Chapter 19

“Ecosystem Essentials”

Geosystems 6eAn Introduction to Physical Geography

Robert W. ChristophersonCharles E. Thomsen

What is this an example of?

Ecosystem

Figure 19.2

Plants (Vegetation)Critical biotic link between solar energy and the biosphereBase of vast majority of food webs

About 20 species of plants provide 90% of the human food supply

Wheat, corn (maize), and rice are half

Convert carbon dioxide to oxygenTranspiration elevates atmospheric humidity

Photosynthesis and Respiration

Figure 19.5

Distribution of VegetationFive major factors:

Climate (temperature and precipitation)

Topography (elevation, slope)

Soils (nutrients, minerals)

Biotic Influences (dispersal mechanisms)

Disturbance (natural or anthropogenic)

Climate

Figure 19.8

Life Zones

Figure 19.9

Carbon and Oxygen Cycle

Climate Change

Figure 19.23

What’s limiting these distributions?

Figure 19.12

Soils – nutrients, minerals

http://www.cfr.washington.edu/Classes.esc.520B/ImagesNorthFork/Serpentine6SM.jpg http://www.krisweb.com/krisnavarro/krisdb/ac/dscn2166_sm.jpg

http://nrs.ucdavis.edu/mclaughlin/images/plants/Seep.jpg

Serpentine

Dispersal Mechanisms – Fruit and Seed

http://www.cas.vanderbilt.edu/bioimages/pages/fruit-seed-dispersal.htm

Osage orange (Hedge apple)These huge fruits ooze sticky, white latex when bruised. 

They are large and hard - what would want, or be able to eat them?  

Probably were once dispersed by extinct megafauna (large mammals) that died out soon after humans arrived in North America.   

http://www.cas.vanderbilt.edu/bioimages/pages/fruit-seed-dispersal.htm

What about this fruit?

Extinct Megafauna

http://sscl.berkeley.edu/~anth122/mammoth.gif http://www.intersurf.com/~chalcedony/gomp.jpg http://mishilo.image.pbase.com/u36/zidar/upload/23675731.pbtooth1.jpg

Mammoth

Gomphothere

Tooth

Disturbance

NaturalWater, wind, volcano, fire…

Anthropogenic (human-caused)Deforestation, fire, development…

SuccessionEcological succession – when newer communities replace older communities of plants and animals

Primary succession – an area of bare rock or disturbed site with no previous community

Secondary succession – some aspects pf a previously functioning community are present

Succession

End Chapter 19

Geosystems 6eAn Introduction to Physical Geography

Robert W. ChristophersonCharles E. Thomsen