1. Soil and Productivity

2. Importance of Soil Soil: the layer of material that covers the land
Where plants anchor and grow
Made of weathered rock, decomposing plant and animal matter
Has spaces for air and water movement
Soils differ in organic content which effects the ability to support plant life.

3. Layers of composition 3 major types of soil
Horizon A: Topsoil
Horizon B: Subsoil
Horizon C: Parent Rock
Horizon D: Bedrock
Each layer has different characteristics depending on where it is found.

4. Grasslands
Horizon A is deep and supports root growth; small particles of rock mixed with decaying plant and animals (Humas).
Horizon B is the subsoil (mix of dirt and rock).
Horizon C is mostly large pieces of rock.
Horizon D is bedrock solid rock.

5. Forest

6. Deserts
Horizon A: limited plant growth so little decomposition, so thin top soil or none at all.

7. Disturbing soils Soils change over time naturally
Human impact: deforestation leads to increased erosion of topsoil (no roots to hold soil in place)

9. Feeding the Human Population!

10. Productivity of Ecosystems
Ecosystems have different productivities, based on light availability, soil types, precipitation, temperature, nutrients.
Productivity: the quantity of biomass of plants produced each year on a given area (g/m2)

11. Productivity of different ecosystems:

12. Sustaining life
Biotic: living part of the environment. Ex: plants and animals
Abiotic: non-living part of the environment. Ex: elements, air, and water.

13. The key events - respiration and photosynthesis
Photosynthesis takes carbon dioxide, water and energy to produce carbohydrates and oxygen.
Respiration takes carbohydrates and oxygen, combines them to produce carbon dioxide, water, and energy.