provide support for organisms
provide nutrient source
Soil phase of terrestrial ecosystems
support for organisms
- entire weight of flora and fauna
- no soil/ air partition unlike sediments/ water in aquatic
Soil phase of terrestrial ecosystems
nutrient source
- site of entire detrital (decomposer) food chain
- vital for nutrient cycling
- different soil properties affect nutrient and water availability,
hence, soil properties related to ecosystem productivity
Organisms phase of terrestrial ecosystems
- in terrestrial ecosystems, organisms can leave a permanent mark but this is rare is aquatic
- organisms can determine habitat for other organisms, complex relationships eg: trees controlling light to the understory
- succession of species is biotically controlled (abiotic in aquatic)
Example of organisms determining habitat for other organisms
trees controlling light to the understory
