Zusammenfassung der Ressource
Ecosystem concepts
- Biosphere
- Area between Earth and atmosphere where all life exists.
- Includes all three parts of the physical environment; atmosphere, hydrosphere, lithosphere.
- Biomass
- Sum total of all living matter within biosphere at any given time.
- expressed as dry weight of tissue per unit area E.g. tonnes/hectare
- Mainly of terrestrial origin due to veg efficiency on ratios of 100 to 1 compared to oceans.
- Animal biomass greatest in rainforests.
- Oceanic biomass greatest in tropical reefs.
- Standing crop
- Characteristic biomass of a particular ecosystem accumulated over time.
- Environment
- Collective term, includes all conditions in which an organism lives.
- Abiotic (physical, non-living) Biotic (living).
- Abiotic includes temp, water, light, wind, gases, pH, nutrients. Biotic is all living organisms.
- Ecosystem
- A community of living organisms and non-living things working together. Life cycles of all organisms are interlinked to the environment.
- Community
- describes all populations of species within a habitat.
- Population
- All individuals within a particular species within a habitat.
- Biome
- Large global ecosystem.
- It is named after the most dominant veg found there E.g. tropical rainforest.
- will contain climax communities
- Biome type is usually controlled by climate but economic development has changed the nature of some biomes.
- typography, soil (edaphic) and biotic factors control biome nature too.
- Dead organic matter (DOM)
- All dead, decaying plant and animal remains that make up surface litter and soil humus.
- Important to ecosystem, may be greatly in excess of biomass in weight.
- E.g. greater in temperate grasslands where DOM exceeds living biomass 5:1.
- Habitat
- The physical env within which an organism lives.
- Used on three different scales: macro (continental) - meso (regional) and micro (small microscopic scale).
- Organisms must be adapted to suit habitat. It must fall within the ecosystems ecological niche.
- Four factors influence habitat: Climate (light,
temp, moisture, exposure) Topography (altitude,
temp, slope angle), Edaphic aspects (soil
chemistry, nutrients, moisture) and biotic aspects
(grazing influences and human activity).
- In aquatic habitats, water chemistry and light penetration also vital.